Re: Topband: Series LC to notch AM broadcast ?

Hi Jim, When I lived in Melbourne Florida, I had an 920 KHz AM station with a four tower array a short distance from my house (I forget the exact distance, it was probably on order of 1/2 mile). The daytime pattern beamed toward my house with a TPO of 5KW. At the time I was using a Ten-Tec

Re: Topband: Series LC to notch AM broadcast ?

On 2/20/2022 9:41 AM, jim.thom jim.t...@telus.net wrote: Has anybody tried using a simple series L-C to notch out ONE offending AM broadcast station ? I'm talking about wiring from hot side of coax...to Jim VE7RF _ See: MFJ-8504AN, AM Notch Filter 73 Rick N6RK

Re: Topband: Series LC to notch AM broadcast ?

The secret to using this sort of solution is to apply just enough of it to kill off the mixing products that are the result.  The good news is that you get (generally speaking) a 3:1 payback - so 1 db attenuation of the BC station will knock the mixing product down by 3 dB.  So 45 dB (as the

Re: Topband: Series LC to notch AM broadcast ?

We had a 1550khz in town and a 1450khz moved 2 blocks away from 1550. Yep mix products on 1650khz and 1350khz. ( and to some extent 1500khz ) a simple 1550 notch on the top of the 1450 transmitter eliminated the mix products and didn't bother the 1450 transmitter. Don W4DNR On

Re: Topband: Series LC to notch AM broadcast ?

On 2/20/2022 3:33 PM, Grant Saviers wrote: Somewhat related was my effort to produce a pair of 80m notches so CW and SSB could run 80m simultaneously on Field Day (separate antennas). While the CW guys would be ok with 20KHz BW, not so for the SSB team. Just below a Rx 40db notch was about the

Re: Topband: Series LC to notch AM broadcast ?

>>HP filters offer little rejection towards the top end of the AM broadcast band. like 1200-1710 khz. << I built several HP filters with >40 db attenuation on 1.7 KHz based on QST, I don't remember the year 90's about it. But some good information here >

Re: Topband: Series LC to notch AM broadcast ?

Being the simplistic cheapskate that I am, I got rid of all my AM IMD with a 2k pot in the receive line. :-) Tip from W8JI about 40 years ago. Just attenuate everything. Works for me. 73 Mike W0BTU On Sun, Feb 20, 2022 at 11:42 AM jim.thom jim.t...@telus.net < jim.t...@telus.net> wrote: > Has

Re: Topband: Series LC to notch AM broadcast ?

Somewhat related was my effort to produce a pair of 80m notches so CW and SSB could run 80m simultaneously on Field Day (separate antennas). While the CW guys would be ok with 20KHz BW, not so for the SSB team. Just below a Rx 40db notch was about the best I could do with a one db loss Tx.

Re: Topband: Series LC to notch AM broadcast ?

On 2/20/2022 9:41 AM, jim.thom jim.t...@telus.net wrote: Has anybody tried using a simple series L-C to notch out ONE offending AM broadcast station ? Sure -- although I don't remember doing it, I knew about it almost from when I was first licensed 65 years ago. 73, Jim K9YC

Re: Topband: Series LC to notch AM broadcast ?

Hello Jim, Better, I think, is this notch, found at the IRCA Reprints: https://www.ircaonline.org/editor_upload/File/reprints/irca-reprint-index.pdf Look for Reprint A-063, An RF Notch Filter by VE6JY. You

Re: Topband: Series LC to notch AM broadcast ?

I will try if you are or anyone is interested getting the design of this filter we use on a AM radio broadcast antenna when we use it on 160 Meters. This is NOT just a matching unit to match the antenna for us to use on 160 meters. BUT also a pass band filter for 160, a High pass filter

Topband: Series LC to notch AM broadcast ?

Has anybody tried using a simple series L-C to notch out ONE offending AM broadcast station ? I'm talking about wiring from hot side of coax...to chassis / groundlike via a T connector etc. On paper, it should work. Did some minor research, and one comment was that by using higher values of