Base Antenna Portable mount???? Anyone??

[drdx]

Hello all. I'm looking to broaden my radio horizons and get into more portable operation. Specifically, I want a good way to mount an Imax2000 for use at the park or beach. I'm after the ability to have a much more than my mobile efficient antenna that would allow battery powered operation with good signal, or more likely some booteee spankin operation with my mobile hooked up to it, taking advantage of a better antenna system.

Long ago, I saw a deal that was a flat plate that you parked on and it had a base pipe deal that you could slip a vertical into to hold it up, using the vehicle. I thought I may fabricate up something like that but was wondering what others use. I'd kinda like something that didn't rely on the vehicle that I could set up maybe next to a tent. I'm thinking about maybe a 5 gal. Bucket with a concreted in base pipe, but that sounds heavy. I do have a ground rod driver that I could take along, pound a base into the ground, and go from there. I'm thinking something very basic and CHEAP that I could use at a high spot that could support an imax on a short 10 foot or so mast. Surely someone on her has crossed this bridge before. When I have a tree around, I can just attach the antenna to that but I want an all purpose independent idea. What are your thoughts?

-drdx

[Red Warrior]

I personaly do not like the IMax or any other "no ground plane" antenna. The reason is the lack of the second half of the antenna makes the antenna difficult to tune and inefficient. Any slight installation pecularity makes the coax a radiator and a counterpoise. The reactance of the antenna can be extremely high.

That being said, I would recommend using a slingshot to erect an end fed zepp or a center fed dipole. Hams have been using portable antennas for years and these have proven to be great performers. After use, simple pull the antenna down. roll it up and throw it in the back seat.

[721HACKSAW]

I have seen the "park on" mounts many times, mostly at Hamfests. At over 20'+ that Imax gets wobbly fast without some kind of broad or heavy base. The "hose clamp" type of clamps come in large diameters and are quick to use but you still have to have something to clamp it to. A large thin flat plate, possibly alluminum, (I'm thinking old road sign) with tent stake holes in each corner. The "Jury Rigger" in me is really gonna go nuts thinking about this one.
I assume no responsibility for any personal injury or Youtube videos that may result in any of these ideas!

[heavyD]

My opinion would be stick with an antron 99. Easy to handle and quick setup. Use a tripod mount. The military has some portable masts that are 30-40 feet plus. For one man set up I'd go with a 20 foot or pole on a tripod. I think one manufacturer the army uses is blue sky antennas.... i think. I'm pulling that out from way back. If you can get one of those you'll LOVE it

[drdx]

Wow, thanks for all the input. I have dipoles laying around, and one that is pvc based and takes screw in antennas for a rotatable deal. The only reason I went with the imax is the ease of use. It's kinda like a big J pole or something. I could always to both, now that would be fun. I haven't thought about using stakes, that may work. I have some aluminum plate and a pipe flange so I may start there.

-drdx

[heavyD]

I personaly do not like the IMax or any other "no ground plane" antenna. The reason is the lack of the second half of the antenna makes the antenna difficult to tune and inefficient. Any slight installation pecularity makes the coax a radiator and a counterpoise.

I agree that the imax is not the best antenna made but the antenna is not difficult to tune whatsoever its usually flat from 1-40 out of the box. The second half is wound wire in the base of the antenna. I have one and like I said its not perfect but it is very efficient and it is not normal or regular for the coax to be a counterpoise, I have heard of this being a possibility but have never seen it.

[Slim Pickins]

My plan that I came up with for using with my travel trailer was to get one of those extendable painter's poles that are made of fiberglass and aluminum and fasten an A99 to the top of it. You can get these that extend from 8' - 23' at Home Depot for about $30. I was planing to make a base from plywood and pvc pipe (about 18" square plywood with a short length of pvc standing in the middle) Drill a couple holes in the plywood for metal tent stakes. Have a hose clamp close to the top where you can tie on some nylon rope for guylines to some more stakes. With a couple of junior helpers to hold the guylines you should be able to push up the pole with the bottom in the pvc/plywood base then secure the lines to the tent stakes. I figured I would stake the base too in case someone, say one of the junior helpers, or something, in my case one of the dogs bumped into it.

I haven't tried it yet so I can't offer any pictures or reviews but I think it should work.

73s
Paul

[Red Warrior]

I personaly do not like the IMax or any other "no ground plane" antenna. The reason is the lack of the second half of the antenna makes the antenna difficult to tune and inefficient. Any slight installation pecularity makes the coax a radiator and a counterpoise.

I agree that the imax is not the best antenna made but the antenna is not difficult to tune whatsoever its usually flat from 1-40 out of the box. The second half is wound wire in the base of the antenna. I have one and like I said its not perfect but it is very efficient and it is not normal or regular for the coax to be a counterpoise, I have heard of this being a possibility but have never seen it.

A little light reading on the subject.

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['Doc]

A 5 or 10 gallon bucket filled with water, not concrete. Or two or three of them.
That Antron and Imaxx uses the coax for the "ground", or other half of it's self. One method for portable work is to ground mount the thing and lay radials around it connected to the "ground" point of those antennas. The more the merrier.
Any fairly tall trees? Throw a cord over that tree and suspend a dipole, horizontally or vertically, your choice.
Lots of options, only limited by your imagination.
- 'Doc

[231]

Yea, I usually strap the Imax or A99 to a 10' pole and tie it off to the pick up. That's always worked well for me. I've also used a painter's extension pole with a wood tip which would extend about 23' or so. It worked great for inverted 'V' dipole set ups...also tying it off to the truck. The only hassle with that though is of course I have to pull everything down if I want to go somewhere. At camp sites, there are almost always trees so I'll usually hoist up one of my dipoles. But I've thought it would be cool to set up a field day kind of affair guyed off with rope, too.

If you have a couple of whips for a flat top 11m dipole, how come you don't just put the Imax on top of the mast and put the dipole under it as ground plane radials? You should be able to guy it off with tent stakes provided people aren't tripping over the feed lines and guy ropes. Run a switch box to the feed lines and pick your polarity. Or ground mount the Imax like Doc suggested with tons of radials, and put up the dipole also.

The ideas are almost endless...and it sounds like you are going to have allot of fun!

[ogdoa]

I should be done with my Antron mobile setup this weekend. I am mounting it in the back of my 90 Chevy p/u. The plan is a quick disconnect setup. I dont want to spend an hour setting up an antenna. I have a 10' section of mass that I will use wing nuts on u bolts to attach to the antenna. We are welding in a 3 foot section of mass that is slightly larger then the 10' section in the back of the truck. I already have the pipe and a hole drilled through it for the pin to hold it down. This should be enough but just in case I am running guide lines to the four corners of the truck. I will permanently mount these to the mass and they will attach to the truck with hard rubber bunjee cords. If I cant get through with the 102" I can just pull in to a parking lot and throw the big antenna up. Does anyone know if I can use a quick disconnect between the two sections of the antron? If not I will have to unscrew it every time.

[nutcracker]

I know a guy that use to have an old pickup and would drive to the top of the mountain to talk skip, he used some kind of big vertical no ground plane antenna with a pretty decent setup. He used the tail gate to raise and lower the antenna, simple enough.. In the back he carried 2 10' sections of fence railing that fit together. The one end was u bolted to the tail gate and the antenna went on the end of the second section. You just picked up the gate until it locked, and could have an instant 20+ foot tilt over mast.

['Doc]

About a quick-disconnect between sections of that antenna, don't do that. Why? Cuz you just changed the length of that antenna by however tall that 'QD' is, which will change how that antenna is tuned. Depending on who made that quick-disconnect, it's usually the 'weak' point in any antenna, so not exactly all that 'robust', right? If you think it would really help speed putting that antenna up, you can certainly do it with some preparation work.
Something else to think about...
No matter how well an antenna is tuned, if you change something with that antenna, or you move it, change it's environment, you've changed it's 'tune'. Maybe not much, but it will change because any/everything around that antenna affects it. (Almost guaranteed with a mobile antenna, right?) So, as 'yucky' as it may seem, it's really, really handy to have one of those tuners handy to take care of the 'small stuff', you know? Every radio I've had in the last 20 something years has had one of those tuners built into it. No, they haven't been CB radios, but it doesn't matter, it's the same idea. They are NOT cheap, but 'cheapness' depends on how lazy you are, and I'm lazy.
- 'Doc

[ogdoa]

I've had it mounted on top of my old house and when I relocated I did not change anything and mounted it on the roof. No change in swr. I figure if I mount it up and tune it in with the quick dc I should be ok. If i mount it and adjust it while sitting in a parking lot with nothing around, it should remain the same every time I hook it up. I just need to be sure that I park it in a wide open area every time. I will be using an antenna switch to go between the antennas so I do not have to disconnect the coax from the amp everytime I pull out the base antenna.. I already mounted the pvc tube that the antenna will slide into under the truck. I was wondering though, if after installing a quick disconnect, I could adjust those two rings on the bottom and that would adjust the length that the radio sees?

[drdx]

Yea, I usually strap the Imax or A99 to a 10' pole and tie it off to the pick up. That's always worked well for me. I've also used a painter's extension pole with a wood tip which would extend about 23' or so. It worked great for inverted 'V' dipole set ups...also tying it off to the truck. The only hassle with that though is of course I have to pull everything down if I want to go somewhere. At camp sites, there are almost always trees so I'll usually hoist up one of my dipoles. But I've thought it would be cool to set up a field day kind of affair guyed off with rope, too.

If you have a couple of whips for a flat top 11m dipole, how come you don't just put the Imax on top of the mast and put the dipole under it as ground plane radials? You should be able to guy it off with tent stakes provided people aren't tripping over the feed lines and guy ropes. Run a switch box to the feed lines and pick your polarity. Or ground mount the Imax like Doc suggested with tons of radials, and put up the dipole also.

The ideas are almost endless...and it sounds like you are going to have allot of fun!

Yes, the possibilities are endless. I'm cramped for space this trip so lucky to bring what I'm bringing. My soonest opportunity for portable is easy- I have an elevated beach house deck that I can affix the vertical pole to with bungees or whatever but for the future I'd love to have the switched arrangement for camping. I do think a ground mounted imax with a nice 16 radial deal would work well. My 1/4 wave one her at home does and it has lots of blockage. I'd think an imax in the clear well radialled may work good.

-drdx

[420Snowman]

I also have an Imax and I think you are on the right track for ease of setup, power handling, tuning, and durability, (in case the "stand" decides to give out). I would go easy, get a heavy patio umbrella base that fills with water, take it to your spot, fill it up and put the mast in it. You could use a few guy wires just to be safe, but that would be fairly easy. I was thinking of that for my campsite!

Snowman