1. posterid:392039
  2. Thai Score

Re: Thai Score

Guy Atkins
 

I believe I've read it in a crystal radio enthusiasts forum, but it's my understanding that the "Dissipation Factor" of various plastics, foam, (or other materials) is what makes the difference. A very low dissipation factor is desirable.

Check out this list of "Electrical Properties of Plastics": Electrical Properties of Plastics

 

73, 
Guy Atkins
Puyallup, WA



---In ultralightdx@..., <michael.setaazul@...> wrote :

Any idea why some foam results in poorer performance?
Last year I tried a "knock-up" with old hotel-radio
ferrites, good litz (with and without a silver-plated
air-spaced variable C) and whatever was to hand. So maybe
the UK-sourced foam was part of the reason for disappointment.
Could it be that some foam has metallic content?
To try again, I would have to try foam from different
sources on a hit-and-miss basis. As LW and MW is dying
in Europe, I am reticent to risk too much outlay and will
probably return to a longer single ferrite rod and/or
1meter dia frame loop

Michael

On 04.03.16 23:50, D1028Gary@... [ultralightdx] wrote:

> <<< I am in the process of gathering materials to build the 3 " FSL
> antenna, I am just wondering where you can buy the Oatey 4x4 foam closet
> spacers? >>>
> The Oatey 4" foam spacer material is sold at Home Depot stores within
> the USA, and is located in the plumbing section of such stores. It is
> extremely cheap, with a full roll of the material (good enough for 2 or
> 3 antenna jobs) costing just over $1.
> Because this material is so cheap and because it is actually quite
> important for proper FSL coil sensitivity, substitutions are not
> recommended. Already one DXer did a very good job in constructing his 3"
> FSL PL-380 model but used a different type of foam, and ended up with
> seriously reduced MW sensitivity as a result.
 
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