P25 Antenna?

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Hi Everyone, I hope someone can help me out? I am using a Antenna Specialist Cellular/PCS magnet mount antenna for my vehicle. The radio I am using is a BC296D. I listen to VHF it works great, UHF not to good, My main interest is P25 & VHF, I have all local primary CCS in it. But I often lose the CC signal I have to turn the radio off and on repeatedly to recieve the CC. And that does not all ways work. Is it my Antenna? Any help is appreciated.
 
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N_Jay

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lockoutspecialist2 said:
Hi Everyone, I hope someone can help me out? I am using a Antenna Specialist Cellular/PCS magnet mount antenna for my vehicle. The radio I am using is a BC296D. I listen to VHF it works great, UHF not to good, My main interest is P25 & VHF, I have all local primary CCS in it. But I often lose the CC signal I have to turn the radio off and on repeatedly to recieve the CC. And that does not all ways work. Is it my Antenna? Any help is appreciated.

You antenna is designed for 800/1900 MHz and it sounds like you want 150 MHz?:confused:

As for P25, antennas are all about band, and not about modulation/format.
 
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I understand it is not made for VHF. Why wont it work for better for 800MHZ? This was my question from the start, forget about vhf/uhf.
 
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N_Jay

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lockoutspecialist2 said:
I understand it is not made for VHF. Why wont it work for better for 800MHZ? This was my question from the start, forget about vhf/uhf.

You did not say you wanted 800 MHz?

What are you comparing it to?
 
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Sorry guess it left the 800 part out the first post. I am comparing it to the basic rubber antenna that came with the radio.
 

mancow

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I have that same antenna (I think) and it works great. It has the open coil at the bottom and the closed plastic one toward the top.

Is that similar to yours?
 
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mancow said:
I have that same antenna (I think) and it works great. It has the open coil at the bottom and the closed plastic one toward the top.

Is that similar to yours?
Yes it is the exact same one, I have 3 of them same problem Yes it does work great when they want to I also have 2 bc296d both have the same problem:confused: :confused:
 
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I am still stumped! So what I did was put the attenuator on all of the 800 CCS and it works fine, I am not losing the CCS now. The only think I can think of is that the scanner was getting overloaded????? Is this possible? Craig 121
 
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ka3jjz

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Yep - you're experiencing what is typically known as 'desense'; basically speaking, evidently something in your area is so strong in or around the freqs you are using, that the scanner locks onto that instead of what you want, and turns down the sensitivity on anything else.

73s Mike
 
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ka3jjz said:
Yep - you're experiencing what is typically known as 'desense'; basically speaking, evidently something in your area is so strong in or around the freqs you are using, that the scanner locks onto that instead of what you want, and turns down the sensitivity on anything else.

73s Mike
Thanks there are a lot of cell antennas with in a 4 mile radius of this area.
 

ka3jjz

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Oh that will do it, no doubt about it. I experience the same when I drive to work - 2 cell antennas, the main tower for Baltimore Gas And Electric and 1 county tower within 3 blocks of me, and my 245 just dies. No surprise there. Once I drive about a mile or so away, all returns to normal. 73s Mike
 

kb2vxa

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Hi all,

I have this massive cell tower 1/4 mile away and have no problem hearing 800MHz with a 3dB gain antenna at 40' HAAT. I have no desense problems at all even with the municipal tower a block away and more licensed transmitters in this postage stamp size town than you can shake a stick at, I'm quite literally surrounded by antennas within sight.

Am I just lucky or is there something you guys are failing to communicate here? I suspect incomplete information, looks like a puzzle with a few pieces missing. Mike, if you have to be a mile or more from the tower I suspect a lousy receiver. Having had a mobile 2M setup for a number of years and several rigs I can tell you that all receivers are not created equal, nor are they endowed by thier creator with certain inalienable rights, among these are servicable life, operability, and the persuit of signals. What the manufacturer never tells you are the critical bits, that's what the ARRL lab testing is all about. Too bad there isn't the equivelent for scanners and SW receivers, "the truth is out there" but you have to find it yourself "if you want to believe".

Edited for "inaliens". (;->)
 
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I'm just 1/4 mile or less from a 8 + storie hospital that has every cell service provider on it plus the state wide 800 DTRS and numerous other repeaters. Craig
 
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kb2vxa

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Hi again Craig,

You're still not telling the whole story. I just got done debunking that myth so what else is there you're not telling us? I'm suspecting your receiver but the only definitive answer can only be given by your receiver. Without running it through a whole battery of tests little may be said, your best bet is trying this one and that until you find one that works properly in your environment.

Like I said I have used a number of 2M rigs in harsh environments and all but one got clobbered with desense and intermod, perchance I bought one at a hamfest that was immune. It just happened to be a Yeasu with "Track Tuning" similar to what Bearcat used before Uniden bought the company, sorry if I don't remember the name. The "front end" tunes a fairly narrow band segment depending on which band segment it's receiving at any given moment. Operation is similar to commercial radios which employ the same function giving them far superior receive charaicteristics unlike most scanners that amplify every frequency from DC to light before IF conversion. You've probably heard about pre-amplifiers making such problems worse and it's for the same reason, strong out of band signals playing hob with the receiver.

I hope I've given you some sort of clue given what little I have to work with. Here's another, my scanner is a Uniden BC796D which doesn't experience any major difficulties in this RF rich environment. You just may attempt to borrow one or have someone who owns one check it out at your location, you have nothing to lose and everything to gain, maybe a new scanner that works for you.
 
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I got 2 bc296d's same problem with cell/pcs antennas. We got a scanner meeting coming up in a week and a 1/2. This will be a good discussion. Thank You all for your input. I am happy that I am no longer losing the CCS. Craig
 

thehammer

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I have a 396T and have the same problem when I arrive at work. There is a cell tower next door to our yard. When I get within a block of the place my display goes haywire. I dont recieve any trunked transmissions while Im in that area. I havent tried conventional freqencies in the area. I was stumped when it first happend. Im sure that your radio is fine. Mine works great outside the 'trouble' zone.
 

kb2vxa

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Hi Hammer and all,

"There is a cell tower next door to our yard. When I get within a block of the place my display goes haywire."

That's an extreme condition, I wouldn't expect ANY scanner to function properly in that close proximity to the tower. That Yeasu I mentioned went haywire at approximately the same distance to a communications tower I passed regularly while the others were overloaded within about a mile. That's the difference I was talking about, I don't suppose even my bandpass filter would have worked well enough THAT close to the tower.

"I am happy that I am no longer losing the CCS. Craig"

I'm happy for you Craig and thus endeth the discussion.
 
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"It ain't what people know that bothers me. What gives me the most trouble is people that think they know everything"
 
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