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Author Topic: Panadaptor question  (Read 584 times)
FOXBAT426
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Posts: 381




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« on: May 19, 2019, 09:58:57 AM »

I would like to incorporate a panadaptor into my dxing. I've been away from the hobby for awhile and in the past owned a Flex SDR 1000, which I liked very much. I currently own a Yaesu FT-950 what seems like a good rig for adding a panadaptor via an RTL dongle. I would like to  hear from hams that have used both a traditional rig with a panaadaptor and also a dedicated SDR radio such as a flex or Icom 7300.  were there big differences in performance? Would the traditional rig/panadaptor combo via the rtl dongle allow for using the extended filtering provided by the panadaptor software such as in HDSDR? How does the sensitivity in the amplitude of the signals compare between the two set-ups?  I would like to be able to see weak signal DX with the ability to just click on signals. would it be better if I just bought a dedicated sdr rig like a 7300 or flex radio. Will I get the same performance with the FT-950/rtl combo? I will admit there is something nice about having a traditional radio right in front of you.

73 and good dx!    john
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K7RJB
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« Reply #1 on: May 19, 2019, 10:12:50 AM »

I don't see a IF output on the FT950.

Is there a mod kit to bring it out?

It seems so...  https://nt1k.com/my-ft-950-now-has-sdr/
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FOXBAT426
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« Reply #2 on: May 19, 2019, 10:17:58 AM »

yes, but you have to open the radio to access it. its not broken out on the back panel like some rigs.
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KD7RDZI2
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« Reply #3 on: May 19, 2019, 11:19:37 AM »

In principle you could pick the signal from any of the three IF at 69.450 MHz/450 kHz/30 kHz.
69.450 is fine for the RTL dongle but the ADC is just 8bits allowing a dynamic range of only 48db or so. That is really mediocre. You will easily overload it. I would prefer other receivers with at least 14bits ADC
450 kHz would need a converter such as http://www.sat-schneider.de/download/Mixerflyer.pdf
30 kHz needs nothin' just a 96Khz sound card.
Depending on how wide you would like to have the spectrum you can decide where to pick the signal. See the block diagram and choose.
In any case I would put a buffer amplifier (also homemade) between the IF and the converter or the sound card to not decrease the signal of the rig.
I have never had a FT950 but I did modify in 2003 a triple conversion Drake 2C made in 1967 and got stunning results either with  the 450 kHz converter or tapping the last IF at 50Khz. In my case I preferred the 450 kHz converter solution. Using Quisk on Linux I use this solution not just to see the spectrum but I use it as the main receiver. The difference is rather terrific.

Having said this the LP-PAN solutions appear to me very well thought.
« Last Edit: May 19, 2019, 11:25:50 AM by KD7RDZI2 » Logged
VE3PP
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« Reply #4 on: May 19, 2019, 05:25:03 PM »

yes, but you have to open the radio to access it. its not broken out on the back panel like some rigs.

You do not need to open the rig and add the IF board if you don't want to.

I have fed my SDR PLay RSP1A by using the uTune jacks and engaging that feature.

I do the same on my FTDX-1200 now.
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FOXBAT426
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« Reply #5 on: May 19, 2019, 08:28:11 PM »

Very interesting. Can you point me to some instructions on how to connect this up and get it to work properly?   Thanks. John
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KB1GMX
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« Reply #6 on: May 20, 2019, 09:50:39 AM »

In principle you want to pick off the sample signal before any filter in the radio is applied
or the result is outside the the filter bandwidth you will see substantially little of the band.

So the pic off point is before the 69.45mhz filter.  After that filter anything 15khz or more
off the filter center frequency will be attenuated.  The further down stream you go the
 more the radios built in slectivity will make seeing the full band difficult.

As to the particulars of connecting that for your radio you need to consult mods DK or other site.
Likely there is a published mod for that.

Allison
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KB8E
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« Reply #7 on: May 20, 2019, 09:59:12 AM »

Allison is correct, what you'll see on the panadapter is limited to the spectrum passed by the filters preceding the tap-off point. The correct point would be before any IF filters.

Sam
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KD7RDZI2
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« Reply #8 on: May 20, 2019, 12:05:53 PM »

Allison is correct, what you'll see on the panadapter is limited to the spectrum passed by the filters preceding the tap-off point. The correct point would be before any IF filters.

Sam

Provided that Allison is ALWAYS correct Grin ,  the correct point depends very much on the purpose. If you want to use it merely to have a spectrum I agree with you unless there are no side effects like overload etc. If you want to actually use it as an additional receiver I might prefer after some filtering. If you want to exploit all the filters up to the last IF stage the SDR software adds additional DSP filtering, notch, noise blanker etc.
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