External keypad
Contents
1. There is a chance of damaging the radio if the 8V supply has been wired incorrectly Pins 1 2 3 5 6 and 7 on the front panel s round connector should be connected straight through to the same positions on the 8 pin round plug Pins 6 and 7 GND will be connected to each other In addi tion you should check the resistance between pin 3 and pin 6 when each of these buttons is pressed the ohmmeter reading should be as follows M1 button 1 5 KQ M2 button 3 0 kQ M3 button 5 2 KQ M4 button 9 9 KQ Freq DOWN 4700 Freq UP 00 PCARA Update September 2014 page 11 If all is well plug your microphone into the modi fied MFJ adapter then plug the adapter cable into your Icom transceiver s MIC socket Before you check opera tion you will need to enable External Keypad capa bility using the radio s Set Mode menu For the IC 7410 hold down the Menu button to enter Set we ww PA RA Mode then wed WVniporeal PEGO NOE Adinpier choose menu MFJ 1261 item 37 f External Keypad and change from the default OFF to KEYER SEND by rotating the VFO dial control For enabling of other Icom models check your radio s Instruction Manual Make sure that the four keyer memory buttons are working correctly along with the normal functions of the microphone PTT UP DOWN and microphone audio If you are using a headset which requires receiver audio from the radio you wi2. ee might have an Icom radio with an 8 pin modular jack I have provided a smaller diagram for Icom Modular Microphone Con nector to an Icom Modular Radio I have not been able to test this arrangement myself Sal SH IN fit eet a SHES a 7 gies a eE gt J J D g AAR ALAA al O oi PS Bow apu og aie ra ae a alameda Modified j jumper E me an Icom 8 pin round microphone connected to an Icom radio with 8 pin round MIC input epe ge ee e e y e e a T a a a i e e Le A L W iela eia a _ oe s mietan peana H H A 2 z u cae T 1 f EOI ae mi Jumper settings for an Icom modular microphone plug connected to an Icom radio with modular MIC input Step by step In order to setup an MFJ 1251 adapter for a straight through con nection first move the jumpers from lt their default settings onto new headers as shown in _ the appropri ate diagram see the photo along side for an example You should then carry out a continuity check with a multimeter on its ohms position to confirm the connections from the 8 pin round micro MFJ 1251 with modified jumper settings for an Icom 8 pin round microphone plug to an Icom 8 pin round MIC connector PCARA Update September 2014 page 10 phone connector on the front panel to the 8 pin round microphone plug on the supplied cable The important pins to check are 1 Microphone input 2 8V D
3. into the trans ceiver s MIC connector which will either be a screw on 8 pin round type or an 8 pin modular jack type Icom does not sell a suitable external keypad as an accessory for their HF transceivers but they do provide the circuit diagram for an external keypad in the IC 7410 Instruction Manual four different resistor values are connected between pin 3 UP DOWN and pin 6 GND of the 8 pin round microphone plug when a memory button is pressed 4 7 KO 2 2 kO 555 15hO 1 560 25 t5 Topin 555 Front view Schematic from Icom IC 7410 User Manual for an External Keypad that can access the four stored memories In recent years the BetterRF Com pany sold an i Mate external keypad for Icom radios The i Mate cost 85 and was wired between the existing microphone and the radio s MIC connector Unfortu nately BetterRF does not seems to be in business any more The i Mate external keypad was manufactured by BetterRF Do it yourself I decided to build my own external keypad but first I needed a suitable case for mounting the micro phone connectors plus the four push buttons for select ing memory contents At a recent hamfest I had spotted an MFJ 1251 Universal Microphone Converter This is a small metal box with front panel connec tors for both an 8 pin round micro phone plug and for an 8 pin modular a ei plug Separate Loo lce cables are pro vi
4. pin 3 and pin 6 locations Pin 1 is closest to camera up photo and accompany ing diagram The Icom HM 36 microphone has two buttons on top labeled UP and DOWN for changing frequency and memory channel I wanted these buttons to continue opera tion when connected through the MFJ 1251 adapter The UP and DOWN buttons work in a similar way to the memory keyer buttons the DOWN button connects MIC pin 3 through a 4700 resistor to ground pin 6 while the UP button directly grounds MIC pin 3 Pinout and wiring of the unused modular jack position J2 on the MFJ 1251 PCB component side 8 AF output varies with AF 7 GND Microphone ground oh GND PTT ground 4 Microphone input a 2 8 V DC output 3 Frequency up down I 6 PTT 4 Squelch switch Icom 8 pin round microphone connections as seen from the front panel From the IC 7410 Instruction Manual All you need to do to arrange for continued UP DOWN operation is to connect pin 3 of the 8 pin round MIC connector on the MFJ 1251 front panel to pin 3 of the empty modular jack position J2 A short length of wire can be soldered between the appropriate pins J2 pin 3 should already have one of the wires from the four push buttons connected to it via 1 5 KQ Final check Before you plug the modified MFJ 1251 into your expensive Icom radio take a moment to verify all the connections using an ohmmeter
5. C output 5 PTT 6 GND PTT ground 7 GND Microphone ground Next you will need to drill four holes for the momentary switches in the lid of the MFJ 1251 case For the Radio Shack switches holes should be 17 a diameter and spaced 4 apart Position the line of holes equidistant from the front panel and rear panel to avoid other components inside the metal case Mount the four Radio Shack switches in the holes then solder connecting wires and four resistors to the switches as shown in Icom s circuit for an external keypad The resistors I used 1 5 kQ two off 2 2 KQ and 4 7 kQ 1 8 watt came out of my junk box P p een dears age abe RE Chie cl tie The four momentary push button switches and four resistors are mounted in the lid of the MFJ 1251 metal case The components mounted in the top cover have to be wired to Pin 3 and to Pin 6 of the 8 pin round microphone connector output The easiest way to do this is to employ the empty position J2 which is pro vided by MFJ on the circuit board for an additional modular jack socket but which is not used in this par ticular prod uct J2 is located just beneath the front panel A 8 pin round connector Access for sol dering to J2 is available if you gently push the round connec tor wires out of the way see the close Close up shows two wires from the case lid switches soldered to the empty RJ45 modular jack position J2 at the
6. External keypad If you have an Icom HF transceiver then you might find this project of interest build yourself an external keypad for around 34 00 Key memories Recent Icom HF transceivers such as the IC 7410A and IC 7000 have a built in electronic memory keyer capable of storing up to four messages Some models also have a voice keyer to record short voice announcements The memory keyer can be helpful for sending your callsign and standardized contest exchanges for example CQ CQ de W2NYW W2NYW and 2A ENY Calling up the stored memories is carried out using soft keys positioned around the display You need to be in the correct part of the radio s menu system before these options appear On the IC 7410 the sequence is to select CW mode press the Menu button to reach Menu M1 press the F 4 KEY selection then press the F 2 SEND function key The four memory keys M1 M2 M3 and M4 then appear on the display This Habbo TUCO 1 741 pra ne 3 i m o id Icom IC 7410 display showing MENU key and function keys F 1 to F 5 ready to send from the four CW memories is not very convenient especially if you want to use the function keys for some other purpose such as the Band Scope Plug in shortcut Fortunately Icom allows connection of an exter nal keypad to call up memory keyer contents at any time This keypad is normally plugged
7. ded for con necting the adapter to either type of MIC socket on the radio The MFJ adapter allows one manu facturer s microphone to be used with another manu facturer s radio which is often wired differently Headers and jumpers inside the case allow for a variety of interconnections so that for example an Alinco microphone with a modular plug could be used with an MFJ 1251 Microphone Control Center from MFJ Enterprises PCARA Update September 2014 page 9 Icom radio having an 8 pin round MIC socket I thought the MFJ 1251 would provide a good basis for my external keypad At the ARRL Centennial Convention in Hartford I pur chased an MFJ 1251 adapter from MFJ s own booth The price was 29 95 Next day I pur chased a packet of four momen tary pushbutton switches from Radio Shack part number 275 1547 price 3 99 These are the normally open type Total so far 33 94 Radio Shack momentary push button switches The right connections The first task was to evaluate the circuitry of MFJ s Universal Microphone Adapter MFJ provides an Instruction Manual containing the schematic plus con nection diagrams for various combinations of micro phone plug and radio manufacturer My plan was to use the Icom radio s original HM 36 microphone with the matching 8 pin round MIC socket on the Icom transceiver Unfortunately that straight through combi nation is not included in the manual No
8. ll also need to manually wire pin 8 center pin on the round micro phone connector through to pin 8 on the output con nector in a similar manner to the wiring for the UP DOWN buttons External keypad with the four memory buttons M1 M4 suitably labeled F O F 1 fi p OE Universe a a FESTINA MVE Ready for some CW The external keypad based on an MFJ 1251 is shown in line with the Icom HM 36 hand microphone and cabled to the Icom IC 7410 8 pin round MIC input at bottom left Choose your Icom Bear in mind that different Icom HF transceivers may need some modification to these instructions especially if the radio has a modular MIC jack Check the radio s Instruction Manual for connections to the microphone for suggested circuitry of an external keypad and for the Set Mode menu item that will enable the external keypad Icom models with a memory keyer include the IC 746 Pro IC 756 Pro 2 and 3 IC 7000 IC 7100 IC 7410 IC 7600 IC 7700 and IC 7800 The high end IC 7700 and IC 7800 have a separate 3 5mm stereo input jack for their external keypad Best of luck with this little project My own exter nal keypad has already been put to good use for some DX CW contacts NM9J PCARA Update September 2014 page 12
9. t unexpected though Careful examination of the schematic showed that MFJ selects four wires coming in from the microphone for MIC GND MIC AUDIO MIC PTT plus the 8 volt DC feed to power any microphone circuitry labeled THRU PASS These four lines are then connected through appropri ate jumpers WI SIERRRIGLNI f Oe 3 to the correct Ce el in numbers CE AE IE on the radio s E OnI m HH HA MIC con wit a ee at ae a nector for al POR Siow am ae RADIO MIC gie DRON a R Fiinta N i GND RADIO se ee ees MIC AUDIO rr fat RAED tu f l lal l oo IN O10 RADIO PTT _ 98 of T T flap ie al ee va and the 1 THRU PASS E 8V DC line Ha The black ae ovals in the cdl diagram MFJ 1251 jumper settings for an Alinco alongside modular plug microphone connected to an show the Icom radio with an 8 pin round MIC input default jumper set tings for an Alinco modular microphone plug con nected to an Icom 8 pin round MIC connector In order to arrange a straight through micro phone connection for Icom to Icom all you have to do is combine the left hand side of the diagram for your micro phone con nector with the right hand side of the diagram for your radio s MIC connector See the accompany ing picture for an example for Icom 8 pin Round Microphone Con nector combined with the diagram for an Icom 8 pin Round Radio sim ss x atti ie tie 0 For readers who sas no
Download Pdf Manuals
Related Search