RadioShack Pro-18 Mobile Antenna

Seanm214

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Apr 15, 2019
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83
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Kings Park, NY
I put the mag mount on top of the car and ran it through the door. Doesn’t look like the coax is getting pinched. The weird thing is in some areas the antenna just won’t work. For example I just went to the grocery store with the antenna and I had no trunking signal with the antenna in the parking lot. I unscrewed the mag mount coax bnc from my scanner and put in the rubber duck and I was getting reception!! How is it that I was getting signal with my rubber duck and not my mag mount antenna!!?? What’s wrong here?
 

mmckenna

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I put the mag mount on top of the car and ran it through the door. Doesn’t look like the coax is getting pinched.
OK, that's good. Just be aware of abrasion and water intrusion.

The weird thing is in some areas the antenna just won’t work. For example I just went to the grocery store with the antenna and I had no trunking signal with the antenna in the parking lot. I unscrewed the mag mount coax bnc from my scanner and put in the rubber duck and I was getting reception!! How is it that I was getting signal with my rubber duck and not my mag mount antenna!!?? What’s wrong here?
Could be a number of things...

With some scanners, a strong nearby signal from a cell tower or other transmitter can over power the receiver (even though it's on a different frequency) and effectively deafen the receiver. Think of it as being at a party and trying to listen to a cute girl with a soft voice, meantime the drunk quarterback is screaming in your other ear.

Simulcast systems can have issue, too. The signals arriving at your antenna at different times can effectively cancel each other out. Some scanners are not good at handling this.

Could be an issue with the antenna, mount or connectors.

And while the exterior antenna should work well, the disguise antennas are not your best choice. They are a compromise between performance and looks.
 

sallen07

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That's one of my retirement plans, travel the country doing NMO installs for hobbyists/hams that don't feel comfortable doing it themselves.
Sadly you're on the wrong coast or I'd be first in line. :)

That, and developing gimmick antennas and charging way too much for them. It's a veritable gold mine!
As long as you have "super" or "magic" or "ultra wideband / high gain" in the name then I'll buy three!
 

mmckenna

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Sadly you're on the wrong coast or I'd be first in line. :)
Oh, I was always thinking doing it with an RV, traveling the countryside doing what I do best. Either that, or hit hamfests, easy to find people with lots of mag mounts there. I might even consider asking permission before drilling the hole in their wife's minivan.

As long as you have "super" or "magic" or "ultra wideband / high gain" in the name then I'll buy three!
Abso-freakin'-loutly. I was figuring on mounting a paper clip in a PVC pipe and marketing it as a low profile "digital" antenna with coverage from -15Hz to 40000bajillionHertz with 90dBrio gain (dBrio = Decibels over a random inanimate object). I'll include 100 feet of RG-59 with 5% shield with cheap Chinese UHF connectors on each end. Only $49.99 on eBay with $99 shipping.
 

iMONITOR

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Oh, always the drill. Always.

That's one of my retirement plans, travel the country doing NMO installs for hobbyists/hams that don't feel comfortable doing it themselves.

That, and developing gimmick antennas and charging way too much for them. It's a veritable gold mine!
I know, I know, just just having fun! :p

Yes there's big money in gimmick antennas! Yet it's odd you would think there would be more companies making "good" antennas for scanner users but most are a compromise in one form or another.
 

WB9YBM

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May 6, 2019
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Niles, IL
I want to run it through the passenger side door but don’t want the door to crush the coax and I’m wondering what the proper procedure is for this as I am new to all this.
open the window a crack and feed the coax through that; if wind noise gets objectionable, a towel stuffed in the crack might work...
 

Seanm214

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Joined
Apr 15, 2019
Messages
83
Location
Kings Park, NY
OK, that's good. Just be aware of abrasion and water intrusion.



Could be a number of things...

With some scanners, a strong nearby signal from a cell tower or other transmitter can over power the receiver (even though it's on a different frequency) and effectively deafen the receiver. Think of it as being at a party and trying to listen to a cute girl with a soft voice, meantime the drunk quarterback is screaming in your other ear.

Simulcast systems can have issue, too. The signals arriving at your antenna at different times can effectively cancel each other out. Some scanners are not good at handling this.

Could be an issue with the antenna, mount or connectors.

And while the exterior antenna should work well, the disguise antennas are not your best choice. They are a compromise between performance and looks.
Is there anything you think I could do to try and fix it?
 

tvengr

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Feb 10, 2019
Messages
3,373
Location
Baltimore County, MD
Have you considered mounting it inside the car on the rear window deck? At that frequency it will work better than you might expect.
I have a BNC straight thru panel mount connector mounted on a metal bracket bolted to the frame inside my vehicle. For 700/800 MHz, it works great using a Remtronix REM-800B antenna. That would be perfect for the Suffolk County Motorola and P25 systems. I also have an Austin Condor which I use if I want to monitor high VHF and UHF. There is no problem with RF penetration into vehicles at higher frequencies. Low band is a different story. I have window tinting, but it doesn't seem to affect performance. That being said, it is still better to mount an antenna on the roof, but I prefer not to advertise the presence of radios in my vehicle. You would be surprised how well the Pro-18 will work putting the REM-800B antenna directly on your radio. Your scanner can be updated to receive P25 Phase 2 and DMR with the Whistler Legacy Upgrade. It converts the Pro-18 to a Whistler WS1080. You can use the Whistler 1080 EZ Scan for programming and firmware and library updates. There are many reports of better performance after the upgrade.
 
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krokus

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I put the mag mount on top of the car and ran it through the door. Doesn’t look like the coax is getting pinched. The weird thing is in some areas the antenna just won’t work. For example I just went to the grocery store with the antenna and I had no trunking signal with the antenna in the parking lot. I unscrewed the mag mount coax bnc from my scanner and put in the rubber duck and I was getting reception!! How is it that I was getting signal with my rubber duck and not my mag mount antenna!!?? What’s wrong here?
I saw which antenna you have, but not which mag mount you are using. The cabling used with the mount could be basically soaking up the signal.

The overload/desense option has been mentioned. If your scanner has an attenuator option, try turning that on.
 

Seanm214

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Joined
Apr 15, 2019
Messages
83
Location
Kings Park, NY
I saw which antenna you have, but not which mag mount you are using. The cabling used with the mount could be basically soaking up the signal.

The overload/desense option has been mentioned. If your scanner has an attenuator option, try turning that on.
Ok so you want me to turn on the attenuator. Someone else told me to turn the attenuator off.
 

krokus

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Ok so you want me to turn on the attenuator. Someone else told me to turn the attenuator off.
You should try it both ways.
1) If you have a weak signal, the attenuation can lower the signal too much, and make it unreadable.
2) If you have a strong interfering signal, causing the gain circuitry to lower the gain on the signal you want, the attenuation of the interference might let the gain circuit work as intended. (This is called desensitization.)
 
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