FM-Notch Filerer by RTL-SDR?

[iMONITOR]

How does RTL-SDR's FM-Notch Filter compare to others like PAR Electronics, or Stridsberg's? Over the years I've used FM-Notch Filters manufacture by PAR Electronics and Stridsberg with great results. I opted for the RTL-SDR this time as I was using it with an SDR that has SMA coax connectors on it. It doesn't appear that PAR has SMA as an option, however Stridsberg does, but it cost $115.00 and the RTL-SDR cost only $14.95. To be fair the RTL-SDR was sourced from CHINA. PAR and Stridsberg are made here in the U.S.

I know the RTL-SDR is popular but is it any good or is just inexpensive? For those of you that use the RTL-SDR Notch Filter how well does it work? Has anyone performed any actual test? I want it to block the FM 88-108 MHz band well, yet I don't want it to weaken the VHF air-band at all. Any feedback is appreciated.

PAR Electronics---------Stridsberg------------------RTL-SDR-----

 

[737mech]

I've had Par FM trap for years and tried the rtl-sdr. Even tried them together inline. I think the RTL-SDR is functional but like you said the SMA need adaptors and I don't like making too many changes with adaptors. Especially when your feedline is Belden 9913 or LMR 400. I have no experience with any Stridsberg products so I can't comment on them.

 

[dlwtrunked]

How does RTL-SDR's FM-Notch Filter compare to others like PAR Electronics, or Stridsberg's? Over the years I've used FM-Notch Filters manufacture by PAR Electronics and Stridsberg with great results. I opted for the RTL-SDR this time as I was using it with an SDR that has SMA coax connectors on it. It doesn't appear that PAR has SMA as an option, however Stridsberg does, but it cost $115.00 and the RTL-SDR cost only $14.95. To be fair the RTL-SDR was sourced from CHINA. PAR and Stridsberg are made here in the U.S.

I know the RTL-SDR is popular but is it any good or is just inexpensive? For those of you that use the RTL-SDR Notch Filter how well does it work? Has anyone performed any actual test? I want it to block the FM 88-108 MHz band well, yet I don't want it to weaken the VHF air-band at all. Any feedback is appreciated.

PAR Electronics---------Stridsberg------------------RTL-SDR-----
View attachment 106760 View attachment 106761 View attachment 106762

Attached is from some tests I did. I did not keep save the results for the RTL-SDR or for the Digikey that I tested as the results were clear that the Mini-circuits was clearly superior in both notch level and notching the appropriate range. Note that other filters I checked did noticeable undesirable attenuation in some UHF frequency ranges. As a result, I bought several Mini-ciruits filters and use two having an FM broadcast station 0.8 miles from me. No discernable bad effects at other frequencies. (I do use an RTL-SDR filter with handheld receivers-not as good but the others are too larger.)

 

[PDXh0b0]

 

[ka3jjz]

Just as an aside, did anyone try to contact Dale at PAR and ask him whether SMA connectors could be used on that filter? You may not know this, but Dale is / was a RR member, and has been known to be very responsive to requests.

Emails are cheap, y'know. Just sayin'

Mike

 

[iMONITOR]

Just as an aside, did anyone try to contact Dale at PAR and ask him whether SMA connectors could be used on that filter? You may not know this, but Dale is / was a RR member, and has been known to be very responsive to requests.

Emails are cheap, y'know. Just sayin'

Mike

I didn't reach out to him but that's a good idea. I did check his web site and I didn't see that option offered. I do know he does make customer filters so it's possible. With SMA becoming more and more common today he might.

 

[Ubbe]

Has anyone performed any actual test?

FM bandstop filter comparison | RadioReference.com Forums

I have switched to coax with SMA connectors on almost everything, as amplifiers, filters and scanners and radios are mostly SMA. I use pigtails with different connectors at the ends to connect to other connector types. Adapters for F and BNC and N aöso seems to be of good quality for SMA. One thing to look out for are that SMA seems to unscrew themselves very easily and when used at hard to reach places like antennas it is advisable to use the lightest form of thread lock fluid.

/Ubbe

 

[iMONITOR]

FM bandstop filter comparison | RadioReference.com Forums

I have switched to coax with SMA connectors on almost everything, as amplifiers, filters and scanners and radios are mostly SMA. I use pigtails with different connectors at the ends to connect to other connector types. Adapters for F and BNC and N aöso seems to be of good quality for SMA. One thing to look out for are that SMA seems to unscrew themselves very easily and when used at hard to reach places like antennas it is advisable to use the lightest form of thread lock fluid.

/Ubbe


I've noticed that also Ubbe. No worry about the thread lock fluid insulating the conductivity of the shield/ground?