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DIY Manpack

Posted: Wed Nov 13, 2013 9:29 am
by mattltm
I've been using my FT-857 as a portable station for a while now and it's taken a bit of a battering so I thought it was about time that I built it into a manpack style frame and gave it a bit of protection.

Originally I just had the 857 in a soft case and it got chucked into a bag with everything else. I get things started, I built a simple bracket made of aluminium strip that held the battery, tuner and radio.

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This worked fine for a while but I wanted something that looked better and protected the radio a little more. I saw a few examples on Youtube where people had built a kind of exoskeleton frame and put the equipment inside it. That solution was rugged, kept all the equipment together and looked good so I decided to have a go at upgrading my shambles of a portable station into a real manpack...

I found a suitable bag from the local surplus store to use as the basis of my manpack. A simple olive drab pack with 2 side pockets and molle loops to expand if needed.

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I measured the internal dimensions of the main pocket and used AutoCAD to design a frame to fit inside. I decided to make the frame from 15mm copper water pipe as I had some spare and just needed a few simple fittings.

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After checking that the FT-857, LDG Z11Pro11 Tuner and battery would fit inside, I cut the copper pipe and started to assemble.

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Once the frame was dry assembled I tested the equipment for fit before soldering the frame together using a blow torch.

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Soldering the frame was easy but I wish I had used the type of connectors that are not pre soldered. The ones I used had a ring of solder inside the connector so I had to make sure each connector had the correct tube inserted before I applied heat.

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A quick test fit in the pack to make sure it fitted.

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With the basic frame done, I cleaned it up and started to add the fittings. First, some aluminium strips to support the battery. I tried to solder the strips to the copper but it was very messy so I ended up using some small rivets instead.

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Next up was the strips and bracket to support the FT-857.

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Followed by the antenna connection brackets and ATU support.

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I cleaned the frame again and rubbed it down with wire wool before giving it a coat of paint. I used some "truck bed" paint from the local auto store which was billed as "hard wearing" and leaves a textured (think sandpaper!) finish.

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I wanted to soften the frame up a little and protect the paintwork on the base and handles so I found some DPM bandage (originally for my dogs injured leg) and used it to wrap parts of the frame. It's a bit spongy and makes the handles a bit more comfortable.

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The LDG tuner was attached to the frame with some double sided foam tape. This stuff is used in cars to fix trim and is very sticky!

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Next to go in was the FT-857. It sits in the original mobile mounting bracket with the microphone clip attached via a bracket screw.

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Last to go in was the battery. I use a 7Ah 12v SLA battery and usually run the radio at 20W or less. The battery is held in place with a webbing strap (I need to get a black or green one to replace the orange one!) and connects via powerpole connectors for easy charging.

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All complete and in the pack ready for action.

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I intend on adding extras as I get used to using the pack and hope to end up with a complete station in a simple to carry and robust package.

Re: DIY Manpack

Posted: Wed Nov 13, 2013 3:24 pm
by emclean
have you had any heat issues with transmitting in the bag?

Re: DIY Manpack

Posted: Wed Nov 13, 2013 9:13 pm
by TacAir
Goodness!
Thanks for the detailed photos! How about some of the rig in action?


I'll have to say, my mobile outfit was lame in comparison. (MRC-108 and PRC-104)

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I started out humping one of these beasties.... Man- portable HF, two grunts to carry the 'station'.

Re: DIY Manpack

Posted: Wed Nov 13, 2013 10:55 pm
by dtwn92
Great post and thanks for the pics. Love the set up. Hope it works like you want it too.

Re: DIY Manpack

Posted: Wed Nov 13, 2013 10:56 pm
by DementedDigital
I've seen a bunch of cobbled-up manpacks over the years, but that is the nicest one I've seen yet! Excellent work!

Re: DIY Manpack

Posted: Wed Nov 13, 2013 11:20 pm
by angelofwar
That is the epitome of awesomeness! Very impressed!!! :clap:

Re: DIY Manpack

Posted: Wed Nov 13, 2013 11:29 pm
by MaconCJ7
I'll be the guy that says it. With the first few photos I was thinking "Hmmm... let's see where he's going with this." And then you posted one of bare copper pipe in a pack. "WTF are you thinking? Are you seriously about to bolt all of this to a bare metal frame strapped to your back?". And then you finished it up, and like others have said "Nice!".

Do you have a charging system hooked up all quick detach like, or do you have to remove the frame from the pack for charging?
Is it setup for comms on the go, or a setup as you need it?

More pics of you using it. Very good job on fit and finish. You made it look like a legit mounting system.

Re: DIY Manpack

Posted: Thu Nov 14, 2013 12:00 am
by Radio guy
Very innovative and nice work. I see your feeding some sort of whip with an LDG tuner and they are not really designed to be used as a whip or random wire tuner and are more of a coax line flattener. Have you used it much in the configuration shown?
Radio Guy

Re: DIY Manpack

Posted: Thu Nov 14, 2013 12:30 pm
by trailhopper
real nice work,

Re: DIY Manpack

Posted: Thu Nov 14, 2013 12:46 pm
by mattltm
Thanks all for your comments. I'm pleased with how it looks.
emclean wrote:have you had any heat issues with transmitting in the bag?
None yet but I have only been running it at 20W. The frame keeps the fabric of the pack away from the radio and leaves lots of gaps for airflow. I'll rack it up to 100W the next time I am out, keep an eye on the heat and report back.
TacAir wrote:Goodness!
Thanks for the detailed photos! How about some of the rig in action?
Thats a nice system. I miss the days when I played with real green radios (not military but uk.gov service). Is that a H-250 handset? More pics and reports as the system evolves.
MaconCJ7 wrote: Do you have a charging system hooked up all quick detach like, or do you have to remove the frame from the pack for charging?
Is it setup for comms on the go, or a setup as you need it?
The battery is connected with powerpole connectors and so is the charger so it's easy to unplug from the radio and pop the charger on. At the moment, I have to remove it from the pack (takes 10 seconds) but I may bring the connectors up to the top with a charging/operating switch and maybe an external power input connection.

It's set up ready to go whenever I want it. Just put the antenna on and tune up.
Radio guy wrote:Very innovative and nice work. I see your feeding some sort of whip with an LDG tuner and they are not really designed to be used as a whip or random wire tuner and are more of a coax line flattener. Have you used it much in the configuration shown?
Radio Guy
I Put the whip on just to test in and see how it performed. I know it's not a great choice for the LDG but I had it handy and wanted to get on the air. Tunes fine on 20M and 10M. A little iffy on anything else! Worked a W4 station last night on 20M using the whip and 20W from the beach so it's not bad for a quick bodge. I intend on building a 9:1 UnUn for the base of the whip to make it a better match for the LDG.

I was over in France today and picked up 2 x 5M fibreglass Crappie poles and 1 x 6M Crappie pole. They are compact and only 58cm when closed. I may use the 6M one to make a vertical with an UnUn at the base and the 5M ones to make a delta loop with a 4:1 balun at the base.

Re: DIY Manpack

Posted: Fri Nov 15, 2013 5:24 pm
by CitizenZ
What does the frame weigh? Without the radio.

Re: DIY Manpack

Posted: Sat Nov 16, 2013 1:49 am
by mattltm
Here are the weights:

Radio: 5.6lb (2.1kg)
Tuner: 1.5lb (0.6kg)
Battery: 4.7lb (2.15kg)
Frame: 3.6lb (1.6kg)
cable and connectors: 0.8lb (0.4kg)
Bag: 3.4lb (1.5kg)

Total: 19.6lb (8.9kg)

Re: DIY Manpack

Posted: Sat Nov 16, 2013 4:44 pm
by CitizenZ
Not too heavy. Looks great.
As long as there is a good electrical connection between the components and the frame it should act as a larger ground plane as well.

Eta; you could add a mounting point for a hanging wire counter poise. Maybe a five foot wire for when you're walking and a longer one when you're at camp.

Re: DIY Manpack

Posted: Sat Nov 16, 2013 5:19 pm
by mattltm
Good thinking. I'll add a radial connection point during the next "upgrade".

Re: DIY Manpack

Posted: Mon Jan 13, 2014 12:48 am
by Bethlehem
I love this thread. I've been designing my "manpack" for a while and this thread has made me more excited than ever. But I'm a new HAM, and although I passed the test, I could really use some advice on the usefulness of my radio. I was going to build a manpack on the US military A.L.I.C.E. backpack frame inside a large ammo can (for solar flare / EMP) protection. The radio I have is the Yaesu FT-2900 R/E. It's a 2 meter radio. My question is whether you think 2 meters covers enough of the spectrum. My goal is to cover as much as possible. I won't be using this radio for local emergency information, but rather to reach as far as possible on as many bands as possible. I really like the design and quality of the radio, as well as its high output, but it only operates on the 2 meter bands.

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Re: DIY Manpack

Posted: Mon Jan 13, 2014 2:09 am
by mattltm
It's just 2M. That's a tiny slice of the avaliable spectrum. Useful for local communication around 20 - 30 miles but not much else without relying on third party repeaters.

IMHO You would be much better off saving and getting one of the "shack in a box" radios that will cover from 160M up to 70cm and give you world wide communication capabilities.

Re: DIY Manpack

Posted: Mon Jan 13, 2014 4:59 pm
by CitizenZ
Bethlehem wrote:I love this thread. I've been designing my "manpack" for a while and this thread has made me more excited than ever. But I'm a new HAM, and although I passed the test, I could really use some advice on the usefulness of my radio. I was going to build a manpack on the US military A.L.I.C.E. backpack frame inside a large ammo can (for solar flare / EMP) protection. The radio I have is the Yaesu FT-2900 R/E. It's a 2 meter radio. My question is whether you think 2 meters covers enough of the spectrum. My goal is to cover as much as possible. I won't be using this radio for local emergency information, but rather to reach as far as possible on as many bands as possible. I really like the design and quality of the radio, as well as its high output, but it only operates on the 2 meter bands.
I think if you read what you posted you answered your own question. It's a 2 meter only radio (actually it receives more, but essentially what is called a mono band radio). There is a lot you can do with that radio, good antennas and maybe add a computer for some digital modes, but obviously it doesn't work on other bands. There are about 20 amateur bands. No one radio can do them all.

Also your idea of using an ammo can to protect from EMP is flawed. Won't work. What you have is a good inexpensive mobile 2 meter radio. Learn to make good use of it. It is suitable for a manpack or go bag type set up. You can out fit it with a bag, battery, antenna, computer, etc. Either for grab and go or pack it to a mountaintop/remote location. From a mountain top with a directional antenna you could get much longer range than is usually possible from the 2 meter band. Basically as far as you can see. From a mountain top that could be 100+ miles.
With the addition of a hand held 70cm radio and suitable antenna you could also hit satellites and work half of the continent.

Re: DIY Manpack

Posted: Mon Jan 13, 2014 9:31 pm
by Bethlehem
Also your idea of using an ammo can to protect from EMP is flawed. Won't work.
Thanks for the advice. I've been thinking about selling this radio anyway so if it's too limited I'm willing to drop some money on something more versatile. - I don't mean to hijack the thread over the EMP topic, but I'm wondering why you say it won't work. It's my understanding that as long as the rubber seal is out, the paint is removed so the metal is making contact, and the components aren't touching metal inside it would work. I know it would take some work to make it into a good faraday cage. Is there a better way?

Re: DIY Manpack

Posted: Mon Jan 13, 2014 10:50 pm
by Tater Raider
The antenna has to be outside the Faraday Cage to get signal and if it is it will pick up the EMP and blow out the radio.

A backup radio in a Faraday Cage as a spare part, on the other hand...

Re: DIY Manpack

Posted: Tue Jan 14, 2014 12:25 am
by Ryder358
An EMP strong enough to fry electronics would cripple nuclear plants and their ability to cool the fuel rods resulting in over 100 meltdowns just in the USA. Unless you have a really good plan for dealing with that; I don't think there's much point to worrying about Faraday Cages.

Re: DIY Manpack

Posted: Tue Jan 14, 2014 2:58 am
by Bethlehem
The antenna has to be outside the Faraday Cage to get signal and if it is it will pick up the EMP and blow out the radio.
I would only use the Faraday cage as a storage option. I wouldn't expect to use any electronics during any type of solar storm or similar drastic event. I understand how the cage works and wouldn't expect it to function during an event.
An EMP strong enough to fry electronics would cripple nuclear plants and their ability to cool the fuel rods resulting in over 100 meltdowns just in the USA. Unless you have a really good plan for dealing with that; I don't think there's much point to worrying about Faraday Cages.
I think 100 meltdowns would be the end for it all for the USA. There are two nearby nuclear plants of which I'm able to witness the output of their steam stacks as I drive to job sites. I see two of them daily. I guess that means I'm toast along with my wife and children. If that's true then I either need to start blowing my money on hookers and booze or I should relocate, (I don't know where) where nuclear meltdown/fallout isn't a threat.

Re: DIY Manpack

Posted: Tue Jan 14, 2014 7:00 am
by Ryder358
You can look up an NRC US nuclear map to see. The western half of the country wouldn't be as bad. It wouldn't be immediate, they should be able to self sustain for around a week at least with out fuel resupplies. I came to this conclusion through research and being a 3rd party inspector at a generating facility but I'm not going to claim I'm 100% right. If an EMP happens I think I'll head to south west Canada :) (or try)

Re: DIY Manpack

Posted: Wed Mar 25, 2015 10:44 am
by abiffmaster
Awesome job on the manpack design.

Can you provide measurement details? The diagram showing the measurements is too small to see.

Thanks.

Re: DIY Manpack

Posted: Wed Mar 25, 2015 12:54 pm
by mattltm
Thanks.

It's been working very well and has saved my radio from plenty of knocks and bumps!

PM me your email addy and I'll send you the CAD plans and a bigger design image.