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I would think the fella is getting the RF from the ground side of his
antenna.
A mile at the away at the AM broadcast band isn't very far away. If the
radio
station is in the USA they have to use a fairly extensive radial system,
etc.
There is company called ICE run by a Ham in Maryland that builds
bandpass
filters for contesters. Model 419 covers all the ham bands and mates to
the
FT-1000 for auto switchings. That system would reduce any incoming
signals
outside the band of operation. They are not expensive as I just bought
one
at a local hamfest for $75.
I believe the FT-1000 tuner is used on receiver but that question should
go
to Yaesu for confirmation.
HAVE FUN,
dave
Nick Kennedy wrote:
> This is a restatement of a problem that a ham was kind enough to post
> for me ... I have a lot of trouble with receiver overload on my
> FT-1000, apparently when I'm using physically large antennas. The
> antennas are a 195 foot long Marconi (52 foot vertical, 143 foot
> horizontal) and a 180 foot long dipole (c.f. zepp?) feed with twin
> lead. These antennas present "reasonable enough" impedences so that
> the FT1K's ATU can load OK and transmit on several bands, but serious
> receiver noise from overload is a big problem. The AM station doesn't
> seem THAT powerful or THAT close to me: It's about 1 KW day and 500 W
> night and is about a mile or so away. I'm sure it's overload because
> switching in a few steps of attenuation will make it drop out
> completely while desired signals are merely attenuated as
> expected. Questions: I read some years ago that some transceivers
> don't use their ATUs on receive. I wonder if this is the case with
> the FT1K. Or maybe with early S/Ns? Also since these antennas aren't
> presenting a good 50 ohm impedence at the antenna terminals I assume
> using an outboard high pass filter might be a problem. (Filters need
> a good match, I'm told.) Maybe it would be possible to add one
> internally, ahead of the receiver section. It would degrade receiver
> performance below 160 meters but might be worth it. Anyone tried
> anything like this? Any other insights or ideas for me? 73, Nick,
> WA5BDUnkennedy@cswnet.com
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I would think the fella is getting the RF from the ground side of his antenna.
<BR>A mile at the away at the AM broadcast band isn't very far away. If
the radio
<BR>station is in the USA they have to use a fairly extensive radial system,
etc.
<P>There is company called ICE run by a Ham in Maryland that builds bandpass
<BR>filters for contesters. Model 419 covers all the ham bands and mates
to the
<BR>FT-1000 for auto switchings. That system would reduce any incoming
signals
<BR>outside the band of operation. They are not expensive as I just bought
one
<BR>at a local hamfest for $75.
<P>I believe the FT-1000 tuner is used on receiver but that question should
go
<BR>to Yaesu for confirmation.
<P>HAVE FUN,
<BR>dave
<P>Nick Kennedy wrote:
<BLOCKQUOTE TYPE=CITE> <FONT FACE="Times New Roman"><FONT
COLOR="#000000"><FONT SIZE=-1>This
is a restatement of a problem that a ham was kind enough to post for me
...</FONT></FONT></FONT> <FONT FACE="Times New Roman"><FONT
COLOR="#000000"><FONT SIZE=-1>I
have a lot of trouble with receiver overload on my FT-1000, apparently
when I'm using physically large antennas. The antennas are a 195
foot long Marconi (52 foot vertical, 143 foot horizontal) and a 180 foot
long dipole (c.f. zepp?) feed with twin lead.</FONT></FONT></FONT> <FONT
FACE="Times New Roman"><FONT COLOR="#000000"><FONT SIZE=-1>These
antennas present "reasonable enough" impedences so that the FT1K's ATU
can load OK and transmit on several bands, but serious receiver noise from
overload is a big problem. The AM station doesn't seem THAT powerful
or THAT close to me: It's about 1 KW day and 500 W night and is about
a mile or so away. I'm sure it's overload because switching in a
few steps of attenuation will make it drop out completely while desired
signals are merely attenuated as expected.</FONT></FONT></FONT> <FONT
FACE="Times New Roman"><FONT COLOR="#000000"><FONT SIZE=-1>Questions:
I read some years ago that some transceivers don't use their ATUs
on receive. I wonder if this is the case with the FT1K. Or
maybe with early S/Ns?</FONT></FONT></FONT> <FONT FACE="Times New
Roman"><FONT COLOR="#000000"><FONT SIZE=-1>Also
since these antennas aren't presenting a good 50 ohm impedence at the antenna
terminals I assume using an outboard high pass filter might be a problem.
(Filters need a good match, I'm told.) Maybe it would be possible
to add one internally, ahead of the receiver section. It would degrade
receiver performance below 160 meters but might be worth it. Anyone
tried anything like this? Any other insights or ideas for
me?</FONT></FONT></FONT> <FONT FACE="Times New Roman"><FONT
COLOR="#000000"><FONT SIZE=-1>73,</FONT></FONT></FONT> <FONT FACE="Times
New Roman"><FONT COLOR="#000000"><FONT SIZE=-1>Nick,
WA5BDU</FONT></FONT></FONT><FONT FACE="Times New Roman"><FONT
COLOR="#000000"><FONT SIZE=-1><A
HREF="mailto:nkennedy@cswnet.com";>nkennedy@cswnet.com</A></FONT></FONT></FONT></BLOCKQUOTE>
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