Wide Pan-Adapter

There are several modifications available to access the lower IFs (intermediate frequencies) of the TS-2000. One common application is to build cheap pan-adapters / band-scopes by using SDRs (software defined radios) like the SoftRock or similar devices.

Most modern radios including the TS-2000 got roofing filters. They limit the passband
of the first IF stage of the radio, so the following amplifier stages and mixers don’t get overloaded by strong signals.

Unfortunately, with such a roofing filter, the bandwidth of the lower IFs and therefore
the panoramic display will only be a few kHz wide. The only way to avoid this limitation is to take the signal before it gets filtered by the roofing filter. The TS-2000 got two frequencies (75 MHz and 69 MHz) at the first IF stage, depending on what short wave band is selected. This will be out of range for most short wave SDRs, but fortunately there are some cheap DVB-T receivers on the market, which cover that frequency area very well. They can be used as a scanner, too, and only cost a few bucks. Search for “RTL USB dongle” at Google or Ebay (chip “RTL2832U” and tuner “R820T”). You get the needed software for free, “HDSDR” for example can be used as a panadapter software and even allows remote-controlling the TS-2000. See http://www.hdsdr.de
If you pefer Linux, “Gqrx SDR” might be a good alternative. See http://gqrx.dk/

The signals at the first IF are rather weak, and therefore it is not a good idea to connect the SDR input directly to that stage. This would reduce the sensitivity of your radio and probably make it deaf. So you need a small buffer amplifier board in between, with a high impedance at its input. Jack Smith offers such a board, called “Z10000”. You will find it here:
http://www.cliftonlaboratories.com/z10000_buffer_amp.htm
Because the board is rather small, shipping to Germany (and probably to other
countries) takes only about 2 US$.
About +4 dB gain should be enough. So R7 of the board should be 220 ohms. The USB dongles easily get overloaded, so keep the gain low. Even 0 dB should be fine (use 500 ohms for R7 then).

Please find the document to do the modification here:
Wide Pan-Adapter for the TS-2000

4 thoughts on “Wide Pan-Adapter

  1. I have taped into the first IF with one of the RTL Dongles and it works ok. But when I adjust the Low or High band width controls it moves the signals on the computer dislay.

  2. Thanks for your input, Denis. Yes, confirmed. It seems that only the HICUT setting affects the signal. Not a big issue, I think, because I always use a default setting with 300Hz LOCUT and 3000Hz HICUT and only change it in difficult situations.

  3. Carsten, you failed to mention what gain one should set the Z10000 for. I’m presuming that since it’s primary function is isolation and you do not want to overload the dongle, something like 3db to overcome losses would be appropriate?

    1. I got my Z10000b board already assembled by Jack, and he used +4 dB. (R7 with 220 ohms)

      Indeed the gain shouldn’t be higher, because the dongles easily get overloaded by big nearby signals. Perhaps even no gain would be enough, then R7 should be 500 ohms. I got a report that skipping the board also works, but this might bring in some noise into the signal path.

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