folding antenna for backpack radio

[clanusb]

Alright, well I've always been into camping and backpacking, but this will be the first time actually bringing along my ham radio for emergency communications just in case we don't have cell phone service. I have a Yaesu FT-8800, which I use for my base radio the majority of the time, and for long road trips as my mobile. I am going to find a way to mount it into either a pelican case, or a ammo can, similar to this link:
Mounting an Icom IC-V8000 in an ammo can for portable use
My Plan is to have a battery on the bottom of the case/can, removable radio and mount on the side with the controls/screen facing up, and a speaker right next to that. Sort of like a home-made civilian version of a PRC military radio. I'd also have all the other connections for other power sources in the can in the voids. However, my main concern is the antenna. I've looked at telescoping antenna's but those aren't flexible enough or rugged enough for backpacking. My goal is to have this case/can fit into the Radio Pouch of the USMC ILBE Main Pack, hence the reasoning for a flexible antenna. So here are my questions..

1) Does anyone have any helpful comments on what kind of battery to use?
2) Does anyone know of any 2meter antennas such as the kind the military uses for their portables? ( Toy Soldier )

 

[popnokick]

Fold-up is not what you're looking for

You want a 2M roll-up J-pole. There are many commercially available, and it's fairly simple to make your own. Do they work? I have a QSL from the Space Shuttle from a QSO made entirely with a roll-up J-pole. Here are but a few of the links out there on the web:

Portable Roll-Up 2-Meter J-Pole Antenna

The 2-Meter Roll-up J-pole Antenna

Ham Radio Outlet | MFJ MFJ-1730 | POCKET ROLL-UP 2M ANTENNA

 

[clanusb]

Will these still work, while partially sticking out of the pack?

 

[popnokick]

Rollup for portable, not mobile use

Sure, the rollup antenna will work "sticking out of the pack". Actually, it must stick out of the pack... way out... to work correctly. If you read the details on any of the links I posted, you'll see the rollups have a short length of coax cable before the twinlead (radiating) portion of the antenna begins. You simply suspend the radiating end (the one without the coax connector) vertically from a tree or other overhead object. Just to be certain, you asked about a portable - not mobile - antenna. The rollup is for portable use, i.e. when you stop and hookup the radio for portable (temporary location but not mobile-in-motion). Your bigger problem is going to be power. Your Yaesu can pull 8.5 amps in the hi-power transmit mode. That is going to make short work of a battery that will be small and light enough that you'll want to carry it in a backpack. Maybe you need a combination of a compact radio with a lightweight battery and flexible antenna that could be used mobile or portable. I think they make something called a "handie-talkie" (HT) for that ;-)

 

[LtDoc]

Aside from having to be electrically conductive, the physical characteristics of an antenna are pretty 'flexible'. If it will stand up by it's self, or if you can manage some sort of support for it, ordinary wire will work as well as anything will. Length is not as much of a problem on VHF/UHF as with HF, naturally. For 2 meters or 70 cm, I honestly don't think a usable antenna shouldn't be a problem. Not always very convenient, but oh well, that's the way it goes. A 'gain' antenna, a typical 5/8 wave mobile for instance, would only need an adequate counterpoise to work. (Won't be 'perfect' by any means, but certainly usable.)
From there, your imagination is you only limits. Being 'practical' is also nice. Mounting a mobile antenna on an aluminum foil hat just ain't gonna work very well... maybe?
- 'Doc

(There are enough 'puns' in this to satisfy almost anybody! It's still true though.)

 

[Essexscan]

Check out the Radiowavz MBITR TVAS its flexible but rated for 30watts max designed for the PRC-148-152

MBITR TVAS

 

[prcguy]

The Radiowavz pack antenna is a knock off of an antenna designed by some GI's to cover the 30-90MHz range and they had absolutely no electronics or antenna knowledge whatsoever when they came up with that POS.

I've tested the wind it through your pack antenna and compared to the stock supplied MBITR and PRC-152 1m blade antenna elevated high on a pack over the 30-90MHz range and the Radiowavz antenna is a dummy load in comparison.

There is an entire community of military folks who are unfortunately very misled on antenna theory by a few that come up with these silly ideas claiming things like "you gotta use a full wavelength of wire" and "zig-zaging the wire on your pack will fill in areas on transmit better than a whip" and other useless info. Its worse than CB.

There are a few mil antennas that might be useful for the OP on 2m and if I can dig a few out of the garage I'll post some pics.
prcguy

Check out the Radiowavz MBITR TVAS its flexible but rated for 30watts max designed for the PRC-148-152

MBITR TVAS

 

[Essexscan]

prcguy I'm glad you posted I was looking at that antenna myself. I'm looking for an antenna for a go-bag that i can keep the radio inside and have the antenna outside but has to be able to be banged around like a military flexable antenna for 2m. If you have any ideas when i could find something i'd appreciate it alot

 

[clanusb]

prcguy I'm glad you posted I was looking at that antenna myself. I'm looking for an antenna for a go-bag that i can keep the radio inside and have the antenna outside but has to be able to be banged around like a military flexable antenna for 2m. If you have any ideas when i could find something i'd appreciate it alot

exactly what im looking for.

and i do have two HT's, but i dont think 1-5 watts with a standard motorola "duckie" would get me very far in the back country mountains.

 

[cfn]

How will the portable J-Pole work with 70 cm?

 

[W6KRU]

exactly what im looking for.

and i do have two HT's, but i dont think 1-5 watts with a standard motorola "duckie" would get me very far in the back country mountains.

Increasing power from 5W to 40 W will only make a 9dB (~1.5 S units) difference. If you are in a bad location, The extra power isn't going to help a lot..

 

[clanusb]

Increasing power from 5W to 40 W will only make a 9dB (~1.5 S units) difference. If you are in a bad location, The extra power isn't going to help a lot..

your right, but my HT's are Motorola MTS2000's. They aren't field programmable, which is a downside, but they can take the beating and they would be programmed with the local repeaters before going into the area. Again..this set up for the yaesu would be for back up emergency use.

 

[W6KRU]

Yeah that's a problem with commercial handhelds. I just can't imagine packing a 50 watt radio and a battery to support it and hauling it up and down hills on my back. I hope you're young and strong.

 

[RadioWARE]

You could hardwire a PL-259 through the can on the top. This could be used to screw on a 19 inch whip for 2m or an external connection for the J-pole coax.

 

[mancow]

Honestly, for a true life or death do or die situation I would take one freq over any other and thats 121.5 AM. Every commercial aircraft is monitoring that almost like a network of low earth satellites.You are almost guaranteed to raise someone within a few minutes if not instantly. There would likely be questions to answer later on but if it saves a life who cares?

AM aircraft HTs are abundant on ebay, such as the old King KX-99, Icom IC-A21 etc... plus they even have built in NOAA weather receivers.