Mobile Antenna Options

[Nick23]

I recently had my coax break on my mag mount. A hole in the roof is not an option. One option is a door jamb mount or flat mount maybe by the rear tail light. Another option is a tri or quad magnet mount on the roof. Votes?? Any other options I have overlooked? I have a 99 Toyota 4Runner.

I want to purchase an Xforce TnT 350hd in the future. Could the door jamb or flat fire stick mount be better for this since they are hard mounts? Or could I run a magnet mount with 400 max watts?

I have a Predator 10-K 12 inch shaft and a Wilson Silverload 4 foot. I would not have a problem with buying a 102 if I the mount was down by the tail light though.

Thoughts?

Thanks guys,

Nick

 

[CTStallion]

I like the door jam mount options you are considering; Diamond and Comet (among others) make some pretty robust mounts in that particular configuration.

The higher you mount it, the better.

I prefer these sorts of mounts over ANY magnet mounts, as you can actually 'ground' to the car body with these, unlike the capacitance match you obtain from a magmount.

Don't get me wrong, magmounts DO have their place, and they DO work; I've just not had much luck running high power (say more than 500W) through them. But for a barefoot radio, even up to 100W (IF the antenna is rated for it, and you have a good match & swr) I'd say a magmount is fine.

For example: on 40 and 80 meters, with hamsticks, the only way I can obtain a good match with a magmount is to add more coax, as I find that I need that "counterpoise" in order to match it. However, if I take that SAME tuned antenna, and put it on a trunk mount, or a hatchback, or a door jam mount which is GROUNDED to the car body, I don't need all that extra length of coaxial cable in order to obtain a match.

At 20m and above, it's a crap shot; sometimes I need the extra cable, sometimes I don't.

10/11/12/6 meters: magmounts work just fine with as little as 12-18 feet of coax, no doubt because the length of the coax cable approaches or exceeds 1/2 wavelength on these frequencies. This is precisely WHY a person can run QRO with a magmout Wilson 5000/1000/K40 or a Penetrator 5000 without issue. Try the same magmount, with the same small length of coax cable on a 40/60/75/80 meter hamstick, and it won't work nearly as well as far as obtaining a proper match. Of course, it ALSO has to do with the 'radiation resistance' of such a small antenna at these low frequencies as well, but for all intents & purposes, and to keep the explanation as simple as possible: mobile antennas grounded to the car body are BETTER / magmounts are worse.

 

[AL567]

Sirio 5000

 

[AL567]

Sirio 5000

Appears to be a door jamb mount

 

[W5LZ]

The 'biggy' as far as mobile antennas is how tall of an antenna can you deal with? Or, just how short of an antenna do you absolutely have to have?
Mounting a mobile antenna as high as possible is a good idea. It's not the height that matters, it's getting the antenna where it's not 'obstructed' by things. Antennas would much rather be above metal than beside metal, and hate being under metal. If you try to at least keep an antenna sort of happy, you tend to 'do' better than not.
I've yet to find a vehicle that doesn't have some sort of 'knock-out' in it so that you can get from the inside to the outside. May not be in the most 'handy' places, but they are there. A few extra feet of feed line is almost always better than pinching coax cable in any way.
How about how you mount the thing? That's another one of those 'compromise' thingys. If whatever mount can handle the size/weight of your antenna, then knock yourself out with it! It's a pretty good idea to be sort of 'conservative' when you talk about 'abilities' of antenna mounts. Having more than needed is always better than not having enough. You gotta be at least sort of realistic about things or abilities.
So which antenna would I recommend? I ain't gonna recommend any particular brand, model, or type. The longest antenna you can live with will be better than a little bitty 'shorty'. Then it's up to you...
- 'Doc

 

[binrat]

If it was me, 102" SS off of the back bumper, then Sirio 5000 mounted something like above.. The predator would be next and lastly the Wilson.
The TNT350HD is an awesome amp but I would ensure your antenna is mounted and the SWR is done prior to hooking the amp up.

 

[222DBFL]

Sirio pl5000, or how tall is the predator? Put it on top, hard mount. Good coax and and power and ground for the amp. As well as ensuring a good VSWR reading should would be good IMO, if height isn't an issue, put the 102" ss whip up top. Using side mounts will make you more directional as in whatever corner it's mounted on, versus the top near center, would make you more omnidirectional. Listen to these guys and what they are telling you as they know what they are talking about. Like posted, your system is only as good as the antenna system in front of it. You can have 1000 watts and not talk 10 miles if you don't have all your ducks in a row. And your antenna system is one place I would not recommend skimping on. JMO and some will disagree, but put some money into your antenna system before you buy any amp. In the end you will get your name called more often with a proper setup. God bless.

 

[M0GVZ]

If it was me, 102" SS off of the back bumper

NOOOOOO. The current maximum of the antenna is right next to a parallel sheet of metal that is the ground plane.

There's no reasons not to drill a hole in the roof. Usually the excuse is the old "resale" value however this can be overcome by putting a small colour coded sharkfin GPS antenna in the hole when you sell the car and advertising that as a feature. Some people even assume they're a factory option because the colour matches.

 

[AL567]

Sirio gutter mount

I found a gutter mount for the Sirio 5000. The picture is the gutter mount with the so239 connector.

 

[Robb]

I found a gutter mount for the Sirio 5000. The picture is the gutter mount with the so239 connector.

Interesting . . . But it will make your antenna somewhat directional; being biased on either side of the vehicle . . . In addition, I doubt that your gutter mount will support the stresses of a tall antenna like the Sirio 5000 w/o knockig it off . . . Nice find - tho. Prolly work better as a mount for a 2m antenna - lol . . .

 

[AL567]

You know, you're probably right I never thought about that. I have mine hard mounted. That is a pretty heavy and long antenna. The gutter mount may be intended for one of their smaller antennas. Probably shouldn't have speculated it is for the 5000 series. Very good point Robb.

 

[M0GVZ]

The Diamond K400 is definitely able to support a Sirio 5000. I've used one with a Little Tarheel 2 with a 6ft whip on.

 

[binrat]

NOOOOOO. The current maximum of the antenna is right next to a parallel sheet of metal that is the ground plane.

There's no reasons not to drill a hole in the roof. Usually the excuse is the old "resale" value however this can be overcome by putting a small colour coded sharkfin GPS antenna in the hole when you sell the car and advertising that as a feature. Some people even assume they're a factory option because the colour matches.

While not ideal, it works. I have a friend running one and it works.

 

[Nick23]

I just looked at Comet and Diamond hatchback door jamb mounts. Would I just buy a heavy duty CB stud to put on it. Would it fit on those ham mounts?

 

[Nick23]

NOOOOOO. The current maximum of the antenna is right next to a parallel sheet of metal that is the ground plane.

There's no reasons not to drill a hole in the roof. Usually the excuse is the old "resale" value however this can be overcome by putting a small colour coded sharkfin GPS antenna in the hole when you sell the car and advertising that as a feature. Some people even assume they're a factory option because the colour matches.

First up the wife doesn't want a hole in the roof. Second this damn Japanese Toyota has a very thin roof. I would be worried about running an antenna like a 10-K even with a backing plate.