July 2009 - Crawford Broadcasting Company
Contents
1. _ The Local Oscillator from the tornado as an entire wall is gone Cars were turned over windows blown out HVAC units tossed around like baseballs a construction trailer was thrown across a road but thankfully God protected everyone The only injury to speak of happened to a man who was videoing the tornado from his condo He was thrown and received a broken collar bone I am very grateful for God s protection and pray the people that experienced this tornado realize it is only by God s hand they were saved Waist high weeds were a real problem at the KLZ site We had several days of this kind of weather This is something Colorado hasn t seen in ten years My dad and I were at Coors Field for a baseball game on the fourteenth of June We had been watching the sky get darker It began raining and we decided to walk around the concourse because our seats offered no cover As we were walking we heard the tornado sirens go off About ten minutes later after a funnel cloud was spotted several blocks away they evacuated everyone to bathrooms and the stairwells We stayed there for thirty minutes or so until we decided ourselves it was safe We were just on the edge of the storm system that was moving away from us We had over a week of torrential rains and out of that week I think the KLTT T1 failed us twice The first time was the beginning of the month the week the bad weather started The KLTT IS2. 17 stable Blame my stubbornness or simply my desire to use something I paid for but I have fought the urge to downgrade back to Windows XP for quite some time Big now But with the release client of Microsoft s newest OS change was on the horizon Back in January the public got a glimpse of Windows 7 via Microsoft s released beta version Although I had the opportunity to play around with the beta on a friend s computer I wasn t completely ready to take a leap of faith and install a beta OS on my machine In fact I typically try to stay away from any new OS for the first year to ensure all of the bugs are worked out That all went out the window pun intended last week My uber power home built computer dedicated to running Flight Simulator had been running on Windows 64 bit Vista Ultimate since its first boot up While recently chatting with a friend of mine he asked why I hadn t tried the recently offered Windows 7 Release Candidate RC My 64 bit Vista system had been giving me some software compatibility problems recently and the frustration probably showed I decided to do some research and see what I came up with If it wasn t going to be Windows 7 I was sincerely considering moving back to the comforts of XP The Local Oscillator July 2009 Reading through a variety of related message board posts and other resources I was pleasantly surprised to hear very positive comments about Win 7 It se
3. until next month The Local Oscillator July 2009 KBRT e Avalon Los Angeles CA 740 kHz 10 kW D DA KCBC e Riverbank San Francisco CA 770 kHz 50 kW D 1 kW N DA 1 KJSL e St Louis MO 630 kHz 5kW U DA 2 KKPZ e Portland OR 1330 kHz 5 kW U DA 1 KLZ e Denver CO 560 kHz 5 kW U DA 1 KLDC e Brighton Denver CO 1220 kHz 660 W D 11 W N ND KLTT e Commerce City Denver CO 670 kHz 50 kW D 1 4 kW N DA 2 KLVZ e Denver CO 810 kHz 2 2 kW D 430 W N DA 2 KSTL e St Louis MO 690 kHz 1 kW D 18 WAN ND WDCX e Rochester NY 990 kHz 5 kW D 2 5 kW N DA 2 WDCX e Buffalo NY 99 5 MHz 110 kW 195m AAT WDJC FM e Birmingham AL 93 7 MHz 100 kW 307m AAT WEXL e Royal Oak Detroit MI 1340 kHz 1 kW U DA D WLGZ FM e Webster Rochester NY 102 7 MHz 6 KW 100m AAT WRDT e Monroe Detroit MI 560 kHz 500 W D 14 W N DA D WMUZ e Detroit MI 103 5 MHz 50 kW 150m AAT WPWxX e Hammond Chicago IL 92 3 MHz 50 kW 150m AAT WSRB e Lansing Chicago IL 106 3 MHz 4 1 kW 120m AAT WYRB e Genoa Rockford IL 106 3 MHz 6 kW 65m AAT WYCA e Crete Chicago IL 102 3 MHz 1 05 kW 150m AAT WYDE e Birmingham AL 1260 kHz 5 kW D 41W N ND WYDE FM e Cullman Birmingham AL 101 1 MHz 100 kW 410m AAT WXJC e Birmingham AL 850 kHz 50 kW D 1 kW N DA 2 WXJC FM e Cordova Birmingham AL 92 5 MHz 2 2 kW 167m AAT e SC h Corporate Engineering 2150 W 29 Ave Suite 300 D
4. Oscillator The Newsletter of Crawford Broadcasting Company Corporate Engineering J ULY 2009 e VOLUME 20 e ISSUE 7 e W C ALEXANDER C PBE AMD DRB EDITOR Slowdown I keep hearing that we are in the midst of a slowdown Perhaps the economy has slowed down but I sure haven t In fact I m as busy as I have ever been Why is this the case Some of it is just timing projects lining up on the calendar and conspiring against me with no relation to the economy or anything else in current events Some however is because of the economy We have to do more with less and find ways to economize As we have said before in these pages we are getting back to the basics of our trade changing the way we operate That makes us all busier It also makes us more efficient like the automobile engine that develops its greatest power output at high RPM We so very much appreciate each of our engineers and their efforts to save the company money Not a week goes by that one or more doesn t come up with an idea some means of operating more efficiently or stretching a piece of existing equipment past its useful life We are blessed to have such a cost conscious crew folks that take the principle of stewardship very seriously indeed It is my hope that all this work is not just drudgery I hope our engineers are having fun getting their hands dirty doing the things we used to do all the time There is a great deal of satisfaction to be had fro
5. This is not rocket science Everyone in the technical side of the business already knows this So why then does MP3 have such a devoted following even with its technically inferior platform And why does satellite radio survive despite the fact that it has never earned a dime in profit That s not rocket science either Because with the wide variety of formats and music types available on those media people can tailor their listening to only what they want to hear Yes that tends to make listeners more provincial in their music outlook but it also makes those two media more competitive and popular The absolute variety available is intended to give the public what they want It adds up to niche programming and within their own realm MP3 and satellite own all the formats Traditional broadcasting must adapt to confront that business model If it does it will survive and thrive There should be no alternative There s a dent in satellite radio s armor on that issue you know With the illegal consolidation of the two service companies earlier this year came also the reduction of available audio formats on the air much to the consternation of those folks who used to love to listen to them That scenario The Local Oscillator July 2009 comprises an opportunity for broadcasters using HD especially with multicasting on the FM band if they choose to pursue it Putting it another way The future viability of our belov
6. 000 EEV which is slightly different from the standard 4CX15 000A tube The main difference is in the way the tube filament is constructed The EEV tube utilizes a filament mesh instead of the normal tungsten filament wire used in standard manufactured tubes There are other differences in the tube construction which are way above my technical tube rebuilding knowledge so I won t go into detail on those differences On Monday June 15 I installed one of the EEVs in the WLGZ FM transmitter and I am happy to report that everything went extremely smooth The new tube tuned up exceptionally well and the transmitter readings were almost identical to the factory readings As we were soon to need a tube replacement for the WDCX FM transmitter I ordered another one from Freeland I was curious to see if this one would perform as well as the one I installed in the Rochester transmitter On Saturday night June 27 I arrived at the WDCX FM transmitter site to install the new rebuild The first order of business was to get the auxiliary transmitter fired up into the aux antenna but it would not come up at all I had plate voltage about 8 6 kV but no plate current or output at all I first checked the exciter to see if there was output This was okay so I next checked all the power supplies to insure that all were working No problems were found with the screen bias and control supplies so I again attempted to bring the transmitter up with
7. engineer a CPBE and a CBNT We have the utmost confidence that Joe will settle in quickly and do a great job with the technical operation of our great Detroit cluster Please extend every courtesy to Joe should he call seeking your wisdom We look forward to hearing from Joe in these pages in the near future Complexity As I was doing a walk through of our Detroit facilities with Joe last month it occurred to me how complex those facilities are Long gone are the days when a radio station consisted of source equipment a mixer an STL an audio processor an exciter a transmitter and an antenna In a modern state of the art facility there are multiple layers of infrastructure In our Detroit facility there is the Wheatstone Bridge Router layer that serves as the The Local Oscillator July 2009 backbone of the entire plant This operates over two separate Ethernet networks providing both control and digital audio transport Then there is the digital audio layer that feeds into and out of the Wheatstone system The analog audio layer runs in parallel with the digital path for microphones headphones monitors and other analog only applications Then there is the NexGen digital media system with its file servers audio servers workstations audio cards and software The Wheatstone feeds the STL paths for the remote and local transmitter plants These include Moseley DSP6000 and APT Oslo units each with its own complexities T
8. it is a very valuable member of the team and you ll have to pry the thing out of my cold dead fingers All five tons of it Having said all that there is a kind of fly in the ointment issue with the thing and that is the difficulty in being able to monitor it via the Internet for possible problems and off line incidents which have happened a little more often in the last year or SO The UPS 150 and its ilk as delivered have a couple of ways of being remotely monitored One is via phone modem which is a well developed system that s reliable stable and just about unusable anymore except by the UPS s factory customer service department They just flat out love it Thing is who in their right laptops out here in the real world has the ability to go on line with a phone modem anymore No one who s not running Windows ME what with the Internet now being so 12 ubiquitous Which brings us to our next issue Yes there s an RJ 45 Ethernet ready port on the UPS two actually with which one can hook the UPS right into a switch and thus put it on line Brian and I spent a lovely rainy afternoon recently running the cables with which to make that connection But while the phone modem setup was designed and implemented during the golden era of dial up Internet access the Ethernet system was designed at precisely the same time that is quite a while before the present 100 Base T system was as well known an
9. our cameras While on the roof the horses decided they liked my car One horse decided the antenna topper would be a snack I looked down and the entire antenna was bent over We were able to get the horse to stop but not before the yellow cap off my Jack In the Box head was gone The month of June is over and I pray July brings less tornado warnings and more rain Until next time that s all folks Digital Diary by Larry Foltran Corporate Website amp Information Technology Coordinator The Best Thing Since XP Ever since Microsoft announced their latest contribution to the operating system landscape Windows 7 the IT community has been watching each status update with very skeptical eyes Why We ve been here before with the release of Vista We hear them talk about all the great things it will do and how great our computers will run with it but the end result is basically a disappointment I find it very interesting how nearly three years after Vista was released educated computer consumers still look to use its predecessor on their systems In fact based on statistics released in May of this year XP still holds the majority of the market share nearly eight years after its public d but I must admit that I have had three computers under my roof that run MS Vista and I haven t had too many issues Although it can be a bit cumbersome to work with at times and is a major resource black hole it is very
10. their tech support actually expects you to repair it in the field though they re happy to do it for you if you choose that route They even include vendor information for most small parts you don t have to buy a common chip from them you can order it from Digikey or Mouser if you like That s just good business as far as Um concerned And boy I hate to put it like this but guess which transmitter company will be far more likely to get our business in the future Okay glad I got that off my chest That s it for this time short and sweet Gateway Adventures Rick Sewell CBRE Chief Engineer CBC St Louis I had a silence alarm on KJSL on a recent Saturday evening I was at the local Olive Garden celebrating my birthday When I looked at the timing of the alarm I realized it coincided with the time of a network newscast Since the satellite receivers all reside at the KJSL transmitter site that was the logical place to start Since it was summer I figured that my pesky friends the wasps had probably taken up residence in the LNB of the satellite antenna There s nothing like a trip to the transmitter site to celebrate your birthday When I got to the transmitter site the first thing I noticed was that the satellite receivers were all working After checking the Intraplex the multiplexer used to transport the satellite audio back to the studio I found it was working correctly After going throug
11. this package from Microsoft will be free Yes I did use the works Microsoft and free in the same sentence Anyone considering upgrading to the Windows 7 RC should keep in mind that it will expire early in 2010 and you will be required to either purchase full license of the operating system or install a different one Current reports show that the full retail version of Win7 Home Premium will be 199 99 and the more robust Ultimate edition will be 319 99 Microsoft has also announced that only their Basic and Home Premium versions will be available to the average consumer but I suspect some specialty computer retailers will have it available Further Windows 7 will have an instant upgrade feature In other words all of the perks of the next version up will already be stored on your computer Using the upgrade tool will simply enable the next version s group of features Based on what I ve seen thus far Windows 7 is a welcomed improvement on Vista With consumers basically tapping their feet and saying this better be good it seems as if working under pressure worked for Microsoft In my honest opinion another stray shot from Microsoft in the battle between PC and Mac would have resulted in a mass exodus to the Apple side of the field Although I don t believe that this will end that debate it may help preserve the current army of Microsoft driven PC users But did I mention that Windows 7 will run on a Mac
12. until locate a file named clipbrd 6 Drag and drop the clipbrd file into your Start button menu 7 You may also put a copy of the clipbrd icon onto the desktop of course Note that you may also find the file in the 386 directory in a compressed form with the file name of clipbrd ex_ Go to the command prompt and navigate to the 386 directory then type in this command expand clipbrd ex_ clipbrd exe Copy the file that is produced to the system32 directory and work with it from there Double click the clipbrd icon to display the contents of the clipbrd then highlight and copy it to wherever you want The AndyRathbone com web site is yet another one of those neat little tip line web sites that you just might want to book mark for your own good Until next month The Local Oscillator July 2009 The Portland Report By John White CBRE Chief Engineer CBC Portland I hate to complain about the weather Rose festival is over so the rain has stopped But don t you know some people are never satisfied Now I want both sun and a calm day Some recap is in order Some years ago we had an earthquake near the Portland metro area It did some significant damage in the Scotts Mills area about 45 miles southeast of Portland It snapped one of the rafters in my garage at a knot hole but there just wasn t any extensive damage in Portland Fast forward a year or so The towers were painted 14
13. DN also went down during this episode so we could not get KLTT on the air We ended up using my dad s notebook computer to put KLTT on the air He has a Blackberry with unlimited tethering so we were able to use his phone as modem connect to the KLTT Internet stream hook up an audio cable to his computer and put that on the air It didn t sound 16 July 2009 perfect but it worked The T1 and ISDN were down several hours evidently due to rodents chewing on the telco cables in the splice pedestals near the site This ended up saving us hundreds of dollars The only other T1 problem we had was the last Friday in June the 26 The T1 went down that morning and Qwest had it up by 5 00 pm I have no idea what the problem turned out to be After dealing with several computer problems I decided to take a break and start mowing at the transmitter sites The growth at the KLZ and KLTT sites is becoming a real problem because of all the rain We have waist high grass and weeds at both sites While Keith ran the tractor and brush hog I mowed inside the tower bases The string trimmer a late model Troy Bilt quit on us for some unknown reason in the middle of my work We ended up taking it in to a repair shop and should have it back early this month Then as I was mowing inside the fenced area around the KLZ barn I ran over a tree stump that was hidden in the tall grass This bent the crank shaft of the mower Boy was I mad We had se
14. airs makes us stronger and believe me repair shop rates aren t getting any cheaper I used to make fun of the small market engineers I actually used to be one who had to do everything from equipment repair maintenance to HVAC work to unstopping the plugged up toilet Many highly paid broadcast engineers are now out looking for work because they either forgot how to do this or have become so complacent in their jobs that they refused to once again get their hands dirty This is Our Opportunity to show our employer our true worth How we handle our job duties during the tough times will make us better engineers and will define our employment opportunities for years to come WDCX FM Buffalo WDCX AM A WLGZ FM Rochester As I stated in last month s column I reported that the tube in the WLGZ FM Continental transmitter had to be replaced soonest and I was reluctant to purchase another Econco rebuild due to the numerous problems I have experienced in the past On several occasions I have gone through two and sometimes three rebuilds before I got a tube that would work This is not only time consuming but costly in making numerous trips back and forth to the transmitter site not to mention the wear and tear on the tube socket by inserting and removing the tube numerous times Taking the recommendation from Art Reis I purchased a new rebuild from Freeland products in Covington Louisiana The tube I installed was a 4CX15
15. atured on the SBE 26 s program list The difference this time was that it came directly from the horse s mouth I won t go through all that was talked about However the current economic malaise notwithstanding there is progress to report First the drought of truly portable HD receivers is about over We of the SBE chapter who The Local Oscillator July 2009 attended this meeting got a demonstration of a real gem of a radio an FM HD thing that s less than a quarter inch thick by my guess smaller than an old fashioned Sony floppy disk and cute to look at with its digital readout that takes about 60 of the front of this thing But the big news is that this radio is hot By this I mean the sensitivity and selectivity of this thing beats every other HD receiver out there Many of the SBE Chapter 26 meetings this one included take place in WKQX WLUP which is located in the middle of the second floor of the Merchandise Mart in downtown Chicago That place is notorious as an RF black hole even with the Hancock Sears and Aon transmitter sites less than a mile and a half away Analog is on most radios noisy and HD has been heretofore in forget it mode in there Not on this little hummer On this radio HD 1s 2s and 3s are quite listenable inside those walls The sound even on the very non primitive ear bud phones is excellent better than the speakers on a few of the HD radio models I won t name And the p
16. aving the originals in place I talked some last month about the process of the tower company tower engineer and myself working through all the steps while looking for problems I won t repeat those steps here but I do want to highlight the need to pre work problems as much as possible Tower work has now begun and below is a pic of the new parts lazier cut and drilled galvanized and painted prior to installation As a precaution all work is being done with wind less than 10 mph Now all I need is sun no rain and no wind I have talked about the transmitter building at Mt Scott Built originally in 1948 and extensively remolded in 1985 the building is quite large by today s usual small container standards The building has restroom and kitchen along with a fair bit of floor space For quite some time we have had the desire to consolidate office and transmitter facilities Beyond the cost savings quite a few other logistical advantages make that attractive In the last few months everything has fallen into place to allow that to happen Given just the regulatory issues alone this was no small task I have plumbing HVAC tower painters visiting on near daily basis in preparation It s going to be an interesting summer The Local Oscillator July 2009 Rocky Mountain Ramblings The Denver Report by Amanda Alexander CBT Chief Engineer CBC Denver Thankfully the month of June was a fairly quiet one at
17. d developed as itis today And it shows Back then knowledge of how an Ethernet system was wired and set up was not assumed even for the techno masses So Active Power in its infinite wisdom made the decision that initialization of the Ethernet system on their UPS line would be something that only a factory trained person could do That s right We have to bring out a UPS technician to do something that normally we of the Crawford Geek Squad or even the real Geek Squad could do blindfolded Case in point The system requires both an IP address and a port number However the only way to enter either from the front panel of the UPS controller is to press the up or down arrow keys on the controller until the port number or IP address you want comes up There is no numeric keypad on the unit That means that if you want to get to Port number 7500 you have to press the up arrow key that number of times until you get there Seriously And there is no place on the front panel to set subnet mask gateway or DNS It s enough to turn a thumb drive into a thumbscrew Well it s 2009 folks May I be so bold as to suggest that maybe it s time for a software update from y all which would allow those of us who know what we re doing who wish to use the real Internet to monitor our local UPS for problems using Active Power s software package CS View to do it Even if it cost something remotely semi reasonable I thin
18. d each situation is different Profound 1 Finally and this came out in the meeting there s a lesson for those who are non engineering types Understand that HD radio 1s technically superior to either satellite radio or to the MP 3 technology that are so in vogue these days While all three popular forms of digital audio media employ some measure of digital compression HD s compression is much less aggressive than is the case with the other two The MP 3 algorithm in particular removes so much of the digital information from the bitstream in the interest of storing the most digital audio in the least amount of digital space that the audio which comes out of it tends to sound gritty and fatiguing I will contend until three days before they bury me that that s not why digital audio exists and to this day I don t own or operate an MP 3 device and for just that reason My ears have enough problems without having that sort of thing to fight with Additionally because both of HD Radio s competing technologies have inherent data rates of 32 kbps or less the frequency response on both is limited to 50 Hz 15 kHz period not CD quality HD Radio s data rate is not limited to 32 kbps although in some cases some of the HD services could be such particularly those services which offer primarily talk programming On most of HD R s music formats the data rate is usually set at 48 kbps which is above and beyond CD quality
19. dividual breakers I can Fe z i ADN cy ba A ER A Se Se ZS Sey A S fi Ke AT ZEN measure the current at each level of the tower geg moving the ammeter The current indicated is three times the actual current which gives more accuracy on a meter that was designed to read hundreds of amps By the way the meter shown also reads DC amps in the clamp on mode I have found that feature very useful Even more exciting than tower lights are HVAC systems 15 years ago we installed our Nautel ND 50 transmitter We also installed a new 12 5 ton cooling unit to handle the transmitter and building requirements This provided us with a closed system that provided cool clean and dry air to the transmitter This was a huge improvement over bringing in huge amounts of hot and dirty air in the summer and moist air in the winter The one problem with the new system was that the unit was either a lemon or just a poorly engineered air conditioner probably both From the very beginning it had problems Over the years it had coils fans motors relays and compressors replaced again and again For this reason I was truly excited to see it removed and replaced by a new and hopefully better unit The new air conditioner arrived at the right time The day before delivery the old unit quit working Oil was coming out of it and it blew fuses That would have cost four figures to repair Fortunately the weather was moderate and the a
20. e was that the new rebuild required more screen voltage to make power so I had to re tap the screen transformer to achieve licensed power It took me several tries to get the shorting plane in the proper position to achieve a definitive peak in the PA screen current reading I was either too high or too low causing the PA tuning to reach the limit before obtaining a peak reading Remarkably I was only about a quarter inch off in cavity height from my initial adjustment to get the capacitance right and reach the sweet point for the PA tuning control Thus far I am highly impressed with the two Freeland tubes I have installed and would not be reluctant in recommending them for your next rebuilt tube purchase Not only were the tubes good the price for the rebuilds were several hundred dollars cheaper than Econco built tubes If any of your stations are using the cheap LCD caller ID boxes on your incoming call in lines and you are not happy with the hard to see displays I have found a really nice LED caller ID unit at Home Depot online These units displays are 1 linches wide by 1 inch tall and use LED technology They are manufactured by Telnote Technology and cost a mere 49 95 each They display the caller name and phone number and they will store the information from the last 25 callers Telmote That about wraps up another month here in the great northeast and until we meet again here in the pages of The Loca
21. ed medium is in the hands of the programming departments Engineering industry wide has done its job in perfecting the quality of the sound which folks can hear It s up to those who put all those formats on the air to bottom line give listeners what they want A final observation and a question Remember two decades ago that there were two not one consumer videotape formats VHS and Beta Beta was far and away the superior system technically But it was VHS which became market dominant There s a lesson there which should not be ignored As to the question Is there an organization for radio format programmers like we engineers have with the SBE I suspect not but maybe just maybe there should be now That s because it s not the station down the street that s the real competition anymore It s the kids MP3 players and the satellite radio sets in the cars We have to aim our response at them It s the only way the broadcasters can win the hearts and minds or re win shall I say of the people That is key to our future viability Putting our UPS on the Network This is just your basic Why is this rant In past issues you ve heard me extol the virtues of our Caterpillar Active Power 150 kW flywheel UPS which is presently in action at the Power 92 site to keep the power to the transmitters clean and thus the station on the air The box has eliminated over 900 outage incidents and counting As such
22. eded maintenance on our generators The good news is that both of our generators are now running well and ready for the summer Our tractor also got a good going through and though it is quite old 1964 vintage it continues to run very well We tore up our fire road and re leveled it making the fire department very happy with us They have stopped by a couple times in the last month and expressed how happy they are with our above and beyond brush clearance and building upkeep Until next month the Lord bless you and keep you the Lord make his face shine upon you and be gracious to you the Lord turn his face toward you and give you peace The Local Oscillator July 2009 The Chicago Chronicles By Art Reis CPBE CBNT AMD Chief Engineer CRC Chicago Left over from last month In our last episode I mentioned my problems with the filaments not coming on in our BE FM 30T main transmitter at mmm Power 92 and I mentioned as follows the final amplifier filament transformer is one of the more overbuilt parts of the transmitter There s a reason for that Il let you figure it out If you can t Ill tell you next month Well that s now and here is the answer The final filament transformer has to be built to handle two things The rather sizable amount of power handling which goes into properly heating the filament of a massive final tube and the need to handle the possibility of plate potential b
23. emed to be a stable platform and its resource usage is more like XP than Vista I was even more pleasantly surprised border line ecstatic when I discovered that the 32 bit version utilized all 4gb of RAM unlike the 32 bit version of Vista Better resource management and the broader compatibility of a 32 bit system I m in Download of Windows 7 RC from the Microsoft site was relatively easy After a short form that is required to be completed you are provided with a download link and certificate number for Win7 The download is actually an ISO file or disc image so software that accommodates burning the ISO to disc is required I should also add that a blank DVD and DVD burner is needed With disc in hand and the data from the computer backed up it was time to install Based on my experience it s always best to do a clean install format when dealing with a new OS Yes they do offer upgrades but that typically results in added frustration down the road I changed the boot order in the computer BIOS and restarted the machine booting from the Win7 installation disc As expected from Microsoft the setup wizard was easy to use and I was humming along on Windows 7 within 15 to 20 minutes At first glance Windows 7 looks a lot like Vista with some subtle differences although I m sure there will be some changes by the time it hits shelves Some of the most noticeable differences are in the task bar The colorful icons to the righ
24. en those rights have been taken away or censored our freedoms as spelled out in our nation s constitution will only be words on paper If nothing more last The Local Oscillator July 2009 month s column got a few of you thinking that yes something is wrong with our nation s way of thinking and change starts with one man and one idea We can learn more about the future by looking at the past We have been through hard times before and as a nation have always come out of hard times stronger and wiser than ever Nothing lasts forever and this recession will soon pass What we do with the opportunity that awaits us will define this country for years to come As acompany Crawford Broadcasting has instituted tighter controls over spending including wage freezes and capital expense purchases being deferred or cut out all together this year Each purchase order request is carefully examined and a determination is made to the extent of the need for the request Will it save us money in the long run Is the purchase a necessity or a luxury We as engineers are learning to do more with less In recent years when a piece of equipment failed we either sent it out for repair or took the easy way out and replaced a board or module where applicable Years ago we used to actually fix equipment down to the component level in our shop We must get back to this way of thinking for every dollar we can save the company by doing in house rep
25. engines power distribution systems and all that Our facilities are very complex these days and this complexity requires a certain skill set on the part of the engineers to whom we entrust them Just as the man piloting the airliner you bought a ticket on must have extensive knowledge of weather aeronautics engines fuel systems avionics hydraulics pneumatics navigation airspace FAA rules and know how to fly the airplane radio engineers must have a vast store of knowledge of a wide array of technologies and know how to operate the equipment And just in case you were wondering that s why they call us engineers and not technicians The New York Minutes Brian Cunningham CBRE Chief Engineer CBC Western New York Hello to all from Western New York To those of you who a e think that the only readers of a The Local Oscillator are those closely associated with CBC think again In last month s New York Minutes I wrote about the state of our nation s economy and how if we our government don t change our spending habits we could possibly be on the brink of national bankruptcy I heard from several readers via email both in agreement and totally against my viewpoint Now UU be the first to admit that I am not either left or right wing I am only concerned with the prosperity of our nation The U S 1s still the greatest place on earth to live work and voice your opinion without repercussions and wh
26. ening up and they re looking for another source of revenue It s just that simple Case in point I have an Omnia processor here with a bad AES chip I can t be 100 certain that this is the problem because they don t include a schematic and will not provide one I asked I had to trace the trails on the PC boards and I could have missed something But as far as being able to replace a 20 pin CS8420 SOIC chip Good heavens that s just a no brainer The kids that I was training 20 years ago were able to do that with solder wick a toothpick a fine point iron and a little patience and care According to factory service at Omnia my choice is to send the unit to them Not only will they charge a handsome fee to replace that chip I get to do without the processor for weeks while it s at the factory I m not picking on Omnia they re certainly not the only offender What really sparked this rant was my recent experience with the BE FMI 73 HD transmitter This is actually their FM 1C1 500C1 modified for HD R transmission BE includes the manual for the FM 1C1 with it but with little documentation of the modifications I called and asked for the correct documentation and or for tech support to replace an output transistor certainly within my skill set and was told that my only option was a 1 700 module swap Contrast this to Nautel who still bless their hearts not only provides detailed service information but
27. enver CO 80211 email address crisa crawfordbroadcasting com 19
28. etween filament and ground Read that the hi potting of that transformer is of critical importance Between those two factors final amplifier filament transformers are built like tanks and cost like it too But then again when was the last time any of us had to replace one Don t look at me I m totally innocent of the experience The one that gets me is the filament transformer for the RF final on the old Harris MW 50 rig Hi potting to 27 kV and handling AC power sometimes in excess of 1200 watts of direct filament roasting power all on its own Massive responsibility there I m impressed Now here s my next trivia question Why is it advisable to raise the filament voltage on a new high power beam tetrode utilizing a thoriated tungsten filament to its full rated voltage for the first 100 200 hours of operation Do you know the answer If not look it up if you can If you can t find it and you don t know it don t despair P Il tell you next month More Leftovers It s uncanny that both Brian Cunningham in Buffalo and I had the same tale of woe to tell about the 4CX15 000A tubes we use in our respective Continental rigs in last month s LO Brian asked in his missive that anyone who was using Freeland 10 Products as their rebuilder please drop him a line and funny thing about that I d gotten off the phone mere moments before with Randy down in the bayou about my own issues I called Brian and t
29. gadgetry The best I ve gotten is well most people don t have your skill and we don t want to take the chance that hey UU butcher that multi layered PC board with a soldering iron Sorry I m not buying that for several reasons 1 It s not only written into the warranty it has always been understood that if a customer butchers a piece of equipment all bets are off The warranty is void and they re on their own 2 Now replacing a 128 pin PLCC isn t for the faint of heart I acknowledge that But that s still no excuse for not providing a schematic There are many other components on that board that could easily be replaced in the field even the surface mounted ones It s just not that big of a deal 3 I wouldn t object if they put common sense limits on this maybe require factory service while the unit is in warranty and or require that parts and service info only be sent to certified engineers I have an FCC General Class license that I earned the hard The Local Oscillator July 2009 way and I m SBE certified Nor am I boasting when I say that the fact is most of our engineers are certified in one way or another with many years of experience in the field We re not kids off the street 4 If the manufacturers were really serious about this they would charge rational prices for replacement modules and factory service They re not fooling me for a minute the economy is tight
30. guy at the factory could reasonably expect that the caller at least knew how to use common test equipment and tools that the caller could follow along on the schematic and help them find the problem Nowadays as often as not they d have to literally tell the local engineer where to put the red wire thingy from the meter and which scale to use with no assurance that the measurement will be done properly But that s as far as I ll go to be fair to the manufacturers There are also plenty of us who design build and repair equipment all the time We re called engineers for a reason we re not just repairmen we craft unique solutions to one of a kind problems We have years of experience yes even with SMT components know the theory can read schematics and can troubleshoot down into the guts of the equipment and were being left out in the cold More and more frequently nowadays this is what happens 1 You open the manual and there s no schematic 2 You call the factory no sorry they won t sell you a Service manual or even a schematic 3 Can they at least tell you which voltages to look for on these components Uh no sorry They expect you to send the unit to them or to buy a replacement module or do a module swap I ve tried explaining to these people that I m a certified engineer with decades of experience in building troubleshooting and repairing all sorts of electronic
31. h the chain feeding the satellite receiver audio I found that a switch used to route the audio feed from one satellite channel or receiver to another so that we can access multiple channels and receivers on one path to the studio was no longer putting out audio The control and status channels were The Local Oscillator July 2009 still working it was just the audio circuit that was the problem It was nice that it still switched the channels and gave a status output but the most important part of passing through the audio was a definite problem Since we had a couple of different feeds to accomplish over the weekend I found a way to get all the feeds that would be used for the weekend using a spare Intraplex channel and some creative finagling at the studio I decided to retire the old switch since I had already planned doing just that on my long term project list Recently we had taken the stations to an all digital chain at the studio and had freed up a Broadcast Tools ACS 8 2 analog switch that only had a four years of service and offered more channels and many more advantages over the older switch at the transmitter site Obviously I moved that project up to the top of the list since I didn t want to constantly go to the transmitter site and manually change satellite feeds Since much of the wiring would be very different from the older switch I decided to completely rewire the whole satellite receiver switch wiring This
32. he paths are 950 MHz RF and landline T1 Ethernet paths are provided either out of existing T1 bandwidth or by piggybacking Moseley LANLink units on the RF path Then at the transmitter sites are exporters importers Exgines HD exciters RF exciters and RF amplifiers Following those are phasing and coupling systems transmission lines and antennas And then there are the remote control and monitoring systems satellite antennas receivers and transmitters electrical mechanical HVAC systems tower lights and backup generators As Joe and I were looking at the seemingly endless wall of equipment racks in the engineering room Joe remarked that his first priority would be figuring out what the audio path of each air chain was That I said was a very good place to start Then I thought but did not say Good luck Don t get me wrong Joe has no doubt figured out the audio paths by now But I was thinking at the time what a special set of skills is required to be able to not only figure out but also maintain and care for such a complex facility A person would have to have a good understanding of analog and digital audio Ethernet network architecture and transport protocols file servers and operating systems digital radio systems and architecture compression algorithms and telco loops And I haven t even mentioned RF transmitters receivers filters phasing amp coupling systems monitors controls internal combustion
33. included the control status and audio wires We have four receivers at the site each with multiple channels of audio so having this switch in line will give us greater flexibility in the future as programming changes occur One great advantage of moving to this switch is that you can add another switch on the expansion input so that we can handle even more varying feeds if necessary As for the birthday celebration even though it was cut short a bit it worked out okay because I had plenty of leftovers the next day Valley Notes Steve Minshall Chief Engineer KCBC The subject of my last column in The Local Oscillator was tower lighting The adventure continues KCBC had one beacon lamp failure and the towers were due for re lamping so we had a crew come and take care of the lamps KCBC runs 50 kilowatts which does not allow for any tower work but we have an hour and a half in the afternoons where we can run low power without losing any revenue We decided to finish our LED side marker retrofit at the same time as the re lamping of the beacons In order to replace the side marker fixtures on two towers and replace the beacon lamps on all three towers in the time available required three climbers one for each tower It all went like clockwork The tower companies are quickly becoming more expensive all the more reason to go with LED fixtures The KCBC beacon flashers are an old fashioned variety They are actually
34. ir outside was still clean so we just ventilated the room with the old blowers while the new unit was installed The new air conditioner appears to be built much much better than the old unit and the cost was quite reasonable I look forward to reliable and uneventful operation The Local Oscillator July 2009 Catalina Tales By Bill Agresta Chief Engineer KBRT Greetings from Santa Catalina Island Though our great move forward of last month continues it has not been without the usual island oddities Just as we got deep into a project painting the wood trim around our main building our friends at the Conservancy decided to tear out the asphalt road that goes past our place and begin experimenting with concoctions that they are spraying over the dirt in the hope that it will harden similar to pavement So far all they have accomplished is to create lots of dust that has not made us very happy especially during our painting project That project in itself brought on quite a surprise as we began scraping the wood only to find most of it was either rotted or termite eaten This of course has made a job that we planned to be quick and simple into a major headache As goes most things here it seems this job has put the brakes on a few other small projects as we focus on getting things into shape for summer here on the island Keep in mind that our transmitter plant is one of the tour bus stops that hundreds of tourists visi
35. k that would be worth it to have such an update on the rig just for the convenience and peace of mind that monitoring the UPS the way that everything else is remotely monitored would provide On the other hand the thought of paying several hundred bucks for a service call just to set up this UPS for Internet control and monitoring and then for the same service person to come back and deal with it in case anything goes wrong with it just leaves me cold Sorry The problem is the Customer Service Department down at Austin the Lone Star State Austin not the Minnesota Spam Austin has The Local Oscillator July 2009 less than no use for the modern Internet Their attitude is The phone modem at 56 kBaud is the fastest most reliable way we have to control all of our product out there in the field That Internet way is just too slow Well I have news folks It s 2009 as I ve said and we ve just upgraded our incoming ISP connection with the addition of several new IP addresses and the new engineering IP address now split off from the actual Internet connection and the one which handles the UPS feed is working just fine now thank you very much even through our non licensed LANLink 900 It s ready we re ready and you should be ready I say it s time to get with the program Let s go Wherefore Art Thou Clipboard Finally I had an occasion recently to be involved with a program which developed a
36. l Oscillator be well and happy engineering News From The South By Stephen Poole CBRE CBNT AMD Chief Engineer CBC Alabama HOT And Humid It has been oppressively hot here with temperatures in the mid to upper 90s and air quality so bad that your throat gets raw just walking outside It s extremely humid too If you sit in an air conditioned room for while and then go out to your car your clothes will literally become damp Naturally this affects the equipment Thankfully we converted WDJC FM to a sealed air system when we installed the new building last year W YDE FM is the only site that remains vented to the outside world The holdup has been the HVAC contractors this time of year they re so busy just handling service contracts they don t have time for anything but emergencies Todd Jimmy and I have been looking at what s required to do it The Local Oscillator July 2009 ourselves A Certified Rant TM You have been warned I m really going off this time because I m frustrated and angry Put your helmet on and open a window then UU get started Old timers like me came up troubleshooting building and modifying circuitry at the component level We basically had no choice the older tube equipment in particular was both bulky and heavy There was no practical way to ship it back to the factory Not that we did that very often anyway We were expected to repair it i
37. m repairing a piece of equipment or completing a project In years long past I lived for that satisfaction The transition to disposable equipment and a send it in repair model has made such a misty memory for most radio engineers It has been very enjoyable engaging some of you in email and telephone dialog about the proper plate voltage on a tetrode amplifier or what might cause the common point resistance to increase And of course I have the privilege of helping Amanda with a hands on project from time to time showing her how to troubleshoot and repair a MOSFET H bridge power amplifier or PDM modulator So the economy may be in a slump but radio engineering at least within this company is alive well and busier than ever And that s just the way we like it Changes Most of you by now know that Tom Gardull has left our company to pursue other interests We very much wish Tom the best in his future endeavors Joseph Joe Huk has joined our company as chief engineer of CBC Detroit Joe comes to us from the auto industry where he worked designing and testing automobile receivers for Visteon Ford This gives him a unique perspective that few other broadcast engineers have Joe has an extensive broadcast background as well having worked for John F X Browne and in private consulting engineer practice as well as working for a number of radio stations over the years Joe is a Michigan registered professional
38. n the field whenever possible in fact a station engineer who couldn t soon found him or herself out of job We were expected to understand tubes transistors and the then new and revolutionary integrated circuits that were starting to appear particularly op amps Back then it was just taken as a given that when you ordered a piece of equipment the manufacturer would include 1 An accurate and complete schematic 2 A theory of operation that walked you through how the unit operated 3 A detailed parts list 4 A detailed wiring list if applicable Basically you received all of the info that you needed to troubleshoot it in the field You were encouraged to call tech support if you just couldn t figure out the problem but in general you ordered the parts and you replaced them Times have changed and not for the better To be fair to the manufacturers I realize that there are some engineers who barely deserve the name nowadays These are people who simply don t have the background or training to properly troubleshoot a piece of equipment I freely acknowledge this and it s one reason why I have been proud to work with Cris on the SBE s Education Committee We not only need to attract young talent into our industry they need to understand what s really going on inside the Magic Boxes that we use to make RF and audio So UU grant that much in the old days when someone called tech support the
39. no success As it was getting late into the night and I was getting tired and nowhere fast I decided to abandon the tube installation until the next day On Sunday afternoon I again addressed the auxiliary problem I suspected that the tube was not getting drive However I found that the two 4CX250B tubes were working as noted by the multimeters readings for the left and right driver K readings about 170 mA When I muted the exciter the driver cathode reading would drop about 30 mA on each tube This assured me that the IPA was working so I looked further into the PA section of the transmitter All the components in and around the tube socket looked good so with the plate energized I turned the PA grid tuning capacitor about 1 4 turns and the transmitter came to life After about a minute of run time I heard the familiar snap and flash from underneath the PA cavity I shut down the transmitter to investigate and The Local Oscillator July 2009 found that there was some corrosion around the cavity door that caused the arc over A quick cleaning took care of the problem and the transmitter was up and running once again Once I was sure that the auxiliary would stay on the air I began changing out the tube on the WDCX FM main Continental transmitter This was the second Freeland tube I have installed and I am happy to report that it went just as smoothly as the WLGZ FM installation several weeks earlier The only thing to not
40. old him what I d learned Since then Stephen Poole from Birmingham has checked in with something like the same experience from a couple of years ago Bottom line We aren t losing our minds This is real Now what do we do about it To put it succinctly the 15 000A Beer an CHE unique issue in that the Eimac tube design has changed slightly over the years and this has made rebuilding that bottle kind of a hit or miss proposition Add to this the fact that the A version utilizes a hairpin filament structure design which is actually harder to rebuild Randy over at Freeland recommends either the Eimac 4CX15 000R tube or the English Electric Valve version of the A tube both of which incorporate a mesh filament design which is easier to rebuild and according to the Eimac web site a better choice for FM use at 108 MHz due to lower filament inductance Either way I m giving one of them a try likely an EEV tube and next month TI let you know how that turns out Brian already has and he loves his Mine came in but had an anomaly so unless the story progresses before the end of June TU have to write the final evaluation for the August issue of the Local Oscillator The Silver Bullet An HD Update The Chicago Chapter of the SBE Chapter 26 had as its June program a demonstration about HD Radio from Ibiquity Radio s Tom Walker This is the third time in the last six months that HD Radio has been fe
41. problem during installation which generated a rather involved error message The manufacturer in its instructions requested that the automatically generated error message be found in Clipboard blocked copied and pasted into an E mail and sent to their customer service E mail address It was then that I began to realize that Clipboard long ago a staple of the Windows operating system had somehow faded into oblivion Finding out even how to access Clipboard was taking on the dimensions of finding out how to give a cat a pill or put two drops of nose drops into a baby s nose It all sounds so easy heh heh heh Long after I d lost the error message about two hours I got both frustrated and a small inspiration Google To make a long story short I found myself face to face with the Andy Rathbone website andyrathbone com and a clue as to what 13 had happened to Clipboard Oh it s still there within XP but getting to it is almost problematic Almost I ll give the Cliff Notes version of how to resurrect it here but do go and look the whole thing up on Andy s website It s rather fascinating 1 Click the start menu button and open My Computer 2 Open your C drive 3 Double click on the Windows folder click on the line which says Click Here to Show Files 4 Double click on the System32 folder again if need be click on the line which says Click Here to Show Files 5 Scroll down the page
42. rice Tom s guess is something around 60 The only knock so far No AM Not yet Otherwise so good a value is this radio that I already have a name for it The Silver Bullet It is one of the three things which HD Radio needs the most right now it will be available within 60 days and it should make next Christmas much brighter for the medium Well see Second and on the HD Power increase front let s just say that it s moving steadily through the regulatory pipeline Understand that the proposal is for an increase of HD power of anything up to 10db below the unmodulated FM carrier A station can opt to raise its HD power from 20 dBc on up to the full 10 dBc allowed In practice things might just work out something like this For major markets to get proper penetration into all those big downtown buildings most stations would probably go all the way to the full 10 dB increase The name of the game there is building penetration Out at the more rural areas of the country however where there is hardly anything like that sort of man made terrain a more modest 4 to 7 dB increase in HD power levels may tend to make more sense The ball game is even more complex down below 92 MHz where interference contour rules are on the NPR et al set are a whole lot different than they are above the 92 divide Look for HD power levels in most cases to be much more modest down there Bottom line Everything depends on the situation an
43. sign flashers I installed these new in 1991 and now they are just plain worn out I have begun to retrofit each flasher with a solid state unit The relays are 20 years old and are also at the end of their lives I am replacing the flashers and relays in each unit I have found that the fuse holders are also in poor condition so they will get replaced too At another company we recently acquired a 400 foot tower This tower actually had the wrong lights on it for 20 years The one beacon it should have had three was never very bright and as far as I can tell it ran for years without replacement the reason being is that it was fed with 10 wire I have not calculated what the voltage at a 1240 watt beacon fixture is with more than 800 feet of 10 wire but it must be low It s not very often that you get to completely replace a tower lighting system conduit and all but that is exactly what we did The new system is all LED and supplied by TWR Lighting The Local Oscillator July 2009 The controller is very nice with alarms for each level of the tower plus a power fail and flasher failure alarm The new LED beacons are even more efficient than their predecessors way more efficient The current draw on the individual fixtures turned out to be so low that it was difficult to read with a clamp on ammeter My solution as pictured was to make three turns in the neutral wire feeding the tower By switching on in
44. t each day during the summer months so we always gotta look great We did manage to complete the much needed maintenance on our water tank that had begun to rust One of the things I have found up here at the KBRT Ranch is that the salt air has a major effect on any and everything If you leave your tools outside for even a couple days you can count on finding them rusted Because of this I try to use stainless steel hardware whenever possible Still however the rust seems to eventually find its way even into rust resistant material Another interesting aspect of our painting projects is that they all must follow a Conservancy color scheme that is they must basically blend in with the surroundings So this leaves us with a choice between the color of dirt and the ever changing colors of the weeds Because of the weeds seasonal color changes we almost always just match the color of the surrounding dirt a very beautiful tan color that yes does become very boring I have not spent much time inside the transmitter plant this month other than dusting weekly to help offset the clouds of dust coming from the road that remains torn up as they experiment trying to find something that works Of course I guess repaving it with asphalt is out of the question I look more like a mechanic this month than a transmitter engineer As Pastor Enrique and friends paint and repair I have been bouncing between helping them and some ne
45. t have been replaced by very basic looking white icons Instead of only displaying the current time the date and time are now present in a very compact arrangement The text in the task tabs are basically gone replaced by compact icons Multiple associated windows such as your Internet Explorer and a download window as an example are now grouped under the Internet Explorer icon on the task bar Hovering will expand 18 the list of items open with some descriptive text next to it In general it seems as if one of Microsoft s goals with Windows 7 was to make the interface more compact and less obtrusive In terms of system resources Windows 7 runs like a dream Flight Simulator runs as it should on a computer with such high end specs as opposed to how it did on the same computer under the control of Vista Software compatibility has been no issue and I ve actually been surprised to see many manufacturers already providing system drivers for Windows 7 If a certain application won t work in Win7 I ve read that there is a XP mode that can be used although I haven t experimented with that at all Unfortunately with Microsoft there is always bad that comes with the good No longer available on Windows 7 compared to Vista are Windows Mail and Windows Calendar It s not a huge problem if you re a fan of these tools because they will be offered in a separate package called Windows Live Essentials What s even better is that
46. veral trees cut down around the area so it could be painted and a fence could be put up The tree cutters left all the debris there With the ivy that has been growing around the entire property at KLZ and the tallness of the grass concealing everything I couldn t see anything on the ground We were able to order Amanda s car is irresistible to the horses at KLVZ the parts needed to fix the mower and will hopefully have it fixed and working shortly so I can finish my work First though I will comb the area for stumps and other debris in hopes of removing as much as I can I am slowly learning about mowing and trimming as these are things I have only done at work Thankfully I have a father who tells me what not to do while mowing typically after I ve done The Local Oscillator July 2009 it at least I know now I also learned that I cannot wear shorts Ouch While visiting KLVZ several times we noticed the horses kept eating our wood tower base fences Jerry Ford the owner of the horses ended up putting livestock fence panels around each tower base fence to keep the horses from eating them That worked great until one day when a horse got stuck in the panels around the new building and ended up pulling the panels apart This allowed the horses to get under the building The horses did some damage to the conduit there and we were able to fix it ourselves On this particular day my dad and I went on the roof to adjust
47. where she took shelter friends house which was my second destination I turned down a feeder street and just as I _ d C turned the tornado came down and landed in a field less than a quarter of a mile away I had no idea which was this tornado was going I just knew I didn t want to be stuck in a car when it hit I turned down the first street I came to and saw two people outside The wife had been doing the same thing I was She saw the tornado and wanted to get home She apparently sped all the way home with her young daughter in the back They waved me into their house so I could have some shelter It began snowing hail or so it seemed It was coming down fast and hard While the rest of us huddled in the basement the husband stayed outside captivated by the tornado that was passing by Thankfully the tornado passed us completely If I would ve gotten to where I was going I would have encountered golf ball size hail and would ve had a lot of damage to my car The tornado went through the Southlands Mall an outdoor mall with lots of people This mall has everything you want a Lowe s just up the street Wal Mart Best Buy Petco Ross and several other small shops and restaurants They ended up having to close the mall down for two days as several HVAC units were ripped off the roofs of these places causing gas leaks Only one place has yet to reopen I can only assume it took a direct hit
48. work T1 problems were at a minimum We did have some torrential rains the beginning of the month One storm on June 7 brought an EF 1 tornado dangerously close to me K I had been out running errands for my parents while they were on their way back from Grand Lake Colorado I noticed the drop in temperature at my first stop but didn t think anything of that and the black sky As I left the neighborhood I was in it began hailing pea sized hail Yet again I thought nothing of it You d think that after living in tornado alley for thirteen years I d have figured out what this meant It looked darker to the west so I figured the storm was moving west to east which is the usual pattern around here I heard the tornado sirens go off as I was nearing Quincy Reservoir a few miles from my next destination I immediately begin looking up at the sky while driving I was thinking that if I kept driving east I would get out of this What I didn t see was how dark it was southeast The houses were in the way of my view I got to an intersection probably less than a mile from where I was going and the hail really picked up and got bigger too I noticed fences were blown down and in the road At that point I just floored it I noticed rotation in the sky and knew I needed to get to shelter I was trying to make it to my 15 Too close for comfort Amanda took this photo from the front yard of the house
49. years ago time flies and the center tower was converted to a grounded base skirt fed tower The skirt system was later replaced in an upgrade There were numerous lamp replacements along the way and don t forget the LED conversion All in all we have had tower crews on the tower on a regular basis Then this last fall while evaluating another project we discovered some warped diagonals on the tower The warping wasn t extreme and there was no event to point to for an explanation Thus began the visit to the mystery detective With a photograph I had from 2000 and one that Cris had from 1996 or so we enlarged that area of the tower and were able to show the damage had existed for some time and just not been noticed We believe the damage is a result of the Scotts Mills earthquake We can t be sure and in the final analysis the real goal is to implement a repair Here is where the tower structural engineer enters the picture We are working with a local engineer who is quite familiar with our towers He was involved with the original modifications to install a 7 bay FM antenna since removed I want to talk a little bit about that process Our structural engineer s recommendation was to upgrade the damaged members In order to maintain structural integrity during the repair we 14 wanted to avoid removing any diagonals if possible The ultimate decision was to mate new diagonal sections with the existing diagonals le
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