[amsat-bb] Re: 2 Meter TV Interference

[Charles Suprin]

I didn't think there were any vhf stations left. All the numbers on the
channels now are virtual. All the tv antenna plans are for uhf bands. A
quick look in the Boston market and the lowest channel is 19, channel
2 at 500MHz. Are there places that still use vhf?

Charles
On Dec 7, 2011 1:38 PM, "Bob Bruninga" <bruninga at usna.edu> wrote:

> HPF above 500 MHz?  Then the TV would not be able to see anything but a few
> UHF channels.
>
> What is needed is a stub filter.  Just a piece of open ended coax 13" long
> "T"ed into the antenna lead....
>
> The 13" is about 66% of a quarter wave at 2 meters.
>
> Done
>
> Bob, WB4APR
>
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> Behalf Of Gordon JC Pearce
> Sent: Wednesday, December 07, 2011 3:02 AM
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] Re: 2 Meter TV Interference
>
> On Tue, 6 Dec 2011 21:17:55 -0600
> Wyatt Dirks <wyattdirks at msn.com> wrote:
>
>
> > Just recently I have been having troubles with a neighbor while I am
> working the FM satellites(SO-50 and AO-27). The setup I am currently using
> is my mobile setup because I am unable to put a base station up for many
> reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2
> Larson
> mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof
> of
> my truck an the 1/2 wave is mounted on a mount opposite the factory
> installed FM/AM radio whip. It doesn't seem to matter what antenna I use
> for
> the problem to occur. Then I use either the arrow antenna or my cju for the
> downlink.
>
> Use 5W into a hand-held Yagi.  You'll get far better results.
>
>
> > Today I had another local ham over at the request of the neighbor and his
> mobile Kenwood radio did the same thing to the neighbors tv when he
> transmitted on 2 meter with 50 watts out. He also recommended that they get
> a filter. I did not see the specs on the filter nor do I know what
> bandwidth
> it was for.
>
> What you want is a highpass filter that will lop off everything below
> 500MHz.  The chances are that your TX output is clean enough but the little
> amplifier in the splitter for the TV is causing all sorts of intermod - and
> probably covers from broadcast VHF radio to the top of the TV band.
>
> --
> Gordon JC Pearce MM0YEQ <gordonjcp at gjcp.net>
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