[Kenwood] TS870 Band Data to switch Dunestar filters

[John Tait]

Subject: [Kenwood] TS870 Band Data to switch Dunestar filters

  Hi Bob..
                   This mod has been written up by Winfried Kriegl
DK9IP/KH7CD . You can see it at Joe Duerbusch K0BX 's excellent site at
http://www.qsl.net/k0bx/. Joe has lots of good mods and info at his site..
      Vy 73
          John EI7BA        http://www.iol.ie/~bravo/




> One area where Yaesu has always won out over Kenwood is in the provision
of
> 4 bit band data at an accessory outlet on the back skirt of the radio.  No
> such output has been provided by Kenwood so doing automatic antenna and
> band-pass filter switching has always been a problem.  Sure some logging
> programs provide band data output from the LPT port on the computer but if
> you are operating a multiple radio set-up and your computer crashes then
> your filtering can drop out and your radio can be fried.
>
> Today, I decided to solve this problem once and for all.  A quick look
over
> the 870 circuit and then a look at the rig itself gave me the answer.  The
> external ATU socket on the 870 is redundant, certainly as far as my needs
> are concerned.  I removed this (a very straight forward operation) and
> replaced it with a 9-way female Cinch connector to which I attached a very
> small piece of strip board on which I wired 6 npn open collector buffers.
I
> connected the buffer transistor bases via 5k6 1/4W resistors to the
> collectors of Q10, 11, 12, 14, 15, 16 on the foil side of the Final unit
> filter board using a piece of ribbon cable.  This was pretty easy too, as
> Kenwood put spare pads here which were very convenient.
>
> This simple mod gives me decoded & buffered band data output suitable for
> directly switching antenna selector relays and band-pass filters.
>
> Now this is WAY better than the Yaesu band data output as I don't need to
> invest in a Band Decoder.
>
> Whole mod took me about 2 hours.  If this is of interest to anyone I can
> probably put together some further details should anyone need them.
>
> 73
>
> Bob 5B4AGN, P3F, ZC4ZM
>
>
>
> - - -
>
> Your moderator for this list is:
> Larry Wilson KE1HZ kenwood-owner@mailman.qth.net
>
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>


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