Portables, antennas and remote mounting

[laythrom]

Recently I’ve been (technically) “arguing with myself” about how to wear my comms gear while out in the field and basically decided to fall back onto a similar setup that I used in the Army (radio mounted to my plate carrier) and that got me to thinking; this is where I could use some much more experienced knowledge.

I would like to run a ‘remote’ mount for my portable’s antenna (I.e. wear the 5000 in a pouch on my back, run my coax through the molle loops and ‘mount’ the antenna up by my shoulder).

My worry here is, How much will I screw the concept of a ground plane by running the antenna remotely?

Do I need to compensate for the ground plane since I wouldn’t be using the radio’s chassis for that purpose?

Or am I possibly overthinking this and the remote mount won’t really affect the Tx/Rx?

Or (finally) would the back steel rifle plate (since I can’t exactly afford ceramics) act as a GP itself?

Any insight would be much appreciated.



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[prcguy]

Long before the popular military "TCI MAST" came out that allowed the Army guys to remote their MBITR whips on MOLLE straps, I did some research on the same subject using an MBITR with remote mount and a "tiger tail" style ground element. The results with a somewhat tuned ground radial were much better than without, and better range than just the stock antenna on the radio.

At the time I was trying to prove, which I did, that a recommendation of winding a bunch of coax center conductor through a military backpack or trauma plate carrier worked better than the stock antenna on the radio, which it did not.

Bottom line is you can easily remote your radio antenna with its SMA or TNC or whatever connector, wherever you want using a jumper cable with matching connectors and use a 1/4 wavelength long dangling counterpoise wire attached right at the antenna and cable junction. You won't harm the radio with no ground plane but you will loose some range without one.

If your lucky you can solder the counterpoise wire to a lug that will fit between the antenna and RF adapter and have the friction of the antenna connection hold the lug in place. Worse case you can tack solder the counterpoise wire to the last adapter or connector at the antenna and cover that junction with heat shrink. Your steel trauma plate will probably provide a good enough counterpoise if the antenna mounts right to it and you can get a good and short electrical connection to it.

Many years ago I made up several remote antenna mounts with different lengths of coax, some with RG-58 style and some with miniature RG-316 Teflon coax and sent them to guys deployed in Iraq and Afghanistan for their MBITRs and got great reports like "you should market this thing!" Their target frequencies were mostly in the 30 to 70MHz range where a ground plane for a hand held is more challenging. Then TCI developed their remote antenna thing which became the standard. Mine still works better because of the counterpoise wire.

Recently I’ve been (technically) “arguing with myself” about how to wear my comms gear while out in the field and basically decided to fall back onto a similar setup that I used in the Army (radio mounted to my plate carrier) and that got me to thinking; this is where I could use some much more experienced knowledge.

I would like to run a ‘remote’ mount for my portable’s antenna (I.e. wear the 5000 in a pouch on my back, run my coax through the molle loops and ‘mount’ the antenna up by my shoulder).

My worry here is, How much will I screw the concept of a ground plane by running the antenna remotely?

Do I need to compensate for the ground plane since I wouldn’t be using the radio’s chassis for that purpose?

Or am I possibly overthinking this and the remote mount won’t really affect the Tx/Rx?

Or (finally) would the back steel rifle plate (since I can’t exactly afford ceramics) act as a GP itself?

Any insight would be much appreciated.



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[lmrtek]

use a 1/2 wavelength antenna and no need for a GP