Very good information and I thank you. Never considered the loss
factor and where to put preamp in the line. I think my answer is
better antenna and I am thinking of putting a discone on roof and
running coax to my desk. sounds like that is the way to go. Do
discones have gain? I am trying to hear 800mhz system that is approx
30 miles away

"Bill Crocker" wrote in message ...
I've had mixed results with preamps. Ideally, if you could mount a roof-top
antenna, with the preamp close to the antenna, it would then amplify the
signal, and "push" it down the coax, into your scanner. There are some that
work like this. However, most preamps are at the other end of the coax,
next to your radio. The problem here is two fold. Much of the original
signal has already been deluted, due to loss in the coax. Noise has been
picked up, on the coax, then amplified, along with the signal.

Another problem you can encounter when using a preamp is desensitizing the
radio, due to front end overload. Most state-of-the-art scanners, alreay
have sensitive circuits, and preamps can overload these circuits, causing
them to attenuate the signal, overall, therefore negating the benifit of
using the preamp to begin with.

Considering your distance, you would benifit most, from a good outdoor
antenna, mounted resonably high. Keep in mind, the loss in long antenna
cables, can have a negative impact on your end result. I would try to keep
the lenght of your coax to a minimum, 30~50 feet at most. Use high quality,
low loss coax, with high quality connectors, properly attached. Antennas,
and coax, have been discussed countless times, in the groups, so rather than
reterate all that, just do a search on Google.

If you decide to go for another preamp, check he
http://scanner.greamerica.com/amp.html

For antennas, check these links:
http://www.grove-ent.com/scannerantennas.html
http://www.universal-radio.com/catalog/scanants.html

Bill Crocker



"Jim" wrote in message
om...
Is there a good scanner preamp out there? I bought one of those coax
inline jobs from RS and it did nothing at all for my BC 245 or my BC
9000. I didn't notice any change at all. I am out in the country and
miles away from where I want to scan and I am thinking maybe I should
try different antennas now. Preamps just don't seem to help any. There
was an antenna called the condor is that still available?

I am trying to hear 800mhz system that is approx 30 miles away

Maybe it's been discussed (I just tuned in) but have you considered a
vertical beam antenna, like a TV antenna on it's side with just a slight
tilt.
I suspect you are fighting a loosing battle. My son (a fire fighter) lives
on top of a hill (you can see for miles from his porch) has tried to monitor
the 800 system in the city that he works in ( aprox 30-35 miles as the crow
flies) and can't even get an occasional peep out of the system.

I've never used a preamp on the 800 freq's but have on other freq's (HF and
VHF) and they have all (some homebrew and some store bought kits) been very
disappointing, seem like they raise the noise level more than anything. RM~

Check out eBay...search on YAGI, you see numerous high-gain antennas in the
800MHz band.

Bill Crocker


"Jim" wrote in message
om...
Very good information and I thank you. Never considered the loss
factor and where to put preamp in the line. I think my answer is
better antenna and I am thinking of putting a discone on roof and
running coax to my desk. sounds like that is the way to go. Do
discones have gain? I am trying to hear 800mhz system that is approx
30 miles away

"Bill Crocker" wrote in message
...
I've had mixed results with preamps. Ideally, if you could mount a
roof-top
antenna, with the preamp close to the antenna, it would then amplify the
signal, and "push" it down the coax, into your scanner. There are some
that
work like this. However, most preamps are at the other end of the coax,
next to your radio. The problem here is two fold. Much of the original
signal has already been deluted, due to loss in the coax. Noise has
been
picked up, on the coax, then amplified, along with the signal.

Another problem you can encounter when using a preamp is desensitizing
the
radio, due to front end overload. Most state-of-the-art scanners,
alreay
have sensitive circuits, and preamps can overload these circuits,
causing
them to attenuate the signal, overall, therefore negating the benifit of
using the preamp to begin with.

Considering your distance, you would benifit most, from a good outdoor
antenna, mounted resonably high. Keep in mind, the loss in long antenna
cables, can have a negative impact on your end result. I would try to
keep
the lenght of your coax to a minimum, 30~50 feet at most. Use high
quality,
low loss coax, with high quality connectors, properly attached.
Antennas,
and coax, have been discussed countless times, in the groups, so rather
than
reterate all that, just do a search on Google.

If you decide to go for another preamp, check he
http://scanner.greamerica.com/amp.html

For antennas, check these links:
http://www.grove-ent.com/scannerantennas.html
http://www.universal-radio.com/catalog/scanants.html

Bill Crocker



"Jim" wrote in message
om...
Is there a good scanner preamp out there? I bought one of those coax
inline jobs from RS and it did nothing at all for my BC 245 or my BC
9000. I didn't notice any change at all. I am out in the country and
miles away from where I want to scan and I am thinking maybe I should
try different antennas now. Preamps just don't seem to help any. There
was an antenna called the condor is that still available?

Bill Crocker ...

^ Check out eBay...

That's cruel.


^ ...search on YAGI ...

A Yagi is not difficult to construct, especially if it is for receiving only.
All that are needed are a wire clothes hanger, wire cutters, soldering iron,
and 50-75 ohm coax. Measure the driven element for about 900 MHz and visually
estimate the lengths of the remaining elements.

Frank

Frank 01c3e0d2$ea858a00$0125250a@czvmuxeghkikgbva...

^ All that are needed are a wire clothes hanger, wire cutters,
^ soldering iron, and 50-75 ohm coax.

Since the driven element can be a di-pole cut from the coax conductors, even
the soldering iron isn't necessary.

Frank