K9EQ AH-4 Universal Interface User's Manual
Contents
1. 4 Resetthe rig s mode power if it was changed and begin operating Note that any many cases it is only necessary to retune when changing bands To be compatible with the K9EQ Universal AH 4 Interface the rig should have convenient means of adjusting output power o Availability of a mode that emits a carrier AM FM or CW o A keying line that operates at a maximum of 20 volts and 100 ma The interface will pull this line to ground when it needs to key the transmitter o Theradio generates a 1 KHz tone when tuning This allows the use of SSB modes If the speech processor is turned off it may not be necessary to adjust power output when tuning Note that this feature may or may not work reliably depending upon how stable the rig s output is for a given audio level Full Interface The full interface adds the following features to the basic interface o interface generates an adjustable negative ALC voltage This reduces the transmitter s output when tuning Note that this feature could require frequent adjustment since the radio s characteristics may change with temperature and voltage 5 232 interface that allows computer based rig control and logging programs to interface with the radio The interface can be used with Icom and Yaesu radios Kenwood should work also but has not been tested o The RS 232 interface will key the radio when DTR is asserted This allows a computer sound card based prog2. DescrItiOn soc etr et et e ER e Rn e t te ta e be T et et en es M 12 eoru MT O 14 B sic Interface z ie ete eite ned te pine cede tides 14 E E 14 UU 15 Power output control using AM mode uet ete t e eb c tee dre ie 15 Interface PEE 15 K9EQ 4 Universal Interface Rev 5 Page 2 www hamoperator com Troubleshoot Bs 16 PIDE 18 HEEL 21 4 Radio Interface Theory of Operation toes bete aet eoe teneo ce 23 Forward An updated version of the manual may be available Check with www hamoperator comfor updates as well as additional information and feedback from other users This product may require modifications from the stock design to work with your radio Information on interfacing with different radios will be published when available Warning Itis possible to damage your equipment by using the interface described in this document Use of this document the AH 4 Universal Interface or any information from www hamoperator co
3. Interface ControlsConnection Copyright 2001 2002 K9EQ and HamOperator com K9EQ 4 Universal Interface Rev 5 Page 20 www hamoperator com Parts List Digikey P4049A ND ee quo recess Deae Digikey P5148 ND 014 ds nex P4016A ND C9 C12 C17 Capacitor Aluminum Electrolytic 1 uf 25V C18 C19 Capacitor Disk Ceramic 0 1 14 16 Notussd O O 140 Digikey 1N4007DITR ND LED Green Jameco 34606 5 ess LED Red Jameco 34622 Diode Zener INS231 5 1 Volt Digikey INS23IBDICT ND Connector 9 sub D female PC mount Digikey A2100 ND 11 12 13 Inductor 10 uH Digikey M7825 ND 2 Push Button Momentary Jameco 162886 Digikey P8006S User supplied external Printed Circuit Board K9EQ 1 001 ON Q2 2 2 Transistor NPN 2N3904 General purpose Jameco 178597 Digikey 2N3906 ND R17 R18 Digikey 4 7KQBK ND M au eem eam Digikey 100KQBK ND EMEN CNN Digikey 2200BK ND UBL ET 100QBK ND Jumper Digikey 36G53 ND HEN NE Digikey IKOBK ND NW IN EH Digikey 36G13 ND o 10QBK ND R22 R25 Quantities are for the basic complete kit K9EQ AH 4 Universal Interface Rev 5 Page 21 www hamoperator com Designation Ul 1 1 Integrated Circuit Microprocessor 16C54C 04 P K9EQ 01
4. be off 2 If you have connected the audio interface and are operating SSB turn off speech processing if on and skip to step 5 3 If you are operating SSB switch to a mode that generates a carrier such as CW AM or FM 4 Adjust the power output to approximately 10 watts 5 Press the TUNE button on the interface The status LED will begin to flash and the rig will key on the air Within a few seconds the rig should unkey and the status light should remain on This indicates that the AH 4 15 in line and tuned to the frequency 6 Readjust the rig s mode and power and being operation Note that if the AH 4 does not tune because you are running SSB and are using the audio interface you can adjust the mic gain setting to trim the power output Also check to make sure that speech processing is off If it is on it will tend to max out the RF output That is after all why we want to run speech processing The 4 can be removed from the antenna circuit by pressing the UNTUNE key This should be done when changing bands otherwise the receiver s sensitivity will be reduced The status indicator has the following meanings o Off AH not tuned and is out of circuit bypass mode On The 4 is tuned o Flashing slow The AH 4 is tuning o Flashing fast An error has occurred and AH 4 is not tuned This can occur when the 4 is not connected K9EQ AH 4 Universal Interface Rev 5 Page 14 www hamoperator co
5. flat side of the 78L05 with the pins down the pins from left to right are Output Ground Input When looking at the front flat side of 2N3904 or 2N3906 with the pins down the pins from left to right are Emitter Base Collector K9EQ AH 4 Universal Interface Rev 5 Page 8 www hamoperator com The narrow side of 1 U2 represent the flat side of the device components mount on the top side of the board U5 and R24 are not used These are on the board to allow for future software development with non volatile memory The short pin on the LEDs is the cathode and is attached to pin 1 square pad J1 J2 and J4 can use right angle connectors This may simplify connection depending upon how the board is mounted See the parts list The connector kit includes right angle connectors The basic version requires a jumper from pin 9 to 16 of U3 This is done to prevent the rig from keying up as the input to the microprocessor floats Component Identification Verification In the following steps a 9 volt battery may be used as a power source when the board is not connected to the AH 4 and U3 is removed Initial Basic Version Checkout After construction is complete perform the following verification steps 1 Verify that all components have the correct values and are wired according to the documentation 2 Apply approximately 13 8 volts to the interface 72 pin 5 13 8 J2 pin 4 GND Verify that the power LED
6. impedance audio source may be loading down the board s output K9EQ AH 4 Universal Interface Rev 5 Page 17 www hamoperator com Schematics TX AUD COMP AUD IN RIG AUD OUT C18 14 3 0 1uF 4 7K 1K L1 START OUT 9 D1 J1 2 RIG AUD IN RFS START 44 4 4 7K R19 0 1uF J4 2 2N3904 220 L2 TX OUT J2 1 J4 1 Q2 R2 COMP GND J2 4 c2 TX J1 4 R23 001uF 44 5 2 3904 14 8 43 2 42 5 13 8V IN 41 3 K9EQ 4 Universal Interface Rev 2b 13 8 OUT e Sheet 1 of 2 Copyright 2001 2002 K9EQ and HamOperator com K9EQ AH 4 Universal Interface Rev 5 Page 18 www hamoperator com 5 2 4576 2 C7 22pF 22pF U1 PIC16C54 R13 R14 C17 4 7K Dc AUD t UNTUNE 1uF 1K R25 STATUS Vss SDA EUN as MAX232 U3 1uF H v 220 c13 D8 5V 1uF C1 R12 t 001uF R11 TX ALC 2 2 Data from rig NE 44 Tiin 5K 7 Data to rig T2in 2 2 5 4 7 Riout Rtin R20 R24 R2out R2in C15 GND COMP GND 1K cum 001uF o Jump pins 9 16 when K9EQ AH 4 Universal Interface Rev 2b JP1 2 JP1 1 U3 not installed Sheet 2 of 2 Jumper for Icom Copyright 2001 2002 K9EQ and HamOperator com K9EQ AH 4 Universal Interface Rev 5 Page 19 www hamoperator com TUNE J3 3 UNTUNE J3 8 A D2 Red J3 1 K9EQ AH 4 Universal Interface Rev 2b
7. lights If it does not confirm correct assembly of U2 and associated components Verify input and output voltages with a DVM K9EQ AH 4 Universal Interface Rev 5 Page 9 www hamoperator com Apply approximately 13 8 volts and verify that the status LED flashes If not confirm correct assembly of the status LED and the oscillator circuits X1 Verify with a that 5 volts is applied to U1 pins 4 and 14 and that ground is applied to U1 pin 5 Install the preprogrammed PIC16C54C microprocessor at U1 into the IC socket Be sure to orient pin 1 towards the upper right Pin 1 is indicated by a small circular dimple on the top of the chip Be careful not to bend the leads under the chip while installing it Make sure all 18 pins are properly seated in the IC socket Attach a resistor 1 1OK between 13 8 volts and START OUT J1 pin 2 Press the TUNE button and apply power Release the TUNE button Examine the START OUT signal with a DVM It should be at approximately 13 8 volts and decrease to approximately 0 6 volts or less when the TUNE button is pressed Attach a resistor 1 10 between 13 8 volts and RIG TX J1 pin 1 Press the TUNE button and apply power Release the TUNE button Examine the TX OUT signal with a DVM It should be at approximately 13 8 volts and decrease to approximately 0 6 volts or less when the UNTUNE button is pressed Press the TUNE button and apply power Release the TUNE button The status LED should be off Sho
8. pressed the TX OUT line will be asserted The status LED will turn on when the KEY IN line is asserted To resume normal operation remove and restore power Symptom My rig always keys up when I run a particular software package Solution The software package is probably asserting DTR Either press the UNTUNE button when turning the board on this prevents DTR from keying the transmitter or power up the board after starting your computer program If you have the basic version place a jumper between pins 9 and 16 of U3 Sympton My PSK31 program will not key the rig Solution Power the board off and on again see above for DTR disable Configure the software to assert DTR to key the transmitter Symptom When I key the radio the RF output shoots up even when I m not tuning This is particularly bad when I turn up the mic gain Solution Audio may be getting into the radio via a ground loop between the interface power supply and radio Take the interface ground directly from the radio Symptom The audio output is hard to adjust I have the pots turned down almost all the way Solution See above Also it may be necessary to increase the values R13 R15 and or R17 to reduce the audio gain to the rig Symptom There is not enough audio output to drive the computer Solution Decrease the value of R18 and or increase the value of R19 The board is designed to use mic level inputs Some rigs wire all audio inputs in parallel Another low
9. things happen when transmitting The AH 4 untunes or other unexpected events occur Solution RF is getting into the control lines Use appropriate RFI techniques to filter all connections to the interface Symptom The AH 4 tunes on some frequencies but not others Solution The antenna system is not appropriate for the frequency where there is a problem Try making changes to the antenna See www hamoperator comfor antenna suggestions Symptom The AH 4 does not tune on any frequency Solution Either the antenna is not connected or there is an error in the wiring between the rig the interface and the 4 Symptom The AH 4 attempts to tune but stops right away and remains untuned Solution The rig must put out 5 to 15 watts of RF or tuning will not proceed Verify that the rig is putting out the appropriate amount of power when tuning is started Symptom The status LED flashes on and off when I first apply power to the interface Solution This is normal It indicates that the microprocessor is running Symptom Is there some way I can force the START OUT and TX OUT lines on and off for testing also like to be able to tell the status of the KEY IN line K9EQ AH 4 Universal Interface Rev 5 Page 16 www hamoperator com Solution Yes there is Use debug mode Press and hold the TUNE button and then apply power to the interface When the TUNE button is pressed the START OUT line will be asserted When the UNTUNE button is
10. 001 custom programmed IC socket 18 pin for above Jameco 112230 Digikey NIM78L05A ND U3 0 1 Integrated Circuit RS 232 level converter Maxim Jameco 24811 Me cy MAX222CPEND IC socket 16 pin for above Jameco 112221 04 05 00 1 1 Crystal Quartz 2 4576 MHz Jameco 101274 Digikey X069 ND Connectors only included with the connector kit Mating connector for AH 4 Molex 03 09 1041 Digikey WM1308 ND Pins for above Molex 02 09 1104 Digikey WM1101 ND 1 1 Connector 4 pin Molex KK optional Digikey WM4202 ND st or Digikey WM4302 ND rt Pl Mating connector to 1 Digikey WM2002 ND 1 1 Connector 5 pin Molex KK optional Digikey WM4203 ND st or Digikey WM4303 ND rt g P2 Mating connector to 12 Digikey WM2003 ND J3 J4 1 2 Connector 8 pin Molex KK optional Digikey WM4206 ND st or J3 must be straight Digikey WM4306 ND rt ang P3 Mating connector to 8 Digikey WM2006 ND J3 Pins for P1 P3 1 For P1 P2 P3 GL MEN Digikey WM2200 ND Note Jameco is generally less expensive than Digikey Jameco www jameco com Digikey www digikey com A complete kit of parts is available from K9EQ Visit www hamoperator com for details Please report any errors in this manual to K9EQ K9EQ AH 4 Universal Interface Rev 5 Page 22 www hamoperator com 4 Radio Interface Theory of Operation The AH interfaces to the radio with two wi
11. K9EQ AH 4 Universal Interface User s Manual MH C 5 2 1 K9EQ AH 4 Universal Interface Rev 5 Page 1 www hamoperator com Table of Contents FRO Wal Ges ene ROSEO AE P RR rne M e 3 M atning e I RD OD dn to Dp EREMO 3 Description and Introduction o eO ee ERE Redi e DER ERES 3 Board HIStory e tee pes DEO eR e UR EE EAD IE 2 Why sethe AHA Ee EE A RO e Ie RO RET Ae DRY Oei tt leet ect 4 M M 4 ailes 5 tOM e nE EE banda leds XR URS ERREUR 5 EDI 6 Optional components dente ee e PHP RE eH IEEE D RU E ER ae te dee P a OP S 7 Construction Notes tre tee RR COSI OR TER GRE I ERE ERU UD ORE ROS Nt a ER d Es 8 Component Identification ce a n e e ice ee E EI RA ehe 9 eet atenta e ete RR t 9 Initial Basic Version Checkout EE RUE IRE EINE ve 9 Full Version i e er Ur D e rer REED 10 Final Basic Version Checkout eR oO D ARD P EUR RR ER PR ERRARE es 10 Pinal F ll Version Check Out eerte NOR SUE ERR UN RU eret a re pen 11 Circuit
12. P1 must be installed or preferably jumper J4 6 and 7 together when making the cable Do not use this jumper with Yaesu The interface should operate with Kenwood radios as well but this has not been tested TRX Manager is a good rig control program The demo version of this program will allow you to test the interface of virtually any radio The interface also provides for keying of the radio via the computer using the DTR pin Computer Audio Interface This interface uses resistors and capacitors to couple the computer and the radio Some PSK31 interfaces use transformers and optical isolators to reduce audio hum I have not had a problem with audio hum on any of my equipment using this interface R23 was provided to allow additional ground isolation between the computer and the interface rig Normally this resistor can be shorted If you have problems with hum and suspect a ground loop try using resistor values of 10 100 ohms Follow the instructions with the sound card program for adjusting the audio input and output levels on the computer When using a sound card interface turn speech processing off With the mic gain set to a normal position adjust R16 for the correct RF output level for the mode you are using Visit www hamoperator comfor links to software that can be used to test the interface Troubleshooting Visit www hamoperator comfor late breaking news and to post comments and questions regarding the interface Symptom Funny
13. e phone patch output to provide rig audio to the interface Use a suitable audio input phone patch packet etc to provide audio input from the interface The RS 232 should connect to the computer s serial port using a non null modem cable K9EQ AH 4 Universal Interface Rev 5 Page 12 www hamoperator com Computer audio connections should be made to line out and microphone in Typical Connections basic AH 4 operation no PSK31 1 1 UE Connect only if using ALC option ALC Input Audio input mic level Connect to rig for main ground __ ue For PSK31 operation with a computer add the following connections J4 1 GND Audio GND to computer w series resistor to minimize ground loop currents 212 Audio output to rig Connect only if using audio tone to generate RF output for tuning J4 4 Phone patch out Audio in from rig use phone patch out or other source For computer interfaces add the following connections 21 0 7 K9EQ 4 Universal Interface Rev 5 Page 13 www hamoperator com pu E Serial Data Out Short with 14 7 for rigs that have a common in out data line Icom Short with J4 6 for rigs that have a common in out data line Icom BEEN eS md Operation Basic Interface Tuning 1 Turn the power supply and the HF rig on The power LED on the 4 interface should light The status light should
14. he rig to a carrier mode and adjust the output to 5 15 watts I presented the board to a good friend of mine KOZE for review His comment You could get twice as much stuff on the board Well being a ham radio operator and being cheap er I mean frugal I couldn t let board space go to waste Hence some improvements were made The first improvement was to have the board generate a 1 KHz tone If you were in SSB this would eliminate the need to change modes You could also adjust the tone level to control the power output assuming speech processing is off The second addition was to provide an ALC output to the radio This 0 to 4 volt signal would cause the transmitter power to roll back to 5 15 watts when the tuner was engaged More on this later K9EQ AH 4 Universal Interface Rev 5 Page 3 www hamoperator com Getting negative voltage from a positive supply was bit tricky Once again KOZE came to the rescue Why not use one of those RS 232 chips that generate their own negative and positive voltages So a MAX 232 was placed on the board It s very sad to see an RS 232 chip with only one port in use That s when I added a computer interface to allow logging and rig control programs to communicate with the rig Well if you have RS 232 and you can key the transmitter you almost have everything you need to interface the computer s sound card to the radio I would after all like to run PSK31 A few resistors and capac
15. itors later I was running PSK31 Proud of my new board once again I showed it to KOZE for his approval His comment You could get twice as much stuff on the board While KOZE figures out what features should be added I now have a full interface that let s me use the AH 4 with virtually any radio simplifies the tuning process provides computer control of the radio and let s me run PSK31 Why use the AH 4 The K9EQ AH 4 Basic Universal Interface allows the use of the Icom AH 4 and similar antenna tuners with most HF rigs The 4 is intended to be used with certain late model Icom radios such as the IC 706 and IC 746 The AH 4 communicates with the radios using two control lines Since the radio and the AH 4 can communicate the AH 4 offers the following advantages over conventional wide range automatic antenna tuners o Tuning is accomplished using about 10 watts of power from the radio o The power from the radio is split between a dummy load and the antenna thus the radio sees a maximum SWR of 1 1 1 while tuning this prevents damage to the rig s finals o maximum of 350 mW is radiated during tuning minimizing Other hams will appreciate your use of the AH 4 o Tuning is never done under full load This can prevent premature failure since the contacts of the tuning relays never switch while high voltages are applied There are over 20 relays in the AH 4 o Thereis positive indication that tuning has been accom
16. ive circuitry The negative voltage is clamped to approximately 5V by D8 and is current limited by R21 R12 adjusts the voltage R20 is used to provide slightly greater adjustment range When the microprocessor detects a signal on pin 10 it causes the rig to transmit The U3 the MAX232 chip generates 8 and 8 voltages from the 5 supply by switching capacitors C9 C12 in sequence It provides an RS 232 interface between the computer and the radio R24 is required by Yaesu radios to provide a current sink to ground the radio does not drive the line low Icom radios use a single wire for both transmit and receive Either JP1 must be installed or J4 6 and J4 7 must be shorted When J5 pin 4 is asserted by the computer either a logging PSK31 or similar program the level is converted by U3 and presented to pin 10 of U1 If not tuning U1 asserts Tx when this is detected There two exceptions to this If DTR is detected when the board is powered up or if UNTUNE is pressed when the board is powered up transmitter keying via DTR is disabled This allows use of the board with software that continuously asserts DTR This also allows the basic version of the interface to operated when U3 is not installed R18 and R19 provide a voltage divider to interface the high level output of the rig to a microphone input on the computer sound card C19 provides DC isolation R16 and R17 provide a voltage divider to interface the line output
17. m Setup If you intend to operate SSB and want to automatically generate the correct amount of RF output for tuning you will need to adjust the audio output level If you are operating CW AM or FM or have not connected the audio interface no adjustment is necessary 1 Connect the rig to the AH 4 and antenna 2 Adjust the microphone gain on the rig to where you normally run it 3 Turn speech processing off 4 Set the rig to SSB 5 Switch to 10 meters 6 Monitor the RF output of the rig You can do this with the RF output meter in the rig or an external meter If you don t have an RF power meter you can still adjust the interface by trial and error 7 Turn R14 on the interface board fully counter clockwise 8 Press the TUNE button If the tuner does not tune because the power is below 5 watts turn R14 clockwise a small amount Repeat until the AH 4 tunes 9 If the AH 4 does not tune because the power is above 15 watts turn R14 counter clockwise a small amount Repeat until the 4 tunes 10 Repeat steps 8 and 9 for the other bands on which you intend to operate Note that once you have completed calibration you can make small adjustments to the mic gain setting to change the power output during tuning Power output control using AM mode Many radios on the market allow you to adjust the AM carrier output level This can be used as a convenient way to adjust the power output during tuning Simply set the carrier ou
18. mis done at your own risk Do not use this information unless you are willing to assume all responsibility The kit employs components that can be damaged by electrostatic discharge Description and Introduction Hello and thank you for your interest in the KOEQ 4 Universal Interface The interface is designed to allow you to use the Icom AH 4 remote automatic antenna tuner with virtually any HF rig I started this project after I purchased an Icom 706 and AH 4 I was very impressed with how well the tuner worked It was almost effortless to build wire antennas throw them in the trees and work plenty of DX The first contact with my first antenna a loop I built in the garage was with Belgium Ilooked at other antenna tuners on the market and concluded that the AH 4 was the one I wanted to use It is well designed rugged and priced very competitively From my point of view it had only a few disadvantages The documentation that comes with the tuner is not very good and I couldn t use it with my other radios While I really like the 706 like to be able to use the tuner with my Yaesu FT 990 I addressed the first disadvantage by publishing information about the AH 4 at my web site www hamoperator com The second disadvantage is addressed by the KOEQ AH 4 Universal Interface Board History The first version of the interface was the basic version It would tune the AH 4 when the TUNE button was pressed but the user had to set t
19. of a computer sound card to the auto patch input of the rig R16 allows adjustment of the output level C8 provides DC isolation R23 limits ground loop currents to reduce hum The microprocessor U1 is a dedicated preprogrammed Reduced Instruction Set RISC controller manufactured by Microchip It contains a one time programmable instruction set memory of 512 words The basic chip is programmed with code written by K9EQ This code performs all of the necessary logical and timing operations to control the AH 4 Installation The interface can be built in any suitable enclosure It can be built such that the LEDs and push buttons are either on the circuit board or mounted on the enclosure Circuit components should be protected against shorting to another circuit or static discharge The ground connection should be attached to the same ground that the HF rig uses For the ALC option to work properly this ground should be located at the transceiver This is typically obtained from the rig s 13 8 volt power supply The AH 4 is also connected to this supply ground I highly recommend running the 13 8 V and GND connections straight to the radio The TX OUT line from the interface attaches to a point on the HF rig that when grounded causes the rig to transmit Note that this interface assumes the rig uses a 13 8V control line that is brought to ground to key it The START OUT and KEY IN lines connect to the appropriate location on the 4 Use th
20. plished o tuner can be disengaged at any time permits receiving on other frequencies o best bang for the buck The AH 4 is less expensive than similar tuners on the market Unfortunately those without the appropriate late model Icom HF rigs have not been able to take advantage of the AH 4 That is until now The K9EQ Universal 4 Interface allows the AH 4 to be used with virtually any HF rig Once installed the tuning operation is simple There are two versions of the interface a basic and a full version The basic version allows the AH 4 to interface with almost every HF rig The full version adds an RS 232 and a computer sound card interface Basic Interface Some people may not actually want all of the KOZE inspired features For these folks I have broken the board down into the original basic interface and a full interface The following tuning process is used with the basic interface 1 Settherig to the desired HF frequency K9EQ AH 4 Universal Interface Rev 5 Page 4 www hamoperator com 2 Ifyou are not in SSB or have not connected the audio interface change the mode to one that emits a carrier AM FM or CW and adjust the power output to about 10 watts 5 15 watts will work If you are in SSB you will need to turn off speech processing 3 Pushthe TUNE button The AH 4 will automatically tune A status light indicates that the AH 4 is tuning and the final tune status
21. ply for the rig and 4 is connected to 13 8 In and ground This voltage is regulated down to 5 by U2 for use by the microprocessor U1 C4 and C5 provide stabilization for the regulator and LED D4 provide an indication that power is applied C6 and C7 form the clock circuit for the microprocessor U1 The frequency is not critical but should be near 2 4576 MHz microprocessor uses software timing loops Running the controller at higher or lower clock speeds may cause timing errors with the interface to the AH 4 R8 PB are used to start the tune operation Normally U1 RB6 is pulled high by R8 When the push button is pressed the input is forced to ground The microprocessor detects this state change and begins the tune sequence Similarly R7 PB2 cause the microprocessor to untune the AH 4 The tuning status is indicated by LED D5 The LED current is limited by R9 The value of this resistor may be increased to reduce power consumption K9EQ AH 4 Universal Interface Rev 5 Page 11 www hamoperator com While tuning the microprocessor generates a 1 KHz square wave on pin 2 This square wave is filtered by R13 and C17 to remove some harmonic content and to reduce the amplitude The audio output level is adjusted by R14 and coupled to the rig via R15 C18 C18 provides DC isolation While tuning the microprocessor asserts pin 1 This causes U3 pin 7 to go negative D7 blocks positive voltage to the ALC dr
22. ram like Digipan to key the radio o A computer sound card radio interface has been implemented This allows SSTV RTTY CW PSK31 and other sound card based software to work with the radio For more information please visit www hamoperator com I am always interested in hearing your comments about this manual the interface the AH 4 or any subject you care to discuss 7375 Chris KOEQ Construction The K9EQ AH 4 Universal Interface may be built using prototype construction techniques or by using the printed circuit board These assembly instructions assume that you are using the printed circuit board Rev 2 Construction options The board may be built with the one of the following three options K9EQ AH 4 Universal Interface Rev 5 Page 5 www hamoperator com and UNTUNE buttons on the PCB o and UNTUNE buttons on the PCB and also mounted externally o External TUNE and UNTUNE buttons The following options are also available LEDs on PCB o LEDs mounted remotely External buttons and LEDs allows more flexibility in mounting while onboard components make it simpler to build and get working Basic Version The basic version requires the following parts C2 C3 C4 C5 C6 C7 C8 C17 C18 D1 D2 D3 D4 D5 D6 J1 J2 J3 L1 L2 L3 01 02 Q3 R2 R3 4 R5 R6 R7 R8 R9 R10 R13 R14 5 01 UIS 02 2 K9EQ 4 Universal Interface Rev 5 Page 6 www hamopera
23. re connection A START signal is issued by the radio to start the tuning operation KEY signal from the tuner indicates when the tuning has started the tuning has failed or the tuning has been completed The tuning operations works as follows 1 2 9 A tuning operation is requested by the radio the radio asserts the START line The AH 4 microprocessor is reset and begins running its program after approximately 300 ms When the AH 4 is ready it asserts the KEY line AH 4 routes the RF through the power divider measurement circuitry and tuning network The KEY signal causes the radio to transmit a carrier at about 10 watts of output power The 4 verifies that the power is between 5 and 15 watts If not the 4 aborts the tuning operation If the power is between 5 and 15 watts the AH 4 begins the tuning operation Approximately 250 ms after the AH 4 starts tuning the radio removes the START signal When tuning has been achieved the AH 4 remo ves the KEY signal and switches the RF to pass only through the tuning network The microprocessor is then halted The radio stops transmitting when the KEY signal is removed If the AH 4 was unable to achieve tuning it removes the KEY signal for 20 ms asserts it again waits 200 ms then finally removes the KEY signal This causes the radio to indicate a not tuned condition If the band is changed on the radio the tuner is reset This causes the tuning network to be remo
24. rt the KEY IN line to ground The status LED should turn on Initial Full Version Checkout Plug in U3 Attach the board to a 12 volt power source Verify that the voltage at U3 2 is approximately 8 5 If not verify installation of capacitors C9 C12 Verify installation of U3 Confirm that outputs are not shorted As above but verify the voltage at U3 6 is approximately 8 5 volts Turn the power off While pressing the TUNE button apply power Measure the voltage J2 2 While pressing TUNE adjust R12 The voltage should be adjustable over the approximate range of 0 75 to 0 5 volts The voltage should go to zero when TUNE is released Press TUNE and adjust R12 for minimum output full counter clockwise Final Basic Version Checkout This completes testing of the interface board Connect it to the power supply rig and AH 4 Perform the following in circuit tests 1 Turn the power supply Adjust the rig for power output i e RF and mic gain turned down SSB mode Press the TUNE button Verify that the rig switches to transmit for about one second and then returns to receive The status LED should be flashing If this test fails verify that grounding the TX OUT line causes the rig to transmit Make darn sure you didn t connect the TX OUT line to something that either has voltages much higher than 13 8 or something that can source a lot of current like the power supply Place the rig in AM FM or CW mode Key
25. the rig and adjust the power until it is about at 10 watts Unkey the rig Press the tune button Verify that the rig keys on for several seconds then unkeys Verify that the status light is on Check the SWR It should be less than 1 5 1 If this test fails check wiring between the AH 4 and the interface Turn the RF power up to 120 watts or whatever the radio will do whichever is less Transmit Verify that the status light remains on and the SWR is less than 1 5 1 If not verify that RF is not getting into the control lines Reduce the RF output of the rig to less than 10 watts Change to a frequency where it is known that the antenna has a high SWR Press the UNTUNE key and verify that the status light goes off Key the rig and verify that the SWR is higher K9EQ AH 4 Universal Interface Rev 5 Page 10 www hamoperator com Final Full Version Checkout 1 Connect the interface to the radio Perform the following tests for those features that you intend to use or are connected See Installation section for connection details 2 Connect the rig to a dummy load and set it to SSB Turn the speech compressor off and adjust the mic gain to a normal position Monitor the RF output Press tune Verify that RF output is generated Adjust R14 to vary the output Key the mic Verify that there is no output 3 Use Digipan on the computer to key the radio select for keying the radio Verify that Digipan can key the radio If not
26. tor com Fig 1 Assembled Basic Board TOP 6 Y 25 a amp EM 7 PM Em D Optional components The following components are not required and may be substituted as follows with the corresponding change in protection RF immunity or feature Required substitute action and change is indicated short provides short circuit protection D6 short provides reverse voltage protection 11 13 short provides RFI protection D4 R6 open provides power on indication K9EQ AH 4 Universal Interface Rev 5 Page 7 www hamoperator com Figure 2 Component Layout TOP 000 3 9 einisLe cie e1 eim Yee 27 e Construction Notes Electrostatic warning U1 and U3 may be damaged by electrostatic discharge Ground your body using the appropriate equipment prior to handling these components or the board once these components are installed View the board conponent side up with lettering upright Refer to Figure 2 for parts placement Use the photograph on the cover of this manual for additional parts placement assistance It is recommended that you use DVM to verify the component values of the resistors A magnifying glass may be useful for reading other component part numbers and values When looking at the front
27. tput to about 10 watts Set the rig s mode to AM prior to tuning and hit the TUNE button Return the rig to your desired mode when tuning is complete and you are ready to operate This is a good method to use if you don t plan to use AM If you do use this method either turn R14 fully counter clockwise or omit resistor R15 since audio output is not necessary Full Interface Power output control The power output during tune may be automatically controlled via one or a combination of several techniques Use either the AM technique or the SSB audio output technique discussed under the basic interface above Disconnect the ALC feature if you don t plan to use it The ALC feature generates an ALC voltage during tuning The voltage can be adjusted in the setup mode by turning the power on while the TUNE button is pressed In this mode the rig will transmit and the ALC voltage will be generated when TUNE is pressed Set the rig to a carrier mode or use the tone feature with SSB Press TUNE and adjust R12 until an output of 5 to 15 watts is obtained on all bands you plan to use with the AH 4 Note that the ALC set point may change due to temperature band voltage and other K9EQ AH 4 Universal Interface Rev 5 Page 15 www hamoperator com operating conditions If you plan to use this mode I recommend mounting an adjustment pot on the interface enclosure panel not included Computer Interface If the interface is used with Icom equipment J
28. ved from the circuit The 4 uses 12 volt inverted logic and an open collector transistor to ground to perform signaling The radio provides 13 8 volts to the tuner It also provides a START line that is pulled up to 13 8 volts inside the radio The radio pulls the START line to ground to assert the signal start the tuning operation Similarly the AH 4 pulls the KEY line to 5 volts through a 22 kohm resistor diode combination The radio also pulls this line to 13 8 volts through a resistor The AH 4 pulls this line to ground to assert the signal indicate tuning status to the radio K9EQ AH 4 Universal Interface Rev 5 Page 23 www hamoperator com
29. verify that the RS 232 cable is wired correctly 4 Transmit with Digipan Verify that RF output is generated Adjusting R16 should vary the RF output Adjust audio levels on the computer if necessary 5 Connect the rig to an antenna Verify that Digipan shows signals on the waterfall display Adjust audio levels on the computer if necessary 6 Hey it works Go getsome of that DX Circuit Description Refer to the KOEQ AH 4 Universal Interface schematics L1 C1 L2 C2 and L3 C3 are used to filter RF that may be present on the control lines When the microprocessor U1 asserts START Q1 conducts with base current limited by This causes the AH 4 control line START OUT to be pulled to ground through D1 D1 provides protection against a reverse polarity connection Similarly when the microprocessor U1 asserts Tx Q2 and associated components cause the HF rig connected to L2 to key This design assumes that the HF rig is solid state and uses an approximately 13 8 V control line shorted to ground to key the transmitter If this is not the case for your radio additional interface circuitry may be required When the KEY IN signal from the AH 4 is asserted brought to ground Q3 conducts with base current limited by R3 When Q3 conducts the KEY line to the microprocessor U1 goes high D3 is an optional component that provides reverse polarity protection for Q3 R4 forces Q3 to a known state when the AH 4 is not connected The power sup
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