Nubee Questions-VHF/UHF Antennas

[Pyroboy]

New guy here. I have been reading here for a while but this is my first post.

I got my licence in early 2012 and picked up a Kenwood TH-D72A handheld with a Comet M-24M mag mount antenna. My primary purpose was to have APRS capability and for communicating with other 4x4 drivers in the BC backcountry. I also use the radio on my dual sport motorcycle for the same purpose. I had a CB for a few weeks but they aren't very popular anymore.

Of course, I am now getting more interested in expanding my range and making more distant contacts. I plan to get a Kenwood TM-D710A for the truck in the near future and I would like to get better antennas for the truck and to set up a decent base station.

For the truck, I am looking at the Comet CA-2X4SR and the CSB-750A.

My first question, is, does it matter if these are mounted in the mddle of the hood, on the edge of the hood or on the front bumper? I would prefer to use the bumper as it is the most secure from tree damage from a height and rigidity perspective. However, I thought the antenna would work better mounted on a good ground plane, like the hood. The roof is not an option due to potential tree damage.

My second question relates to power capability. Both antennas are rated at 150 W and the TM-D710A has a 50 W rating, but are the ratings comparable?

I also plan to set up simple base station using the handled for now. I am looking at a Comet GP-3, 6 or 9. I planned to mount the antenna from the facia of the house, about 30 ft. Above ground. Our neighbourhood is about 100 ft above sea level and is generally higher than anything around for several miles. I plan to run coax to my station and just connect the radio when needed. Is there anything special I should consider when mounting and grounding the antenna?

Thanks,

 

[W5LZ]

I think your mobile antenna choices are both good, but they do have disadvantages. Both are 'stiff' antennas, they don't flex much at all, so will put stress on where ever you have the things mounted. The CA-2X4SR Is very nice if you need a fairly wide banded antenna. Besides 2 meters and 70 cm it works well on other 'close' bands to those. If you don't have a use for those 'close' bands, then it's probably not the best choice you could make. I've used one for several years, on more than one vehicle and it serves my particular purposes very well. It will do just fine if mounted on the hood or fender. I've also had a CSB-750A (or one of that series of antennas), but found that it really didn't perform significantly better than the CA 2x4SAR. Being much taller, and no more flexible, it was very good 'limb-catcher'. I don't have it any longer. I also have a Comet GP-6 for fixed use (more than one) and find it does well. Had a GP-1(?) before the one in use now and there is no comparison.
As with any antenna, higher is better. You have to stay within 'reason' with that. My base antenna is something like 20 feet high and does well. Wish it were a couple of hundred feet high, but then, that's not practical for me at all (RATS!). Antennas also 'like' to be above metal, not beside metal, and don't 'like' being under metal at all, sort of. That does NOT mean that a fender mount for a vehicle isn't usable, just maybe not as 'perfect' as it could be, you know? The 'ideal' mounting location for YOU is what is most practical for YOU.
I 'do' APRS too, I think it's fun. Have a '710 and like it, although it isn't my 'primary'
APRS radio. It'll do APRS just fine but I use a separate APRS transmitter (Byonics) for the mobile and it suits my needs. (Laptop for display, scanner for receiving, separate antenna.) Of course, as everybody knows, if you ain't got Kenwood, you got squat! Couldn't resist that one, sorry.
If you aren't using the radio for APRS then the '71A is the exact same radio as the '710 and doesn't cost as much. If you don't use 70 cm then the TM-281 is also a very nice radio. (Can you tell I like Kenwood??)
You know what will 'work' for you better than I do so the decision on what to get and how to use it is up to you.
Have fun.
- 'Doc

 

[KingCobra_CDX882]

With regards to the GP-3,6 and 9 ..

I used the GP-9 for many years..
Excellent antenna..

The GP-3 is so so at best
( i can not tell you about the GP-6)

Your height of 30 ft is fine
(especially how you mentioned being higher then rest of area)

You Might want to consider the Diamond Version.
Built a bit stronger and longer lasting

Diamond X510 electrically is same as the Comet GP9

You also can consider the Diamond X710
(both a taller and higher DB gain dual bander antenna)

 

[Pyroboy]

Thanks for the information! Any suggestions for more flexible mobile antennas? The M24 is great but doesn't work as well as I'd hoped. I could mount one to the rear edge of the hood but it's pretty weak steel compared to the bumper, which is a bit massive.

Mobile wise, I suppose I could use the Kenwood 71A as a repeater of sorts if I have the TH-D72 with the GPS. I'd like to keep the UHF option open for now.

Sounds like I'm set for the base station. Time to order some more toys. My wife will be pleased.

 

[W5LZ]

That 'M-24' is a 1/4 wave antenna at 2 meters and will have no gain, in fact, it will have a slight negative gain. They work well in any situation that any other 1/4 wave antenna will work. On 70 cm they are a vertical array, meaning one 70 cm antenna 'stacked' on top of another 70 cm antenna. It should have some gain on 70 cm. The 'M-24' isn't going to be the best antenna in all situations, a 1/2 wave or 5/8 wave will typically out perform them. That's about as 'normal' as it gets.
If you are willing to have separate antennas for 2 meters and 70 cm, AND willing to do the required switching between the two, it opens up a larger selection of options/possibilities. There's a cost though, either in $$ or in convenience. Another aspect of it is how you plan to use all this. One simple solution is don't drive under anything that will 'rub' off the antennas. Yeah, right. Right??
- 'Doc

 

[Pyroboy]

...Another aspect of it is how you plan to use all this. One simple solution is don't drive under anything that will 'rub' off the antennas. Yeah, right. Right??
- 'Doc

Sure! Driving in trees is a bit of a disease, just like radios!

 

[depark]

a 1/2 wave or 5/8 wave will typically out perform them. That's about as 'normal' as it gets.
If you are willing to have separate antennas for 2 meters and 70 cm, AND willing to do the required switching between the two, it opens up a larger selection of options/possibilities. There's a cost though, either in $$ or in convenience. Another aspect of it is how you plan to use all this. One simple solution is don't drive under anything that will 'rub' off the antennas. Yeah, right. Right??
- 'Doc

Get the 2 seperate antennas and use a Comet CF416W Duplexer. That way you don't have to do any cable switching.