Mag mount reception

[bubbamark]

I tried a search and didn't find what I was looking for. Maybe I wasn't asking the right question so I am just going to post hoping I can find an answer.

I listen to mostly 800mhz in the area I am in. I primarily listen to 2 counties. I have the 800mhz rubber duckie and it works good. I wanted a mag mount in hopes of getting the other county I listen too to tune in better when in my vehicle. I live in 1 county and work in the other so I like to listen to both when driving to work and while at work.

I bought the Radio Shack mag mount and installed it on the roof of my dodge ram in front of the third brake light. I also have a cb antenna up there as well and both coax are run through the 3rd brake light. The porblem I have is I get better reception with the rubber duckie attached even when driving than I do with the mag mount. At times it the mag mount comes in fine but is usually staticy. If I change to the rubber antenna it's clear.

The mag mount is only a few days old so I don't think any connections would be dirty. I did take out the whip part and cleaned the bottom with some fine graded sandpaper as I have read that maybe there was some enamel on it being it's new but it didn't help.

The coax isn't pinch anywhere that I can see either. I thought maybe it was getting pinched by the brake light but it's good.

Any advice I could look into would be greatly appreciated!!

Thanks

Forgot to add that when I turned on the local weather frequency the roof mount pulled the signal in much better than the rubber antenna. So it does seem to work for other frequencies. Just doesn't seem to be pulling in the 800mhz very well. I thought this antenna worked well for 800mhz?

 

[Dewey]

Just a guess... possible desense due to the better antenna? You didn't mention which scanner you are using, but the GREs are more prone to overload than the Unidens. This can really make a difference when giving the GRE "better" reception... outside antenna, in very RF rich environments. Cell phone towers in the area?

I hope you get it all sorted out!
Dewey

 

[bubbamark]

I am using a Radio Shack pro 164. Really isn't any cell towers around that I would consider close enough to mess with it. The static is heard in the town I live in and also the town I work in which is about 20 miles from home. I thought maybe I was getting a much stronger signal now with the external antenna so I tried the antenuator and that made it worse. I can pick up both counties perfectly inside the warehouse I work in no problem at all with the rubber antenna but if I go out into my truck and plug in the external I will get static. The rubber antenna plugged in and inside the car get a better signal than the external antenna.

I have tested this with the key off in the truck and nothing on but the scanner. I know the antenna is working for some frequencies cause like I said before if I listen to the weather channel that comes in much clearer with the external hooked up that the rubber antenna.

 

[SCPD]

I have a Railcom antenna and it works very well on all bands but it only likes a handfull of scanners since it has a 3db gain but on the scanners that it works on it gets out about 100 miles.

It does not like the handheld scanners it overloads them like my pro 94 and 95 it works very well on my Pro 2052 i get out around 100 miles on it.

 

[Halfpint]

Did you try it in any other locations before you went and mounted it?

I've used one of those antennas on all sorts of vehicles over the years and with assorted other antennas and have found that there really isn't just one location for all situations. I have also found that sometimes one experiences `interesting?' / `unexpected?' interaction between any other antennas that might also be mounted no matter how careful one may have been.

 

[jackj]

You didn't list the model number of the antenna you bought, is it rated to work at 800 MHz? If you have an ohm meter then check between the connector's center pin and the outer shell, it should be open if the antenna doesn't have a loading coil at the base. If there IS a loading coil at the base of the antenna rod then the antenna isn't an 800 MHz antenna. Check between the center pin and the antenna rod, it should show shorted as should the connector's shell and the mag-mount base. You might also consider taking the antenna back to Radio Shack, it sounds like you either have a defective antenna or one that isn't rated to work at 800 MHz.

 

[gmclam]

I have two different mag mount antennas I use, one of which is Radio Shack. The scanners I run mobile these days are the PRO-97 and PSR-300. The mag mount always makes VHF work better. If I use an RS800 rubber antenna, sometimes I need to use the attenuator for 800 MHz (now that there's a new tower near me). I never need the attenuator when using the mag mount.

I also have a Dodge Ram (2500) and place the antenna just in front of the third brake light. I do not have other antennas up there. I do have a camper shell, but it is fiberglass. I run my coax through the extended cab side door and that enables me to remove the antenna when I need to more easily.

The older antenna of the two is only a VHF antenna, but works just fine on 800 MHz. The newer antenna is rated from 25 to 1300 MHz, and works the same as the older antenna on VHF, not as good at 400 MHz and the same at 800 MHz. So, if one mag mount (or whatever antenna) does not do what you want, you might try a different model.

 

[bubbamark]

I am using the Radio Shack model number 20-283 rubber antenna and the Radio Shack 20-032 mag mount antenna. I will try and move it away from my CB antenna. The scanner antenna is about 1 to 1.5 feet in front of the cb antenna. Maybe the cb antenna is interfering with the scanner antenna. I'm going to try a few different things this weekend and see what I come up with.

 

[davidgcet]

the cb antenna could be messing with it when you TX on the CB, but at 1-1.5' away it should not noticeably affect RX normally.

i would lean towards a bad antenna or connector. if it was front end overload the attenuation should improve it some and not make it worse. can you take it back and get another one?

 

[bubbamark]

Yes I shouldn't have a problem taking it back. I just bought it last weekend. Plus it's already starting to rust where the little screw tightens the whip to the base and it isn't even a week old. LOL

 

[jackj]

According to the Shack's web site, this antenna should work at 800 MHz. Double check that you have the two antenna rods placed properly. If you do then it must be a bad antenna.