BPF-AIR Air Band Band Pass Filter

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nycrich

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I use one of those. However it will depend on what type of background noise you are trying to eleminate. If you are trying to elimate electrical noise it would do nothing. The band pass filter will filter SOME interference from AM, FM, and some paging interference. Be aware if the signal is very strong it will attenuate but still be there. Also if you have a scanner that have front end overloading, amplified antenna, or cheaper scanner with poor selectivity it would help, but not make a big difference. Exactly what type of noise are you trying to eleminate/attenuate?
 

nycrich

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The band pass filter would not help you. It is designed to only reject frequencies below and above the listed the listed filter. Static noise or white noise cannot be eliminated unless you use the squelch.
 

K4DHR

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Skud said:
just the normal static you hear from AM freq.
That's just AM for you. You'll never get full quieting like you can with FM. AM is just signal to noise...the stronger the signal is in relation to the noise, the less noise you'll hear.

You can take some steps to control/eliminate noise from sources in your home and vehicle that will help make some weaker stations more readable, I'd go that route before dumping money on filters like that. Turn some things off around the house or try some basic grounding/bonding in your car and see if the amount of noise decreases. Doing that is cheap/free.
 

BOBRR

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AOR Airband Filter ?

Hi,

Have a GRE PSR 500/

Re the AOR ABF 128 (the 125 is apparently discontinued).

I live about 10 miles away from a local airport.
I can hear planes calling in to the Tower just fine; really loud and clear.

Have a devil of a time trying to pick up broadcasts from the Tower.

Don't really know how to categorize the noise, frankly.

Just always a lot of "static" riding along on the signal.
If not for the static, would probably be more than enough "real signal"

Think this filter would help any ?

Was confused reading the Posts as whether it would be good in eliminating "static" or just "noise" any ?

Anything cheaper to do the job ?

Thanks,
Bob
 

ka3jjz

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Bob most tower xsmns aren't meant to carry 10 miles ground coverage - so your better bet is not necessarily a bandpass filter, but a better antenna. Now I wouldn't get rid of the bandpass filter - since the GREs seem to have a somewhat hotter-than-normal front end, and seem to be more sensitive to getting junk like pagers and such, building a civil air ground plane (or similar) with the bandpass filter in-line would be quite effective.

Just keep in mind the bandpass filter will kill signals on either side of its designed frequency - so if you want to hear UHF, make sure the bandpass filter is offline, or you'll hear very little if anything at all. 73 Mike
 

Air490

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My experience with filters has been that it is better to try and find the problem, then get a filter that cuts it out, rather than get a filter that only lets in some things. I'll explain...

I had a problem with interference on VHF airband. After a bit of research I found it was FM broadcast signals that were the problem. I tried the ABF125, and it did help but didn't solve the problem because it reduced reception across all the other bands. The best solution I found was to get a filter that cut out FM broadcast signals. It worked a treat.
 

k4njk

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AIR490 is right on the money. I experienced the same problem with interference. The first step was to narrow down the cause (also FM broadcast) and then pick the appropriate filter to minimize the problem (PAR FM in my case).
 

nycrich

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Sounds like you have a very weak signal from the tower. The signal is not above the "noise floor" of the receiver. Sometimes it will just break above the noise floor and you can hear it; if propagation is good you might temporarily hear it. However you will not be able to improve the signal if it is below the noise floor. Better antenna, directional antenna, moving antenna higher will improve the signal to increase and move out of the noise floor level . Receivers have a noise floor which includes noise from the internal components ( Eg transistors, etc). It is a fixed level that cannot be changed, unless by different design circuitry. More expensive receivers with higher tolerance components will have a lower noise floor value, and allow you to receive DX signals that cheaper units cannot descern. Improving antenna performance, better cabling, and a list of other that forum members can suggest will better your chances. However in you particular case the filter will not improve your problem since the signal is below the noise floor limits.
 

af5rn

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This topic actually surprises me a little. The civil air band is the only band I have not had out of band interference on! I have never had other bands disrupting my air band monitoring, but I constantly have trouble with air band disrupting my VHF-Hi monitoring in a big way. Such is the downside of living in the DFW airport pattern.
 

wxmike

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I'm in the same boat. I live 16 miles from the airport and most days i listen are bad and In the noise floor "static". On other days, the tower will come in so loud that i have to turn it down and this is on clear and cloudy days. Cant point my finger on this one.. I have unplugged and powered just about everything off in the house and has no effect. I have the OmniX Antenna about 40 foot in the air using LL 600 Cable.


Here is my setup:

1) Pro 197 PRO-197 39,000-Channel Digital Desktop Scanner - RadioShack.com

2) JEFA Tech Low Loss 600 Cable Assembly

3) DPD OmniX Antena from dpdproductions.

thanks
 

ATCTech

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That may not be as hard to explain as you may think.

ATC will typically have a main and a back-up transmitter and receiver on each frequency. In our case, we intentionally use 2 different on-airport sites for the local frequencies, for security reasons and to eliminate a single point of failure of both radios at the same time - power failures, landline cuts and so forth. Those two sites may be far enough apart, with markedly different obstructions to your location, and the antenna heights just different enough that you're more line of sight to one location than you are the other. Our controllers will switch between transmitters (and receivers for that matter) regularly since there's no technical performance difference between them. Usually they switch because an aircraft may mention a bit of background noise, or due to maintenance activity on the radios and so forth. Aircraft would not notice the difference, but ground to ground coverage might be noticeably different for you.

Bob
 
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