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I am planning a trip with a large group in 6 weeks. We will be spread out in small groups on a trail in a mostly desert plateau landscape perhaps 5 miles apart, but mostly in a straight line.

I'm new to amateur radio, but I have been studying and I intend to take the test for my technician license next week. I have just ordered a Baofeng uv 5r and a Nagoya NA-771. My initial plan was to just change out the antenna on the radio and clip the radio to the side of the backpack, but I've been thinking about it and wondering if there would be sufficient advantage to make it worth mounting the antenna to the backpack frame, or even possibly mounting two with about 16 inches of separation to make my transmissions slightly more directional in front of and behind me. There is a repeater in the 70cm band 10-20 miles from where we will be hiking, but we will only use that if needed to call for emergency help.

It seems like with 5 watts, and the distances involved, I probably don't need to worry, but there will be no cell coverage, so I want to make sure I'm prepared. Would it be worth mounting on the backpack? Should I just add a rat tail on the radio and call it good?

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    $\begingroup$ If your backpack frame is aluminum, then “clip the radio to the side of the backpack” might be worse than either having the radio on your body or an antenna on top of the frame, because of the nearby metal. $\endgroup$
    – Kevin Reid AG6YO ♦
    May 7, 2015 at 3:08
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    $\begingroup$ It's also might be better if the backpack frame is a more efficient radiator than whatever antenna is on the radio, or if it happens to work as a parasitic element which increases gain in the desired direction, like a Yagi-Uda. $\endgroup$
    – Phil Frost - W8II
    May 11, 2015 at 23:52
  • $\begingroup$ Does the backpacker need to be concerned about RF exposure? $\endgroup$
    – Brian K1LI
    Sep 27, 2018 at 1:43
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    $\begingroup$ @BrianK1LI from a 4W radio? $\endgroup$
    – NL - Apologize to Monica
    Sep 27, 2018 at 2:19
  • $\begingroup$ This "Amateur Radio RF Safety Calculator" suggests it may be on the edge: hintlink.com/power_density.php $\endgroup$
    – Brian K1LI
    Sep 27, 2018 at 11:46

6 Answers 6

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If you are worried about range the best thing you can do is get a full sized antenna that you can remotely mount, either on your backpack or elsewhere, and feed it with a short feed line (pigtail). The rubber ducky antennas that come with HT's are very lossy. There are several 2m/440 antennas that can break down with a small allen wrench, so that you could use the ducky most of the time and only have the larger antenna hooked up when you are planning to be further apart, or you are trying to reach the repeater.

The phased array you mention would be something that you could try, but it takes some doing to get it just right. I wouldn't slap that together and hope it works.

The nice thing about Amateur Radio is that you can try all kinds of things. My son is creating a walking stick that contains a break-down 6-meter moxon antenna, complete with balun, for use when he is hiking in Alaska with his 6m/2m/440 HT. I plan to outfit my small sailboat with a VX-7R and a 1/4 wave vertical on the top of the mast to shoot 6m to my car, and then cross-band repeat from there to 2 meters at 50 watts.

The options for what you can do are endless. The options for what will work and work well in a pinch are fewer, but very rewarding when you find them.

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Will getting the antenna higher and in the clear improve things?

Probably.

How much?

Something between "some" and "not at all". It depends on what's in your pack and the very specific geometry involved. The easiest way to quantify the change is to try it and see.

Is it worth doing, given the necessary work, and the inconvenience of having an antenna sticking above your head which will smack into trees and poke people in the eye when you take off the pack?

Only you can decide.

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  • $\begingroup$ Trees won't be a problem. I guess the biggest issue I was thinking about as I started the whole thought process was that wearing the radio on the belt is less than ideal, but once I put the aftermarket antenna on, the belt really wouldn't be comfortable anymore. By hanging it on the side of the pack it is probably already enough of an improvement. $\endgroup$
    – NL - Apologize to Monica
    May 6, 2015 at 21:45
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    $\begingroup$ @NathanL Seems like you are overthinking the problem. Where you clip the radio probably isn't going to make any huge difference. $\endgroup$
    – Phil Frost - W8II
    May 11, 2015 at 23:56
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When backpacking with others where regular radio contact is planned, I will typically clip my Yaesu FT-60 to the side of my pack in a way that positions the antenna higher than the top of my head and then use a hand speaker/mic clipped to the shoulder strap where I can easily reach it.

As to antennas, I pitched the rubber duck that came with my HT and bought a Diamond SRJ77CA 16" antenna. That has made a huge difference in both transmitting and receiving, especially as you get farther apart.

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If all your radios will near the same height (plateau) with nothing between them (like mountains), then the biggest limitation will be the curvature of the earth. With a 2m radio, this limits you to pretty close to 3-5 miles between radios where reception starts to get questionable. If your groups are each just under 5 miles apart, pretty much only neighboring groups will be able to hear each other.

The best way to increase the distance is to raise the height of one or all the antennas. At the margins, even a foot matters. A balloon might help, but a collapsible push up pole would help more. (Or a J-pole hung from a tree, if you have trees.) Another possibility is to get longer antennas suitable for the frequency you are using.

If the antennas are above the frame of the backpack, then the metal in the frame will not interfere. You could ground the radio to the frame, but it would be equally effective to hang a pigtail from the radio. (Either arrangement helps if you mount the radio to the backpack instead of holding it.)

If you want to get really crazy, you could probably hard mount the antenna on the frame with some kind of extension and run coax to the radio so the weight of the antenna doesn't stress the radio. A simple monopole won't work in this situation -- you need a full dipole (which a pigtail provides) or a J-pole or something.

If you can find a repeater within range, it gives you the height necessary to cover the distance.

Whatever you do, I suggest you try it (with some distance) before you go on the trip.

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  • $\begingroup$ Live trees and foliage significantly attenuate VHF and UHF signals. You may have to raise the antenna above the trees. $\endgroup$
    – Mike Waters ♦
    Sep 27, 2018 at 12:11
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I would bring a small canister of helium, small weather balloon, light wire, tiny fishing pole and float your antenna up to increase your range. All these things would be valuable in an emergency situation in other ways.

Or send the the whole hand held radio up and use a Bluetooth mic eliminating the need for a electrical or antenna running the length of the fishing line.

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    $\begingroup$ Good idea. However, the size of a helium-filled balloon required to lift an antenna and coax might surprise you. Check out the links on this Google search. Also, if the wind is blowing hard enough it will pull the antenna over at quite an angle while lowering the balloon quite close to the earth. For this reason, the larger the balloon, the better (ditto for minimizing the weight of the antenna and feedline). I suggest adding size vs. lift, etc. to your answer above. $\endgroup$
    – Mike Waters ♦
    Sep 26, 2018 at 20:42
  • $\begingroup$ @MikeWaters I would use a thin bare wire and you can use it with any radio from a valley. The canister can be 85%helium 15% oxygen. $\endgroup$
    – Muze
    Sep 26, 2018 at 20:49
  • $\begingroup$ You should try that before you go backpacking. :-) Before you do though, check out these 33 previous Q&As about balloon-supported antennas. A vertical that's tens of feet tall may not have enough useful low-angle radiation on 70cm. $\endgroup$
    – Mike Waters ♦
    Sep 26, 2018 at 23:43
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Antennas, for plain olde FM ... the higher the better, the bigger the better.

To answer the question, take as much as is resonable to lug along. Probably some testing before hand is in order.

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    $\begingroup$ Hello, and welcome to ham.stackexchange.com! Let me warn you that this site is different from forum-style sites; we're trying to build a database of excellent answers to well-posed questions. The tour does a good job of explaining. After you answer a few questions your reputation will rise enough that you can comment, which is where we do most of our chatting here ;) (There is also a chat board.) Again welcome, and we'll look forward to more from you! $\endgroup$
    – rclocher3
    Sep 27, 2018 at 22:39
  • $\begingroup$ @rclocher3 FYI, I think that you could 'convert this to a comment', pending moderator approval. (Having said that, I'm not sure that it should be converted.) In fact, non-moderators can flag, edit, etc. any post, and moderators will get a notice and decide whether to approve it. I forget the details, but were you aware of that? $\endgroup$
    – Mike Waters ♦
    Sep 28, 2018 at 1:47
  • $\begingroup$ @MikeWaters converting an answer to a comment seems to be a moderator-only privilege. I could of course flag the answer and mark that it's not an answer, but that's not quite the same thing. $\endgroup$
    – rclocher3
    Sep 28, 2018 at 16:38
  • $\begingroup$ @rclocher3 Yeah, you're right. Sorry. Editing and flagging is available to most everyone; and depending on the action, there might be a place to type in a comment. I would have to temporarily log out of mod privileges to see. $\endgroup$
    – Mike Waters ♦
    Sep 28, 2018 at 16:47
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    $\begingroup$ @rclocher3 I'm kind of violating the commenting rules here (by not moving these comments to chat yet), but I also wanted others to see that they are encouraged to do these things. ;-) $\endgroup$
    – Mike Waters ♦
    Sep 28, 2018 at 16:55

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