AM broadcast bands on all frequencies / bands (SDR2/SDRUno)
Posted: Fri Apr 05, 2019 5:53 pm
I imagine this topic has been beat to death but I didn't find anything specific using the search engine - not including the one on a very nice home built high pass filter.
My question/comment is two-fold:
a) my FT-950 receives nicely on 80 and 40 meters (all I've checked). Nicely meaning given my modest antenna situation. I can tune in on LSB voice transmissions just fine. However, the SDR2 is a different story altogether. Using the same antenna, I can see 10 KHz spaced AM signals on both the 80 m and 40m ham bands on the SDR2, even with the MW/FM filter selected (I"m using Ch A of the SDR2). The filter doesn't have any noticeable effect visually on the spectrum scope. I can select many of these AM signals and demodulate and hear the AM broadcasts - only slightly muffled. These AM broadcast signals are just burying any ham band signal reception. I could only barely hear one ham station transmitting on 3.915 MHz I think it was, but it was coming in a solid S9+ on my FT950. This is all just some observation for my upcoming question. I live near Dallas so I imagine there are lots of AM broadcast stations I guess.
Note: I can also select Ch B (with my antenna still connected to Ch A) and I can see the 10 KHz spaced signals on the spectrum scope but at a very low signal level (down below -140 or -180 on the spectrum display as I recall). I don't know if this is coupling from Ch B to Ch A internally inside the SDR2 or maybe I just need to terminate the Ch B input with a 50 ohm load. I also put some snap on type filters around the USB cable as well as the power cable to the mini pc right at the input to the pc DC input.
b) I plan to buy, if y'all can recommend it, a PAR BCST-HPF high pass filter. I know I could build something but I'm fine just purchasing something in the interest of time. If you have had success with this filter or one like it I'd appreciate your inputs.
Am I missing anything (besides reading the user's manual in more detail)? I believe I had low-IF selected but I haven't played around with much else.
Thanks for reading and any help you can offer.
My question/comment is two-fold:
a) my FT-950 receives nicely on 80 and 40 meters (all I've checked). Nicely meaning given my modest antenna situation. I can tune in on LSB voice transmissions just fine. However, the SDR2 is a different story altogether. Using the same antenna, I can see 10 KHz spaced AM signals on both the 80 m and 40m ham bands on the SDR2, even with the MW/FM filter selected (I"m using Ch A of the SDR2). The filter doesn't have any noticeable effect visually on the spectrum scope. I can select many of these AM signals and demodulate and hear the AM broadcasts - only slightly muffled. These AM broadcast signals are just burying any ham band signal reception. I could only barely hear one ham station transmitting on 3.915 MHz I think it was, but it was coming in a solid S9+ on my FT950. This is all just some observation for my upcoming question. I live near Dallas so I imagine there are lots of AM broadcast stations I guess.
Note: I can also select Ch B (with my antenna still connected to Ch A) and I can see the 10 KHz spaced signals on the spectrum scope but at a very low signal level (down below -140 or -180 on the spectrum display as I recall). I don't know if this is coupling from Ch B to Ch A internally inside the SDR2 or maybe I just need to terminate the Ch B input with a 50 ohm load. I also put some snap on type filters around the USB cable as well as the power cable to the mini pc right at the input to the pc DC input.
b) I plan to buy, if y'all can recommend it, a PAR BCST-HPF high pass filter. I know I could build something but I'm fine just purchasing something in the interest of time. If you have had success with this filter or one like it I'd appreciate your inputs.
Am I missing anything (besides reading the user's manual in more detail)? I believe I had low-IF selected but I haven't played around with much else.
Thanks for reading and any help you can offer.