DIY Field Antennas

[arajca]

Has anyone used any of this gentleman's antenna designs for CAP field comm ops?

W2IK's WEBPAGES

If so, can you post your results as far as suitability and durability?

[tribalelder]

Built one for me.  I've helped others build them. I like it.  The antenna is mild gain.  On VHF, the tallness is your best friend.  It's lightweight, compact and CHEAP.  Only going up 12 feet, you can get away w/o guy ropes.  With a 'drive-on' foot, you can have a mast up in 5 minutes or less.  You do need a SWR analyzer to tune it, however.

I have used the same poolpole to hold a 50 foot/leg crossed HF dipole on 4 and7 MHz.

Have used it in Chicago winter weather. 

If I were the king of comm, I would decree that every company vehicle with a vhf radio have one of these and a drive-on foot in the back.

May not be the tool of choice for gale force winds.

[floridacyclist]

Either that or http://www.tfn.net/~gfloyd7/antenna

[tribalelder]

There are also some great 1/2 copper plumbing pipe j-pole designs.  While it is not as portable as the poolpole/wire j-pole in PVC, they are more durable.  And, they're still cheap enough to be treated as expendable.  1/2 plumbing pipe gives a relatively wide bandwidth.  Still need that antenna analyzer to get it right EASY and quick.

73 magazine had a good design, set up for PL-259 antenna connector in the late 80's- I've got it somewhere.  Another member has had one of these on his house for 15 years.  A couple years ago, I had an antennna party making those 8 guys made about 12 in a morning--one of those antennas went with the IL contingent to Katrina, where it was put in use. 

[floridacyclist]

You don't even need a mast if you have trees...makes wire antennas that much more feasible for ground teams. All you need are trees and a way to get a line up into the tree. With altitude being one of the biggest improvements you can make, it's worth carrying a way to get an antenna high in a tree even if the antenna is the mag-mount off your van with a counterpoise (19" of wire tied to a steel plate and stuck to the magnet) hanging below.

For foot-portable use, I use a 4oz leather bag of lead shot specifically made as a throwing weight and sold through arborist supply stores (I bought mine at the local John Deere Dealership). It's compact and is good for up to about 35 ft or so. Tied onto 170lb nylon cord (paracord doesn't slide well through tree), it's heavy enough to pull the end back down to the ground as well.

if I have more room, I go with either a wrist rocket and a 1oz sinker tied to 20lb monofilament or the aforementioned tater cannon with a piece of aluminum wire (sold for tying chain-link fences to the poles) shoved through the tater and formed into a loop for tying to. With a fishing reel loaded with 300ft of flourescent 50-lb test and hose-clamped under the barrel (or someone standing nearby with a rod and reel), I have yet to find a tree here in FL that I can't get a line over.

Once the line is over, pulling paracord (or the lightweight 170lb cord if you led off with lightweight fishing line - the 170lb stuff by itself works well for temporary field installs) over the tree is pretty simple, then haul your antenna up high.

[arajca]

Several of the areas I'm looking at potential deployment are above tree-line, around 12 - 13,000 ft.

[Al Sayre]

How about helium baloons?  You can get a small high pressure tank at the local weld shop for around $50, and a hand full of those big rubber punch-ball balloons with the rubberband at Walmart for a couple bucks.  Should be enough to lift a long wire a couple of hunded feet...

[floridacyclist]

Several people have played with this in ARES and the consensus is that they're great for toys or to play with on Field Day, but not for serious short-term deployment. Given the hassles involved in setting up and inflating a balloon big enough to raise an antenna and feedline only to have the wind blow it into a nearby tree and having to carry enough helium on a deployment to go through several launchings (unless you can find a way to get the helium back in the tank after each recovery) and I can see where it becomes impractical.

Still sounds like fun and you can have even more fun breathing the stuff and then calling Mission Base for a radio check

[Al Sayre]

That's why I was thinking about those punch-ball thingys, they're a lot thicker than regular baloons and would stand up to trees a lot better.  Put on 3-4 good long pieces of string or 50 lb mono to use as anchor lines, and it shouldn't blow too far unless you've got a lot of wind...

[gistek]

The biggest problem with helium balloon antennas is the weight. Using a sturdier balloon requires more heluim to lift the same amount of wire. Plus, the higher you want the wire, the more it will weigh. Really. Each foot higher adds the weight of that foot of wire to the total mass.

One of my favorites was the 40 foot extension ladder. We laid it down and attached the center feed points of the dipole antennas to the top of the ladder and guy lines to the middle of the extension section. (we made sure everything was laid out so nothing would tangle. We then raised the ladder to vertical and guyed the bottom section. Next we raised the extension to it's fullest height and anchored the upper guy wires. Finally we spread the dipole legs to the inverted V formation and anchored their tie-lines. Took us less than 30 minutes to assemble and raise (ok, yes, we practiced several times beforehand). We were one of the first clubs on the air that Field Day.

[JoeTomasone]

I built and use this antenna with excellent results:

http://hometown.aol.com/alonestaryank/selfj.html

I also built a base for it out of 2" blackpipe which eliminates the need for guy wires in low/no wind environments.    I also have a length of PVC that can be screwed on to the bottom so that the whole arrangement can be leaned against an interior wall of a building.   Using this, I can access our local CAP repeater, which is about 12 miles away, plus most of the local HAM repeaters.   Outside, it works great, especially considering the low cost.


I worked with W2IK back when we were both in NY and in ARES together - VERY sharp guy.

[arajca]

That's the one I'm working on. I made  "H" base out of 1/2" black pipe that stood, unguyed, on the sidewalk at my meeting last week with a mobile-base converter and a 5/8 whip antenna. Once I get the appropriate meters, I'll start on the j-pole portion.

I'm also working on the man-pack antenna.

[JoeTomasone]

I made  "H" base out of 1/2" black pipe that stood, unguyed, on the sidewalk at my meeting last week with a mobile-base converter and a 5/8 whip antenna.

I did mine out of 2" pipe.  Much more of a PITA to lug around, but much more stable. 

Once I get the appropriate meters, I'll start on the j-pole portion.

Just use his measurements for CAP-VHF.    It's reasonably broad-banded and works fine for both CAP-VHF and 2M ham.

[arajca]

I made  "H" base out of 1/2" black pipe that stood, unguyed, on the sidewalk at my meeting last week with a mobile-base converter and a 5/8 whip antenna.

I did mine out of 2" pipe.  Much more of a PITA to lug around, but much more stable. 

Once I get the appropriate meters, I'll start on the j-pole portion.

Just use his measurements for CAP-VHF.    It's reasonably broad-banded and works fine for both CAP-VHF and 2M ham.

Quite likely, but since I am using one of the EFJ mobile, I don't want to risk problems.

[JoeTomasone]

Quite likely, but since I am using one of the EFJ mobile, I don't want to risk problems.

I'm using one as well.    As long as the SWR on the channels you are using is less than 2:1 or so, you're good.   

[floridacyclist]

I had our comm officer try to tell me that we were only allowed to use commercially-sold antennas on any corporate radios.

This was the same person that puts cigarette lighter plugs on 50W mobiles.

[JoeTomasone]

According to our (common) WG/DC, there is no such directive, and FLWG does not have such a restriction, although other Wings could implement one.    As far as FLWG goes, you can use any antenna (presumably one that will not damage the equipment!).

BTW, a 50W radio CAN be connected to the cigarette lighter IF:

1. The plug and lighter socket can handle the required amperage OR

2. You run low enough power to be under the maximum amperage. 


I run my EFJ through the cigarette lighter in my newer Jeep (not the one at Comm Camp!) with no problems, including audio issues.   My lighter socket is rated/fused for 30A.   

[floridacyclist]

Not all lighters are created equal, plus good wiring practice says you should wire directly to the battery with an appropriate size of wire if at all possible.

Besides, plugs make it harder to hook it up as a base station, especially if they did not break the wire with a set of Powerpoles. You found that out at Comm Camp

My other problem with using lighter plugs for the radio is that it takes up a power port that we need for the laptop, GPS, AA battery and cellphone chargers.

[JoeTomasone]

Not all lighters are created equal

Exactly my point above!

plus good wiring practice says you should wire directly to the battery with an appropriate size of wire if at all possible.

Agreed, but on the reasonably new and expensive vehicle, I wasn't about to go poking holes in the firewall.   Plus, the radio is not yet mounted for much the same reasons, plus the cost - it comes out and goes in the house when I get home.

Besides, plugs make it harder to hook it up as a base station, especially if they did not break the wire with a set of Powerpoles. You found that out at Comm Camp

I neglected to add that it is so - a CLA-PP adapter plugged into the PP'ed EFJ bare lead from the box.

My other problem with using lighter plugs for the radio is that it takes up a power port that we need for the laptop, GPS, AA battery and cellphone chargers.

Currently that vehicle isn't set up for a laptop, the nav system is factory, and the cell charger is in the other power port.    The AA's are in the solar charger. 

Now, the "real" comm Jeep (the one at Comm Camp) draws all radio power from the 2 marine batteries in the rear, which recharge both from the alternator and from solar.   However, that vehicle may be going bye-bye, at which time I will have to migrate that setup to the newer vehicle.  The major problem there is a dizzying lack of antenna and radio mounting options.   My purchase was fueled by a little too much testosterone and too little forethought.   

[floridacyclist]

Unfortunately, the vehicle that radio was intended to go in was the squadron van. Rather than bolting it down to something, the decision was made to put it in a wooden stand that sat on the front floor between the seats where it could become a missile in case of an overturn - which of course never happens to 15-pass Ford E350 vans. In reality, I found it was easier to install my own radio (A Kenwood TK730) for missions using battery clamps and PPs rather than going through the rigamarole of tracking down the comm officer so he could unlock the comm shack and let us get the radio.

Meanwhile, I was going to say that "I want my Nissan to be set up just like your Jeep", but I've promised it to Stefan since he's using his bonus to pay for our bike trip. Knowing him, he'll probably trick it out even more than I would have.

What in the world did you get anyway? I'm not too worried about vehicular HF antennas...you get a lot better performance out of a simple dipole and that only takes 10 minutes to set up.

[SarDragon]

Not all lighters are created equal, plus good wiring practice says you should wire directly to the battery with an appropriate size of wire if at all possible.

Besides, plugs make it harder to hook it up as a base station, especially if they did not break the wire with a set of Powerpoles. You found that out at Comm Camp

My other problem with using lighter plugs for the radio is that it takes up a power port that we need for the laptop, GPS, AA battery and cellphone chargers.

I have a 2001 'Burb, so that's my limited knowledge base. Get a hold of schematics for your vehicle and see if there are unused ports on your interior junction boxes. I found two in mine that have enough capacity, and I no longer need to worry about getting through the firewall; Chevy already did it for me.

Specific places to look for are heavy duty trailer or camper, cop options, and upscale accessories. You might not have any of this stuff, but there are still places to plug in the harnesses.

[JoeTomasone]

What in the world did you get anyway? I'm not too worried about vehicular HF antennas...you get a lot better performance out of a simple dipole and that only takes 10 minutes to set up.

I bought a 2006 Jeep Commander.   The major sticking points are:

1. The spots on the rear hatch door where I would normally put the trunk-lip mounts (Diamond K400C) have bends to them. 

2. The luggage rack bars are 4"-5" wide - too wide for any luggage rack mount that I can find.

3. The luggage rack track is a U-shape with lip - can't seem to figure out anything good there.


So for the moment, I am making do with a mag mount for VHF/UHF, but really want to get the ATAS mounted on there someday - and the K400 is about the only mount that will handle it (so sayeth Yaesu; all hail Yaesu).   

It may be for the best in the long run since the job I think I landed today will have me travelling, and I hated taking the other Jeep to the airport and unscrewing/lowering the two antennas to get in the parking garage.     

[floridacyclist]

/
My other problem with using lighter plugs for the radio is that it takes up a power port that we need for the laptop, GPS, AA battery and cellphone chargers.

I have a 2001 'Burb, so that's my limited knowledge base. Get a hold of schematics for your vehicle and see if there are unused ports on your interior junction boxes. I found two in mine that have enough capacity, and I no longer need to worry about getting through the firewall; Chevy already did it for me.

Unfortunately, this is a corporate van that we are talking about...we can't do much of anything involing new wires etc. When we run missions, I have to undo the battery and hook on a set of wires with powerpoles so that I can hook my radio up since half the time the comm officer isn't available to open up the comm shack and install the radio for us. He is concerned that if we put the radio in the van and Wing takes the van, we'll loose the radio.

It's easier to just use my own truck; at least it has a radio and 4WD

[arajca]

IIRC, every corporate vehicle is supposed to have a vhf radio installed. Contact your wg DC and see if a radio can be assigned to the vehicle. Worst he can do is say no.

[floridacyclist]

I did. He said no. Apparently that is considered the squadron's responsibility.

[JoeTomasone]

I did. He said no. Apparently that is considered the squadron's responsibility.

Vans aren't in the Table of Allowances as far as I can see - so I'm not sure how that's being dealt with since the vans are obviously considered reassignable Wing assets that a Squadron presumably wouldn't feel they should spend money on.   I'm going to see what clarification I can get for my own edification; I'll pass along the results.

[gistek]

My husband and I are both Hams and our 2 meter mobile is glove box mounted, similar to the photo in an earlier post. Since neither of us are physically able to install wiring in a vehicle, we decided to have Best Buy run the power cable. They did a very good job and, if/when we sell the van they will uninstall the connector for free.

One concern I have for glovebox mounting is the heat. Many radios become quite warm, especially when running high power. Our mount requires the glove box be open when the radio is being used.

We use a 2m mag mount duckey with the coax run through the back window for our mobile antenna.

[Hawk200]

Unfortunately, this is a corporate van that we are talking about...we can't do much of anything involing new wires etc. When we run missions, I have to undo the battery and hook on a set of wires with powerpoles so that I can hook my radio up since half the time the comm officer isn't available to open up the comm shack and install the radio for us. He is concerned that if we put the radio in the van and Wing takes the van, we'll loose the radio.

Sounds like good reason to get an adapter for the "power port" (cigarette lighter to us older folk), and a magnetic mount.

It's easier to just use my own truck; at least it has a radio and 4WD

Then again, you're probably better off with that. Fewer worries about getting stuck.

[arajca]

I did. He said no. Apparently that is considered the squadron's responsibility.

Vans aren't in the Table of Allowances as far as I can see - so I'm not sure how that's being dealt with since the vans are obviously considered reassignable Wing assets that a Squadron presumably wouldn't feel they should spend money on.   I'm going to see what clarification I can get for my own edification; I'll pass along the results.

I was reviewing the TA and found that each corporate vehicle is supposed to have a mobile vhf radio. You can find it in the "Command and Control Communications" section, pg 17, line B1.