800MHz reception experiment question

[altec]

I was reading this link http://www.radioreference.com/forums/antenna-forum/135913-800-mhz-portable-scanners.html and have a couple of questions on how to amplify the control channel.

Outside the house with my portable 396 I can barely get the control channel to come in using rs 800MHz antenna. It has quite a bit of static but barely readable standing still. The signal is about 50 miles away. I want to amplify the signal. Would this work if I built a 800MHz yagi antenna? If it does improve the signal pointed in the right direction about how many elements would be ideal?

Also sort of a stupid question but after I placed all the elements on the boom without the driven element and put the portable scanner using the 800 RS antenna next to where the driven element at standing level, would I get improved reception trying this? Thats without the driven element and balun standing at ground level pointed in the towers direction. Like I said you can monitor the system standing outside almost but could this improve reception without having to erect a tower for the squirrels to play on?

All in all just picture it as this, "I like sitting in a chair outside in the lawn sipping on tea and enjoying the sun. If I had a yagi mounted to the yard table with my scanner next to it would I get improved reception? Thanks, Altec.

 

[mtindor]

I was reading this link http://www.radioreference.com/forums/antenna-forum/135913-800-mhz-portable-scanners.html and have a couple of questions on how to amplify the control channel.

Outside the house with my portable 396 I can barely get the control channel to come in using rs 800MHz antenna. It has quite a bit of static but barely readable standing still. The signal is about 50 miles away. I want to amplify the signal somehow. Would this work if I built a 800MHz yagi antenna? If it does improve the signal pointed in the right direction about how many elements would be ideal?

The way to improve 800 mhz reception is to (a) use an antenna designed for that band, (b) use a directional antenna such as a Yagi if possible, (c) put it up as high and unobstructed as possible, (d) use quality coax to feed it [something like LMR-400] and keep the coax runs as short as possible. There are actual signal amps available for 800 Mhz, but if you have trash coming in, you'll mostly be amplifying trash.

Also sort of a stupid question but after I placed all the elements on the boom without the driven element and put the portable scanner using the 800 RS antenna next to where the driven element would be at, would I get improved reception doing this? Just curious, thanks Altec.

If you do that, you may see some indication of improvement, or not. The antenna / scanner will have no physical attachment to the antenna nor will the antenna be in any way tuned. It'll simply be a passive response to some metal hovering near your handheld antenna. Improved reception could not be guaranteed, would not be likely, and would not be consistent.

Mike

 

[altec]

Well, that rules out sitting in the yard sipping tea and flipping burgers on the grill listening to a conversation 50 miles away. That was just a idea I thought of. A yagi setup on the ground table. If I did erect a tower it would have to be 35 to 45 feet up in the air. LMR cable is good stuff. They got two different kinds. The stiff vs not so stiff. Its only 35 ft tall, can you use something else other then lmr coax? Also what connectors would you recommend for the balun? I'm leaning towards a N connector.

 

[N_Jay]

Yes, No, Maybe.

Yes, it would make the signal somewhat directional and raise the gain.

No, not as good as a properly designed yagi, as you still don't have a reflector element, and the tuning would be a bit off because the driven element is not a dipole cut for the frequency.

Maybe, because no one here is able to tell you how strong the signal is that you are receiving, how much gain is needed, and how much gain you will get.

 

[Hoofy]

altec,

Don't get discouraged because no one knows the answer to your problem.

Try building a yagi for the frequency you need. There are many instructions on how to build a cheap one. Just Google for home brew yagis.

Don't worry about the high priced coax until you decide what will work and whether you want to make it permanent or not. A short run of rg58 for testing will work. Try it at table level and see if it is good enough. Putting it up 35 feet and using lmr-400 doesn't mean that it will work.

Experiment a little and try different antennas you never know what might work the best.

 

[Hoofy]

Here's a link for directions to many different antenna's. Its about the best one I've found.


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