Need help with no reception

OK956

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I have a BCD325P2 that I carry in my car on my on the job routes.

I recently mapped out where I receive no reception. By no reception I mean an absolute dead zone where I am getting the NFM reading on the display.

I've already upgraded to a Remtronix but it hasn't been much of an improvement.

Everything I want to monitor is in the 800 band P25 system.

I'm considering getting a Larsen tri band but I'm unsure if it's even going to help in these complete dead zones.

I dont want some big 3 foot whipper antenna on my vehicle.

Does anyone have any ideas or experience to know if the Larsen tri band will improve reception in these complete NFM dead zones. There is quite a few. It accounts for probably half of my travels and the towers are probably 15 miles but lots of buildings and crests and valleys.

Thanks in advance!
 

K4EET

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I have a BCD325P2 that I carry in my car on my on the job routes. <snip> ... the towers are probably 15 miles but lots of buildings and crests and valleys. <snip>
I see that you have not gotten any responses yet on your posting. That is probably because you did not provide much specific detail like city and state, systems that you want to monitor, etc. If we don't have a clue what route you take other than you might be 15 miles from the closest tower in an urban canyon, I would have to say that yes, you will have some severe reception problems. I would also have to conclude that in all probability, even an antenna 10 feet tall is not going to perform well. If you are that far from towers in a heavily congested downtown setting like Chicago, you would be doing good to pick up a transmitter that was a half-mile to a mile away. Sorry, but big buildings cause a huge amount of signal attenuation.
 

trentbob

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I concur, we need a lot more information than that. Narrow FM is a mode like AM or FM. So not sure what you mean that you just get NFM.

Could be your problem is your radio is not programmed properly or adjusted properly for the type of systems you're trying to hear, you say you're listening to 800 megahertz p25 systems so maybe you're listening to a Phase 2 tdma simulcast system (700 and 800 mix) or a Phase 1 simulcast system (800) that are subject to simulcast distortion secondary to LSM? Your 325 P2 isn't going to do well with that regardless if you have an external antenna.

So maybe you are in a rural area and in that case a mobile antenna certainly will make all the difference in the world if you're just using the antenna on the radio now.

I have used the Larsen tri-band antenna for many many years. Last year I upgraded to the new one that has a reinforced base and a spring but it is the same antenna as it always was.

It's an excellent antenna but you have to install it properly, because it's an NMO mount, you get your best results by drilling a hole over a magnet or lip mount.

Although it's a short run of coax I always replace RG58 with a lower loss coax. If you are really in no reception areas it should be mounted in the center of the roof of your car.

So give us more information, you simply might just be out of range of the systems you want to listen to.
 

OK956

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Thanks for the info.

I scan Tulsa Police, Tulsa Sheriff, Highway Patrol etc which all use the same control channel.

They operate on a Motorola Type II Smartzone system.

I'm scanning from a suburb that borders the north side of Tulsa and I am not surrounded by any tall buildings at all. I can see the Tulsa skyline from some areas if that gives you an idea of the lack of buildings.

So my guess would have to be it's because of some low lying areas.

By NFM, yes it's the narrow frequency modulation acronym. But it will display that when it is also stating it cannot find the control channel. Basically it's just in areas where my reception is such a dead zone that I cannot pick up the control channel. It's not like the transmissions are crackly, it's just flat out dead.

I guess I can try a mobile antenna and if it's still dead then I'll sell the antenna.
 

trentbob

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Ah... that's the information we need. Your radio should work just great on a type II smartzone system. Just make sure the proper sites are activated for where you're traveling and that you're not locked onto one that's too far away. Always keep the sites local and to a minimum.

If you're going to get a mobile antenna the Larsen tri-band antenna is your best bet. I've used one I'm going to say for decades now LOL . You don't necessarily need the new one with the spring. I think you can still pick up the old one for about 25- 30 bucks... the nmo mount will be more.
 

IAmSixNine

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Moto type 2 systems are not narrow band. The channels are 25khz wide.
Do you mean P25 Phase 2? If so those are NFM channels and phase 2 operate at 6.25 khz spacing using TMDA channels. Huge difference between the two.
Keep in mind if your in a vehicle your surrounded by metal and glass. All of which are insulators from RF signals. SO if your 15 miles away from a system that is designed for local coverage and has multiple sites at lower power than an external antenna would be the next step.
 

OK956

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Ah... that's the information we need. Your radio should work just great on a type II smartzone system. Just make sure the proper sites are activated for where you're traveling and that you're not locked onto one that's too far away. Always keep the sites local and to a minimum.

If you're going to get a mobile antenna the Larsen tri-band antenna is your best bet. I've used one I'm going to say for decades now LOL . You don't necessarily need the new one with the spring. I think you can still pick up the old one for about 25- 30 bucks... the nmo mount will be more.
Thanks! Yeah I got the control channel and alternate control channels programmed in so it must just be some low-lying trouble spots.

I am curious though how it is officers in the field can receive near perfect reception on a hand pack radio with a stubby 4 inch antenna but for a scanner you sometimes need a much large antenna to get reception.
 

OK956

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Moto type 2 systems are not narrow band. The channels are 25khz wide.
Do you mean P25 Phase 2? If so those are NFM channels and phase 2 operate at 6.25 khz spacing using TMDA channels. Huge difference between the two.
Keep in mind if your in a vehicle your surrounded by metal and glass. All of which are insulators from RF signals. SO if your 15 miles away from a system that is designed for local coverage and has multiple sites at lower power than an external antenna would be the next step.
I am not nearly as well versed on these systems as you guys are. I know Tulsa PD is on Motorola Type II Smartzone and Sheriff is on P25 Phase 1.
 
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I am curious though how it is officers in the field can receive near perfect reception on a hand pack radio with a stubby 4 inch antenna but for a scanner you sometimes need a much large antenna to get reception.
You're talking Apples and Oranges.

A professional radio costing thousands of dollars and designed for specific frequencies vs. a hobby scanner designed to receive a broad range of frequencies.

Wonder how your car would do at Indy? :ROFLMAO:
 

DJ11DLN

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Another vote here for the Larsen and NMO mount. I have that on my pickup and it's outstanding. Trying to receive with even a good rubber duck inside the car often just doesn't work. I have a Spectrum Force mag mount on my car because I'm afraid to mess with the side-curtain airbags etc trying to fish coax down the pillars and while its not as good as the Larsen, even it makes a huge difference over trying to receive from inside the vehicle. You're inside the next thing to a Faraday cage so mediocre reception that way is just about a given.
 

trentbob

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Thanks! Yeah I got the control channel and alternate control channels programmed in so it must just be some low-lying trouble spots.

I am curious though how it is officers in the field can receive near perfect reception on a hand pack radio with a stubby 4 inch antenna but for a scanner you sometimes need a much large antenna to get reception.
You're talking Apples and Oranges.

A professional radio costing thousands of dollars and designed for specific frequencies vs. a hobby scanner designed to receive a broad range of frequencies.

Wonder how your car would do at Indy? :ROFLMAO:
Absolutely right doc. I can have my 100 with the remtronix SMA 100 (800/UHF) antenna side by side with the apx 7000 with the 800 stubby which works well on UHF 2 also for RX only and try to listen to an out-of-town P1, P2 or smartzone system and the 100... nothing... but the apx banging in clear as a bell.:)
 

OK956

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Thanks all! I'll probably give the Larsen Tri Band a try or maybe the SpectrumForce. Even if it doesn't help in those dead zones it should at least improve it in other areas.
 

Whiskey3JMC

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Is analog VHF/UHF also affected in addition to P25? If just P25 is affected, perhaps simulcast distortion could be the problem. If you see the word "simulcast" anywhere on the site name, you're probably going to pull your hair out trying to receive it on a non-SDS series Uniden. Have a read here
 

OK956

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Is analog VHF/UHF also affected in addition to P25? If just P25 is affected, perhaps simulcast distortion could be the problem. If you see the word "simulcast" anywhere on the site name, you're probably going to pull your hair out trying to receive it on a non-SDS series Uniden. Have a read here
I hope that's not the case. I do not want to drop the big bucks needed for the SDS.

Although, when the 325P2 receives it receives crystal clear. I haven't noticed any distortion.

It seems to either receive perfect or just flat out receive nothing when I get in certain areas.

Good info to know though!
 

OK956

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Is it possible that the squelch is set too high? Just a thought...
Squelch is good. I've double checked all settings. I think it's just black holes I'm coming across and quite a few which is really frustrating. Especially when something important is happening and i have to quickly double back to an area of roadway that wasnt a dead zone. Smh

I'm trying to decide between the Larsen tri band and the larsen 800 mhz specific antenna.

None of the systems I listen to are low band. All 800 band trunking. Plus the 800 larsen antenna is about 4 inches shorter.

Just dont know which will perform better.

Looked at some of the laird phantoms but they need a ground plane and I'm not wanting to make a permanent body mount. I need to do trunk lip mount.
 

WB9YBM

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There are several reasons why you aren't receiving a signal. For example, if you're in a valley or there's a building, hill, or other obstruction between you and the transmitter, the signal might just be getting blocked. Or, there's a transmitter in the vicinity on a nearby frequency desensitizing your receiver.
 

Whiskey3JMC

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Before you consider another antenna upgrade, could you post a link to the P25 system you're trying to monitor so we can determine if simulcast distortion could be the issue? If it is then I doubt you'll notice any improvement no matter what antenna you use. But I could be wrong, everyone's situation is different...
 
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