[Yaesu] Update on the FT-1000D RX Mod. de K0FF

Thu, 9 Mar 2000 17:57:19 -0600

-----Original Message-----
To: Yaesu@contesting.com <Yaesu@contesting.com>
Date: Wednesday, December 01, 1999 6:08 PM
Subject: Here is the FT-1000D Mod. de K0FF

>The goal>>>To modify the FT-1000D  ( or FT-1000 w/ BPF option) for
>independent operation of both receivers on unrelated bands and/or modes
>using the main antenna and retain the ability to use a Beverage antenna on
>the RX ANT jack.
>Of course, the 1000D already has the BPF option, it's just not hooked up
>A little history:
>The FT-1000D has 2 receivers, 2 audio channels, a common squelch and an
>S-meter on the main receiver only.
>When an internal switch (S1001) is in the RX ANT position, the main
>can pick up it's signal from the antenna hooked up to the Transmit antenna
>jack (SO-239) or a
>separate receive only jack (RCA pin-type), and can be switched between the
>two via a front panel switch marked "RX ANT". The Sub receiver listens in
>whichever antenna the Main one is hooked to, and also must use the Main
>receivers BandPassFilter (MainBPF). This limits frequency excursions to the
>same band.
>The sub-receiver has it's own Band Pass Filter section, which has it's own
>input jack (SO-239), but can only use those when you take the radio apart,
>and operate
>a slide switch "S-1001" to the "F BPF" position. Of course this means you
>must ALWAYS use a different antenna to receive on or you can still operate
>The RX ANT switch, and it will listen on the Beverage hooked to the RCA
>jack. You lose the ability to listen on the transmit antenna. Also you lose
>the ability for the Main Receiver to pick up the Beverage!
>The mod moves the control of relay RL1004  the front panel, brings the TX
>antenna >> on the receive side of the TR switch<< out the back, and ties
>that back into the BPF via a small jumper. This way tou can listen to 2
>separate bands on the transmit antenna (say 10 and 20 on a triband beam),
>and not lose the RX Ant (BEV) function.
>Fortunately these functions are all controlled by relays, and they can be
>split, and operated independently. In the old days we would get out the
>soldering iron (gun, actually) and an electric drill, and just do it. Today
>we have to preserve resale value, so no extra holes please!
>Mod consists of adding 2 Jumpers, remove one plug, and remove one resistor.
>You will also need a 6" coax cable with PL-259 one end, RCA plug opposite.
>You lose the DIM (display dim) button function on the front panel , and
>the Monitorscope 73Mc IF output jack function on the rear apron. (do they
>even make a monitor scope??)
>No functional loss to the radio at all, and you gain the ability to:
>A)  Use the sub-receiver with a separate antenna connected to the BPF
>option's SO-239 on any band. (great for "Antenna Diversity Reception" - I
>use this approach on 6M with transverters).
>B)  Use the sub-receiver on any band/mode using the main TX-RX antenna,
>independent of main receiver's band/mode.
>C) Connect a different receiver to the FT-1000D, outboard style, using the
>main TX-RX antenna. ( an adaptation to the mod would allow the outboard RX
>to share the RX antenna too, if desired)
>D) Use the main receiver on either the TX antenna, or RX antenna while
>any of the above.
>The reason I did it was to listen to the 28.885-6 meter liaison frequency
>concurrent with the 14.345 EME circuit. You may want to run a VHF/UHF
>receiving converter into the sub-receiver as a 14 Mc i.f. to monitor some
>important calling frequency, or propagation indicator, while chasing DX on
>2M EME via a transverter with a 28 Mc i.f.
>.....the possibilities are endless.
>WHAT you are doing is freeing the wiring from the DIM button, rewiring the
>DIM button so as it will operate relay RL1004 on the "RF UNIT" board,
>effectively panel remoting switch
>"S-1001", and providing a connection to the outside world for the main
>antenna from the receive side of the TR relay, via the abandoned IF jack on
>the rear apron.
>First lets get at the DIM switch on the front panel....
>Remove both top and bottom covers. Remove all the screws holding the front
>panel/display in place. Remove the small circuit board that contains the
>MOX-VOX-DIM switches. There is a socket and plug going there for the switch
>marked DIM (has 2-pins 1-red wire, 1-white wire). Remove the plug, and tape
>it back out of the way. We won't use it for anything, just save it there
>retro.This leaves the switch free, and it already has one side going to
>ground through the pcb wiring. Leave all that alone, and solder a long lead
>to the other terminal. The one that switches to ground when you toggle the
>button.This wire gets routed all the way to the bottom rear of the radio to
>the corner near the grounding lug. The board we are working on is the one
>in that corner, and has a large flat, silver box on it. That's the "RF
>In the far back corner on the top of the board are some relays. The one we
>want is marked RL1004 and there is a diode across the coil, D1050. Solder
>our wire to the anode end  (the end opposite the line). Be careful here.
>The other side goes to +13, so check this out carefully beforehand. Simply
>pushing the DIM switch in will now activate the relay, and releasing the
>switch will deactivate the relay. Not Rocket Science but be careful.
>At this time make certain that "S1001" is in the R ANT position where it
>will always remain.
>Next we have to loosen the "RF UNIT" board and turn it over to do the
>jumpers. You will have to remove some screws, and take a few plugs loose.
>Label everything or make a chart so it gets back in the right place. Not
>everything needs to come loose to do this.
>Turn the board over and examine the area around J1013-1, the IF jack, in
>cluster of four RCA pin jacks on the rear of the board. On the solder side
>of the board it series connects to a chip capacitor, and then a zero ohm
>chip resistor. Remove the chip cap and store it for retro. This effectively
>frees the jack up so we can run a short jumper wire from the center pin of
>it, to the center pin of the little coax jack J 1005, which is next to
>RL1001. That's how we bring the main antenna
>out of the set and send it to the outboard receiver, or in our case to the
>sub BPF filter unit.
>That's all, very carefully put it all back together again.
>Install coax cable jumper between the (old) IF jack and the SO-239 on the
>BPF filter.
>Now you can experiment with the functions.
>The panel switch RX ANT continues to take the main receiver between the T-R
>antenna and the RX (Beverage) antenna as before.
>The DIM switch now puts the sub receive between being slaved to the main
>or it's own BPF.
>The coax jumper on the back brings T-R antenna back out for the sub BPF if
>desired (and it will be most of the time).
>Note that you can still use the sub-receiver on the Beverage also, but only
>when the main is too (stock condition). This is the place where you could
>add the adaptation I mentioned in step (C) above, but I see no scenario
>where you would want the sub on Bev without the main on Bev also. If you
>have an individual need for this, contact me.
>This effectivly puts the 2 receivers in parallel across one, antenna, and
>though some loss might be inroduced by double loading, signal generator
>tests show that they are negligible.
>I have tried this and it works but make no recommendations as to the
>suitability of this mod. I have tried to be precise but it is up to you to
>check for errors in application or omission..
>Throughout this and other tech notes that I write, I use the unit Mc/s or
>Mc. If you can only deal in MHz, multiply by 10 to the minus 1, or I will
>glad to provide a free conversion chart for an SASE to my callbook address.
>This simple change should unlock the full potential of this fine radio.,
>which was arguably already the finest I.F. for VHF/UHF transverting.
>Geo, K0FF

FAQ on WWW:               http://www.qsl.net/k7on/yaesu.html
Submissions:              yaesu@contesting.com
Administrative requests:  yaesu-REQUEST@contesting.com
Problems:                 owner-yaesu@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm