Delphi QFM-9 vs RS 6-element for FM Stereo?
 

Is it ok to ask about FM Stereo antennas here?

I'm running this Radio Shack 6-element FM antenna for a station at 107.3

http://www.radioshack.com/product.as...t%5Fid=15-2163

Usually it's clear in mono but not in stereo. Sometimes it's distorted in
mono.

Would a Delphi QFM-9 be much stronger and maybe clear this up?

http://starkelectronic.com/fmpage.htm 3rd one down

Thanks in advance.
--
Ed Light

Smiley :-/
MS Smiley :-\

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Thanks, robots.

I suspect your problem is that the antenna is seeing a signal that has
some components from reflections off of other building, hills, ridges,
etc. It is called multi-path.

My first approach would be to get the antenna higher in the air and then
make sure it 'sees' the transmitting antenna from the station. If you
cannot establish 'line of sight' then multi-path will always be part of
your reception.

Ed Light wrote:

Is it ok to ask about FM Stereo antennas here?

I'm running this Radio Shack 6-element FM antenna for a station at 107.3

http://www.radioshack.com/product.as...t%5Fid=15-2163

Usually it's clear in mono but not in stereo. Sometimes it's distorted in
mono.

Would a Delphi QFM-9 be much stronger and maybe clear this up?

http://starkelectronic.com/fmpage.htm 3rd one down

Thanks in advance.

I suspect your problem is that the antenna is seeing a signal that has
some components from reflections off of other building, hills, ridges,
etc. It is called multi-path.

My first approach would be to get the antenna higher in the air and then
make sure it 'sees' the transmitting antenna from the station. If you
cannot establish 'line of sight' then multi-path will always be part of
your reception.

Ed Light wrote:

Is it ok to ask about FM Stereo antennas here?

I'm running this Radio Shack 6-element FM antenna for a station at 107.3

http://www.radioshack.com/product.as...t%5Fid=15-2163

Usually it's clear in mono but not in stereo. Sometimes it's distorted in
mono.

Would a Delphi QFM-9 be much stronger and maybe clear this up?

http://starkelectronic.com/fmpage.htm 3rd one down

Thanks in advance.

Ed:

Dave is correct in that selecting the correct antenna depends on identifying
the problem first. For example, if the actual problem is receiver front end
overload, then a higher gain antenna will make it worse instead of better.
If the problem is reflections (and sorry, Dave, LOS is not necessarily
reflection free, I used to have to look at the local TV stations between two
elevated water towers, LOS with two ghosts), then antenna pattern, rather
than gain alone will matter. If you want an engineering evaluation, then a
whole bunch of facts are needed, and the two facts which are needed most
will be hard to come by: 1. A spectrum analyzer shot of what appears at the
receiver end of your feedline, plus 2. A audio frequency phase analysis of
the detected signal to determine main and delayed content.

--
Crazy George
Remove N O and S P A M imbedded in return address

Ed:

Dave is correct in that selecting the correct antenna depends on identifying
the problem first. For example, if the actual problem is receiver front end
overload, then a higher gain antenna will make it worse instead of better.
If the problem is reflections (and sorry, Dave, LOS is not necessarily
reflection free, I used to have to look at the local TV stations between two
elevated water towers, LOS with two ghosts), then antenna pattern, rather
than gain alone will matter. If you want an engineering evaluation, then a
whole bunch of facts are needed, and the two facts which are needed most
will be hard to come by: 1. A spectrum analyzer shot of what appears at the
receiver end of your feedline, plus 2. A audio frequency phase analysis of
the detected signal to determine main and delayed content.

--
Crazy George
Remove N O and S P A M imbedded in return address

I can't move the antenna in this trailer park, so my only option is a bigger
one. The signal has cleared up the past couple of days, and I'm hoping it's
more than the weather.

The transmitter is about 30 miles away behind some mountains. I'm pointed at
an aluminum building that's in the next lot. The receiver sees the station
as "dx" rather than local.
--
Ed Light

Smiley :-/
MS Smiley :-\

Send spam to the FTC at

Thanks, robots.

I can't move the antenna in this trailer park, so my only option is a bigger
one. The signal has cleared up the past couple of days, and I'm hoping it's
more than the weather.

The transmitter is about 30 miles away behind some mountains. I'm pointed at
an aluminum building that's in the next lot. The receiver sees the station
as "dx" rather than local.
--
Ed Light

Smiley :-/
MS Smiley :-\

Send spam to the FTC at

Thanks, robots.

Ed:

I would sure try different orientations first. Having to use a reflected
signal is indicative of a poor path, of course. See if there is another
direction which gives more reliable stereo decoding, which may not
necessarily be the strongest signal. Stereo decoding is indicative of the
fewest multipath contributions, and may be in a different direction
entirely. Also, try changing the polarization of the antenna, although
making it vertical will be difficult, as running a mast and feedline in the
same plane as the elements will pretty much destroy the performance. It
will likely need a mounting which is mechanically impractical in your
situation.

--
Crazy George
Remove N O and S P A M imbedded in return address

Ed:

I would sure try different orientations first. Having to use a reflected
signal is indicative of a poor path, of course. See if there is another
direction which gives more reliable stereo decoding, which may not
necessarily be the strongest signal. Stereo decoding is indicative of the
fewest multipath contributions, and may be in a different direction
entirely. Also, try changing the polarization of the antenna, although
making it vertical will be difficult, as running a mast and feedline in the
same plane as the elements will pretty much destroy the performance. It
will likely need a mounting which is mechanically impractical in your
situation.

--
Crazy George
Remove N O and S P A M imbedded in return address