So a while ago, I posted about some issues I was having with SDRConsole and my IF tap. I've moved on from SDRConsole and am now working with HDSDR.
I've discovered after playing with some settings, some signals I wanted, and a BIG signal I didn't want. My radio. So, hopefully I have this posted in the right spot...not always sure where to put these Cross-Topic posts.
After waiting for well over a month, for SOME kind of response from the manufacturer of the IF tap, I finally get a response from them.
After some words basically pointing out what a "Novice" I was with IF taps and HDSDR (wow), here's what he had to say: "When powering down the buffer it does not mean that the SDR receiver will never detect the transmitted signal. If you do some simple calculations, if your transmission power is 10 W, i.e. 40 dBm and your receiver sensitivity is -120 dBm, to not hear any signal you should be able to provide at least a 160 dB isolation between the transmitted signal and the input of the external receiver (SDR)."
Of course he didn't give an example of how he calculated this. Math is my WORST subject. Using an online watt to dbm calculator, 210 Watts PEP (SSB) comes to roughly 53.2 dbm. This is amplifier on. With my amplifier off, my PEP on SSB is 18w or roughly 42.5 dbm.
My little experience thus far tells me it might be easier to get rid of, or "not hear" my signal with the amplifier off, versus on. So how do I accomplish this in HDSDR, if it is in fact a setting in HDSDR that can be adjusted to fix it? Of course, if it is possible to do it with the amp on, it would be better. Assuming again, of course, this can be fixed with a setting in HDSDR, and not some physical alteration I need to make to my station.
Now then, there also comes the issue of the blown out SDR dongles. It seems that it's possible that it's not RF that's damaging the SDR dongle. This is where someone with some electrical knowledge can help. Here's what he had to say about that: "It's more probable, instead, but this should be verified with some lab tests, that there was a voltage difference between the radio and the computer. When you connect your dongle to the USB port, the reference potential (simply known as GND) is the one of the computer. It can happen that the radio has a different reference potential and when connecting the radio to the dongle overvoltage can reach the receiver. But this is not related to the IFace, but instead to the lack of an equipotential wire between the radio and the computer."
Is he basically telling me that I need to attach a ground wire from the radio to my computer? Are there any potential problems anyone can think of that may arise from doing this (if it is, indeed what I think he's telling me)?
TIA for all your help...I'm so close to getting it all dialed in I'm excited again, and not left feeling hopeless!
I've discovered after playing with some settings, some signals I wanted, and a BIG signal I didn't want. My radio. So, hopefully I have this posted in the right spot...not always sure where to put these Cross-Topic posts.
After waiting for well over a month, for SOME kind of response from the manufacturer of the IF tap, I finally get a response from them.
After some words basically pointing out what a "Novice" I was with IF taps and HDSDR (wow), here's what he had to say: "When powering down the buffer it does not mean that the SDR receiver will never detect the transmitted signal. If you do some simple calculations, if your transmission power is 10 W, i.e. 40 dBm and your receiver sensitivity is -120 dBm, to not hear any signal you should be able to provide at least a 160 dB isolation between the transmitted signal and the input of the external receiver (SDR)."
Of course he didn't give an example of how he calculated this. Math is my WORST subject. Using an online watt to dbm calculator, 210 Watts PEP (SSB) comes to roughly 53.2 dbm. This is amplifier on. With my amplifier off, my PEP on SSB is 18w or roughly 42.5 dbm.
My little experience thus far tells me it might be easier to get rid of, or "not hear" my signal with the amplifier off, versus on. So how do I accomplish this in HDSDR, if it is in fact a setting in HDSDR that can be adjusted to fix it? Of course, if it is possible to do it with the amp on, it would be better. Assuming again, of course, this can be fixed with a setting in HDSDR, and not some physical alteration I need to make to my station.
Now then, there also comes the issue of the blown out SDR dongles. It seems that it's possible that it's not RF that's damaging the SDR dongle. This is where someone with some electrical knowledge can help. Here's what he had to say about that: "It's more probable, instead, but this should be verified with some lab tests, that there was a voltage difference between the radio and the computer. When you connect your dongle to the USB port, the reference potential (simply known as GND) is the one of the computer. It can happen that the radio has a different reference potential and when connecting the radio to the dongle overvoltage can reach the receiver. But this is not related to the IFace, but instead to the lack of an equipotential wire between the radio and the computer."
Is he basically telling me that I need to attach a ground wire from the radio to my computer? Are there any potential problems anyone can think of that may arise from doing this (if it is, indeed what I think he's telling me)?
TIA for all your help...I'm so close to getting it all dialed in I'm excited again, and not left feeling hopeless!
Last edited:
