2 Meter Antenna Location

[Captain Kilowatt]

What are we talking about through glass or glass mount you can get both for vhf.With over 10 years experience with commercial twoways i can tell you this . Yes through glass will work at vhf but over 95 % of the ones we fitted ,regardless of brand, ended up being replaced with more conventional types. In the end we only used them when we couldn't fit anything else.Uhf through glass seemed to do better though but they were mostly colinear types.

The problem may be that most windows today have tint and the glass mount antennas are NOT to be mounted on heavy tinted glass know as passivated glass. Larsen mentions this in their glass mount antenna packages and in their literature. You also have to be careful not to have heater wires in the mounting location.

 

[Captain Kilowatt]

Sorry for the off topic Cap but how are those mounted?

They come with a special adhesive that is basically the same thing as the adhesive that glues the rear-view mirror to the windshield. I have relocated a glass mount antenna and used rear-view mirror adhesive to remount it.

 

[vkrules]

Yes I know CK . And aftermarket tint films can be even worse,particularly really dark or reflective tints. When in doubt remove the film.Most manufactures can supply re fit kits, you just can't beat that adhesive they use on the rubber backing.

 

[AL567]

I never liked the glass mounts but I'm open minded. How well do they perform compared to the others?

 

[AL567]

found a dual band Larson glass mount for 109.00 but are they really that good? there's just something about the break in connection at the glass that I just never really liked.

 

[Captain Kilowatt]

There is a metal plate on both pieces of the antenna mount. Those along with the glass itself create a capacitor that will pass the RF. They are not the best type of antenna however they do work and they do solve some mounting location problems.

 

[Singularity35]

They come with a special adhesive that is basically the same thing as the adhesive that glues the rear-view mirror to the windshield. I have relocated a glass mount antenna and used rear-view mirror adhesive to remount it.

Thanks Cap, but does the 2nd post I quoted mean that theres no direct connection to the antenna? That would work for me. I don't like to drill holes in my car.

found a dual band Larson glass mount for 109.00 but are they really that good? there's just something about the break in connection at the glass that I just never really liked.

 

[AL567]

Thanks Cap, but does the 2nd post I quoted mean that theres no direct connection to the antenna? That would work for me. I don't like to drill holes in my car.

There is no physical contact between the coax end and the glass antenna. that's the thing I never liked about glass mounts. I'm sure they work fine like I said though I just don't like the break in connection.

 

[Singularity35]

There is no physical contact between the coax end and the glass antenna. that's the thing I never liked about glass mounts. I'm sure they work fine like I said though I just don't like the break in connection.

I see. I'm going to have to try that. Thanks.

 

[AL567]

I see. I'm going to have to try that. Thanks.

The coax box end glues to interior of the glass and the antenna glues to the outside

 

[Singularity35]

The coax box end glues to interior of the glass and the antenna glues to the outside

Thanks for the explanation. I read back the other posts and I do have heater wires and a tint on my rear windshield. That's probably a deal killer. Too bad, it was looking like what I wanted to have on my car.

 

[Captain Kilowatt]

Something most people do not realize is that a lot of antennas have a capacitor in the matching section that in effect creates a break in the antenna connection.

 

[AL567]

Thanks for the explanation. I read back the other posts and I do have heater wires and a tint on my rear windshield. That's probably a deal killer. Too bad, it was looking like what I wanted to have on my car.

I have the heater wires too on the rear. I'm open to all options within reason. I may end up getting a glass mount and put it on a side window. I didn't think they would perform very well but after reading some of the post I may give one a try. The club I'm in is 50 miles away and so is their repeater that's one reason I wanted to hard mount a really good antenna.

 

[The DB]

There is no physical contact between the coax end and the glass antenna. that's the thing I never liked about glass mounts. I'm sure they work fine like I said though I just don't like the break in connection.

Something most people do not realize is that a lot of antennas have a capacitor in the matching section that in effect creates a break in the antenna connection.

Got to it before me... Unfortunately most people don't understand the nature of RF. Given the right conditions an open circuit can appear to be a short circuit and a short circuit can appear to be an open circuit to RF signals.

A large enough capacitor will appear to be a short circuit to the RF signal, while an inductor (or coil), which always has a direct DC short will often appear to be an open circuit, which is why RF chokes are often made from inductors. The direct connection that many blindly espouse is not always as much better than a capacitive connection than they realize. In the end it really comes down to the needs of the operator and the installation.

That being said, I never really liked the through glass mounts. They work great for cell phone frequencies, which tend to perform through such a connection better with less capacitance, but there just isn't enough capacitance for the frequencies, which by their nature need more capacitance to achieve the same levels of efficiency than the higher frequencies.


The DB

 

[Captain Kilowatt]

The multi band antennas and the colli ear tupe like the Super Gainer series have capacitors built into the antenna separating the various sections. In some cases an ohm meter will read an open circuit between antenna sections.