mobile antenna

[blueangel-eric]

I just got a Comtelco scanner antenna NMO from ScannerMaster.

I read good things about it. But i am not getting much on UHF on my Pro97. I can only hear repeaters in my county but my handheld Diamond RH77CA can pull in from nearby counties. My mini mag mounts worked the same if not a little better. what gives? I can't hear the DPU data, on 452/457mhz, from the remote controlled locomotives until the train is in sight. I should be able to hear trains with DPU locomotives 5+miles away.

I notice my coil is closer to the top of the antenna when the photo on scannermaster shows the coil being closer to the bottom of the whip.

 

[trooperdude]

Check your NMO mount, coax and connector.

It may not be the radiator at all that's the problem.

 

[blueangel-eric]

Check your NMO mount, coax and connector.

It may not be the radiator at all that's the problem.

I'll have to try it on the other mount.
I have it on a new trunk lid mount. I got the mount from Antennas Direct, an ebay store.
Eric Burris

 

[trooperdude]

I'll have to try it on the other mount.
I have it on a new trunk lid mount. I got the mount from Antennas Direct, an ebay store.
Eric Burris

Use a meter.

Ohm it out.

Trunk mounts are not optimal.

 

[tarylheiny]

I bought one in nov and have had alot of reception problems funny if you call scannermaster they can't tell you what comtelco model # it is and comtelco who have bent over backwards for me can't help much cause they dont know what the specs are without a model# aaaaahhhhhhhhhhh any ideas?

 

[ka3jjz]

More specifics about what your 'reception problems' are would be helpful in determining a solution. If you are hearing a lot of junk such as pagers and such, it's not the antenna at fault, but the scanner. It's encoutering levels of RF that it simply can't deal with - too much input at the front end. A filter for the correct range of freq(s) in question is the answer.

Using the attenuator (if you have one) is also useful in determining the issue - if you notice an improvement, chances are you are simply being overloaded. Most think that a bigger antenna is always better - but when you are talking about consumer grade scanners, ain't necessarily so.

73s Mike

 

[blueangel-eric]

More specifics about what your 'reception problems' are would be helpful in determining a solution. If you are hearing a lot of junk such as pagers and such, it's not the antenna at fault, but the scanner. It's encoutering levels of RF that it simply can't deal with - too much input at the front end. A filter for the correct range of freq(s) in question is the answer.

Using the attenuator (if you have one) is also useful in determining the issue - if you notice an improvement, chances are you are simply being overloaded. Most think that a bigger antenna is always better - but when you are talking about consumer grade scanners, ain't necessarily so.

73s Mike

it didn't make a difference because when i was out in the country it didn't pick up anything either. I sent it back and got me just a plain ole 1/4 wave and that helps. and no there is no pagers on UHF here. and the attenuator just made things worse. if i attenuate then how am i supposed to pick up other counties then?

 

[ka3jjz]

Well you got something to work...anyway, how the attenuator would help -if you were being overloaded - works, somewhat simplified like this - sometimes, when an undesired signal overloads a scanner (say, a pager), the scanner will lock onto the pager and reduce the sensitivity on frequencies around it. This is a very loose description of 'desense'; if you put attenuation into the system (or use a smaller antenna) and the desired signals improve, it's one sign that this is what is happening. It's a very common pain in the neck problem in urban areas, where pagers often run rampant.... 73s Mike

 

[N1BHH]

That Comtelco antenna really is a basic unity gain antenna. I've used quarterwaves with no big problems. I use the NMO-150/450/800 from Larsen on my van and works just fine for me. I've always had good results with Larsen's, got NMO-2/70's and others, too.

 

[Skypilot007]

I also use the larson NMO-150/450/800 on a trunk lip mount. It works very good for me.

 

[hoser147]

Hey Eric what scanner ya running?

 

[blueangel-eric]

Hey Eric what scanner ya running?

the stupid Pro97. but i won't use it much anymore except for out of town trips with trunking systems. I now use the FT60R. The pro97 desenses on VHF-hi from FM broadcast and the like on this side of town. Even with a handheld antenna. But the reception problems with the comtelco i'm talking about is that antenna just is deaf on 450mhz. it was worse before i changed coax adapters but still not as good as a plain ole whip. I even tried some high gain UHF collinear's that was given to me and they work pretty good though no good for receive on VHF so i can't use them.

Eric Burris kc0ldt

 

[N1BHH]

When I'm mobile with the Pro-97 and the PRO-2055, I will sometimes just have the 97 on the seat with the OEM antenna and the 2055 hooked to the Larsen and I don't have any problem hearing anything. Yeah, occasionally some signals are crappy, that's because of band conditions, hills (I got lots in my area) and snow on the roof. I just don't get bent out of shape if I don't hear something 100 percent. A man's gotta know his limitations, as Dirty Harry said.

And the FT60R is hooked to a NMO-2/70 and I have the same occasional lousy reception, I just chock it up to nothing being perfect.

 

[blueangel-eric]

When I'm mobile with the Pro-97 and the PRO-2055, I will sometimes just have the 97 on the seat with the OEM antenna and the 2055 hooked to the Larsen and I don't have any problem hearing anything. Yeah, occasionally some signals are crappy, that's because of band conditions, hills (I got lots in my area) and snow on the roof. I just don't get bent out of shape if I don't hear something 100 percent. A man's gotta know his limitations, as Dirty Harry said.

And the FT60R is hooked to a NMO-2/70 and I have the same occasional lousy reception, I just chock it up to nothing being perfect.

I'm not getting bent out of shape!!! I know what is good reception around here and what is not!!! I wasn't born yesterday. I've lived in Emporia for most of my life and been scanning since 1993. I know what to expect of antennas and signals around here. If i'm going to spend what little money i have on an antenna i expect it to be an improvement over the junk antennas i already have.

Eric Burris