Help identify antenna?

[John K5PRO]

I guess this could be posted to the Tower forum, but I haven't partaken in that one. Yesterday I was picking over the remains of a ham station (SK was a former broadcast engineer) and was ogling over the tower and antennas. Quite a nice setup. I climbed to the top and measured 43 feet of tower to where it bends to a point. There is a V doublet fed by a homemade ladder line up the tower side, with ATU at the base to convert it to 50 ohm coax to the shack. The other side has a wire vertical adjacent to the tower, and the tower appears grounded. There are, however, Johnny balls on the three guys. Attached photo. I think it appears to be Rohm 25G for the lower members and near the top the step spacing goes to 18 inches, indicating maybe Rohn 20 section. Is that possible to mix sections? The base is set in concrete, and I didn't see bolts indicating a base unit in the foundation. There is a big copper strap and apparently the yard is underlain with copper screen or chicken wire.

My questions here are:
1) If i take this thing down (and I am tempted, it is so nicely set up, to just remove it and reinstall behind my garage as is) can I just buy a new base unit for a concrete base that I pour, and slip the stubs of the bottom section over it, drill holes for bolts. THis would assume i have the cut the bottom legs at the base. It isn't a tilt over base.

2) What can I use for a gin pole? I would attach this at the top with a pulley above the LP antenna, and lower that first. Then the rotator (a big un) and then lower the pole a section and remove and lower the next section, and so on, until the guys are down, then repeat the process as I climb down.

3) Can anyone identify the log periodic antenna on top? It is a 10 element array and the boom is made of two horizonal parallel pieces of tubing. It doesn't quite look like a HyGain, Cushcraft or KLM antenna. I suppose it could be home brew, but it looks professional.

4) the other antenna (see attached) is a homemade loop made from conduit, with a Aliance rotator. I took it down, have no idea of the frequency range, its a single turn loop with a gap at the top.

Thanks for any advice, is it worth it to take down the tower and LPA? (Price is right, but the labor is significant - a days worth at least)

 

[Todd, KA1KAQ]

Nice set up John, I'd want to move it too!

1.) On the off chance you haven't done this already, check the base to see if it has a pier pin or flat base installed instead of a buried section. This would simplify matters greatly. The flat base simply bolts to anchor rods in the concrete and would be easy to remove. Getting the bottom section loose from the flat base once everything else is removed will likely require some wigglin' and jigglin' to break loose any corrosion between the tower legs and base pins. Then it's as simple as popping the base loose from the concrete, if that's possible.

Barring that, it's down to removing everything above the tower section buried in the concrete and cutting the buried section off flush to satisfy the property owner. Getting a digger in to remove the concrete blob would be pricey.

2.) If you don't have access to a true gin pole/pulley system, you can easily fabricate one from a thick-walled piece of aluminum pipe/tubing with 4 heavy eyelets installed around the top and a large S-hook used to hold the bottom in place over the tower bracing. Simply place the large S hook over the bracing, set the pole inside the hook, and lash/chain the pole firmly to the tower at top. A crude but effective trick learned from an ex-military BC engineer buddy who did commercial tower work for decades.

3.) No idea. Maybe a Force 12? EDIT: Looks more like these:

http://www.tennadyne.com/images/TENNT11_copy2.jpg

http://www.tennadyne.com/images/WD4CWE.JPG

http://www.titanex.de/logper.html

http://www.titanex.de/images/lp_boom.jpg

4.) Any indication if the loop was used for receiving only?

To me, taking down such a system is worth it, provided it doesn't involve risk to nearby property (liability issues) and can otherwise be accomplished in a straightforward manner. This assumes a common sense 'safety first' approach in general, something you are well versed in from your work. My first tower/yagi came from a ham who was moving, and involved an afternoon of work by a crew from the local club to take down and disassemble. A much smaller crew (2-3) put it all back up. 1st contact was 4 Land, second was Chile, third was Antarctica. It beat the hell outta the dipoles in short order.

Any chance you can get some help from friends? It would sure make the job go much easier and likely safer.

[John K5PRO]

Thanks for the tips Todd! Indeed the antenna looks a lot like those two LPAs you attached. The base on the tower is not a plate, or stubs, but the actual tower legs appear to be embedded in the block. So it would need to be sawed off with Sawzall when done. This would be my third tower disassembly and removal. My original one was in 1993, and that Universal aluminum tower (30') is my main mast for a tribander and some dipoles now. My second one is a crank up old model (50') which had three separate metal pipes that were used as stays for the stationary lower section, instead of guys. Guys only tension, these things were bolted at both ends. Unfortunately they each required a massive anchor chunk of concrete, so if I ever use that one i will probably revert to using guy wires. This tower is lying in my field, and I am not excited about putting it up, since the crank and bearings were very rusty, and the cable looks like it could be replaced. However, until now, it was my only source for a tower behind the garage, in center of my 1.7 acres. That would put the apex of a big dipole at top of the tower, instead of hanging free in the air as it is now (using RG8X due to weight). My 30 foot tower is next to edge of lot, behind house, where the yagi and VHF.UHF antenna farm is.

This Rohn tower is very clean and reusable. I am looking to enlist another friend who is smallish like myself, with climb harness, so that two of us can be working at the top with a third ham at the bottom handling ropes to lower things and steer them.

Thanks for the ginpole idea, that was sort of what I was thinking, although i hadn't considered 4 eyehooks, only having one. I suppose if it is oriented OK, one is enough. I am wondering what you mean by S hook to connect to the tower? I was thinking of getting a handful of large stainless hose clamps and screwing them around the pole and a tower leg to secure it temporarily.

I know that some broadcast tower people have been killed due to failing ginpoles in commercial sites. Not something you want to screw up when hauling an antenna using it.

[John K5PRO]

Oh, one more thing, Todd, yes, the loop was probably receiving as it only had a BNC connector (not high power). It is possible that this guy was doing frequency and modulation checks for local MW broadcasters, as he had a counter with calibration tag, some older freq meters, and some big boatanchor mil. receivers.

The receivers, I didn't record the models, but there were at least 3, big things. One I recognized as a BC312 or BC348. Others were RBH, RBA or similar. THey are still there, relegated to trash heap.

[Todd, KA1KAQ]

The 'S' hook looks like a big 'S', except a bit less....round? You slip the lower part of the S over a side brace, which swings the hook downward, exposing the other end for the pole to sit in. If you took two regular old chain hooks and welded them in opposing directions, you'd have the same thing but probably too small for the job.

I don't know that I'd want to trust those Gates type hose clamps to hold it, there's a lot of torque and pressure once you start pulling/twisiting/yanking things loose. We used a small length of chain around the top of the pole to choke it into place against the tower as it sat down on the heavy S hook. The 4 eyelets merely give more flexibility. You can use one for the antenna removal, another for pulling up tools and such, and/or leave a line attached to one (tied off, of course) for emergencies and for letting it down later.

On the loop: Did you notice if the conduit was the actual antenna element, or if it was full of wire?

The receivers, I didn't record the models, but there were at least 3, big things. One I recognized as a BC312 or BC348. Others were RBH, RBA or similar. THey are still there, relegated to trash heap.

YIPERS!!!  Say it ain't so! Those are some sweet receivers, particularly the big RCA Navy sets! Grab 'em, good fleamarket or trading material, if nothing else. Would be a shame if they got trashed.

[John K5PRO]

Ok, I will return and grab the RXs and the antennas. Only problem with the big Navy RX are that nothing moves like that at our local Hamfesters. People are so lethargic as to just want to walk around the indoors vendors and look at the neat LEDS and flashlights. Or ride their little motorized carts. Its kind of disgusting in my eyes. I see less and less interest in BAs or anything with tubes. Its a buyers market, just like houses these days.

Then, posting them on EPAY or online here, means I have to crate them up and deal with shipping problems.

Of course, I could sell them off, pick up only. Think anyone would come out into New Mexico for a collection of Navy Sets? There is a SuperPro 400 there also, but it is in pieces, apparently a parts unit. And a big RF Communications SSB/AM exciter, a huge thing with Collins 455 mechanical filter in it.

[K6IC]

Hi John,

RE:  the LPDA,  am sure it issa Tennadyne,  pair of square alum boom(ette)s,  separated by plastic sheet every so many feet,  and they also had the  stub thingie at the end.  You prob already knew this by now.  73  Nice find,  Have Fun   Vic

[John K5PRO]

Right now I am working on putting together a gin pole setup, with upper pulley, to lower that antenna. And the tower.

[John K5PRO]

Tomorrow's the day. I have three hams coming to help, a rented official Rohn ginpole and lower pulley, several hundred feet of various ropes, tools, harnesses, sunscreen, hat, water, and a BIG 18 foot tandem axle trailer hooked to my truck. Hopefully everything will come apart OK, the wind won't come up, the lightning won't start flashing or I drop the LPA through the guys roof, or worse through the neighbors roof.

I'll take photos and have a final report of the disassembly and removal of that beautiful antenna and tower. Also, I may grab those old RBB/RBC and BC348 receivers if I have any room left in the truck.

[w3jn]

Good luck and be safe, John!  It's gonna be 95 and humid today, I couldn't imagine pulling down a tower in our WX.

You need to MAKE room in your truck for all the other goodies!  A blanket on the roof and a bit of strapping.... may garner you some looks, but there's ALWAYS room for free receivers 

[K1MVP]

John,
That beam looks like the beams that were all over Howard AFB in Panama when I was there
back in the early 90`s.--There must have been at least 5 or 6 of them, as there was
communications squadron on Howard active back then.

The base has been closed since then, and both Howard and Ft. Kobbe are no longer.
There was also Rodman Naval  base, not far from Howard, as I recall.
                                           73, K1MVP 

[k7yoo]

The log is a Tennadyne. I used the 10 element for quite awhile--It is a good antenna. I now have an 8 element waiting to go up as the sunspots improve.
Have fun.
Skip

[John K5PRO]

It was a HOT day yesterday in Albuquerque, we started at 8:30 AM, pulling down the ladder line and dipole, and the spreaders that were mounted of PCV poles on the tower. Carefully wrapped all this up and taped the bundle, as it was so masterfully done by the owner. Roger, K5IP, and I were the primary crew and we got lots of assistance from Bob, KD5MHQ, and Andy, WB9QMH. At the bottom of the tower the homebrew ATU was disconnected and removed, having a roller inductor, a big air variable cap, a mica cap and a balun. It would get replaced with a real balanced tuner in the future, but all of these parts were quality stuff. A Rohn gin pole was rented for $40, and made it happen without incident. I was lathered in SPF45, but still managed to get additional tanning action, as I was up top most of the time. I had 3 ropes, one with a pulley for hauling things, and one with a bag for tools and another for hauling gin pole down and up. The pulley was always kept on the topmost section of tower, to allow lowering the gin pole to the next section for clamping. Of course this meant that I was going up and down each section a few times as the rope was tied, the section loosened (a hammer worked). I had my climbing/rapell harness with a cows tail, i.e., two short pieces of dynamic rope with caribiners, and a separate heavy steel caribiner that I could connect to the tower steel to keep me tight and close. This setup gave me a lot more confidence than my old tower climbing belt with the big lanyard and clips.

The Tennadyne T10 was tricky as when i loosened the U clamps, they torqued a bit in the plastic insulator blocks, as the center of mass caused the big LPA to tilt around. Finally I was able to whack them through, and she was free. We lowered 'er using a pulley at the bottom and a stainless steel caving rapel rack, that was connected to one of the guy anchors. That way the ground team was well out of harms way, and they had a very controlled descent for the antenna. Several elements were caught in the guys on the way down, but we managed to kick them free. That antenna is a monster. Once down, the team worked on removing the elements and splitting the two booms apart, from the insulators. Everything packed into a nice bundle for the 18 foot trailer I borrowed.

We took a break for lunch and airconditioning as well as cold drinks. After lunch we started on lowering the Yaesu G1000 rotator, and then the top section. Gin pole made it happen so easy. Next section, then I hear thunder and see dark clouds to the south. Working fast, I lowered the guy lines, each one with Johnny ball insulators, very heavy duty stuff. At this point I was 30 feet up on an unguyed 25G, and wanted to move down fast as the wind could come up any minute. I was able to remove the next section pronto, and so forth, until we had only a short 5 foot section out of the slab, and lightning and rain started ripping loose. We took a break and waited out, then cut off the lower section with Sawzall, loaded the truck and trailer and headed home, total of 12 hours to get that installation removed.

Next, to start planning for my new tower and antenna, plus all the ladderline and big dipole.

The photos were taken by Bob, KD5MHQ, sure glad he remembered to document this, as I certainly wasn't thinking of that.

[KB2WIG]

There are 'cold packs'  made for 'icing' an sprain, burn etc....  I wonder if they would be of use up on a tower as a personal cooler??  Break the bag and put it in the arm pits or top of the head to keep cool....  justa thought

klc

[John K5PRO]

Here are a few more snapshots of Saturdays antenna party. They were taken by Bob, KD5MHQ.

[w3jn]

Where are the pics of those boatanchor receivers strapped to the roof of yer pickemup, John?

[John K5PRO]

The receivers, well, I had about 15 minutes to look them over. There were 3: A Super Pro 400 basket case, only chassis, not front panel. A RBA or RBB RCA receiver, and another RCA that covered very low freq up to 600 kc. It had a mil # like FFJ-2 or FJJ-2, I forgot to even write it down though. I passed on all of them, due to space and time. Just couldn't allow myself to load them up. So they will probably end up at Electronic Surplus Co, who came swooping in to clean up the remaining tidbits. I did get a FRG7.

[Todd, KA1KAQ]

Excellent job on the tower removal, John. Do you think it was worth it in the end? I seldom think about the dollar factor if something interests me, I can either afford to do it or not. But in the cases where it comes up, I measure the time and expense involved vs. the cost of buying new and having it done for me. From the shots of that set up (especially the ones with you on the tower for scale), it looks like you got a helluva deal! Not only some nice stuff, but from an excellent installation as well. This guy did it right. The open wire feeders to the V looked first rate. Thanks for sharing the story and photos.

The receivers, well, I had about 15 minutes to look them over. There were 3: A Super Pro 400 basket case, only chassis, not front panel. A RBA or RBB RCA receiver, and another RCA that covered very low freq up to 600 kc. It had a mil # like FFJ-2 or FJJ-2, I forgot to even write it down though. I passed on all of them, due to space and time. Just couldn't allow myself to load them up. So they will probably end up at Electronic Surplus Co, who came swooping in to clean up the remaining tidbits. I did get a FRG7.

Ah, okay - as long as they don't get hauled off to the scrap pile, you won't be followed by some voodoo radio curse for the rest of your life.    The last BC transmitter rescue involved a room with extra iron that the engineer hadn't mentioned. We threw in as much as we could, but had to leave some behind along with a nice diesel standby generator. Just didn't have the room, and they were preparing to plow it all under. It happens.

[Ed-VA3ES]

[...] RCA that covered very low freq up to 600 kc. It had a mil # like FFJ-2 or FJJ-2, I forgot to even write it down though.

Sounds like that "RCA" is a Radiomarine Corporation of America AR85XX series receiver. They cover 15 kc to about 650 kc.

[John K5PRO]

Todd,
Yep, was worth it to me. I did spend about 12 hours on site, plus at least another 12 preparing and hauling gin pole, trailer, etc. If I were paid to do this, then, well, things would be different.

I have done this three times now, my first tower was taken down from a SK's site, a 30' Universal aluminum+B&W trap dipole+Cushcraft A34B triband yagi. I think I paid about $150 for all of this, and took it down. This one was an even better antenna setup, plus a taller decent steel tower with guy setup. I did pay a token amount to satisfy the grandson, but consider that the LPA goes for about $1000, the tower for $500 and the rotator for ____, all used, but still working.

I prefer these take down jobs as they prepare me for what the tower will be like installing it. Having a new antenna and tower coming via freight or UPS just isn't the same to me.

73
John

[Todd, KA1KAQ]

And it always goes easier when the original builder did it right instead of 'quick'. Walked away from a take down a few years back with a cheesy stamped and welded/riveted aluminum tower leaning over a house with a yagi on top. Had a pisser of a prop pitch motor at the base to spin it, very well converted in a steel box, with a cool chrome foot peddle controller in the house. Just getting on the tower at the roof made me nervous, and the other fellow with me didn't want to deal with insurance issues if we harpooned the roof.

Interestingly, my first tower was also aluminum (Heights from Florida), and also had a Cushcraft ATB-34 and CDE rotor atop it. Also paid a token amount ($100) to the seller who was moving and just wanted it gone. Weird.