Glass Mount Antenna Question

[mmtstc]

What would be a good Glass Mount antenna for VHF High (specifically the Public Service range) ranges? I am in the process of selecting a mobile but i have no intention of drilling holes into my car.

Another question - a coworker of mine mentioned something abotu some sticker antennas that can be adhered to a window sans an external antenna. any one have experience with those and where one could find one of those as i have had diffuculty

Thanks for any help y'all can give me.

 

[Skypilot007]

I tried one of those radio shack multi band glass mount scanner antenna's. The one that looks like a cell phone antenna but longer. It was a bit long for my preference but I gave it a try. It worked good on VHF but I wasn't impressed with it at all on the UHF and on 800MHZ. I had been using an 800MHZ motorola NMO trunk lip mount and I'm back with that since 800MHZ is where I listen the most on the road. If you can get a trunk lip mount somewhere on your car it will probably out perform the through glass mount. Good luck.

 

[crayon]

Glass mount antennas do not perform well, and you would be wasting your money.

There are several types of lip mount NMO antenna's that do not require you drill a 3/4" hole in the sheet metal of your car. You will need to attach the antenna with sheet metal screws.

This is a very non-intrustive install and will provide a MUCH better quality feed to your radio(s).

 

[firescannerbob]

There are also 3/8" NMO mounts, so if you want to roof mount an antenna, you don't have to drill quite a large hole.

 

[Al42]

Glass mount antennas do not perform well

Unless 1) they're well designed and 2) installed properly.

Then, again, I've only been using them since Larsen first came out with them, so what do I know? A few decades of actual hands-on experience isn't worth as much as "everyone knows".

 

[crayon]

Unless 1) they're well designed and 2) installed properly.

perhaps.

Then, again, I've only been using them since Larsen first came out with them, so what do I know? A few decades of actual hands-on experience isn't worth as much as "everyone knows".

Any comments from me on what you do, or do not know, (either real or imagined) would be highly spectulative.

If someone is able to install an NMO mount or a lip NMO mount, I would think that they would take the pains to install a glass mount antenna correctly. In this thread, (and skypilot007 in this thread) several people saw an increase in performance after *switching* from a glass mount antenna to a mounted antenna.

I do not work in a professional radio shop, but I am always looking at antenna installs. If law enforcement and businesses will take the time to install a non-glass mount antenna, then I belive anybody who is interested in max performance would be following a good example.

 

[MacombMonitor]

[clipped]
Another question - a coworker of mine mentioned something abotu some sticker antennas that can be adhered to a window sans an external antenna. any one have experience with those and where one could find one of those as i have had diffuculty

Thanks for any help y'all can give me.

Here is a link that references the on-the-glass decal antenna:
http://shop.waltel.com/catalog/product_info.php/products_id/341

I don't have any experience with these, so I won't comment on them.

 

[Al42]

If someone is able to install an NMO mount or a lip NMO mount, I would think that they would take the pains to install a glass mount antenna correctly. In this thread, (and skypilot007 in this thread) several people saw an increase in performance after *switching* from a glass mount antenna to a mounted antenna.

But was it the same antenna on a different mount, or a different antenna?

My 2/70s, whether mounted on an NMO in the center of the roof, or on the glass mount at the top or the rear window, show very little difference. (Not "better performance", which is pretty subjective - measured 0.5db difference from the same mobile position [the car didn't move during the antenna move] to the same distant base transmitting antenna - distant enough that the quieting could be measured for both positions.)

I do not work in a professional radio shop

I've owned 2 of them.

If law enforcement and businesses will take the time to install a non-glass mount antenna, then I belive anybody who is interested in max performance would be following a good example.

While a roof mounted NMO is better than a glass mount, that's not the main consideration in LE. For a scannist who doesn't want to drill holes, a well designed glass mount, properly installed, will receive better than the same antenna on a trunk-lip or cowl mount. This isn't a guess - I've measured the differences many times. There's 0.5db loss between the roof and the top of the rear window. There's 5db loss (more than 6 times as much signal loss) between the roof and a trunk-lip mount, to the opposite side of the trunk. (The loss from an antenna mounted on a trunk-lip mount through the quarter posts varies too much with frequency to mean anything.)

BTW, an antenna on a mag mount close to the center of the roof works the same as that same antenna moved to an NMO mount in the center of the roof that has the same length of the same cable on it at VHF-hi and above. (By 100 MHz the difference in grounding starts to show.) On VHF-lo and below, a mobile antenna - any mobile antenna - is a compromise with reality - there's no way to make an efficient and practical Hertzian antenna for 30 MHz that will fit on a car. (Non-Hertzian antenna technology may offer some solutions in the future.)

 

[Al42]

Here is a link that references the on-the-glass decal antenna:
http://shop.waltel.com/catalog/product_info.php/products_id/341

I don't have any experience with these, so I won't comment on them.

Gee, a distributed dummy load. What will they think of next?

 

[crayon]

Thanks for the relpy Al42, very insightful.

 

[fmon]

My RS glass mounts have been installed for 5 years on the lower front comer of the rear side windows of a Saturn LW (the W is for station wagon which has three side windows). Like the battery bunny beating on the drum "it's still working". I also had a set on another car for several years, they were mounted on the back window lower corners. They too passed the "can you hear me now " test.

 

[radio10-8]

California Highway Patrol uses glass mounts on a large percentage of their vehicles and they work just fine. 1 is for the MDT, 1 for their mobile repeater (154.905) and 1 for their scanner. All glass mounted antennas. The only NMO mounts they use are 1 for main radio (42-44mhz) and the Lojack antennas. I have used glass mounts in the past on 2 of my cars and they were great. Also dont forget these great rare earth magnet antennas that you can read on in the antenna forums.