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Author Topic: Survival radio  (Read 21056 times)
KJ4DGE
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Posts: 8




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« on: October 12, 2013, 01:55:49 PM »

Hi, I know this is a stretch but I am looking for people smarter than me that can maybe steer me in the right direction. We have all heard of military man-pack radios. I am looking to create a portable VHF/UHF non-HT rig that has the power of 10 to 20 watts, runs on a luggable battery pack, self contained antenna, etc. I am sure it can be done without amps and such but you never hear other than mobiles of a radio running such a low power output. I am aware of what 5 watts can do with a good antenna so do not even go there. I am talking about a radio setup that can be 2-3 notches up from a HT, but shine in the connection dept. with Li-Ion batteries being such, I am sure the power source is not the issue here. The RF output into a gain or even a J-pole in the trees would be more than enough at 10 watts to get metro coverage full quieting , maybe....Smiley If you see where I am going with this, short of spending money on a mobile in a case clue me in please. Heathkit use to have a amp for VHF years ago that did ten watts or better for HT's. Mirage has their dual-bander for 175.00 but at 45-35 watts that's overkill. Hope someone gets my meaning. Somewhere in-between please.


KJ4DGE
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W4KYR
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« Reply #1 on: October 12, 2013, 02:42:08 PM »

Radio Shack used to sell the 2 meter FM amp HTA-20 in the 1990's. If you look around you could pick them up for $50 used. They put out 20 watts for 5 watts in, these are FM only.

 For 440. look around for the Motorola power amps (I think FM only) these put out 35 watts and sell for $50 to $100 on E-Bay. For the dual band radio..just use a Baofeng UV5RA these sell for $35 new.

Ramsey used to sell 220 mhz power amps, and maybe other bands too. Another manufacturer made a 'docking station' with a built in power supply and either a 2 meter or a 2 meter/440 FM only amp. It was shaped like an L if you looked at it from the side.

If you are going to make this into a manpack, please post the pictures somewhere so we could see it. 5 watts is good, but in some cases it isn't good enough whereas 20 or watts might be the difference.

However for almost the same price, you can get a decent used mobile. Just be careful if you eventually go that route, look at the eham ratings...some of the mobile dual banders turned out to be real dogs...even the ones by 'famous manufacturers'.


As for manpack designs, there are many good ones out there that people put together using ham HF equipment. Some of them look real professional. Another manpack design you should consider building is like the old Motorola "Railroad Radios", "Forestry Radios" and also "Civil Defense" type of radios.

As you can see below, the antenna sticks out from the top, there is a handle, a microphone and the battery is on the bottom and snaps off the unit. People can also incorporate this design with an HF rig as well.

Good Luck



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KB1GMX
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Posts: 828




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« Reply #2 on: October 12, 2013, 07:54:11 PM »

KJ4DGE:

This is not hard.

Find a dual band mobile radio with the power and bands you want.  Put it in a
box with a 18ah 12V gell battery, add a suitable dual band antenna.   For a box
a .50 cal ammo can works (sealable too) and the metal ones can make a fair
ground plane for a dual band whip mounted to it.

Its less effort than a HT with an amp and it can be completely self contained.
Most of the mobile radios are not fixed in power output so even one that can
do 55W  (like my FT1900R) can be reduced to 25 or 10 or even 5W.

Allison
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KG4NEL
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Posts: 443




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« Reply #3 on: October 12, 2013, 07:59:19 PM »

Hi, I know this is a stretch but I am looking for people smarter than me that can maybe steer me in the right direction. We have all heard of military man-pack radios. I am looking to create a portable VHF/UHF non-HT rig that has the power of 10 to 20 watts, runs on a luggable battery pack, self contained antenna, etc. I am sure it can be done without amps and such but you never hear other than mobiles of a radio running such a low power output. I am aware of what 5 watts can do with a good antenna so do not even go there. I am talking about a radio setup that can be 2-3 notches up from a HT, but shine in the connection dept. with Li-Ion batteries being such, I am sure the power source is not the issue here. The RF output into a gain or even a J-pole in the trees would be more than enough at 10 watts to get metro coverage full quieting , maybe....Smiley If you see where I am going with this, short of spending money on a mobile in a case clue me in please. Heathkit use to have a amp for VHF years ago that did ten watts or better for HT's. Mirage has their dual-bander for 175.00 but at 45-35 watts that's overkill. Hope someone gets my meaning. Somewhere in-between please.

KJ4DGE

The closest thing to what you're looking for is something like a Yaesu FT-290R, but they have two glaring problems:

1. Lack of power (2.5 watts, so under what an HT would provide)
2. No tone board

There really isn't much of a mainstream market for what you're proposing beyond the Yaesu FT-817, which would likely cost much more than a mobile rig in a case and include a lot of features you wouldn't need at the cost of output power.

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K5LXP
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« Reply #4 on: October 12, 2013, 09:11:40 PM »

I am looking to create a portable VHF/UHF non-HT rig that has the power of 10 to 20 watts, runs on a luggable battery pack, self contained antenna,
... short of spending money on a mobile in a case clue me in please.

What you're describing is a mobile in a case.  So why wouldn't a mobile in a case work for your application?

Mark K5LXP
Albuquerque, NM
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W4FID
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Posts: 138




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« Reply #5 on: October 13, 2013, 04:10:50 AM »

I have had good success with the plastic ammo cans. They are available from sporting goods stores and pulp flyers like "Cheaper Than Dirt" and come in various sizes. The plastic ones are wx resistant, non corrosive, and come in orange if you want it to be seen or Army olive drab. The lid has a gasket and usually a lock hole or two for security. If you use sealant at any penetrations the contents stay dry. Since they are plastic they are fairly non scratching if you set it on a desk. While not as protective as the Pelican cases they are WWAAAAYY cheaper and lighter.
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W4KYR
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« Reply #6 on: October 13, 2013, 07:08:33 AM »

Regarding the Radio Shack HTA-20 amplifier. I see they have it on E-Bay for $55.  Harbor Freight has 'mini' plastic gun cans for under $7 this month.
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KE7TMA
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Posts: 472




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« Reply #7 on: October 14, 2013, 09:13:14 PM »

Hi, I know this is a stretch but I am looking for people smarter than me that can maybe steer me in the right direction. We have all heard of military man-pack radios. I am looking to create a portable VHF/UHF non-HT rig that has the power of 10 to 20 watts, runs on a luggable battery pack, self contained antenna, etc. I am sure it can be done without amps and such but you never hear other than mobiles of a radio running such a low power output. I am aware of what 5 watts can do with a good antenna so do not even go there. I am talking about a radio setup that can be 2-3 notches up from a HT, but shine in the connection dept. with Li-Ion batteries being such, I am sure the power source is not the issue here. The RF output into a gain or even a J-pole in the trees would be more than enough at 10 watts to get metro coverage full quieting , maybe....Smiley If you see where I am going with this, short of spending money on a mobile in a case clue me in please. Heathkit use to have a amp for VHF years ago that did ten watts or better for HT's. Mirage has their dual-bander for 175.00 but at 45-35 watts that's overkill. Hope someone gets my meaning. Somewhere in-between please.


KJ4DGE

How about something like a Yaesu FT-897 jammed into a Pelican case?  Or a KX3?  Or the FT-817 with the matching Tokyo Hy-Power 45 watt amp?
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WB6BYU
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Posts: 13574




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« Reply #8 on: October 15, 2013, 01:11:48 PM »

There should be a number of the older mobile rigs used that will put out 10 to 20 watts,
and are relatively inexpensive used.  (I've seen several in the $25 to $50 range.)  Might
not have fancy features such as dual-band, dual-receive, etc., but are still quite adequate
for 2m operation.  I recently picked up a pair of older dual-band mobile rigs that are
capable of cross-band repeat for less than $100 each - the interface is a bit quirky, so
I need to put the manual in the case if I have to change the settings, but they work fine
at 10 watts output.

Higher power rigs usually have a low power position.  If not, or if the power levels available
aren't quite what you want, it usually isn't difficult to change the output level.  I still
use my old IC-28A mobile rig that runs 25 watts output - I only took it out of the car
because I needed dual-band capability for the ARES repeater.


A number of differences between a mobile rig and an HT (possibly with an amp):

1) many HTs will get pretty hot at full output.  The mobile rig has better heat sinking,
and, if run below rated power, it should be more than adequate to keep the rig from
overheating as long as airflow is provided.  (That's an important requirement if you
are going to put it in an enclosed box.)

2) HTs generally draw less power on receive, so are better for listening.  In most
cases for emergency communications that would give them an edge, since the
actual transmit cycle should be pretty low.  (My general advice is to listen on an HT,
then switch on the mobile rig and transmit when needed.)

3)  HT's often are not designed to put up with strong signals from a good antenna -
they can be prone to desense and internally generated "grunge" from strong paging
transmitters and other sources.  If you are operating from a central command post
with several other services, this can be a problem.  Of course, even a mobile rig
can be subject to desense if an out-of-band signal is strong enough (this seems
to happen at about 2 car lengths with many rigs I've used) but they tend to have
better filtering.

4)  Getting the antenna up high is critical to good performance, and probably will
make more difference than the specific type of antenna or rig that you choose to use.
If you mean "man-pack" as "capable of operation while walking", then a half
wave whip sticking up above the top of a pack frame is a reasonable choice.  (I made
mine from an old base-loaded CB whip.)  A throwing rope in a bucket helps if you
have trees handy, or some sort of stackable mast sections if you have to provide
your own supports.  A ground plane up at least 15' or so is a huge improvement over
a 19" whip on the back of the equipment at table height.
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KB8TVN
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Posts: 9




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« Reply #9 on: October 27, 2013, 09:18:32 AM »

I know it's only a single band but the yaesu ft-290 with the add on power amp would seem to fit the bill. 5 watts on low 25 watts on high all mode. Believe aftermarket tone boards are still available and if you can find a battery pack then 1 to 5 watts. I would assume as a manpack simplex would be the choice of use making a tone board optional while gaining single sideband they also have 2 vfo's and the ability to program odd splits comes with a handmic and plug for key.
If multiple repeater use on FM is the primary goal then I like others have suggested would go with a mobile radio in a box. Seems to me though lugging a large enough battery around for very long would get old fast.
And of course if you can afford it the FT-897 or FT-817.
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NI3S
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Posts: 67




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« Reply #10 on: October 27, 2013, 06:15:35 PM »

Mirage's amp will only get to full power with 5 watts or better into it.  Reduce the power on the HT and you would have the 20ish watts you are seeking.

 If your setup doesn't need to be operational while moving, getting a method to get your antenna up as high as possible could gain you nearly as much as the amp.  Of course the better the antenna more this counts.  There are a lot of methods to do this, sling shots into trees, collapsible fishing pole etc. 

Many moons ago I built a 2M yagi using an old tape measure, gamma matched if I recall.  It worked pretty good and the price was right.  The unforeseen benefit to this antenna is the elements would wrap around the boom and the whole thing could be compacted.  With a little creativity I'm sure the boom could have been split too. 

Gain from the antenna and a means to get it into the line of sight of whomever you are seeking to contact should be as, if not more effective, than an amp. 

Good luck with your plan.
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NN4RH
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Posts: 335




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« Reply #11 on: October 28, 2013, 03:40:08 AM »

 
Quote
I am aware of what 5 watts can do with a good antenna so do not even go there.

Ok. I won't go there.

But you realize you are ruling out the right answer.

You want about 6 dB over a 5 watt HT with a rubber ducky antenna. Your solution is to carry around about 20 pounds worth of radio and batteries. Just putting a 1/4 wave whip and a "rat tail" on the HT in place of the rubber ducky will get you a dB or two. Seems like a 3 element Yagi that you can take apart an carry would be about a pound and give you the rest of the gain you're looking for.

Just thinking that if I was in a survival mode (the title of this thread is "survival radio" after all) I'd rather carry an extra 20 pounds of water, food, weapons, etc, not 20 pounds of radio and batteries.

But . . . I won't go there.


« Last Edit: October 28, 2013, 03:46:16 AM by WN9HJW » Logged
NN4RH
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Posts: 335




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« Reply #12 on: October 28, 2013, 04:23:22 AM »

If the signal you are receiving is strong enough to de-sense the HT, then you don't need more power in the first place. Stand on top of the nearest hill and set your power to 1/2 watt and that will be plenty.


And what is the scenario - what kind of "survival" are we talking about here? Lost-while-hiking-in-the-woods survival, or zombie apocalypse survival?

If it's lost-while-hiking-in-the-woods survival, then you're better off with a map and compass (or a GPS unit) than a 55 watt radio and an 18 A-H battery pack. (Actually you won't be able to run a 55 watt mobile off an 18 AH gell battery anyway. It'll pull the voltage down below the operating range of the radio. You could run at 10 watts or less.)

If it's zombie apocalypse survival - then it doesn't matter. Anyone you manage to make contact with won't risk their own neck to come and get you, so the zombies will get you anyway. Although . . . that 20 pound "go bag" with the radio you could swing that around and it's heavy enough to knock a few of the zombies down.
« Last Edit: October 28, 2013, 04:28:58 AM by WN9HJW » Logged
W4KYR
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Posts: 622




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« Reply #13 on: October 28, 2013, 09:16:50 AM »

Your best bet for the antenna would be a 'roll up" J-Pole. If you find a tall tree, slingshot a rope over the highest branch and hoist up the J-Pole. Make sure you have enough coax (50 feet?). Perhaps have three 20 foot lengths with connectors, so you don't waste power through 50 feet when all you can reach is 15 or 20 feet. It all should fit neatly in a bag.

And if a tree is not available....maybe one of those 'fiberglass' telescoped masts. At that point it should be guyed if it is going to be a particular location for some time. It may not be practical for back packing, but it beats the next option...

Another antenna idea would be helium balloons, but then again you would have to carry around a tank and keep filling the balloons every couple of hours. Which kind of making that idea definitely impracticable for back packing although doable.
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W7ASA
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« Reply #14 on: October 28, 2013, 06:54:08 PM »

Form fits function.  For me, a 'survival radio' is a just in case radio to summon help, but one of the SPOT messaging units will do that quite efficiently. However, ham radio could used for more than to summon help so it makes a better balance of usefulness -v- weight, so let's think about that.

In general, the limiting factor with VHF/UHF systems is not power - it's obstruction, from terrain, buildings and etc. NOAA and other low Earth orbiting satellites have been sending weather fax images to earth since late in the 20th century in mid-VHF using less power than the average ham HT.  They are roughly 400 miles above the earth when directly overhead. So range per power is not the significant limiting barrier.

Remember that one S-unit = 6 dB.  (...and a calibrated S-meter on a rig is as rare as an honest politician in Washington DC. )   Grin

National Bureau of Standards tested mid-VHF 'rubber duckie' antennas and found that the average 'gain' was -5 dBi. Yup, using a rubber duckie - on average - induced a loss of almost 5 dB.  So, if you use a yagi with a gain of 7 dBi , you are actually gaining 12 dBi  - that is two S-units.  Elevate this antenna even twenty feet and you VERY SIGNIFICANTLY increase your range over flat terrain. Remember though - terrain obstruction is the main killer of line-of-site propagation, so if you are in a 'bowl' in the mountains, you're not getting out. On the other hand, if you are on a ridge line in Colorado, you can talk to Kansas, Nebraska, Wyoming and etc. one an HT.  Location, location , location.

-...-

I always carried a small HF radio - a simple QRP rig on HF with a simple, light and inexpensive dipole will work for NVIS during the day and can work continental and more at night.  CW is preferred, but if you do not do CW, then one of the very inexpensive MFJ-9420's would put you on forty meter VOICE with 10 Watts or a bit more and again, with a dipole , you're quite efficient.  I prefer forty because it's generally open to 'somewhere' around the clock. If your calls of "MAYDAY, MAYDAY, MAYDAY" dose not work, change freq and call out as the North Korean QSO PArty - Kim Jung Un speaking -   DXer's will find you. The FCC will probably find you - but you will be found ( ha ha ) . This rig is not 'competitive'. You won't want to use in during the next CQ WW contest (see N. Korea above for one way to make it work in a contest.) , but otherwise you'll be making contacts with something light, fairly inexpensive (E-bay)  and with a relatively LOW RECEIVE current drain, which is very important.

-...-

As for Zombies, I spray around the house with Deep Woods Zombie Repellant and so far - no zombies. Naturally, I never leave human brains laying around outside after dark where they might attract unwanted attention - that's policy.



>de Ray
W7ASA ..._ ._

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