[Yaesu] FT-1000 overloaded by AM BC station

Sun, 28 Mar 1999 10:02:19 -0500

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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.
 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.

<P>HAVE FUN,
<BR>dave

Nick Kennedy wrote:
<BLOCKQUOTE TYPE=CITE>&nbsp;This
is a restatement of a problem that a ham was kind enough to post for me
...&nbsp;I
have a lot of trouble with receiver overload on my FT-1000, apparently
when I'm using physically large antennas.&nbsp; 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.&nbsp;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.&nbsp; The AM station doesn't seem THAT powerful
or THAT close to me:&nbsp; It's about 1 KW day and 500 W night and is about
a mile or so away.&nbsp; 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.&nbsp;Questions:&nbsp;
I read some years ago that some transceivers don't use their ATUs&nbsp;
on receive.&nbsp; I wonder if this is the case with the FT1K.&nbsp; Or
maybe with early S/Ns?&nbsp;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.&nbsp;
(Filters need a good match, I'm told.)&nbsp; Maybe it would be possible
to add one internally, ahead of the receiver section.&nbsp; It would degrade
receiver performance below 160 meters but might be worth it.&nbsp; Anyone
tried anything like this?&nbsp; Any other insights or ideas for me?&nbsp;73,&nbsp;Nick,
WA5BDU<A HREF="mailto:nkennedy@cswnet.com">nkennedy@cswnet.com</A></BLOCKQUOTE>
&nbsp;
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