Waterfall for external SDR Panadapter?

Hello, I have an IC 7100 with an IF tap installed. I’d love to have Wfview display the waterfall. Currently I’m using HDSDR/OmniRig to view the waterfall.

Thanks! and 73 de K0LOD - Tom

Hi Tom,

How are you measuring from the IF tab? RTL-SDR dongle?

wfview does not have this capability yet. We are simply reading out from the radio’s provided spectrum display. However, I can see adding somethings like this in order to expand the supported radio list considerably. There are many SDRs which provide I&Q streams, for example, and from that one can Fourier Transform and get a nice spectrum display.

If you’re using an RTL-SDR for the IF sample, there may be a way to remotely grab that data.

de W6EL

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Hi Elliot,

I am using an RTL SDR dongle. I am tapping the 1st IF with a frequency
of 124487000 Hz for the 7100.

Thanks for all your great work!

All the best,

Hi Tom,

How much bandwidth do you get on that? This is interesting. I have an IC-718 coming in the mail next week, may have to look into this.

I believe there is a way to stream from the rtlsdr command-line program to an instance of GQRX, but I have not tried it out yet. It would be an interesting experiment for sure! Let me know if you try it.

de W6EL

Hi Elliot,

I can view the band of interest and beyond.

Here’s a link to the IC-718 tap: https://robs-blog.net/Files/IC_718_Panadapter_Mod.pdf I’d consider using a PAT-70 board instead of a capacitor. Panoramic Adapter Tap (PAT70M) Board for 70 MHz IF Transceivers FT857, FT897, FT1000, IC703, IC706, IC756, IC7410 etc

GQRX looks interesting. I’ll have to brush up on my Linux-Fu.

73 de K0LOD

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This is pretty cool!! So you can see the entire ham band of interest, that’s what, at least 500 KHz? Pretty sweet.

I’m seriously getting excited about my beat-up IC-718 ebay special (“for parts / doesn’t work”) which arrives some time next week. I think it’ll work well enough for my enjoyment.

I was thinking of building a little high-speed buffer inside, say with the AD8007 amplifier (have experience with this part).

Now I wonder, what will demodulate better, the RTL-SDR or the Icom’s built-in analog demodulator?


de W6EL

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I have been using a ‘new to me’ IC7100 in competitions for some months now. I added an IF tap with an AirSpy SDR receiver. I added an SMA connector at the front of the rig for connecting the AirSpy. A local PC running HDSDR and OmniRig controls the IC7100 via USB. You just have to set up the IF frequency in HDSDR to get exact frequency readout on the waterfall. I usually listen to the audio from the IC7100 direct, but can use the HDSDR receiver - there is more latency via HDSDR, since it is a fairly old miniPC. My main use is the waterfall and clicking on it tunes the IC7100. Mouse or spacebar is the PTT. Only quibble is that I can’t get the S meter on HDSDR to agree with the IC7100 S meter - if I drop the gain of the AirSpy to match the two, then the waterfall is not sensitive enough, so I have to put up with an S9 noise level on HDSDR. I’m sure the combination is nearly as good as any radio with a built-in waterfall. I’m just hoping that I can use wfview to control the PC and rig remotely.

Hi Tony.

wfview can only display the waterfall for rigs that generate it (IC705, 7300, 7610, 9700, 785x and R8600). All other rigs will get a display without waterfall from wfview.

73 Phil

Hi Phil,

Thanks for your reply - I understand of course that the 7100 doesn’t generate a waterfall, but wondered what extensions to the software could be used to pick up the waterfall generated by HDSDR from the 7100 IF tap. Perhaps I have to look at what network sharing I can do with HDSDR.


HDSDR is windows only. That would break compatibility across the current platforms.

You could set up a local windows system that runs HDSDR, connected to your 7100 and export the window to your remote end so that you still see it. Good examples of software that can do this are vlc, teamviewer or nx nomachine (preferrably but seems that everyone loves vlc, teamviewer etc)

ps “I added an SMA connector at the front of the rig for connecting the AirSpy”

for the sake of my understanding, you mean the body, not the head?

Hi Roeland

Thanks for the suggestions. Yes - I use the 7100 on my desktop with the control unit on top, so the main unit isn’t hidden.