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Bvennink
Junior Member
Username: Bvennink
Post Number: 15
Registered: 3-2005
| | Posted on Friday, July 28, 2006 - 11:30 pm: | 
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Where can a person buy a fiberglass whip and tuner that you see mounted on the military Hummers? What is the freq. range one can tune on these? Maybe some of the people on the forum with military backgrounds could help explain these antennas and how they work? |
Tech833
Moderator
Username: Tech833
Post Number: 1414
Registered: 8-2002
| | Posted on Saturday, July 29, 2006 - 12:36 am: |
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Fair radio sells them. The whips (with tuner) are designed to work from 3 to 30 MHz. |
Slugo4449
Member
Username: Slugo4449
Post Number: 97
Registered: 7-2004
| | Posted on Saturday, July 29, 2006 - 12:48 am: |
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I use a 102" whip and a 4" spring with an Icom AH-4 auto tuner on one of my mobiles and I get from 6 meters through 40 meters. It works but is not that efficient. Nothing beats a resonant antenna.
From what I have seen most military equipment is made to be idiot proof. ie: folded dipole, maxxcom antenna coupler.
The folded dipole is less efficient on all bands than a 1/2 wave dipole except on 10 meters. It aint that great on 10 meters either.
The maxxcom antenna coupler claims to allow any length wire to be a perfect match for any frequencies that it is rated for. The ARRL did a review and found it to be a 50 ohm dummy load with a place to add any random length of wire.
Both of these products are in use today by our Military.
Again, nothing beats a resonant antenna.
Marty
KG6QKJ |
Bvennink
Junior Member
Username: Bvennink
Post Number: 16
Registered: 3-2005
| | Posted on Saturday, July 29, 2006 - 8:22 am: |
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question to Tech 833. What is the address or web site for Fair radio? Also it seems that I have seen a Telex/HyGain antenna label on one of these military whips? |
Tech808
Moderator
Username: Tech808
Post Number: 10664
Registered: 8-2002
| | Posted on Saturday, July 29, 2006 - 9:44 am: |
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Bvennink,
Do a GOOGLE SEARCH www.google.com for: Fair Radio Military Surplus Electronic's
Hope this help's,
Lon
Tech808
CEF808
N9CEF
CVC#2 |
Tech833
Moderator
Username: Tech833
Post Number: 1415
Registered: 8-2002
| | Posted on Saturday, July 29, 2006 - 9:51 am: |
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We are not allowed to post links here. Do a web search for Fair Radio Sales and it will show up.
Yes, various antenna makers have had military contracts. HyGain is one of many. BTW, Shakespeare does all their fiberglass work.
Marty- No exactly so. You are referring to the TF2D type antenna with the resistor in it, but the resistor is not a 'dummy load'. The resistor simply shares any power that would be reflected back to the transmitter. In situations where there would be no SWR (reflected power), the resistor does nothing. In situations where 30% of the transmitter power would be reflected (way in the red SWR), the resistor absorbs more than half of that power, so the transmitter sees very little of the reflected power.
Antenna tuners in use by the military only contain resistors in cases of trying to match a very short radiator, which is an excercise in futility anyway. However, even if you get 5% radiation efficiency out of a mobile antenna on HF bands, that is doing pretty good. If you shove 500 watts into it, that gives you a good 25 watts radiated, which will reliably get you half way around the world on HF. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1319
Registered: 6-2004
| | Posted on Saturday, July 29, 2006 - 10:30 am: |
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I wonder how well they worked when using trees as a radiator? I read an article once about the military using trees as radiators when it was too risky to string a wire. I always wondered how much power was used in that circumstance because they can't be very efficient. I also wonder how the tree weathered the experience in the long term. |
Tech237
Moderator
Username: Tech237
Post Number: 467
Registered: 4-2004
| | Posted on Saturday, July 29, 2006 - 11:22 am: |
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Hollowpoint,
Several years back we ran a tree antenna and using 5w CW worked 56 countries ina weekend. We did try 200w but the Eucalyptus trees sap started to bubble just a little.
The band used was 40m and we tried several gaps between the ends of the coax until we found on that matched and worked.
Mind you that was the same weekend we ran a 300ft longwire attached to a helium weather ballon and blacked out the whole west side of Lake Macquarie. |
Dale
Advanced Member
Username: Dale
Post Number: 587
Registered: 12-2002
| | Posted on Saturday, July 29, 2006 - 12:59 pm: |
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thats pretty cool .that would be awsome to do on 11 meters.especially for people with antenna restrictions.anyone asks its a clothes lines...lol |
Tech237
Moderator
Username: Tech237
Post Number: 470
Registered: 4-2004
| | Posted on Saturday, July 29, 2006 - 5:42 pm: |
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Dale,
Antennas have been hidden as cloths line in the past too.
The ballon worked great until a storm sprung up and the balloon came down with 300ft of bare copper wire draped across several power lines.
You know, when the power guys asked if we knew what had happend no one had seen anything. |
Dale
Advanced Member
Username: Dale
Post Number: 597
Registered: 12-2002
| | Posted on Wednesday, August 02, 2006 - 8:00 pm: |
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lol thats funny tech237.if a person was gonna use coax and string it hoizonalluy would it act like a beam being on the flatside?is there a specif lenth for 27mhz or just what ever lenth i need. |
Tech237
Moderator
Username: Tech237
Post Number: 475
Registered: 4-2004
| | Posted on Wednesday, August 02, 2006 - 8:27 pm: |
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dale,
Let me get home (still at work as I type this - PDT) and I have a couple of articles on using coax as antennas and on making a long-wire style antenna. I'll scan them in zip them and email them to you.
Basically what you could do is take an 27ft plus length of coax. Strip the plastic back form 9ft at one end. Carefully push the braid back over the next 9 ft. Place a plug on the non modified end. Hang the coax up with the plug end near your radio and adjust the amount of shield over the middle 9feet of coax to adjust your SWR.
Congratulations - you have just created a coaxial dipole. |
Tech237
Moderator
Username: Tech237
Post Number: 484
Registered: 4-2004
| | Posted on Saturday, August 05, 2006 - 1:21 pm: |
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Dale,
I finally found the article I was looing for (it had to be in the box right at the bottom). Over the weekedn I'll scan it in and email it to you. |
Ferd1605
Junior Member
Username: Ferd1605
Post Number: 20
Registered: 1-2005
| | Posted on Sunday, September 17, 2006 - 2:02 am: |
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I found my military whips at Collins Radio surplus store about 15 yrs ago , bought a 4 of them they had . about 5 yrs ago they had the base/remote tuner section for one and i just had to have it ... These antenna's are in sections and with 5 togather it it resonant on 11/10 meters with no tuning needed. |
Flat_top
New member
Username: Flat_top
Post Number: 8
Registered: 1-2006
| | Posted on Sunday, September 17, 2006 - 9:50 pm: |
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The most popular HMMWV is a MRC-145, with the VHF(SINCGARS)radio. Most have dual antennas. They are not co-phased and not tunable. The other is the MRC-138, HF Radio. Freq range is 2-29,999.9khz w/ USB and LSB. The antenna is tunable. Although you need an antenna coupler which weighs about 50lbs. You will not see MRC-138 HMMWV driving around with the antenna attached, they are 32ft. Power output is 100 to 400w. |
