I found this page via an eBay link.
It is often said "Small size, high efficiency, wide bandwidth" - choose any two for a small HF antenna. However, these seem to win on all 3 parameters?
http://isotronantennas.com/index.php?ma ... page&id=12
The 20m and up antennas are indeed strange looking beasts. However even the 80m version is still very small. They also do a 6m version.
I am not affiliated with Isotron in any way - just posted in the interests of seeing something different.
73 - Rob VK2GOM / GW0MOH
Isotron small HF antennas?
-
VK2FAK
Re: Isotron small HF antennas?
Hi all.....
That antenna seems a long time hidden away....I looked at some of those reviews and they go back to 1991 and 1994......never to be seen again....
And thats a worry.
John
That antenna seems a long time hidden away....I looked at some of those reviews and they go back to 1991 and 1994......never to be seen again....
And thats a worry.
John
Re: Isotron small HF antennas?
Could easily disguise it as some sort of funky bird feeder 
______________________________________________________________
Colin
VK2CSW
Where are we going? And exactly why am I in a hand-basket?
Colin
VK2CSW
Where are we going? And exactly why am I in a hand-basket?
Re: Isotron small HF antennas?
At my place they would be THE bird feeder... our resident galahs would chew those into a multitude of bits in a month.... but they deserve a place in any art gallery.
Richard
VK2AAH
Richard
VK2AAH
-
VK4WDM
Re: Isotron small HF antennas?
One of our local hams brought one of these for use at his retirement villiage but I don't think he had much joy with it and took it down. I will ask him at our meeting next Tuesday night.
73
Wayne VK4WDM
73
Wayne VK4WDM
Re: Isotron small HF antennas?
They are not highly regarded by the denizens of QRZ.com.
One reference compares them unfavourably to a dummy load!
73,VK6ZGO
One reference compares them unfavourably to a dummy load!
73,VK6ZGO
-
VK2GOM
Re: Isotron small HF antennas?
That's why I always find these reviews interesting. The general score was definitely well above average though, and only really lowered by the occasional 1 or 0 out of 5. But then there are those that score it a 5, and even list all the DX they've worked with one...
Does this mean those that scored it lowly have installed it incorrectly, in a bad location, don't like the manufacturer, or even used 20yr old coax full of water? Without examining their circumstances, nobody knows.
All reviews should be taken with a generous pinch of NaCl, whatever they be for.
73 - Rob VK2GOM / GW0MOH
Does this mean those that scored it lowly have installed it incorrectly, in a bad location, don't like the manufacturer, or even used 20yr old coax full of water? Without examining their circumstances, nobody knows.
All reviews should be taken with a generous pinch of NaCl, whatever they be for.
73 - Rob VK2GOM / GW0MOH
Re: Isotron small HF antennas?
There is nothing that I have seen on that link to have changed my mind on the accuracy of that above statement, call me a cynic or a pessimist (I'm both) if you will but as I see it a small antenna in terms of wavelength = low radiation resistance = poor match, almost any low loss attempt to match the load narrows the bandwidth further still, small also = high Q and/or high losses. Hi Q = narrow bandwidth. Close wound coils = low Q = high losses, close wound coils on plastic formers = low Q = high loss, I assume the formers are PVC? To have high efficiency in a small antenna you have large currents and high voltages, put a large current through those coils and you will be contributing more than your fair share to global warmingVK2GOM wrote:I found this page via an eBay link.
It is often said "Small size, high efficiency, wide bandwidth"
Carbon Tax anyone?I should add that I find it hard enough to get any two of "Small size, high efficiency, wide bandwidth" let alone three.
I am more than happy to be corrected on any of the above assumptions but please keep it nice and play the ball, not the man. It should make for a good debate anyway?
73
Dave
Re: Isotron small HF antennas?
The good reviews are about as good as the results I get with a Terlin Outbacker Perth Plus mounted on the patio.VK2GOM wrote:That's why I always find these reviews interesting. The general score was definitely well above average though, and only really lowered by the occasional 1 or 0 out of 5. But then there are those that score it a 5, and even list all the DX they've worked with one...
Does this mean those that scored it lowly have installed it incorrectly, in a bad location, don't like the manufacturer, or even used 20yr old coax full of water? Without examining their circumstances, nobody knows.
All reviews should be taken with a generous pinch of NaCl, whatever they be for.
73 - Rob VK2GOM / GW0MOH
I've worked DX on 20m with it,& contacts on 80m of around 700km in WA.
I've also worked South Korea on 15m using a CB whip with an extended stinger also on the patio.
Not great antennas,but you can have quite serious contacts with them!
73,VK6ZGO
-
VK2AVR
Re: Isotron small HF antennas?
I found this interesting read on the isotron, basically saying that a good proportion of the radiation comes from the feedline and the antenna itself is really just a way of tuning the system (including feedline) to resonance. The antenna itself doesn't radiate much without a feedline to work against.
http://www.antennex.com/preview/archive ... sotron.pdf
Of course, it's better than nothing and gets you on air - but your signals will be much lower than a full size antenna and since the feedline radiates you may have RFI issues in the shack depending on length of feedline.
Geoff
http://www.antennex.com/preview/archive ... sotron.pdf
Of course, it's better than nothing and gets you on air - but your signals will be much lower than a full size antenna and since the feedline radiates you may have RFI issues in the shack depending on length of feedline.
Geoff