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
I bought a DLW Associates FL1718 filter and have been completely
happy with that choice. I got mine direct from Doug Williams
because I wanted a custom filter with one of the notches centered
right on the broadcaster's frequency. Specs say >90dB attenuation
at that notch frequency. I was willing to
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
Normally - you would only put BCB filters in the receive line - so you
don't need something that handles lots of power. I don't understand why
anyone would be looking at transmit filters for this problem.
There are some basic debugging steps that should be taken to really
understand the nature of
Here is what I used when I had the same problem 50kw line of sight 4
miles 1MHz. Expensive, but worked very well.
http://herostechnology.co.uk/pages/RF_Filters.html
Having the filter between rig and amp worked fine for me. 200w rating
for the Heros.
My power line had ~1v of RF, so ebay Spra
Hi,
Some radios do not have a separate receive antenna connector. The
'friend' wants an out of the box solution. Without a sparate RX antenna
connector it would be required to handle the transmitter power.
73,
Bill KU8H
On 7/29/19 1:24 PM, Tree wrote:
Normally - you would only put BCB fil
Had a similar problem at Field Day a few years ago with WJR (50,000 watt
station). Noticed the problem was not present when antenna tuner was
inline. Many modern rigs have broadband front ends which provide very
little attenuation to out of band signals, and just the addition of an
antenna tuner
When I was in Guam I used a Dunestar 400hpf with good results
Gus K4SXT
> On Jul 29, 2019, at 14:08, Don Kirk wrote:
>
> Had a similar problem at Field Day a few years ago with WJR (50,000 watt
> station). Noticed the problem was not present when antenna tuner was
> inline. Many modern rigs
For signals reaching your equipment via coax shield: I found something that
works very well to eliminate this is a pair of back to back baluns as close
to the rcvr as possible. --Mike, WV2ZOW
On Mon, Jul 29, 2019 at 1:34 PM Grant Saviers wrote:
> Here is what I used when I had the same problem 5
If the S-Meter is close to accurate, the signal on 160 meters is better
than -30 dBm.
One cannot dismiss that the noise floor of the transmitter on 160 meters is
stronger than atmospheric noise and can only be lowered at the transmitter.
Jim - KR9U
>On Mon, Jul 29, 2019 at 9:29 AM Mark K3MSB
Thanks for all the replies. My friend is probably going to go with a DLW
custom filter. I'm embarrassed that I forget about the common mode choke
as I use them here on all bands especially 160M. I told him I'd help him
build one.
73 Mark K3MSB
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On 7/29/2019 10:33 AM, Grant Saviers wrote:
Here is what I used when I had the same problem 50kw line of sight 4
miles 1MHz. Expensive, but worked very well.
http://herostechnology.co.uk/pages/RF_Filters.html
Yes, at 1 MHz, this would work well. Other hams would be
advised that it is ineffe
There is a 50KW AM broadcast station line of sight to my top band antennas.
Caused huge problems at greyline because they are dawn to dusk transmitting.I
built the HPF in the ON4UN handbook. As designed the rejection below 1.8 mhz
was 60 db. With careful tuning of the coils and the use of a spec
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