Scott
Those were some great and intelligent replies.
Those were some great and intelligent replies.
R2500 and 10.7 MHz IF Output
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Has anyone used the 10.7 MHz IF mod with a spectrum display unit? There has been some conversation in the SDR-14 Yahoogroup indicating that the 10.7 MHz IF mod done to the PCR1000 is "unusable" for spectrum display. Obviously we're talking about a different radio here, but is the 2500 similar enough to yield similarly negative results?
Scott, I'm using the IF Outputs on my 2500's for the Digital Voice Conversion Method. At some point I might purchase another one and use with a spectrum analyzer setup, however I'm not at that point just yet.
I recall Eric's testing with a probe attached to his SDM-42A showed signals +- 5 MHz from center, and that he could see clusters of signals moving on the display as he tuned his 2500, but I wonder how many spurs were in there as well. It must be reasonably clean given that you're doing what you're doing with it, Lindsay. I'm just going to have to get it done and see what happens, I guess.
Thanks.
Thanks.
10.7 MHz IF Output Report
Hello,
I had the 10.7 MHz IF mod completed by a tech at the Woods Hole Oceanographic Institute (read: someone that excels at such things) and just got it back today. I have had the opportunity to interface it with a spectrum analyzer. The output is indeed VERY strong, to the point that I had to attenuate it 10 db, which made a distinct display improvement. The output also seems to be quite clean. I've looked at VHF-HI, UHF, UHF-T, 800, and 900 MHz bands with it. I saw one spur on VHF-HI, and have yet to see any elsewhere. As was stated before the IF output works in all modes. I copied the text and photos from the mod that Lindsay completed (thanks to W1PC for his input also) and the exact same steps were taken.
With the above in mind it seems apparent that this will work just fine for spectrum analyzers and/or spectrum display units that will take a 10.7 MHz IF input.
I have compared my R2500 with an Icom IC-R7000's 10.7 IF out as well. The output of the 2500 is definitely stronger than that of the R7000. Weaker signals seem to be more evident with the R2500 than they are with the R7000.
Hopefully this will encourage folks that wish to use these radios for spectrum analysis. Thanks to all that participated!
Hello,
I had the 10.7 MHz IF mod completed by a tech at the Woods Hole Oceanographic Institute (read: someone that excels at such things) and just got it back today. I have had the opportunity to interface it with a spectrum analyzer. The output is indeed VERY strong, to the point that I had to attenuate it 10 db, which made a distinct display improvement. The output also seems to be quite clean. I've looked at VHF-HI, UHF, UHF-T, 800, and 900 MHz bands with it. I saw one spur on VHF-HI, and have yet to see any elsewhere. As was stated before the IF output works in all modes. I copied the text and photos from the mod that Lindsay completed (thanks to W1PC for his input also) and the exact same steps were taken.
With the above in mind it seems apparent that this will work just fine for spectrum analyzers and/or spectrum display units that will take a 10.7 MHz IF input.
I have compared my R2500 with an Icom IC-R7000's 10.7 IF out as well. The output of the 2500 is definitely stronger than that of the R7000. Weaker signals seem to be more evident with the R2500 than they are with the R7000.
Hopefully this will encourage folks that wish to use these radios for spectrum analysis. Thanks to all that participated!
Another note on this IF output modification. On checking, I discovered about 3.7 volts DC on the output.
This is good news Scott, thanks for the updates.
BTW, what Spectrum Analyzer are you using?
BTW, what Spectrum Analyzer are you using?
I originally tested the tap with a Madell AT5010, and after some thought decided to go back to an SDR-14, which is just an awesome piece of gear. It works very nicely with the R2500. I haven't got to the point yet of trying to make the SDR-14 think it's talking to an R8500. Not sure how similar the command set is or if it would work. I'll try that sometime in the near future.
Thanks Scott... I think I'll have to invest in an SDR here in the spring.
scancapecod said:
Actually now that I think of it this probably won't work. If the 2500 is interfaced with the computer it's already running Icom's (or TrunkPCR) software, so I doubt the SpectraVue software for the SDR-14 would talk to it. When the 2500 runs standalone it has no connection to the computer. SpectraVue controls the radio using the radio's serial connection to the computer, or in this case it would be the USB connection that shows up as a COM port.
That aside the combo does work well when the SDR-14 is used as a simple panadapter. There are some spurs, but such is the case when using other radios such as the R7000, R8500, and AR5000. They're easy enough to work around.
You'll like the SDR-14, and it's a very good shortwave receiver as well.
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