SDR-IQ with a ICOM IC-R7000???

[JohnBreen]

Hello,

I discovered a piece written by Lindsay Blanton:

RadioReference Blog: VHF/UHF Spectrum Analysis using the RF Space SDR-14

That article both interests and confuses me. Lindsay wrote that he uses a RF Space SDR-14 and the SpectraVue software with his AOR5000A and he reports some VERY interesting results. Lindsey's article mentions that the RF Space SDR-14 has an upward frequency limit of 30 MHz - how then can the RF Space SDR-14 work with the AOR5000A to provide a VHF/UHF spectrum display (greater than 30 MHz)???

I have been using my Yaesu FT-950 with the RF Space SDR-IQ and SpectraVue software for some time with wonderful results. The computer control with spectrum display and "point and click" tuning is wonderful. I have recently been gifted a ICOM IC-R7000 and two IC R100's. Of course the IC-R7000 has a jack on the rear panel that taps directly into the 10.7 IF for use with a computer. Having grown very fond of the spectrum display for my FT-950, I would really like to set up my SDR-IQ to provide a spectrum display for my "new" IC-R7000. But how is that possible since, like the RF Space SDR-14, RF Space SDR-IQ has an upward frequency limit of 30 MHz?

Has anyone here tried this match-up before and how did Lindsay Blanton get his combination to work with the great results reported in his article? Any suggestions, input or guidance would be greatly appreciated.

Best regards, John (N3JPB)

 

[KC1UA]

See my other post, but the AR5000 communicates with spectravue via its serial port, and allows for actual frequency display and tuning when a signal spike is clicked on. As I mentioned in the other post the SDR is actually tuned to 10.7 MHz, which is the output of the AR5K's IF output (or your R7000's).

Your R7000 would work fine with the SDR-14 as well, but would not be able to display actual frequency info or be automatically tuned to a signal by clicking on it. As I mentioned in the other thread you'd have to spin your VFO to move the signal spike to the center of Spectravue's screen and thus tune it. Still an extremely effective way of finding unknown signals, just not as elegant as the AR5K/SDR-14 combo.

 

[toad99]

The R7000 uses the CI-V bus control interface. I use the ICOM RS232 to CI-V converter to control my R7000 with the Spectravue software. The baud rate is pretty slow (1200) but it works if you don't spin the tuning knob too fast. For non-demodulating spectrum sweeps, I limit the visual display to about 3 mHz since there seems to be a couple of spurious spikes outside this range (Using an SDR-14). Of course, you can also just use the radio's demodulators. You can find several home-brewed CI-V converter diagrams on the web or maybe get a used one on Ebay. Your computer would also need a serial port.

 

[prcguy]

I connected a spectrum analyzer to the 10.7MHz IF out on my Icom R7100 and was very disappointed with the results. The gain of the IF out is controlled by the radios AGC and as you find a signal off in the corner of the analyzer and tune towards it the AGC grabs the signal as it enters the IF filter passband and the signal is greatly attenuated on the analyzer display when your tuned to the frequency and the signal is centered on the analyzer. It makes connecting a spectrum analyzer or SDR to the IF port basically useless. I suspect the Icom R7000 will work the same.
prcguy

 

[toad99]

As an addition to my previous post, if you control the R7000 with the software, the slow baud rate is not much of a problem since you are most likely to click on and interesting signal, which will instantly tune the R7000 to it and center the sweep on the computer display. You can also tune the radio with the frequency dials in the software.

 

[toad99]

I don't see this behavior on my SDR-14/R7000 combination. Since the signal meter is basically showing you the effect of the ACG, the IF gain of the radio should not be affected by signals outside of the last IF filter bandwidth. When I tune directly onto a strong signal, then the IF gain is reduced along with other signals that I may see at the 10.7 mHz output.

 

[JohnBreen]

This is interesting,

KB1UIF says:
February 26, 2013 at 4:43 pm
I connected the HF Ham it up converter and dongle to an Icom IC-R7000′s IF output after blocking the 9v DC out from the IF Out and it worked quite well as a pan adapter, my Icom also has an HF module installed so I can use it from dc to light. Next I will try it with my Ten-Tec Jupiter after I add the IF output to the Jupiter as there is no IF out as standard.
The IF freq out of the Icom was 10.7MHz so I tuned the Ham it up and Dongle to rx that frequency with SDR# and left it there, and tuned the Icom. Bingo instant pan adapter!!