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Author Topic: Curious about Isotron  (Read 10083 times)

Posts: 8915


« Reply #15 on: August 31, 2011, 07:06:22 PM »

There is no substitute for cubic inches.  It is hard to beat 234/468 math when it comes to RF. Shocked

It can be very difficult to get there for many people at least on some bands.

There are lots of ways to reduce the size of antennas while making them perform very well. I wish more people would run them so there were more examples out there.

The trick is to only go as small as you HAVE TO so in that sense there's no substitute for size.  Don't build a two foot 40m dipole when you have space for a 15 foot or 20 foot one.  Of course, if you're sticking your two foot antenna on top of a  15 or 20 foot mast, then it's easy for you to have a 15 or 20 foot antenna.  It doesn't much matter what's on top:

I do have to admit it.  I though it REALLY sucked, but I did make some contacts on it.

FYI: that connection setup is likely dangerous for metering circuitry on many settings.  It's also not as good of a circuit arrangement for differential to common mode conversion as some of the tiny "antennas" on the market, so I wouldn't be surprised if some of them beat my MFJ "antenna" by a huge amount Grin
« Last Edit: August 31, 2011, 07:13:51 PM by N3OX » Logged


Monkey/silicon cyborg, beeping at rocks since 1995.

Posts: 154


« Reply #16 on: September 02, 2011, 02:59:58 PM »

You could do a lot better spending a lot less with just a simple dipole wire antenna.  Wink

Yeah, that's how my sceptical mind works as well... and why I spend so much time in my back yard scheming ways to get more wire up and get it higher.  My wife thinks I've lost my mind! 

I suppose the reason these types of 'antennas' sell is that there are so many of us newer hams that keep open the hope for a 'silver' bullet.  Life experience has taught me that there is no such thing & if it was invented you would find that the cost of 'silver' has risen so much that you can't afford it anyway!

Another reason is the modern ideal of Instant Gratification.  My reading has shown that previous generations of hams spent untold hours researching and experimenting to get the best from their units.  With today's radios that will do everything except make bathroom runs for you, the trend is re-enforced and the same is expected from the antennas.  Being a "poor" man (monetarily speaking) has been a boon in my amateur radio life.  I only have hand-me-down radios to work with and have been forced to make everything else on my own - not to mention the repairs!

Thanks for your thoughts!

George U. Potter Lodge, #912, F. & A. M. of Alabama.
Dave Langham Chapter, #536, Order of the Eastern Star.
Chaos & Critters EXOTIC Animal Rescue - 501(c)(3).

An U.S. Navy Submarine Service disabled Veteran and a proud American Sikh!

Posts: 0

« Reply #17 on: September 02, 2011, 06:39:50 PM »

Reading this thread brought back a dose of nostalgia from my early days
(Teenager) as an amateur radio practitioner.  The Sun Spot Cycle in 1957-
1958 was great!  Although as a teenager I was aware of the Sun Spots, I didn't have any appreciation for them.  Typical iconoclastic teenager!
However the Sun Spots and the Pi Network output of the Globe Scout 65A
provided endless entertainment for the teen age hams around Atlanta.
 We would load up anything from rain gutters, bed springs, heating duct work, 75 Watt light bulbs, etc., to stray cats.   We would try to load anything we could get to
hold still.  The cats would not hold still once the Globe Scout was keyed up!
I worked 14 countries and 21 States on my bed springs!
The only thing that kept a bunch of us from selling bed spring antennas to
other hams was the fact that Gotham Antennas were cheaper!!!
So much for getting rich young!   Cry

Everything radiated.  It would have been a good season for even selling Isotrons.

73,   Cal  K4JSR

Posts: 6994

« Reply #18 on: September 02, 2011, 09:04:19 PM »

The only wire antenna B&W is currently selling is their Terminated Folded Dipole. It is a legitimate antenna design and has beeen around for years.There is nothing at the ends except the supports for the wire. There IS a resister in the junction of the where the ends fold back, but this is well known, well documented, and B&W doesn't hide the fact. No attempt at fraud, no attempt at anything nefarious. It's the way all such antennas work and there are hundreds (if not thousands) in use by the military and MARS stations. I have one in my back yard.

3LK:  I have no idea.  I never even look at their ads anymore.  The reason being I'm simply not interested in a store-bought antenna.

The antenna I checked (X-rayed) had a large (approx. 3" X 6") sealed trap like container at each end of the antenna.  No matter what frequency you loaded the thing the SWR was almost 1:1.  It was a single wire inverted V, not folded.
« Last Edit: September 02, 2011, 09:06:10 PM by K8AXW » Logged

A Pessimist is Never Disappointed!

Posts: 9748


« Reply #19 on: September 03, 2011, 03:42:47 AM »

B&W does not make any more false claims than any other antenna manufacturer does, at least not  lately.  People, however, do tend to dismiss the level of loss associated with the T2FD on some bands and invent some wild stuff about the receiving ability.

I was lurking and casually involved when the "Inverted V" and the T2FD were being played with by someone back up North. The basic theory and article followed at that time were just crazy. For some reason people think traveling wave antennas are efficient, even when only 1 wavelength or much less long, and that folded dipoles can be "traveling wave" antennas.

A German company that made pretty good beams and other antennas came up with a 23 foot folded vertical that was terminated by a resistance. They claimed high efficiency because it was a traveling wave antenna. A friend bought one and installed it, and when I was getting 40 over nine reports with a dipole he was getting S9 reports. Those were the close reports. :-) It was like a dummy load.

Posts: 4283


« Reply #20 on: September 03, 2011, 06:10:57 AM »

Hope not to start a stink, (and no, I'm not planning a purchase), but I am curious about the tiny footprint Isotron antennas.  The curiosity comes simply from never seeing them mentioned, save for one little post that brought them to mind.  Whether they work or not I will leave to those that have tried them and the 'experts'.  I tend to be a sceptic though I enjoy experiment with radiators up in the air... like most of us! Grin

So, what's the scoop?

You already answered your own question......from never seeing them mentioned

Posts: 158

« Reply #21 on: September 03, 2011, 11:30:09 PM »

First of all, let me say that I rarely have negative things to say about an antenna. If you get on the air and make contacts, that makes me happy. Although I have read a lot about antennas, I find many discussions of antennas silly and ridiculous.
That being said, I owned several Isotron antennas. I always wondered about them and I figured, what the heck, they don't take up much space on the mast. I had other antennas but I bought the Isotrons simply to see how well they worked.
They were easily the worst antenna I ever attempted to use. I have made contacts using all kinds of weird and small antennas. Indoor antennas, mobile whips, parts of the house loaded up with a tuner................
I was never able to make a single contact with an Isotron antenna.

I thought you said this was a weak signal mode ? I HAVE a weak signal and he still didn't hear me.

FWIW: My callsign is AB8KT
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