[Elecraft] [k3] Isotropic Antenna

[Doug Person]

I wrote an article for 73 many years ago where I effectively remade the 
Isotron antenna with parts from Home Depot.  At the time, a 20 meter 
version could be built for about $15.  I tested my version extensively 
and for the most part a dipole made with two Hamsticks was quite superior.

They resonate, have good SWR bandwidth and generally radiate 5 watts of 
the 100 watts that goes into them. A "magnetic loop" blows it away.  I 
sold the sample Isotron I bought at a hamfest for $5. (Bottom line - 
they are, as we say in the software business, crapware)

Doug -- K0DXV

On 4/7/2016 5:12 PM, Jim Brown wrote:
> This so-called "antenna" is at best dumb, and at worst a rip-off. As 
> master antenna-designer N6BT wrote some years ago, "everything 
> 'works,' even a light bulb." He demonstrated this by mounting a a 
> light bulb on a wooden fencepost, feeding with coax that he had 
> carefully choked so that the coax could not radiate, and working all 
> continents with it.
>
> As others have noted, antennas like magnetic loops, loaded whips 
> (HamSticks, etc.), and long wires are the weapons of choice with 
> limited space and/or requirements of minimal visibility. If the frame 
> of the building is non-metallic, indoor antennas can work (but can 
> also be mondo noisy on RX). If the frame is metallic, the antenna must 
> be outside. The good news is that the building frame will work fine as 
> a counterpoise (although it may block the antenna in the direction of 
> the building).  A long wire launched away from the building is best -- 
> small diameter enameled wire can be hard to see, and works fine as an 
> antenna.
>
> 73, Jim K9YC
>
> On Thu,4/7/2016 2:41 AM, Petr, OK1RP/M0SIS wrote:
>> I am sure that David talked about an Isotron antennas like this:
>> https://www.isotronantennas.com/
>>
>> I intensively tested/used this antenna in 90's on 40m (product from 
>> Sigi,
>> DK9FN) and I have to say it is a nightmare in overall. From my own
>> experiences the performance of this toy was highly dependent to the
>> grounding availability, bandwidth was very small and tunning was 
>> influenced
>> by ground only but also by closed objects a lot.
>
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