Antenna Trailer Project

So for a couple of years now I've had it in the back of my head to build an antenna trailer. The goal here is to have a trailer I can tow out wherever, crank up a ~40 foot mast, and be operating on HAM without too much fuss. I have all manner of manual crank up field masts and things, but they are a hassle to erect and you need a team of people. So, I guess I am old & lazy enough to want the old & lazy approach.

I've got a M105 rolling chassis that I picked up cheap off GP some time ago that I had in mind to do this project with. The general concept is to weld or bolt together a frame to take an off-the-shelf crank up mast, and maybe add some out-riggers as necessary. There are commercial versions of this (us tower comes to mind) that are very spendy but I am of the feeling it does not have to be very complicated, especially because my antennas are relatively light. http://n6nb.com/twrtrlr.htm is sort of inspiration, just on a military chassis I can tow with a FMTV.

Anyone done this before? I'm starting to shop around for fabricators in the AZ area that might be willing to take it on. I don't have shop space anymore so I can't do it myself. I am open to using a different trailer chassis too.

On the M105, what's the consensus for getting away from the buds wheels? I see a lot of people try to swap the axle but they are also often trying to go smaller in the process. I need the wheels to stay at least as big as they are if not get bigger so the frame is more level with the FMTV.

This is a noble quest! The M-105 would certainly provide a good base for a 40 footer. My needs were simpler and I picked up a 30-ish foot light trailer-tower that is adequate for a rotating dipole, center support for a G5RV, whatever. My little tower trailer is much too small for the LMTV. I will be watching your progress.

I must say though that the tower you referred to is scary looking to me. That is way too much tower for that little trailer. No way that tower will stay vertical in a little wind. If it was guyed then ignore what I said, but I could not see any guy wires, and only flimsy bracing at the base.

LMTV wheels and tires on an M-105 would be convenient, especially if the M-105 hubs could be modified to take LMTV wheels, and share a spare with the truck! Any ideas on that?

I had the same thought about N6NB's trailer, why doesn't it fall over. To his credit he's been making these trailers for a long time now, and has made quite a few of them. My guess is that he simply doesn't use it unguyed in bad weather. My feeling with the M105 is its weight, and I can add some ballast past that, will help steady the tower more than the flimsy harbor freight trailer. I do like the specific trailer N6NB picked for the same reason he picked it - tall, but it folds up compactly because it has a lot of sections.

I've started reaching out to fabrication places to line up a partner. I notice his is bolted together so in theory I could kind of chopsaw up a frame and bolt it together myself but I think I'd rather have a pro weld it.

I think the FMTV wheels would be a bit much on a M105. 800 lbs of wheels! Not to mention the axle. TBH I have no problem with the bud/s wheels other than it's so difficult to get them serviced. If they were a hair bigger that'd be nice so it tows a little more level but honestly it's fine, it works. So I don't know what military wheel I can go to that is going to be a similar size.

So funny enough I own a M1082 trailer. An alternate version of this antenna trailer idea was to have the antenna part built on a skid and I'd just crane or forklift the skid into the M1082 and lash it down. But frankly the M1082 is too much of a chore to drag around off road most of the time, just too big.

To be clear my M105 is just the rolling chassis, so it's really a M103, but I think it was originally a M105 someone pilfered the bed off of.

I'll talk to Moxie and see what he has in mind for the tower that came with the S-280 he just got. I think it is pneumatic operated, but do not know if it is functional. Of course, it's on the east coast and you are out west, so shipping could be a deal breaker. I'll try to get pics at the meeting on Wednesday.

So funny enough I went to buy a US Tower TMM-541SS this morning and imagine my surprise when HRO quoted me $8900! When I looked at them not 2 years ago they were like $2900. The rumor on eham/etc is that US Tower is now a big military / GSA supplier and so they jacked everything up to Uncle Sugar prices and can't sell outside the GSA contract for less money lest they be perceived as doing what they are actually doing. My budget for the tower was 3-4k so this is a deal breaker.

So assuming I can't find one used on-budget, and I did look around not finding any,

This leaves me wanting to find an alternative mast/tower. What was special about the 541SS was a 11' overall length since it was 5 sections and we'll remember a M105/M103 is about 13.75 feet overall. Obviously the tower can stick out a little from the back depending on how the frame lets it swing but all in all I think it is safe to say that particular trailer chassis is not going to take a tower that is 17-20' retracted which is how all most of the other towers are. Tashijan for example has the WT-51 in my price range but it's 20' collapsed.

I don't know what kind of mast he has off the S280 but I actually already own a AB/1386 QEAM which I use for field work. It flies a rotator and a hex fairly well. 33'. So yeah I can see mounting that on something, but I was hoping to get both sturdier for heavy loads, and taller. It does fly the little yaesu rotator and a K4KIO hexbeam pretty well. I left it up year round on this property I used to have. Getting that on a vehicle would certainly be a lot better than nothing, but it's also so compact I could probably just get brackets made up to put it on the LMTV, or an adapter plate that goes into one of the bed pockets. It needs to be guyed though and that's the biggest problem. I really want self-supporting.

You need a m762. https://www.steelsoldiers.com/showthread.php?37846-M762-trailer-with-light-tower

I didn't have the impression the light trailer masts went up very high, but I see in the thread it mentions 37 feet... That's a little less than I had in mind but is serviceable...

-edit easier/cheaper to acquire hens teeth apparently.

Got some pics, finally. If you built this to pivot at the back of the frame and had a foot to attach at the bottom, it would at least start three feet off the ground and go up from there. Guy would be simply a ring on the next to top section to have three cables attached, on ther same principle as the RC-292 antenna.

I've seen some of those masts come up - often from civilian satellite trucks, WilBurt seemed to make a lot of them - but they are all too short for what I am looking for. I like the concept a lot though. My understanding is they did make tall ones - 40+ feet - but I've never seen one come up for sale. I'd be interested though.

I've been searching around these last couple weeks to find one of those US tower masts that fits the dimensions of the application on the used market but so far no luck.

You antenna guys need to keep an eye out for the OE-349. It's called the Antanna Mast Group, (AMG). It's used by the Patriot ADA system. Truck mounted, M927, it has two masts. Hyd erected, pnu shot 33 meters in the air. It would be intresting for you guys. I heard from friends, that some of them might be getting replaced. I think it was made by GTE. Raytheon makes a "Light Antanna Mast, the is supposed to be carried on a "Light Military Truck". Google it. You might find the AMG of interest. I have to admit, I found it a good idea, just not soldier proof.

Here is my AB/1386 kind of for reference. It's been suggested I mount this either to a trailer or a vehicle - there were brackets for that to put it on a HMMWV and think I have seen it on the side of a S-280 also. Either way, just a bit short (33' total) and marginal weight-wise for a beam antenna and rotator. I just really am enamored with that US tower mast because it's self supporting, I like the idea of just crank up and go, no fuss no muss.

aleigh said:

Here is my AB/1386 kind of for reference. It's been suggested I mount this either to a trailer or a vehicle - there were brackets for that to put it on a HMMWV and think I have seen it on the side of a S-280 also. Either way, just a bit short (33' total) and marginal weight-wise for a beam antenna and rotator. I just really am enamored with that US tower mast because it's self supporting, I like the idea of just crank up and go, no fuss no muss.


View attachment 750799View attachment 750800View attachment 750801View attachment 750802

Click to expand...

Where did you get that antenna i'v been shopping for an hf beam that doesn't weigh a ton or create a lot of wind resistance. I live on the shores of the bearing sea we get a lot of wind.

snowtrac nome said:

Where did you get that antenna i'v been shopping for an hf beam that doesn't weigh a ton or create a lot of wind resistance. I live on the shores of the bearing sea we get a lot of wind.

Click to expand...

k4kio.com

I'm quite happy with it.

That first trailer shown scares me. At least without it being guided. That's a lot of mass that could topple over that puny harbor freight trailer. (Not a knock, I have one of those trailers)

Those pneumatic towers are awesome. I'd love to find one for my M105/Comm Shelter.

patracy said:

That first trailer shown scares me. At least without it being guided. That's a lot of mass that could topple over that puny harbor freight trailer. (Not a knock, I have one of those trailers)

Those pneumatic towers are awesome. I'd love to find one for my M105/Comm Shelter.

Click to expand...

Pneumatic masts are regularly on ebay.

oddave715 said:

You need a m762. https://www.steelsoldiers.com/showthread.php?37846-M762-trailer-with-light-tower

Click to expand...

I got one of the light trailers from DOD surplus for the County EMA - Ham Club several years ago. Last week they finally got it done and did a presentation for the County Fire Assoc. I didn't take any photos but will see if I can get some. As I recall with tower up and the extension they added antenna is at 50ft.

Brings me to my question. Their trailer has the original DOD NDT tires so likely at least 40+yr old.

Will wheel/tires from a M720 dolly fit the M416/M762 hubs? Both are 5bolt. According to the M720 and M416 -P are different NSN.

I have several M720 wheel/tires can set them up with so they would newer (15-20yr old) tires.