Antenna Placement

[erchambers]

Ok guys,

The time has come that I must drill holes. I have a 1997 tahoe and I need to know where put them and well...how would you do it?

Going down the center in a straight line is not an option here(even though this is the ultimate place to install antenna's) I dont want to look like a porcipine.

For right now the only thing I have in the truck is a Kenwood TM-D700A Dual band, and 1 BC780(800mhz) and a Radio Shack 2096(800mhz Digital) I will be adding a console and 2 motorola spectras for vhf and uhf ham bands hopefully soon. For now though, with keeping the two spectra antennas in mind where would you mount the two 800mhz antenna's? All the way in the back, Center of the truck? All the antennas will eventually be at the 19" level, and the only big antenna I have on there is my dual band 2/440 antenna, but I do have a smaller one that is 18" that I might put back up there till I get a new black one.

So, any suggestions, tips, arguments...I would love to hear them......this is probably going to be done within the next 2 weeks so I need to get a move on ordering some parts.....let me know what you guys think.


Eric

[Jim202]

You might want to consider going to a tri-band antenna
and using a triplexer to split off to the three radios.
Use this configuration all the time for Public Safety
command vehicles. They have limited roof space.

This way you get three radios operating off of one
antenna. You just need to make sure you have one
VHF, one UHF and one 800 MHz radio for each of the ports.

There are several companies that make the tri-band
antennas. Take a look at STI-CO and COMTELCO for
a start. Austin does make multi band antennas as
well as the triplexer. STI-CO also makes a triplexer.

Jim

Ok guys,

The time has come that I must drill holes. I have a 1997 tahoe and I need to know where put them and well...how would you do it?

Going down the center in a straight line is not an option here(even though this is the ultimate place to install antenna's) I dont want to look like a porcipine.

For right now the only thing I have in the truck is a Kenwood TM-D700A Dual band, and 1 BC780(800mhz) and a Radio Shack 2096(800mhz Digital) I will be adding a console and 2 motorola spectras for vhf and uhf ham bands hopefully soon. For now though, with keeping the two spectra antennas in mind where would you mount the two 800mhz antenna's? All the way in the back, Center of the truck? All the antennas will eventually be at the 19" level, and the only big antenna I have on there is my dual band 2/440 antenna, but I do have a smaller one that is 18" that I might put back up there till I get a new black one.

So, any suggestions, tips, arguments...I would love to hear them......this is probably going to be done within the next 2 weeks so I need to get a move on ordering some parts.....let me know what you guys think.


Eric

[erchambers]

Thanks for the first reply, however that is not an option either....there is be one antenna for each radio, no triplexers or duplexers or anything like that.....but thanks!

[mastr]

You want 5 radios, but "Going down the center in a straight line is not an option here", and you won't use a triplexer. And "I dont want to look like a porcipine". You have imposed too many limitations for a practical install, unless you buy some high dollar covert antennas.

Hitch your pants up, act like a man, and make some 3/4" holes in that 10 year old truck.

[erchambers]

You want 5 radios, but "Going down the center in a straight line is not an option here", and you won't use a triplexer. And "I dont want to look like a porcipine". You have imposed too many limitations for a practical install, unless you buy some high dollar covert antennas.

Hitch your pants up, act like a man, and make some 3/4" holes in that 10 year old truck.

Well one thing is for sure I was not looking for a pissing match here, please folks if you cannot give me your honest opionion regarding my question, then please do not answer. I asked a simple question and gave a few guidelines as to what I want to do and what equipment I am going to have.

If this thread continues with responses like this I will just ask for this thread to be shut down, and I will not post here any more. I value most everyones opionions on here because you are the ones that have done these type of installs.

Thanks once again

Eric

[erchambers]

Also,

Correct eventually I will have 5 radios, I will also have 5 antennas on the truck, I just dont want them all to go down the center, should I put them in a box formation, triangle, etc.....you folks here know what I am asking, and how much room needs to be between each antenna....the two 800mhz are only for recieve and(eventually when put in) the two spectra anteannas and the tmd700a will be the only transmitting radios. I know I am going to have 5 antennas up there, and no I dont ahve to speed high dollar antennas because EACH ANTENNA WILL BE 19" HIGH!!!!!! and yes I WILL BE DRILLING HOLES, but the last two statements are not the subject here.

Thanks,

Eric

[wa2zdy]

You should put them where you want them. The rule of thumb to avoid interaction between the antennas is that they be spaced at least a quarter wave from each other. In the case of a multiband antenna, that means a quarter wave at the lowest frequency. And if two antennas on different bands, they need to be a quarter wave apart on the lowest band used by any of them.

Keep in mind (as this has been debated here before) this quarter wave of separation is the avoid interaction between antennas. It has naught to do with separation as required by repeaters to avoid desense. Desense is a different issue.

I don't know why diplexer or triplexer is out of the question. They work well and are as economical with a multiband antenna as buying multiple antennas. The only thing I can picture is that you WANT multiple antennas on your vehicle. Hey, it's your ride, whatever turns you on.

Also keep them as far from the edge of the roof as possible while maintaining the spacing. At least a quarter wave in all directions is the minimum suggested for the minimally effective counterpoise. More is better. And take note if your counterpoise is only the minimum quarter wave in all directions you will be wasting money buying gain antennas. A good part of their ability to alter the radiation angle to show effective gain is in the larger ground plane.

So as long as you keep them properly separated, within the structural limits of the roof of your vehicle, put them wherever you want them.

[jim]

I put them in a row down the center.

The "box" formation looks like crap. It looks like something that you would see on Hamsexy.com.

In my opionion (and I install TONS of vehicle packages), the in-line formation looks superior to the "box." The box stands out and yells "LOOK AT ME!" The in-line is less subtle.

[w8cmi]

The only options that haven't already been discussed are getting some on-glass antennas (much better at 800 MHz than 150 MHz, by the way) and the can-style and/or "shark fin" low profile transit bus antennas. Pricey, but they work fine. I dunno ... Space 'em out, maybe consider a cowl mount for a gain-type VHF antenna.

You have given yourself a lot of conflicting limitations. Like the other folks said, I'd combine several radios into one antenna if it were my personal vehicle, especially if you don't want to drill a lot of holes.

Lots of antennas on the family car = Hamsexy. No way around it.

[erchambers]

Ok,

I specificly asked for thoughts on 5 antenna's. I am going to drill 5 holes, I am going to install 5 antenna's! I only was looking for information regarding that. I was not looking for information regarding combiners, on glass antenna's, and everyone's opionion on why I am doing this the wrong way.

thanks for all the help but I think I am done posting here.


Moderators please delete this entire thread


Eric

[jhook]

see thats why you shouldn't keep the corn flakes close to the wash room some one might piss in them! damb man having a bad day or what?

[mastr]

I've a few clients like that. Most have only portable radios now. The line down center roof layout is hard to beat.

[jmr061]

So, any suggestions, tips, arguments...I would love to hear them......this is probably going to be done within the next 2 weeks so I need to get a move on ordering some parts.....let me know what you guys think.


Eric


Posted: 28 Aug 2006 08:09 Post subject:

--------------------------------------------------------------------------------

Ok,

I specificly asked for thoughts on 5 antenna's. I am going to drill 5 holes, I am going to install 5 antenna's! I only was looking for information regarding that. I was not looking for information regarding combiners, on glass antenna's, and everyone's opionion on why I am doing this the wrong way.

thanks for all the help but I think I am done posting here.


Moderators please delete this entire thread


Eric

Um, wow you asked for thoughts and opinions and that is what you got. Time to grow up.

Jason

[alex]

I don't really see a reason to pull the thread. I will lock it though since it doesn't look like the OP is going to get the answer he was looking for, although he asked for oppinions/criticism in his origional post.

-Alex