questions about low profile antennas

beaujo_fire · Post by **beaujo_fire** » Sun Sep 24, 2006 7:04 pm

I have some questions about the low profile antennas that are out on the market. I have done some searches on this website regarding my questions but still not sure if these antennas might be for me.

First off. I am installing this on my personal truck. I am not able to drill holes in the vehicle so the typical nmo mounts that I have always used in the past are out of the question. I am aware of the hood lip mounts and I am exploring that option also. I am also aware of the antennas that STI make that will replace my stock am/fm antenna and function as an antenna for my freqs. But I can not find one made for my vehicle.

So first, my setup that will be installed in the truck.

The truck is a nissan titan
vhf - kenwood tk-730
uhf - kenwood tk-830g

I know, this is a motorola board and I have lots of moto gear spectras, maxtracs etc etc.... but the control cables are to big, at least the ones on my current spectras are to big to hide and route where I plan to install the radios and control heads.

What I am wondering, and I probably already know the answers to this are - I have a toolbox that is mounted across the back of my bed. I am considering... and I did say I am still considering, installing a uhf and a vhf low profile antenna on the tool box. I am looking at the ones made by antennex right now. The antennas will be mounted right on top of the tool box which I know is below the heigth of my cab, but other than using whips on my hood lip it is my only option right now.

So I am wondering, will the antennas work worth a crap. I know they will not measure up to 1/4 wave whips mounted on my roof like I have always had, but will they work.

The two kenwoods are programmed with ham freqs primarily. I live near Denver Colorado and the majority of my repeaters that I listen to are located on high mountain tops and such. So we have very wide coverage systems here. I don't listen to ham stuff that much anymore, but I do have it on sometimes in the back ground. So I am wondering, from other user's experiences, will these types of antennas do the job for what I am looking for. What do you think?

As for all the 800mhz apco stuff and edacs stuff that is here in colorado. I just have decided to use my protables laying on the console for monitoring those freqs.

Also, the two kenwoods will actually mount and reside inside of my console. When the console is closed, one would not even know that radios are mounted inside the truck. That is another reason for the low profile antennas.

And yes. This is all due to the wife's demands.

Any constructive thoughts and ideas would be appriciated greatly.

Thanks

Dave

Tom in D.C. · Post by **Tom in D.C.** » Mon Sep 25, 2006 4:59 am

David:

There is no free lunch with antennas. Many of the low
profile antennas have very limited bandwidth, which
for receiving doesn't matter but for transmitting definitely
does -- some of them you can only do about 1 mHz with
decent SWR.

Putting them on the toolbox which is shadowed
by the back of the cab is going to put a big dent in
the performance of the antennas as well.

NCSHP311 · Post by **NCSHP311** » Wed Sep 27, 2006 9:31 pm

I have a Larsen mounted on the side fo my tool box which works great. You should consider an L bracket on the side of the tool box!

gws · Post by **gws** » Thu Sep 28, 2006 4:20 am

[quote="beaujo_fire"]
First off. I am installing this on my personal truck. I am not able to drill holes in the vehicle so the typical nmo mounts that I have always used in the past are out of the question.

If its your truck why cant you drill holes?

60A · Post by **60A** » Thu Sep 28, 2006 5:01 am

gws wrote: If its your truck why cant you drill holes?

Maybe it's a lease vehicle?

Tom in D.C. · Post by **Tom in D.C.** » Thu Sep 28, 2006 5:24 am

Leased? So what if it is. Years ago I put 3/4 inch holes in
the trunk lids of three consecutive PH&H cars I had and
when they went back nobody said a word. That was then;
maybe the leasing companies are smarter now, who knows?

gws · Post by **gws** » Thu Sep 28, 2006 4:09 pm

60A wrote:
gws wrote: If its your truck why cant you drill holes?
Maybe it's a lease vehicle?

Why cant you put a hole in a lease vehicle?

NCSHP311 · Post by **NCSHP311** » Thu Sep 28, 2006 6:06 pm

There has to be at least 20 % body damage for it to affect the price of a leased Vehicle.......DRILL away!

beaujo_fire · Post by **beaujo_fire** » Thu Sep 28, 2006 6:12 pm

Typical thread on here. I asked a question about the low profile antennas. I have since received one response concerning my actual question. I appreciate that one response and also the one about the larson on the toolbox. I realize that the larson will out perform the low profile antenna. I was just looking for some views on how much difference the the signal quality would be between 1/4 antenna and the lo profiles. I also realize that there is a very narrow bandwith on the antennas. That is why I stated they would be mainly for receiving.

Yes the vehicle is leased as if it matters. I was asking about the antennas not about how many of you had the balls to drill a 3/4" hole in a leased vehicle and how you got away with it. I have drilled lots and lots of 3/4" holes for nmo mounts in my time. This is one vehicle I can't do that unless I do it in the tool box or use brackets which I am still considering doing.

I was just looking for info about the low profiles and with the exception of the one response this thread has been turned into what I figured it would be when I wrote my original question.

Thanks guys.

kjfswkr · Post by **kjfswkr** » Tue Oct 03, 2006 5:47 am

very defensive about his posts!!

Kevin

EPC_1111 · Post by **EPC_1111** » Tue Oct 03, 2006 9:46 pm

I cant really think of a way to no drill a Low Profile antenna, after a few hours of thinking bout it. You could use 1/4 wave antennas, on L brackets mounted toward the bow of your tool box. They wouldnt really contrast with your box, or the C posts, Ive done it before.

thebigphish · Post by **thebigphish** » Tue Oct 03, 2006 9:55 pm

what kind of material is the tool box? If it's a diamond plate one or metal, just NMO right thru it, should give you a decent groundplane to radiate off of...if it's one of those tuffy-box (plasticky things) then you might want to bolt some sheetmetal to it to create a groundplane for it - or fWIW go with a groundplane-less antenna and some L-brackets and mount off the edges.

beaujo_fire · Post by **beaujo_fire** » Wed Oct 04, 2006 4:04 am

That is what I have decided to do. I will drill and mount to nmo 1/4 wave antennas in the middle of the toolbox and spread them apart as far as I can. The toolbox is a weatherguard diamond plate box. They do make deep neck type nmo mounts still don't they since this material is a little thicker than that usual metal found in vehicles?

It should work ok.

Thanks,

Dave

Tony · Post by **Tony** » Sat Oct 14, 2006 12:03 am

I have mounted 4 antennas spaced equally apart with L brackets to the back lip of my diamond plate (alum)tool box and they work great. The truck is a GMC 2500 HD long bed and the box is flush with the bed rails of the truck. As for the small antennas I have tried both UHF & Vhf and they fall real short, so short in fact I do not use them. I figure I loose some advantage by not mounting on top of the truck but I also gain some advantages by being able to fold over the antennas when needed.

beaujo_fire · Post by **beaujo_fire** » Sat Oct 14, 2006 11:44 am

Tony wrote:I have mounted 4 antennas spaced equally apart with L brackets to the back lip of my diamond plate (alum)tool box and they work great. The truck is a GMC 2500 HD long bed and the box is flush with the bed rails of the truck. As for the small antennas I have tried both UHF & Vhf and they fall real short, so short in fact I do not use them. I figure I loose some advantage by not mounting on top of the truck but I also gain some advantages by being able to fold over the antennas when needed.

Tony,

I went ahead and mounted one antenna so far, a 1/4 wave spike for vhf hi freqs and 2mtr ham. The antenna actually is slightly taller than the height of the cab so hopefully it will not effect it to much. I know it would be better on top of the cab but that isn't going to happen. The problem with my toolbox is that it is one of the type that the entire top opens at once and swings towards the cab. So I had to set the antenna far enough from the cab so that when I open the box it will not hit my cab. In doing so I am hoping it also helped my signal pattern a bit.

We will see soon.

Thanks for your input

Dave

Tony · Post by **Tony** » Sat Oct 14, 2006 5:51 pm

Yes my tool box swings towards the cab too. I mounted my antennas on the lip of the tool box that faces the tail gate which made the antennas about 36" form the cab. When I raise the tool box cover I have no problem with the antennas hitting the cab. I use a dual band about 56", UHF about 30", a small low band and an expiermental ss whip about 70" tall. I do believe that it helps to have the antennas a little father from the cab but I also believe that there is no subsitute for mounting on the cab but I am resolved not to use this method due to the height porblems. Hope this helps.

beaujo_fire · Post by **beaujo_fire** » Sun Oct 15, 2006 7:13 am

I understand how you did it now. Basically the same as how I have mounted mine. So far I am happy with it. The radios are not installed yet, but I have tested the antenna using my vhf mpa convertacom and it seems to be working really well. Considering, here in denver, almost all the repeaters (both public safety and ham) are located on mountain tops one does not need antennas mounted as high as one does in the flat land states.

Hopefully today I will start getting some radio equipment installed inside the vehicle.

Dave

Tony · Post by **Tony** » Mon Oct 16, 2006 5:09 pm

I understand about the mountains, I have a daughter that lives in Grand Junction and one that did live in Boulder, then Loveland and when I visiged them I found a lot of repeaters but the one that reached out the most was closed which made me wonder why? This will be my last post on this subject as it is getting so I am rambling on. Hope things work out for you . Tony

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