[Elecraft] XV Series Transverter to TS-850

[Stan Rowe]

Hello everyone,
Is anyone using an XV transverter with a Kenwood TS-850? I'm particularly
interested in the possibility of connecting an XV50 to my 850, but I'm not
sure about making the proper connections to the 850's IF.
Thanks for any advice or suggestions.
Stan - K6VWE

[Martin]

Hello Stan,
the TS-850 lacks a possibility to (absolutely) safely connect a transverter.
However, a (unsafe) solution is described in the TS-850?s Handbook.

A better way to connect a TRV is to modify the RX/TX path inside the
TS-850. But this requires major changes to the connections inside and
4 additional bnc- or cinch plugs on the rear panel.
There is a nice article in www.mods.dk, unfortunately in german only.
Maybe the author has a english translation?

If you are REALLY interested, i would try to translate it for you, but
this might take some time.

I did the mod and can now connect whatever i want (transverter,
preselector, converter , rx-ant or other stuff).

[Martin]

JW> Hello Martin DL1IAQ:

JW> I have both a K2 and a TS-850S, and I would like to modify
JW> the 850 for transverter use at some time. I will look at the
JW> article in German at www.mods.dk. I can read German will
JW> some difficulty, but technical topics are more difficult for me.

JW> So, IF at any time you do translate the article, please could
JW> you send me a copy as well. It would be much appreciated.

JW> Thank you for sharing this information with the group.

JW> 73

JW> John, N6JW
JW> K2 #3290
JW> K1 #754.

John, the mod is not an easy job and you will dig deep in your ts-850.
There is no way to build it back to original.
Also, you will need the schematics and some brain.
I did the mod several years ago, i dont remember how long it took, but it was
pretty much work.

When you come to the point where you read ?Cut the cables?, please
be very careful and better think twice! The cables are short,
so cut them in a clever way. Maybe i switched the cables to obtain proper length,
i dont remember exactly. Before you cut any cable, check if they are long enough.

If you have tools and material to make new cables (a crimping device, cables and those tiny plugs
that are used inside the ts-850), you are safe.

Also, note that the lightning protection diode is no longer in the rx-path when a transverter
or other stuff is connected to IF IN!

Here we go:

Have your schematics at hand.

Looking at the rear of the TS850, you see -at the right side- several cinch-plugs ACC,ALC etc.
Between the 2 upper and 1 lower rows, there is enough space for 4 additional cinch-plugs.


How to do it:
Remove top cover.
Remove bottom cover.
Remove filter unit.
Unsolder pl-plug.
Remove rear cover.
Drill 4 holes for the cinch-plugs, about 16mm spacing.
Locate cables CN1 and CN2 on the IF-unit.
One of them leads to the RX/TX-relay-board. Cut it.
Solder both ends to 2 adjacent cinch plugs you mounted to the rear panel.
Mark them Ant out, IF in.
The other cable (DRV OUT) leads to the FINAL UNIT (FINAL IN). Cut and solder to 2 adjacent cinch plugs.
Mark them DRV out, Final in.

Double and triple check the connections. Is FINAL IN next to DRV OUT?
Is ANT OUT next to IF IN?
Check with the schematics.

Check again. If you goof here, you WILL destroy your rig when you transmit.

Thats it.

Install rear cover, pl-plug, filter unit, bottom cover, top cover.

For normal operation, the plugs have to be brigded- drv out<>final in ant out<>if in.

For transverter operation, drv out goes to the tx-path of your transverter.
Your transverters rx-path goes to IF IN. Remember: no diode!

For preselector-operation, use ant out and if in.

For rx-ant operation, use IF IN . Remember: no diode!


Good luck, and... Check the schematics!

[Martin]

Hello elecrafters,

a guy from the topband-reflector asked me to post this to the
elecraft-list.

--- Duane Grotophorst <***@yahoo.com wrote:


Or another approach is to build an external
attenuator that can handle 20W or so for the TX side. Then use
a separate RX IF line to the typical RX antenna of the
HF radio. I have been doing this with good success
with my Ten Tec Pegasus/Corsair radios for some time
now. I use DEMI transverters for 50-432Mhz at the
~100mw drive level. The attenuators that I'm using I
built myself from Vectronics 300W dry dummy loads. I
drilled a hole below the SO239 connector and then
added a BNC connector. Internally I built a "PI"
section attenuator with the 50 load as the input
leg, the other two resistors were 1/2W, I don't remember
the R-values of them off the top of my head but they
were from the ARRL Handbook. I started with 300W
dummy loads to accommodate high duty cycle modes like WSJT
to hopefully avoid having my attenuation value
change during long transmissions.

I build these attenuators to provide ~20dB of
attenuation, the exact value wasn't critical since
the DEMI transverters have 25-dB adjustment range of
their own. In the case of the Elecraft XV transverters
they can accommodate a few watts of input drive so the
level of attenuation could be some less (would
probably need higher wattage resistors for the other
2 sections of the PI in this case). I decided to go
this route because it allowed me to avoid having to dig
around inside the radio for low level TX signals it
also offered more versatility if I ever want use a
different radio as the IF without having to modify
it first. Another advantage is that the worst case
overdrive with a 100W radio would only be about
6-7dB, it may sound like garbage but the transverter should
survive such a mishap. I never liked depending on
ALC schemes or panel settings alone to keep me from
blasting the transverter with 100W of drive. Also by
using ~20W drive level the broadband TX noise of the
100W PA is also attenuated by the attenuator, with
an ALC based scheme that would not be the case, so I
believe this approach provides cleaner drive.
Obviously a low-level IF output from the IF radio is
the best if it's readily available, but that isn't
always the case.

Duane
N9DG

Grid EN53bj