Mark, I had the same problem - I live a mile from 760 AM at 50KW 24/7. I used a homebrew highpass filter and that helped but didn't quite reduce it enough. What I figured out was the signal was also on the coax braid! I put two mix 71 toroids, wound 6 turns of coax through them as close to the rig as possible. Made a huge difference in interference. The signal went from 60 over 9 down to a manageable S8 on the fundamental. Harmonics don't fall into ham bands so not worried about them. Mostly I suffered from severe overload and distortion across the low bands.
HTH 73! Mark KA6WKE Website: https://www.ka6wke.net Live Stream: https://www.ka6wke.net/live-stream YouTube Live!: https://bit.ly/bench-therapy-live Author: 4NEC2 The Definitive Guide EMail List:: 4nec2defgu...@groups.io On Mon, Jul 29, 2019 at 9:29 AM Mark K3MSB <mark.k3...@gmail.com> wrote: > A friend of mine in our local radio club sent me the following email > > "I'm 6/10's of a mile from an AM 910 KHz. transmitter. They operate with 5k > daytime and 2k at night. > > They're S9+45db on 160 meters with clear audio and S9+35db on 80 meters. > have an inverted "V" resonant at 3.715 MHz. orientated east-west, towards > their reflector tower." > > The station is willing to pay for a filter for my friends station, and he > has looked at notch and band pass filters but has concerns. > > I recommended he look at transmit high pass filters to knock out signals > below 1.8 Mhz and provided him with various links: > > https://www.dunestar.com/store/160-Meter-Highpass-Filter-pid-8.html > > http://www.kf7p.com/KF7P/Morgan_Filters.html > > > https://www.dxengineering.com/search/part-type/transmit-high-pass-filters/product-line/dlw-associates-am-broadcast-band-brick-wall-high-pass-filters?autoview=SKU&sortby=Default&sortorder=Default > > I have no practical experience with any of these filters and was wondering > what the TB Gang thought. > > He would prefer one that handled 1.5 KW but I told him he may have to > settle for 200W. > > He prefers an "out of the box" solution. > > Thanks > > Mark K3MSB > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector