Relocating Antenna... WOULD it work better?

[BigBubbaBD]

ok Right now I have my 102" on the side of my toolbox like so.


I did that for a few reasons. (not hitting the half hang drivethrews being on of them)

I also have the antenna mount grounded what I think is good



Having said that, my SWR's are good as far as channel 1 in relation to 40 so the height is fine. But its still not 1.1.1 where ideally everybody wants. But I cant seem to get it any lower because its even just high.

So I was starting to think of a solution and started to think it might be the ground plane... or lack there of on the side of the truck like that.
Is this possible?

And would It help by moving the mount to the CENTER of the toolbox on the back of it. (where the husky tag is)?

It will be a pain having the coax and ground in that location because it would have to drop down and go under the box but if it will make the setup work better i can make myself do it.
Also that might be a better location if I got a 10k sometime correct? It would work there wouldnt it?

[Buffalo Soldier]

moving to the centerline is always advisable--though not always possible...this has to do more with the radiation pattern of the antenna in relation to the body of the vehicle, from what i've read.

in terms of your SWR...congrats on getting the consistancy! now, let's work on the overall picture.
first, 1.1:1 is *everyone's* goal...and vary rarely achieved...so getting as low as possible is really what you're going for.

so, what are your numbers looking like, first.
second: is that *box* grounded?? below the insulator for the antenna itself, the mount and the box looks to the antenna like one solid piece of metal...so is the box grounded separately?
next: what *other* gaps in grounding exist? doors are, for example, rarely grounded--and are almost always a source of a couple .1 worth of SWR.

the overall goal of grounding is to make your vehicle look like ONE piece of metal to the antenna.

also, just as a side note: in addition to checking SWR on channel 1 and 40, you might check channel 20 as well--often the SWR on that channel will be slightly different (usually just a tad higher) than ch. 1 and 40. what is common is to take the average between what is on ch 1 and 40 together (they will usually be similar), then average that with ch. 20.

of course every little bit helps in terms of SWR, so getting it as low as possible is the desired end-state. the other thing to look at is the length of the antenna. to this end, having a *tunable* antanna is useful. with the 102" whip, the only way to adjust the length of the antenna is to physically cut/file the antenna...and for most non-techs, this is usually not advised...cut too much, and you just wasted a perfectly good antenna.
if you find you *must* cut/file the 102" whip, cut with a VERY good saw (you don't want barbs on the end of the antenna), and start with VERY SMALL increments...we're talking 1/16th- and 1/8th-inch increments. and, don't forget that the tip cap should come OFF before you file/saw, and be replaced afterward, as it radiates, too!

what i would do, before i cut *any* antenna, is use a *tunable* antenna first, and see what you can get the SWR down to with *that*...once you see what is *possible* with a tunable antenna, you can try to cut the 102" whip down in very small increments to try to get *it* down to that target.
the problem with this is that every antenna is different, and getting a tunable antenna down to 1.1:1 might be possible on your setup, while a 102" whip might *not* be possible.

i know it took *forever* (literally months) for me to get the SWR on the 102" whip i use on my jeep down to anything below 1.3:1 with any consistancy...and the only way i ended up succeeding was changing out the spring a couple different times.

[BigBubbaBD]

Can multiple pannels be grounded to the same location? Like can the antenna mount, truck bed and cab all go into one cable and bolt to the frame or do they need to bolt seperately.

I just dont know or understand I guess, im not sure either way. Ive hooked up my old radio (4watt) to set the length of the antenna and its as perfect as you can get 1.1 and maby a quarter.

Maby ill just leave it and redo all the grounds.. Think that will help?
I also thought about the spring but the antenna height seems to be correct.. could the spring have a short or something?

when you said box do you mean the toolbox where is it grounded or the truck "bed" (often referred to as a box).. just wanting to clear that up.
the toolbox is grounded to the bed.. the bed is grounded to the same ground wire as the antenna mount.. maby not the best option?

[BigBopper]

ground the tool box to the bed, ground the antenna to the bed also,,,,you want a bigger ground plane that the frame,,but I did ground the frame to the bed of my truck also

[Buffalo Soldier]

from a electrical protection standpoint, grounding separately is always the best policy. if you have a radio, an antenna, the battery, the ignition, etc...all grounded to the same physical location, there's the possibility that a strike on one will goto ground, then up the ground *to* another element.
for example, when i was in the military we would never ground an antenna and a generator to the same groundpoint...if the antenna got hit, there's the possibility that the strike would goto ground, and *some* would feed back up to the generator. losing a radio is one thing...serious, no doubt....but if that is compounded by blowing up a generator, that *might* just be a show-stopper!

from a "trying to lower the SWR" standpoint, though, i don't think there's an issue grounding the bed, the box, and the antenna all to the same place.

box vs. bed: when i said "is the box grounded" --i meant the accessory box to which the antenna is mounted...didn't mean to confuse you with box vs. bed.

[Buffalo Soldier]

not for nothing, but...are you using the SWR meter on the radio, or a separate SWR meter for these measurements?

[BigBubbaBD]

seperate


so basically in your opinion it sounds like I just need to either add more grounds or reground what I have now.

[Godzirra]

Have to watch it thou, if u have to many seperate ground spots you can create ground loops! Which can cause problems like alternator whining noise feedback into radio or cb radio and just poor ground!

[Looney]

leave it if it works man looks good there.

[SmallTruckBigRadio]

All great advice, I'm impressed.
Even with the advice from Looney "leave it if it works ....", because the influence of the cab and bed with the "round radiation pattern" of the 102" whip will be tough to make "flat"

Thinking outside the box...Do a Predator 10K, it's tunable, looks better, and will probably work better.

[BigBubbaBD]

All great advice, I'm impressed.
Even with the advice from Looney "leave it if it works ....", because the influence of the cab and bed with the "round radiation pattern" of the 102" whip will be tough to make "flat"

Thinking outside the box...Do a Predator 10K, it's tunable, looks better, and will probably work better.

Yea I want a 10K. But on my truck and in that location I would get broken or knock it off.
If I ever move it to the center of the toolbox (not sure if it would work best in the front of the toolbox by the window or at the rear at the bedside of the box) I might spring for the 10K and hope I dont damage it

[jessejamesdallas]

I totally agree with Buffalo Soldier.

Usually, with 102" whips when tuning them, they generally end up being too short, and not too high. This is the reason most people use the spring, to raise the over-all height another 6".

Another trick you may try, is to mount a extension bar to your tool-box, and mount the antenna to that, which would put the antenna up-in the air higher, which would let the antenna clear more of the body of the truck (or cab)

This is the way I had one mounted to the rear bumper of my Suburban at one time. The bar is just a pole used to drop ceiling-fans from the ceiling. They come in all size's, and available from Home Depot, and Lowe's.


The antenna is mounted to the pole, using a "Mirror" mount., and the pole is mounted to the bumper, using a round metal plate,that has a place to screw the pole into, which I found in the pluming dept. @ Home Depot. (not sure what they are really used for, but work great for mounting the pole! :D )