Question about a glass mount 800 install

firemedic2150 · Post by **firemedic2150** » Wed Jun 09, 2004 10:36 pm

I am thinking of mounting a glass mount antenna for my 800 trunked 35W Moto. to the back glass of my Dodge Stratus. I have a aftermarket satellite receive antenna that would only be a few inches away on the roof in front of the back glass. Do you think I would end up toasting the front end of the satellite receiver on TX ? Also anyone had any noise generation problems from these satellite antennas, I know they are active antennas ?

Thanks
Mark

tvsjr · Post by **tvsjr** » Thu Jun 10, 2004 4:04 pm

Exactly the opposite.

From another post of mine:

I've got one of the small puck-style antennas on the roof, and it works great... that is, after I ran it totally separately from the other wiring (15 NMO mounts on the roof, plus massive amounts of control and power). The first time I ran the coax down, I was enjoying my XM when I hit the master power switch and lost all signal on the XM (totally 100% dead). So, after a four-letter aria, I had to rerun the coax through its very own path. Now, it works like a charm.

Apparently, the radios (Spectras mainly, in the back) were radiating down the coax enough that, if you paralleled their coax with the satellite coax (little, very poorly shielded stuff) it would totally nuke the satellite receiver.

However, the XM antenna is about 10" from the 1/4 wave antenna on one of my most-used radios, and I haven't had a problem yet. I'm assuming the downconversion done in the antenna is likely done to somewhere <100MHz (due to feedline loss at any reasonably high frequency), so HF might be an issue at sufficient power levels.

firemedic2150 · Post by **firemedic2150** » Fri Jun 11, 2004 11:58 am

Great!!
The radio is remote mounted, and the Sirrus is on the side of the console up front, so should be OK then.

Mark

Bob W · Post by **Bob W** » Sat Jun 12, 2004 2:22 pm

firemedic2150 wrote:I am thinking of mounting a glass mount antenna for my 800 trunked 35W Moto. to the back glass of my Dodge Stratus. I have a aftermarket satellite receive antenna that would only be a few inches away on the roof in front of the back glass. Do you think I would end up toasting the front end of the satellite receiver on TX ? Also anyone had any noise generation problems from these satellite antennas, I know they are active antennas ?

Thanks
Mark

I remember a Motorola product bulletin - early 2000 time frame - warning against running 800 anything (except for cell phones) into glass mount antennas. It seems you wind up with a significant amount of radiation in the vehicle,

ricciticcitembo · Post by **ricciticcitembo** » Wed Jun 16, 2004 7:59 am

Bob W wrote: I remember a Motorola product bulletin - early 2000 time frame - warning against running 800 anything (except for cell phones) into glass mount antennas. It seems you wind up with a significant amount of radiation in the vehicle,

I'll second that.

I also have a glass mount 800, and try real hard not to TX on it with
35 Watts. In fact I AM going to swap it for an NMO.

Also when I tried a Glass mount on UHF is was NFG as well.
works kinda like a radiating resistor Dummy load with leaky coax.

YMMV.

If you got a good RPTR system, you could probably get away with it
if you don't mind the extra exposure to RF inside the vehicle.

It's not the ideal solution, that's for sure. I don't much care for glass
mount even on RX Only since it seems to suck.

va3wxm · Post by **va3wxm** » Wed Jun 16, 2004 8:58 am

My experience with glass mounts was sort of iffy. They're probably acceptable on 800 megs but anything lower and they're more or less useless.

Now I use proper NMO's and the're great!

ROSDJS · Post by **ROSDJS** » Wed Jun 16, 2004 2:03 pm

I'm kinda sad to hear that....I was thinking of going with a glass mount on my '95 Blazer for my UHF......I may switch to one of those hood mount brackets now.....anyone know where i can pick up a decent one??

Matt

firemedic2150 · Post by **firemedic2150** » Thu Jun 17, 2004 12:05 am

As far as usless goes, no they are usufull at the 800 MHz. range because they approach true capacitive coupling at these frequencies. I agree at 400 MHz. the system requires a large amount of tunning to get a "Decent" match, and they do just become lossy radiators generaly below this band. I have installed several on 800 MHz. frequencies, and when tuned they will match a 1/4 wave NMO in performance, the only question that I am raising is to its effect on the Satellite receive antenna close by.

va3wxm · Post by **va3wxm** » Thu Jun 17, 2004 4:24 am

ROSDJS wrote:I'm kinda sad to hear that....I was thinking of going with a glass mount on my '95 Blazer for my UHF......I may switch to one of those hood mount brackets now.....anyone know where i can pick up a decent one??

Matt

Do you mean an L-bracket or a hatchback lip mount? I've got both on my Saturn VUE. The L-brackets came from Larsen and the lip from Comet. Diamond also makes such an animal. You can get them from any ham radio supply shop -- AES, HRO and the like -- in PO and NMO configuration.

ROSDJS · Post by **ROSDJS** » Thu Jun 17, 2004 8:56 am

I'm probably looking for an L bracket with an NMO. I gotta check it out more closely but I wanna put a 1/4 wave on the drivers side of my hood. Local PD uses them with your low band system and they don't look too bad, so I'm hoping the 1/4 wave won't look too bad either. Still disappointed about the glass mount not working too well. I know everyone is gonna say just drill the roof but I don't really wanna, plus I put alot of crap on the roof.

Matt

Question about a glass mount 800 install

Question about a glass mount 800 install

Re: Question about a glass mount 800 install

Re: Question about a glass mount 800 install