View Full Version : another ground plane question

02-01-2010, 05:39 PM
I want to put a mag mount antenna on top of my camper. I'm not sure what the camper top is made from, but it's non-magnetic, and it dents quite easily. So it's big and flat, but maybe not all that reflective?

So should I get a piece of sheet metal from the Depot and just glue in to the top? Or does someone have a better suggestion.. poking holes in the top is an option, but I'd rather not introduce more leaks if I can avoid it.

Also can someone confirm that my HT (VX-7) has a SMA antenna connector? And so to hook it up to normal coax I just need one of these adapters, right? https://www.hamcity.com/store/pc/viewPrd.asp?idproduct=415 is UHF female the same thing as PL-259?

02-01-2010, 05:54 PM
Yeah, it's an SMA connector on the HT. An adapter like what you have linked is what you need. The one we have has the SMA male plug, then really thin coax, then the bigger female PL-259 plug. I like having the short section of cable between the HT and the bigger coax since it makes it easier to handle and takes the load off of the little SMA connector.

I am pretty sure PL-259 is a designation for the bigger coax connectors and dosen't specify female or male... it's just the bigger connectors.

02-01-2010, 05:59 PM
this is like the one we got.

I got it at HRO, but this is just a link to another place for the pic.


02-01-2010, 06:01 PM
Cool, thanks Marco I'm going to order one of them up.

02-01-2010, 06:39 PM

Just FYI when I was setting up the LX to use my HT with an external antenna, I chatted with the guys at HRO about what coax to run, what adapters I would need, etc.

In the end what they suggested for me was to add a coax extension from the NMO mount coax to the front of the truck where the HT was and stay away from using adapters due to signal loss. Your situation might be different with the Mag mount vs a NMO mount since the NMO mount has the thin coax and small connector (mine anyway) already.

I'd have to look at what all I ended up with but I'm pretty sure I come off my NMO mount with the thin coax, right into my thin coax extension (with no adapter) and then into the HT again with no adapter.

02-01-2010, 07:26 PM
I want a setup that any radio could plug into.. a big effective 2m antenna, adequate ground plane, and a coax that could get tossed around to anyone's HT or vehicle that's within a 20' radius. I think the little jumper is what I need, it won't always get used and any loss will be made up for by better than average antenna propagation.

02-01-2010, 10:37 PM
Yeah, it's an SMA connector on the HT.
Just use the adapter. i have one and it works good going to my home made 2M 3 element yagi
I am pretty sure PL-259 is a designation for the bigger coax connectors and dosen't specify female or male... it's just the bigger connectors.

The PL-259 (Male)
and SO-239 (Female)
are both military spec UHF connector callouts. These UHF connector, also called Amphenol coaxial connectors, are a World War II threaded RF connector design, from an era when UHF referred to frequencies over 300 MHz. Originally intended for use as a video connector in RADAR applications, they were later used for RF applications. These connectors were developed on basis of a shielded banana plug.
Banana Plug

UHF connectors are generally usable through what is now known as the VHF and HF frequencies and can handle RF power levels over one kilowatt. Despite the name it is rarely used for actual UHF frequencies as they don't work well above 300 MHz.

The most popular cable plug and chassis-mount socket carry the old Signal Corps nomenclatures PL-259 and SO-239, respectively. The PL-259 can be used with large diameter coaxial cable, such as RG-8/U and RG-9/U, and the smaller diameter RG-58/U and RG-59/U with the UG-175/U and UG-176/U adapter sleeves. The thread is usually 5/8 inch 24tpi UNEF standard. The center conductor jack on the SO-239 will also accept a banana plug.

UHF connectors were replaced in many applications by designs that have a more uniform impedance over the length of the connector, such as the N connector and the BNC connector, but they are still widely used in amateur radio, citizens' band radio, and marine VHF radio.

Just sayin'...

02-02-2010, 08:56 AM
How about a collapsible tower to use with the pop up, rather than a puny mag mount? :thumb::yagi:

Bruce Miller
02-02-2010, 04:24 PM
For $58 you can get a 4 element 2 meter beam with mounting hardware. Go to www.arrowantennas.com. They're in Cheyenne. Exceptional quality and workmanship. It's back packable, too. Mount it to a length of aluminum, or fiberglas, or PVC tubing alongside your RV, picnic table, etc. There is a huge difference between a rubber duckie or a mobile whip compared to a beam. A must have to hear and be heard in remote, mountainous areas.

02-02-2010, 05:17 PM
Go to www.arrowantennas.com (http://www.arrowantennas.com). They're in Cheyenne. Exceptional quality and workmanship.

They made the J-Pole that I have mounted to the back of my house. Good stuff.

02-02-2010, 05:50 PM
Ok, I'm liking this direction.. just need to come up with an easy way to store/transport it... but should fit under one of the benches inside the camper. So that just leaves mounting, and pitching the idea to the XYL.. ;)

They made the J-Pole that I have mounted to the back of my house. Good stuff.

Matt have you transmitted much on that sucker? Let me know if you want to try simplex some night..

02-02-2010, 06:09 PM
I am using the same j pole as Matt