Looking for some pre-amp help

[woebbers]

Im looking for some helping purchasing a pre-amp for mil-air listening. I live in an apartment and have no access to put an antenna higher then my patio porch. Right now im using a Scantenna perched on the 2nd floor deck. Any help is appreciated

Sal
Valley Forge Pa

 

[Ubbe]

It depends mostly on your scanner/receiver.

The RfBay LNA-580 is excellent with extreamly low noise figures and the SSB LNA-3000 is equally good with slighly worse noise figure but so far I haven't been able to hear any difference between the two.

The SSB is a ready to use unit and the RfBay is a module you have to work with a little bit to make it work. Both have around 20dB gain and IP3 of 30dBm which means it can handle very strong RF signals from basestations nearby.

But the receiver needs to be able to cope with the higher signal levels. Most Uniden handhelds and BC780 and BCT15 needs the signal to be attenuated 10-15dB. Perfect if you have a splitter/cable solution that attenuate 10dB. I use a variable attenuater for SAT/TV use and adjust for best reception of weak signals. Receivers like Icom pcr1000/1500 and Pro-2006 can be used without attenuator. At least this is the situation at my place.

Ubbe.

 

[VK2GEL]

http://www.garex.co.uk/vhf_accs/vhf_accs.htm

 

[prcguy]

The preamps mentioned are probably fine for rural use away from any radio transmitting towers but not in an RF congested area. Where I live near Los Angeles they would be in serious trouble without a bandpass filter or very sharply tuned antenna for a particular band.

If the aircraft band is the only interest there are some nice band pass filters available that will allow even a low IP3 preamp to work well without overload.

You will probably get a slight improvement with a preamp in your case but not as much compared to placing the preamp at the antenna feeding a long piece of coax. The noise figure of most preamps will be much lower than your scanners noise figure but local RF noise will probably offset the difference some leaving a smaller improvement.
prcguy

It depends mostly on your scanner/receiver.

The RfBay LNA-580 is excellent with extreamly low noise figures and the SSB LNA-3000 is equally good with slighly worse noise figure but so far I haven't been able to hear any difference between the two.

The SSB is a ready to use unit and the RfBay is a module you have to work with a little bit to make it work. Both have around 20dB gain and IP3 of 30dBm which means it can handle very strong RF signals from basestations nearby.

But the receiver needs to be able to cope with the higher signal levels. Most Uniden handhelds and BC780 and BCT15 needs the signal to be attenuated 10-15dB. Perfect if you have a splitter/cable solution that attenuate 10dB. I use a variable attenuater for SAT/TV use and adjust for best reception of weak signals. Receivers like Icom pcr1000/1500 and Pro-2006 can be used without attenuator. At least this is the situation at my place.

Ubbe.

 

[woebbers]

Pre-amp help

Thanks everyone for giving me your thoughts. prcguy I live about 25 miles from the big antenna towers in Philadelphia.. Everything i need for local police and fire cimes in 5 by 5. So what im looking for is mil-air and maybe commercial air. I live about 15 miles from Willowgrove NAS and about 90 miles north of Dover Air Force base. I know Dover is stretch since living in an apartment Im very limited to antenna height and design. I figured a way I can use a beam type of antenna that may help me in the bands I'm looking to receive. Im using a ES 197 now but hope to own an Icom r8500 in a few weeks


Sal

 

[Ubbe]

I mentioned these two amplifiers because they are imune to strong RF in a city enviroment. I have a big site with probable 20 transmitters, both commercial analog and digital and amateur radios, only 100 meters from my current place. The amplifiers will of course do more for your reception in a rural area.

There are much more affordable amplifiers but they often get overloaded with RF and create intemod and mixing frequencies creating new ones in the amplifier in itself. They might be usable in a calm RF enviroment but why go through all the hazzle and uncertiny of not knowing if the reception could be improved.

Install one of these amplifiers and then forget them, they will not add any negative to your reception but you might have to attenuate the signal entering your scanner.

Ubbe.