A few suggestions Dave:
1. Follow thru on that filter, it can only help. A notch filter for that
one AM frequency may be required in addition.
2. Check on a different radio....a R4C for example; the diodes in the 930
front end filters can wreak havoc on strong signals.
3. Use a FS meter to check for any reradiation; IMD generating diode
joints in any metal in the area, particularly the towers. Salt makes for
excellent diodes.
4. A good Beverage feedline should have a good -80dB of pickup
attenuation when run on the ground and terminated at the far end in 50 or
75 Ohms.
5. Seperate the Beverage primary and secondary 9:1 xfmr windings as
suggested by W8JI, W3LPL, etc.
Let us all know ur progress.
73 Carl KM1H
On Tue, 11 Nov 1997 20:07:13 Dave Mueller <n2nl@algorithms.com> writes:
>
>>I guess it is time to let out a secret.
>> I have access to an antenna which allows me to be one of the
>biggest
>of the big guns from the East Coast. BUT, there is a problem.
>> I am an active duty member of the USCG, and while stationed at
>Training Center Capy May (NJ) I have been eyeing the Loran Support
>Unit,
>another USCG base across the harbor. They have 2 towers on sight, a
>625ft
>top loaded Loran C tower, and a 129ft tower Loran A tower that is no
>longer
>in use. I finally contacted the right person, and I have been granted
>permission to use the 129ft tower whenever I'd like.
>> As I mentioned, it is a 129 foot tall, base insulated tower, guyed
>with
>with a fiberglass like material. There are 100+ radials, each 300ft
>long.
>It is in an awesome location, the Atlantic ocean is only 300ft to the
>South
>East, with salt marsh in all other directions for miles. There is
>quite a
>bit of open space for Beverages. If you want to look it up on a map,
>find
>the southern tip of NJ, it is located between the towns of Cape May
>and
>Wildwood.
>> I am presently feeding the tower directly with coax, center
>conductor
>to the tower and ground braid to the ground system. The tower is
>reasonant
>at 1500KHz, so I am using a MFJ 300w tuner and my kenwood 930
>barefoot.
>Testing with Peter WW2Y and his 4 square 100 miles to the north, we
>are
>very similar strength wise. GW3YDX said Peter was a little louder in
>Europe, while KP4SN said I was louder in the caribbean.
>> Now the problem. I am suffering some MAJOR interference at the
>site I
>have never heard before. It seems to me to be Broadcast interference.
> On
>the transmit antenna it is almost 40Db over S9 across the band. Is is
>a
>wideband hash which varies by 5 Db in strength every 5 KHz or so (gets
>weaker, then stronger, then weaker, ETC). It makes SSB quite
>difficult. On
>CW, my primamry mode of choice, it isn't as bad, about S7, and on the
>700ft
>northeast beverage it is only S3 (the only Beverage I have up at the
>moment). I hear Europe OK on the beverage, but I think weak callers
>would
>be covered up by the noise.
>> Here is the question: Am I correct in thinking this is BCI? What
>are
>the possible solutions? I have 3 possible sourses. #1 there is an AM
>broadcast tower about 4 miles NW of me, just across the salt marsh.
>When
>listening on its TX frequency it pegs the needle with 30db of
>attenuation.
>This is what I think the cause is. #2 The Loran tower 1/2 mile to my
>west.
> It is only used for testing, and is rarely on the air. I don't think
>they
>have used it the last couple weeks while I have been on the air from
>the
>site. #3 there is a Navy VHF aircraft relay beacon (something like
>that) on
>the top of the tower. It is isolated from ground, power is fed to it
>through an isolation transformer, the type used to feed electricity to
>lights on other broadcast towers.
>> I plan on using a 160m bandpass filter which should help a little.
> Any
>other ideas a poor coastie (no money) can try out to eliminate or
>reduce
>this noise?
>>Sorry for running on, I wanted to describe the situation best as
>possible.
>>Thanks for reading it....
>>73, Dave N2NL
>>
>>
>
>
>N2NL@ALGORITHMS.COM
>******************************************
>Dave Mueller, N2NL
>ex KE2PF/NH2/KH0/DU1,3/V63PF
>Machinery Technician, Active Duty
>US Coast Guard, Cape May NJ
>******************************************
>
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