Batboard

HI guys,

Anyone have experiance using one of those? How reliable are they, do they reduce power by a whole lot? It's off a SM120 40W UHF mobile.

Thanks

I am not a big fan of on glass antennas. They tend to have higher reflected power, there are all types of problems with tinted windows in newer vehicles and generally tend to be poor performers. You would be far better off with a trunk lip or mag mount if there is a problem with drilling a hole in the vehicle.

Not recommended...I don't think I've ever seen a positive comment for VHF/UHF glass mount antennas on this board. Personal experience leads me to the same conclusion...they suck. We've tried several different types, none performed anywhere near as well as even a fender mount antenna. They can show no reflected power, and you still lose half of your operating range! Not to mention it can be difficult to eliminate interference it can cause with your AM/FM radio. I suppose if you work well within the range of your given system they might work ok for you, otherwise forget it.

Todd

<font size=-1>[ This Message was edited by: wavetar on 2002-03-05 21:20 ]</font>

What are anyone's thoughts about them for 800 trunking?

Tron

Through-glass gain antennas have been used for years on 4-watt AMPS systems for analog cellular systems. The glass acts as a capacitor in the feedline, and if properly installed and tuned should pass most of the RF with little or no loss.

Problems arise due to improper physical installations (e.g., tinted or metallic glass), or when the installer doesn't bother to take time to tune the system.

I'll take a direct copper connection to the antenna any day over a glass antenna, but when putting the SECOND hole in the car is too much to contemplate then the glass antenna can provide a workable compromise.

Tom, W2NJS
...in D.C.

If you're really ambitious... I would not and have not done this, but have heard of it being done.

Locate your mounting location, drill a small hole through the glass (done by a windshield type shop), mount the internal piece. this is where I've heard two different thoughts.
1) put a piece of copper wire through the hole making contact with the inner surface.
2) (pretty much the same for both theories here) Flow some solder through the hole.
check height of built up solder, and file/sand solder as needed.

The down side to this proceedure is... you might crack your glass.

Like I said... in theory, not tried nor recomended. Note: drilling glass requires a special drill bit.

You're better off with a trunk lip type mount or a 'fender mount'.

I have never found a glass mount antenna that performs anywhere near a permanent mount or clip on! Don't waste your money!

Not that I don't hear what your all saying about glass mounts, BUT. Have been using them for years. Have done some comparison with an 800 SMR system using both a glass mount and a roof mount on the same pickup. Couldn't see any difference between them when the signal was almost at the point of loosing the signal.

What I have seen in the last few years is a sloppy install of the glass mount. Many techs like to mount them lower on the windows than they should. They don't look for the rear window heater strips and go between them.

Yes the new glass is metal tinted and won't work well at all. You may have to ask around about just what the windows are tinted with. May have to go to some other mounting location.

As for the VHF and UHF glass mounts. I also have them in service. Go buy a good one and not the cheap crap that is on the market today. Make sure you get a tunable one. Think the last VHF one I bought was about $45.00 or so.

You have heard it before, YOU GET WHAT YOU PAY FOR.

Jim

Drilling a hole in the glass will do nothing. The antenna's built in tuning network takes in consideration that there will be capacitance between the 2 antenna halves. If you eliminate this capacitance, it will never even come close to tuning properly.
The higher the frequency, the better a glass mount antenna works. 800 works just fine. VHF is so-so, lowband....FORGET IT!! Oh, don't mount it on tinted glass- tint is made up of powdered metallic particles in most glass and will adversely affect the tuning.