Isotron antenna DIY?

[VE3GZB]

http://www.isotronantennas.com/80b.htm

Has anyone ever tried one of these on 80m? How well do they work? How hard is it to build one? How high does it have to be?

73s
geo

[flintstone mop]

It's very sensitive to its surroundings. Even the metal mast can detune it. It's not a DX catcher but they mysteriously do work.
And I think they only handle 200 watts

Fred

[WA1GFZ]

Save your money and invest in a good Bird dummy load.
I laughed at the first time I saw it at the TRW swap meet in Ca. back in '81 and it still brings a smile whenever it comes up. A dog log and coil would work better.

[K1JJ]

The picture below says it all.  Pure junk.  (Caption: "Multiple Isotrons on one mast!" )


This sales statement is laughable:

"THE ISOTRONS HAVE THIS RADIATION "AREA".  The ISOTRONS exceed or equal (depending upon the model) the area of a conventional one-half wavelength dipole (#12 wire)."

Gee... Maybe we should use #0000 welding cable for dipoles to match the Isotron's incredible "radiation area"....


Save your $.

As Frank said, even a small vertical whip with radials would be better.  I've measured a 9' mobile whip on a Blazer for 75M (in the late afternoon for locals) to be down only about 15db from a full size dipole at 60'.  That's not too shabby.



T

[Bill, KD0HG]

Time for an antenna shootout!

Isotron vs. Gotham V-80

[Opcom]

http://www.isotronantennas.com/80b.htm

Has anyone ever tried one of these on 80m? How well do they work? How hard is it to build one? How high does it have to be?

73s
geo

looks like one of the antennas off the "cloud city" in Star Wars.. craaaaaazy.  I talked to the salesman at a hamfest many years ago. He explained why they work and how they are resonant. Apparently they generate very high voltages. But I would not prefer one to a long wire or tall vertical + tuner. It says for space restricted areas so there got to be lots of compromises.

[ka3zlr]

A very Close friend an good fist CW man Called sometime ago, "Jack I'm moving can you Help me get this antenna down" member of the local club, good Egg, by all means show respect yes Sir,.. I make the trip climb the tower remove what looked like a I don't know what...But he swears by it an was bragging to me about this thing...his was cut for 80 meter or built rather it some kind of contraption believe me But it werks...His Call is KB3IN his name is Bob I would think he has email I've never had to email him so I don't know his addy ....

But he Liked......that antenna...


73
Jack.

[Steve - WB3HUZ]

Put up some phased Isotrons and work DX.

[WA1GFZ]

It works compared to what?

[ka3zlr]

What Category would you put this thing in Frank..?

It's a Contraption...

73
Jack.


 

[WA1GFZ]

maybe we need a new section...stuff that doesn't work.

I would put my money into a gotham vertical before that thing. The first time I saw it I asked the guy a bunch of questions.  I think it was as funny as that guy at Deerfield and his gray box antenna invention.

[K1JJ]

Frank said:
"It works compared to what? "


Exactly.  "It works" is probably the most common ham antenna anecdotal story out there.

If a ham has nothing to compare an antenna to; no reference dipole for example - and a mobile whip (a so called "poor" antenna) is down only about 15db from a full size dipole, how would he know he has a poor antenna?  The answer is he wouldn't  know.

Back in May, 1965 my father helped me erect a 55' tree (mast) that I chopped down in the nearby woods. We poured concrete and even added a steel pole at the top wid a pulley and rope.  The first night I had no antenna to raise so I took a 110VAC 100' extension light and raised it up. I loaded the 75W rig into it and could see the light flashing CW up there at 60' in the night.  Lo and behold, stations started coming back to me and I worked all over the east coast on 80M that night - on a lightbulb!

If that were the only antenna I had, then I would have said "it worked."  

I've also lived in apartments where I was happy to sneak a wire out and throw it onto the roof. "It worked."

Little did I know that 40+ years later I'd be playing with antennas that often show a 20db difference over a full size dipole into Europe. Now, that works!     ie, It's all relative.

T

[ka3zlr]

Well then get with Isotron an straighten'em up...other outfits they sell G5RV's everyday an folks buy'em an believe in'em and it's poop antenna too.

There's no use in comparing what this group does on a daily basis and produce quite gud sig's to what the plug an play groups is willing to spend on what they want,,,73
Jack.

[K5UJ]

Another one is "I work everything I hear."

To find out what's going on with the Isotron (one test that is) put a very high Xl common mode choke on the coax up at the Isotron and see how well it does then.  I bet it's another one of these deals where the coax is the antenna.

Rob

[KD6VXI]

Another one is "I work everything I hear."

To find out what's going on with the Isotron (one test that is) put a very high Xl common mode choke on the coax up at the Isotron and see how well it does then.  I bet it's another one of these deals where the coax is the antenna.

Rob

The isotron is an inductor.  Put a "stinger" on the 80 meter or 75 meter model, and you'd have a AM broadcast antenna.

They work.  Akin to a Hustler mobile antenna.  Most of the guys using them are older (no offense to the Seniors), and either can't haul a 6 element 40 meter yagi up themselves, aren't that interested in it anymore, or are restricted by lots or CC & R's.  So, the thing is more than likely being compared to what they where used to as a "working" antenna, something like a Hustler mobile.

I've talked on one of the AM groups with my 100 watt rig, and the ATAS-120 rotary dummy load (screwdriver).  Yeah, people could here me, but nothing like the legal limit full sized 160 dipole at home.  However, Yeasu, as well as the magazines, have all touted the ATAS120 screwdriver as perfect for a pvc flagpole antenna...  They even give measurements for your counterpoise somewhere.  If I lived in a mobile home park, could not have much of an antenna up, I'd sure be happy with this thing on top of a flagpole, and I'd be working 40-70Cm.

So, as others have said, it works, but compared to what?  About as well from what I'd seen as a Hustler or similar mobile antenna.

--Shane


--Shane

[WQ9E]

So, did any of you use a Gotham antenna back in your novice days?  As much as they were advertised they must have sold a few to have enough cash flow for advertising-unless they were a front company for a money laundering operation

I have been licensed since early '75 and I have never seen one, worked anybody with one, or met someone who admits to owning one.  I had put the Boulevard electronics receiver in the same category (advertised heavily but invisible) but I finally found one of those so I know they exist. At least the Gotham antenna looked like it had the potential of radiating a signal.  So one of you loyal Gotham fans, share your experience.

Rodger WQ9E

[Bill, KD0HG]

I had one when I was a Novice in the 60s, Rodger. Not one of their verticals, but a Gotham 4 element 15M band Yagi.

It was an amazing thing. I had been used to working around the midwest with my Knight T-60 on 80 and 40 and a dipole. Ham radio was beginning to be a disappointment. Then I built that Gotham and couldn't believe it, working worldwide DX. I worked *Russia*! And *South Africa*! And *Rhodesia*! And got the QSLs to prove it. Bought IRCs for the first time. I must have worked 40 or 50 countries on that Gotham with that little Knight Kit and S-40 receiver.

The thing about the Gothams was that they were cheap and affordable for someone on a high-school budget. You got a lot of aluminum for other projects, too. That Gotham Yagi was so cheapo that it didn't even have a proper match to the driven element, you were to extend the center conductor of your coax out and tap it directly onto the driven element.

That didn't matter, I didn't even have an SWR bridge and the T-60 loaded it up just fine.

I was even so bold as to mail in a contribution to "How's DX" in QST.

[KB2WIG]

The name says it all.

[W9GT]

I had one of those Gotham 15M beams back in the sixties.  As I recall, there wasn't much to it.  The elements were smaller tubing than you would typically use and they had quite a sag to them.  They just used a U-bolt to attach to the boom with no associated bracket...so they turned around on the boom quite easily and were difficult to keep aligned.  The boom itself was very small tubing.  Yeah, I also remember there was no "match" for the driven element.  You just tapped out a ways with the center cond. of the coax.  The bottom line...they were cheap and within the budget....so a lot of guys bought them.  If nothing else, you could utilize the tubing and parts to build something a little more reasonably engineered.  As I recall, I made a six meter beam out of the stuff from that 15M Gotham beam.  The Gotham verticals were a joke.  Seems like they were nothing but tubing and a coil.  If you ground mounted the thing with no radials, it made an excellent dummy load.
Anyway...lots of fun and a way to get some experience finding out what works and what doesn't.  Also lesson learned....You get what you pay for.

I'm not familiar with the Isotron, but I have heard and worked guys on 40 and 75/80 who were using small magnetic loop antennas.  Hard to argue with the fact that they work, although very narrow banded and you have to use some rugged vacuum variables to withstand the high voltages appearing at the tuning point.  I guess they produce some scary field strength levels near the loop as well.  Interesting concept though.  Especially if you have very limited space for antennas.

73,  Jack, W9GT

[flintstone mop]

It works compared to what?

To a wet noodle

[ka3zlr]

...LOL...

[K1JJ]

Some comments:

Yes, the screwdriver is a nice antenna. After a year experimenting with HB bugcatcher type whips, a bunch of us concluded the versatile screwdriver antenna was roughly as good. The poor groundplane of the car made the top radiator an insignificant part of the system, so the screwdriver was quite adequate - plus remotely tunable!

Batman's Gotham vertical. As I've written many times, I called CQ for three days as a new Novice with no replies using a Gotham Vert on 80M.  No radials and spaced from the house by 1'. (little coax available)  Of course, it would work FB if installed in the clear with a radial field - just like any short, base loaded vertical.

Funny story on the 15M Gotham beam, Bill and Jack.  I remember 15M in 1965. It was dead and so bad I brought my perfectly good working RX into a shop for alignment...  

There's no way to change the world. Isotron will continue to pull in 100's of $thousands selling them. All I can do is advise fellow guys on this BB to consider something else, if they can.  Even a randon end-fed wire or short mobile whip in a flag pole with radials is better.  Even try a magnetic loop using heavy copper tubing. There's  better ways.

T

[W9GT]

It works compared to what?

To a wet noodle

Is that a resonant wet noodle? 

73,  Jack, W9GT

[kg8lb]

It works compared to what?

To a wet noodle

Is that a resonant wet noodle? 

73,  Jack, W9GT

  Easily done with a tune-a noodle salad.

[KF1Z]

Let's be careful not to offend the Macaroni net folks!