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Author Topic: Military ants and radios on/in hummers/tanks etc  (Read 6290 times)
GRANDKODIAK
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Posts: 85




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« on: July 19, 2012, 11:35:30 AM »

Curious, I always see pictures in Iraq or Afg or where of our boys over there in thier hummers and M1's, and they have seemingly GIANT antennas on those things, when I see them on the road sometimes they are folded forward from the rear of the mount, all the way the the hood it seems. I'm assuming its rather low relitive freq, but anyone out there have an idea what they use in terms of hardware, frequencies, modulation methods etc?
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Tech/General

no base station yet

Yaesu FT-7900r VHF/UHF
Cobra 29LX CB
Wouxun KG-UV6D VHF/UHF
AF6WL
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Posts: 147




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« Reply #1 on: July 19, 2012, 12:24:18 PM »

Google NVIS

Also this is a good book on the subject
http://www.antennex.com/shack/Jan02/nvis.html
« Last Edit: July 19, 2012, 12:27:15 PM by AF6WL » Logged
VE9AAE
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Posts: 31




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« Reply #2 on: July 19, 2012, 02:28:17 PM »

Grandkodiak,
While I'm sure a great deal of the info is available from open sources on the Internet, I don't know if this is the ideal forum for potential OPSEC info. There's still a lot of the boys (and girls) in harms way out there.

Regarding the folding down of antennas on the road, it can be SOP so that they aren't flopping around when on public roads/highways (it would suck whacking the antenna against an overpass or low power line), and of course it also depends on the band being used as well as the distance that needs to be covered.

That being said, that's merely my uneducated input; others reading this may have more info to go on.

73,
VE9AAE.
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K0ZN
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Posts: 1562




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« Reply #3 on: July 19, 2012, 08:41:21 PM »


Military radio systems use a wide range of frequencies, power and forms of modulation. Much of it is encrypted now. 

If you do some searching around the internet, you will likely find a good deal of basic specification info on military radios.
For obvious security reasons, frequencies and modes are never going to be "available" or published.

73,  K0ZN
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KE6EE
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Posts: 454




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« Reply #4 on: July 19, 2012, 09:42:00 PM »

"Regarding the folding down of antennas on the road, it can be SOP so that they aren't flopping around when on public roads/highways (it would suck whacking the antenna against an overpass or low power line)."

Heh. The likelihood of running into an overpass or a power line of any height is mighty small out in the tribal areas of Afghanistan.
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WB6BYU
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Posts: 13573




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« Reply #5 on: July 19, 2012, 09:42:49 PM »

Traditional tank sets have used the VHF-LO range, roughly 20 - 70 MHz, where
antenna lengths are reasonable and propagation allowed good coverage in rolling
hills.  Even in WWII some use was made of 200+ MHz for local formations because
it couldn't be heard as far away.  Normal HF operation (below about 20 MHz) wasn't
as common because loaded whips have limited survivability in rough terrain when
they get to rocking wildly back and forth.

These days much short range communications are done in the microwave range
using spread-spectrum modes to make them difficult to detect, intercept, or DF.
Some medium range tactical communications (up to 10 to 30 miles perhaps,
depending on terrain) are still in the low VHF range, though most vehicles will
also be tied in with satellite links for video, maps, real-time targeting, etc.

So that long whip you see on the tank is going to be used primarily in the VHF-LO
range, though it could be loaded up in the 2 - 6 MHz range for NVIS propagation
if necessary.  (The efficiency will be quite low, however.)
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K2CMH
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Posts: 278




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« Reply #6 on: July 20, 2012, 05:38:46 AM »

Quote
Also this is a good book on the subject
http://www.antennex.com/shack/Jan02/nvis.html

That link points to a review of the book.  The link contained in the review for where you can purchase the book seems to point to a now defunct website.

Does anyone have a good link that points to where the book can be downloaded or purchased?
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KCJ9091
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Posts: 0




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« Reply #7 on: July 20, 2012, 06:21:15 AM »

Disregard, old bookmark, didn't go to the book.
« Last Edit: July 20, 2012, 06:28:37 AM by KCJ9091 » Logged
KQ6Q
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Posts: 993




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« Reply #8 on: July 20, 2012, 01:53:48 PM »

The military is pretty much all digital, encrypted, etc.
for an article talking about some of the latest setups, with no mention of frequencies, see

http://defensesystems.com/articles/2012/06/25/project-manager-view-swanson.aspx?s=ds_110712
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VE9AAE
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Posts: 31




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« Reply #9 on: July 20, 2012, 04:02:26 PM »

N6GND
I may have mistaken the comment "when I see them on the road sometimes" for him actually seeing them during training, I hear you about the risks outside of major populated areas there.

As an aside, you should have seen what was left of the AMU when one of our Coyote LAVs hit a low powerline in East Africa...
Radios were OK though!
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ZS6BIM
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Posts: 67




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« Reply #10 on: July 21, 2012, 06:30:18 AM »

BLOS - beyond line of sight – OTM – on the move communications remains a problem – even at times for the formidable US military with their tons of metal cluttering up our skies!
Although a radio salesman may say “V/UHF is good for 10 to 20 miles” he sometimes forgets to mention the effects of terrain and vegetation; drive into a forest or canyon and you’re luck to achieve a couple of miles at these frequencies.

Surprisingly enough it’s here where HF NVIS can come to the rescue however the traditional HF vehicle whip antenna is a poor NVIS radiator and especially at the important low HF frequencies. This is due to the null in a whip’s radiation pattern towards the Zenith.

Bending the whip away from the vehicle can improve the situation somewhat however it’s not too practicable when OTM.
Bending the whip over the vehicle is a safety precaution – check out how power is distributed in towns and villages in many parts of the world! – Forward bending does not aid NVIS and in fact it reduces antenna efficiency.

The solution is to use some form of vertical loop antenna – check out
http://www.army-technology.com/contractors/antennas/comrod-communication/comrod-communication2.html

The above is a pretty solution for a desert however it will be the first thing ripped off the vehicle driving off-road in my part of the world!

The power of DSP has resurrected HF – I believe it’s the only simple means of BLOS and long distance point to point communication not involving a 3rd party. Important for any military unless of course you are the 3rd party! Hi!

73
mike
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LA9XSA
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Posts: 376




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« Reply #11 on: July 21, 2012, 07:22:38 AM »

Heh. The likelihood of running into an overpass or a power line of any height is mighty small out in the tribal areas of Afghanistan.
If they have power in a town, it tends to be a mess of wires though. That goes for many third world towns as well: No planning, and extension cords hung in creative ways. Also trees and washing lines.
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K1CJS
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Posts: 6061




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« Reply #12 on: July 21, 2012, 07:22:57 AM »

From the lengths of some of those antennas, the frequencies seem to be between the 10 meter and the 20 meter bands.
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NQ3X
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Posts: 64




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« Reply #13 on: July 22, 2012, 05:24:24 AM »

Probably not.  As I understand it, most tactical communication is via SINCGARS, which operates spread-spectrum from 30-88MHz. 

At least when I was operating green boxes from 1991-1999, HF was a specialized field, with NVIS even more seldom used, and then never per SOP in a mechanized unit below Division echelon.  The mechanized infantry battalion I was in didn't use HF at all; we had nothing but VHF in the inventory (SINCGARS and MSE).  HF was for special-operations and higher-echelon conventional forces.  Even in the USASOC units I was in, HF wasn't high on the priority list, as the long-range stuff was VHF/UHF via satellite.  I used to do my maintenance checks on the satcom rigs by kerchunking local repeaters. Wink

Anyway, I have no real knowledge of what's inside military vehicles in 2012 other than what I read on the Internet.  SINCGARS is, according to the available literature, still the standard, operating encrypted narrowband FM on VHF.  It was scheduled for replacement but that got cancelled.  It's actually a pretty cool system, with a combination of voice encryption and "frequency hopping" that is in itself pretty darn secure; unless you have the exact same hop-sync, you hear nothing.

73 de Bob NQ3X
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KC9TNH
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Posts: 304




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« Reply #14 on: July 22, 2012, 05:54:08 AM »

NQ3X's post is the best summation & still valid. Honestly, most of this stuff is googlable (vendors are very proud of their wares & USG isn't their only customer).

For Bob, you may be interested to know that a Signaleer I know (recently transferred) who spent a fair amount of time downrange managed to get his head out of the box to solve his OTH issue, and regularly made his contacts HF NVIS from his outlying location via a HMMWV and a bumper-mounted wire, at that height, tied off to whatever was necessary. It's still a capability that's used, but it sure ain't doctrine. That Soldier's design? He got it off an internet ham site devoted to off-road HF'n   Shocked   and modified his personal hummer   Shocked.
 
Wink
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73
Wes -KC9TNH
"Don't get treed by a chihuahua." - Pete
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