scanner pre amps

Anyone know if those old Uniden America, model BC 104, 25 MHz to 1 GHz preamps really work or not, I have the feeling they just amplify the noise level.

Same question for the old GRE pre amp, 100 MHz to 1 GHz, variable gain 1 to 20 Db.

I have the GRE amps and they work if you are not in a high RF area.

I agree with buddrousa. Amps can help if out in rural areas and cause more problems tan they are worth in urban areas.

They work best if you can get the amp right up at the antenna.

I live just outside the outer edges of suburbia and have tried the GRE SuperAmp and a couple other amps with mixed results. The one real success story in with a Wingard TV amp I bought 15 years ago. I use it on my R8500 connected to an ST-2 and it works great. My GRE SuperAmp works well on the Icom as well and will seem to work pretty good on the scanners but I need to reduce the gain a fair piece to avoid overload.

This winter I am going to try putting that Wingard up in the attic connected directly to the antenna and see how that works on my various receivers.

It's pricey but the Jim M-75 available from Scannermaster works pretty well. Has three band pass filters for different frequency ranges and you can tune the gain from +20 db to unity to -20 db attenuation. If you live in an urban area I agree with the others, avoid a preamp altogether.

Before purchasing a preamp consider the following steps.

1. Get the very best antenna you can afford designed for the frequencies of interest. For example, I wish to receive fire dispatches from the next county. I would get a yagi with as much gain as possible for my budget.

2. Mount this antenna as high and in the clear as possible.

3. Use the lowest loss coax available.

Having done all of the above, can I receive the signal? If yes, then you are done. If no, can it be received with the squelch open? If yes, then consider the preamp. If no, you are done.

A preamp will not make an impossible signal usable.

Other factors. Preamps amplify noise and other signals. Most scanners (and some newer commercial radios) lack front end preselection. They are easily overloaded and preamps will make this worse. Intermods may become worse. In fact, these strong signals may overload the front end of the scanner and reduce sensitivity nullifying the gain from the preamp even if they don't cause audible interference.

While I agree with what was stated about about the best antenna, highest location and lowest loss cable, at the end of the day this can be expensive and not always practical or possible.

I have to have attic mounted antennas and only have RG-6 feed through the house.

I use a wideband, Ultra Low Noise Amplifier right at the base of the antenna and have very good results, if needed, I can use lower quality amplifiers to overcome cable and splitter loss.

Suggest you read this thread - http://forums.radioreference.com/general-scanning-discussion/337054-help-pre-amps.html

Need some help on deciding which booster to buy. Live in ILL 90 miles SW of Chicago.
Trying to pick up Star com a p25 sys. Dist 1 IDOT. I have been told that the signal does not reach where I live. Purchased a 10 db Yagi had no luck.
Thinking about a booster or just giving up.
Looking at A GRE Super amp Mounts to my hand held or a Wine Gard LNA-200 mounts by my antenna.
Thanks Snow Bird.

A friend gave me a cable tv amp and when I lived in a house, with a scantenna, up high, I got all kinds of stuff. NYC CT PA NJ and ME. Now I am at the moment stuck in an apartment and still use the amp, (indoor ant) and from the middle of Long Island, I still get stuff from NJ a little from CT. My window faces east so not much from the west. I am researching a new LNA and started this thread.
http://forums.radioreference.com/software-defined-radio/334694-low-noise-amp.html

Also been reading about the LNA for All LNA for all: LNA for all - Low Noise Amplifier for many applications from 28 MHz to 2500 MHz

Took a break for the holidays. But I will be upgrading to a better amp...

Thanks Dave3825 for the help.

Read this - http://forums.radioreference.com/sp...mp-10-off-december-other-useful-rx-items.html

Also consider these if you want a integrated LNA with a Bias T, but request the seller to add the inductor on the Amplifier board, he communicates well.

Ultra Low Noise Amplifier 10 - 3000 MHz Gain 20dB NF=0.65 dB with ESD + Bias Tee | eBay

Also message this seller, he has developed a small, flexible and low cost Bias T as well.

If Mini Circuit could make these with F-connectors (male on the input and female on the output I would buy half a dozen to put on my attic antennas (ST-2's)!

I might buy one anyway and see if I can use adapters and see how well it performs. I live out in the desert so the noise floor is pretty low here anyway so these might work pretty well for me.

I can tell you it works fine with Adapters. I have a UHF to SMA male feeding directly into a high dB FM Broadcast band notch filter then into the Amp and then make into a Bias T that powers the Amp and then connected directly a 125 foot run of RG-6 cable. I have another higher noise figure F connector amplifier and a F connector bias T before I feed a 8 way splitter configuration.

You can pick up some of these - SMA-F Adapter SMA male to F-Type male plug straight RF Coax Adapter Connector | eBay

http://www.ebay.com/itm/2-Pcs-SMA-t...285227?hash=item210562da2b:g:33sAAOSwI-BWQXj9

This Amp rocks, I ordered another one this weekend with the 10% off. I just wish they would ship via USPS, even Priority Mail would be way cheaper than their shipping options.

Keep in mind these are 5 Volt Amplifiers, you can use a USB supply if it can support the current of the number of Amps.