AM Notch Filter

[737mech]

Filters Filters Oh My!!???? Now I see RTL-SDR is selling AM Broadcast Notch Filters on Amazon. Can anyone here input comments on what they help ? I already asked Dale at Parelectronics and got a swift accurate reply...He said the AM stuff overloads the 120M and 80M Ham bands. So is this a good thing to add to a very sensitive front end GRE scanner? Don't guess I ordered one for testing and will post results soon. I am inviting comments and opinions here. Please post??

 

[nanZor]

I had to use one on my Commradio CR-1a sdr radio for exactly that reason. 160 was totally desensed, and on 80 and even 40m, I could hear my local station just down in the noise - of course exactly on two freqs I monitored a lot.

 

[737mech]

Added RTL-SDR 2.6 AM filter

Ok I got this to be specific the RTL-SDR AM notch filter. Just learned they are no longer available on Amazon? I like it, helps my setup, would tell all my milair scanner friends to buy one!! Especially if you live in a crowded city full of radio stations. I have no test bench equipment but the tests are on youtube. All I can pass on is it helped me. I get clear milair uhf 225-400 alot better. My scanners bct-15x/gre-410/pro-2042. Just to add I also use fm notch and vhf 162 notch from par electronics. So three filters but I'm happy I can hear more.

 

[vagrant]

Thanks for the post. Looks like they are available on Amazon now. I will pick one up to test.

I am plagued with too much RFI. Some local AM stations are part of it at home and work locations. I use one of Dale's AM filters at home, among other PAR filters. They all work well. For mobile and portable use I use a HPN-30118 combination AM/FM filter because of it's size and convenience.

For military air Dale's specific filter for that was a welcome addition, including an AT-197 discone. I am only missing the Angle Linear 225-400 preamp now.

 

[prcguy]

Good luck on finding the Angle Linear preamp, Chip retired and shut down his business.
prcguy

Thanks for the post. Looks like they are available on Amazon now. I will pick one up to test.

I am plagued with too much RFI. Some local AM stations are part of it at home and work locations. I use one of Dale's AM filters at home, among other PAR filters. They all work well. For mobile and portable use I use a HPN-30118 combination AM/FM filter because of it's size and convenience.

For military air Dale's specific filter for that was a welcome addition, including an AT-197 discone. I am only missing the Angle Linear 225-400 preamp now.

 

[vagrant]

Good luck on finding the Angle Linear preamp, Chip retired and shut down his business.
prcguy

Yes, I am well aware I am late to the game on that item or I would have one in hand. Surely prcguy you have three of those and would not mind selling me one of them.

For now I am using that GRE amp. That device is a mess, but with a low gain setting and inline with the filters it does help.
----

To the OP, those notch filters are set to arrive today. I will post after some testing.

 

[Thunderknight]

I bought the RTL AM filter (2.6 MHz HPF) on Amazon just recently. It made a big difference on almost completly eliminating the local AM stations on my RSP-2, where they were quite bad up to about 5 or 6 MHz. The built-in filter on the RSP-2 made little difference, but the RTL made a huge difference.

 

[vagrant]

That $16 RTL-SDR High Pass Filter does a very good job on reducing AM broadcast signals. Its performance is similar to a PAR AM filter that cost me much more. The PAR filter is a bit different, but if your goal is to attenuate RF below 2.6 MHz, this inexpensive filter is a very good choice.

For kicks I also tested a HPN-30118 HPF (High Pass Filter) at the same time. It worked better than either the PAR or the RTL-SDR. The HPN-30118 is $50 and it is a 30 MHz HPF as well as a notch filter for FM. That cut off is pretty high compared to the other two. As advertised, it is better suited for scanners that typically RX 30 MHz and up.

- For my scanners at home, mobile and portable I continue to use the HPN-30118.
- I will incorporate a few more of the RTL-SDR filters for use with SDR RX devices and dongles. For the price one simply cannot go wrong to add this to their listening device tool kit.