Re: Thai Score


Everett N4CY
 

Gary,

I again see that you fail to recognize any of my work and, or experiments with the FSL and other ferrite experiments. Rightly so Steve and Kevin should be given credit too, as they too did a lot of experiments with the FSL. All three of us made/did  a lot of experiments with different FSL configurations, communicating with each other, off list, each contributing to the final product. I don't proclaim to be an expert, however, I put in many hours of experimentation operating under the "What If" and came up with many results that I believe were of value to the group, or some of the group. I is not just all about "Gary". 

 My conclusion, based on my experiments, is that 1/2" thick polyethylene foam is a better choice for a FSL and also in my Stacked Toroid Loop Stick experiments too. Using 1/2" foam gave a few more kHz of band coverage vs thinner foam, with no loss in performance. I also saw no loss in inductance using the same length of wire, however, there were a few less turns using 1/2" vs 1/4" foam. 

In some of my early experiments I used EVA foam and later found that it gave a little higher inductance vs the PE foam, for the same number of turns/length of wire, but could never see any difference in performance between the two foams. 

I buy my foam from The Foam Factory http://www.thefoamfactory.com/closedcellfoam/polyethylene.htmland use the 1/2" thick 2.1 # density.

Everett N4CY










On Mar 6, 2016, at 8:35 PM, D1028Gary@... [ultralightdx] <ultralightdx@...> wrote:

 

Hi Michael,
 
<<<   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   >>>
 
The choice and thickness of the foam between an FSL's coil and its ferrite material is a major factor in determining an FSL's ultimate sensitivity. The 1/4" (6mm) thick Oatey foam is strong and resilient, and has provided excellent results in FSL antennas since 2011. Along with substitutions in the type of Litz wire and ferrite material, substitutions in the type of foam are not recommended if someone wishes to obtain the designed MW sensitivity in a hard-wired FSL Tecsun PL-380 project.
 
After the U.K.'s Graham Maynard published his original Ferrite Sleeve article in 2011 there was a torrent of experimentation here in the U.S. to determine the best possible components for maximum FSL sensitivity. Ferrite bars, ferrite rods, Litz wire, foam material, frame material and variable caps were all thoroughly investigated. Various brands of foam material were tested in various thicknesses, and the original FSL experimenters (Steve, Kevin and I) determined that a thickness of about 1/4" (6mm) was close to ideal for maximum sensitivity. In my own FSL's I settled on the Oatey foam as the ideal type because of its low cost, thickness and durability. I'm aware that this type of foam may be tough to track down in foreign countries, but is a DXer is very serious about building the FSL-PL-380 model and needs the Oatey foam to complete his parts list, I'm very willing to send a pack of the foam for the cost of postage.
 
73, Gary DeBock (in Puyallup, WA, USA)
 
     
 
 
 
 
-----Original Message-----
From: Michael michael.setaazul@... [ultralightdx] <ultralightdx@...>
To: ultralightdx <ultralightdx@...>
Sent: Sun, Mar 6, 2016 6:24 am
Subject: Re: [ultralightdx] Re: Thai Score

 
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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