Spectrum Display

I wanted a spectrum display on my radio and this display had to be a waterfall display. Since the signal strength is displayed as color on the waterfall, you have a third dimension and this leaves the conventional 2D displays way behind. The obvious choice was to add a Software Defined Receiver as a Panadaptor. When you start talking about a Spectrum display or Panadaptor for a radio, you immediately think about IF out and the second receiver tracking the main receiver and there are several programs / radios out there that will do just that.

I went ahead and purchased a SDR-IQ from RFSpace and it was fairly easy to set SpectraVue up to track the IF on my TS-870. The IC-7800 does not have an IF out. I loved the waterfall display and the ability to see signals show up etc. but I soon realized that I did not like the tracking part all that well. Tracking was great when doing band switching, but I wanted to see as much of the SSB part of the band that I can and not necessarily have the display centered on my current frequency on the radio. So, if I am tuned to 14.160, I want to see 14.150 to 14.300 and not 14.085 to 14.235. This was fairly easy to do on the TS-870 which has a connection for an external receiver - i.e. it has splitter on the antenna. On the IC-7800 I had to add an external antenna splitter into the Rx signal path. So I would just set the SDR-IQ up as a conventional receiver connected to the RX out and have the center frequency of the display set appropriately.

This arrangement worked exceptionally well except for band or mode (CW/SSB) changes. Every time I change bands I had to go out there and manually re-enter the appropriate center frequency. I looked at the various software packages out there that will work with the SDR-IQ and I decided that I like SpectraVue the best - but it had no memory system that would allow me to store the various bands - so I had to keep a cheat sheet on the side and enter the center frequency every time I did a band change.

SpectraVue does have a defined interface that is published in section 3.1 of the manual. Since I am familiar with Visual Basic, I used that to develop a little side app that will:

This program is very specific in what it does and as such does it very well for me. It is not parameterized and have no setup - i.e. the US band allocations are hard-coded. If you are happy with all those restrictions, you are welcome to have a copy.

I am working on the next step - and that is for my program to act as a bridge between DxLab Commander and SpectraVue. If I change anything on the radio this information will get propagated through to SpectraVue.

There is also 'n bonus that I can demodulate 2 in-band signals in the SDR-IQ.

Here is a comprehensive set of links to the various SDR's out there.