Thai Score


Gary DeBock
 

The attached photo is from the predawn reception of 1575-VOA (Ban Phachi, Thailand) on the "barefoot" 3 inch FSL Tecsun PL-380 Ultralight here in Puyallup, WA, USA this morning. The lady is speaking in Burmese, according to the VOA ID heard at 1430 UTC.
 
 
Fairly common on west coast table receivers and large external antennas during the fall season, at 7,329 miles (11,795 km) the station isn't common at all on hand-held portables at inland west coast locations in the month of March.
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)
"Science Fiction PL-380" barefoot
 
 


David Henry
 

Hi Gary,

Great stuff!!

Just to add that I had a surprise visit from this station on 28 February 2016 at 22:31 UTC here in Aberdeen, Scotland. I have been testing my new SANGEAN DT-250 and I was sitting on a very busy 1575 kHz in the late evening when suddenly in the midst of the mayhem came the familiar VOA 'Yankee Doodle' sig tune, followed by the VOA voice ID in English. A new programme then started in an UNID language and then quickly faded down never to return. I was assuming it would have been from the Sao Thome transmitter, but Allen Willie pointed out that on 1575 it is from Thailand! Pretty amazing for barefoot!

So far, I am really liking the DT-250. Selectivity could be better, but it is streets ahead of my SONY SRF T-615 in that respect and it has given me a heap more pest-free channels.

Cheers,
David Henry
Aberdeen, Scotland.


Joe
 

Gary,

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?


Gary DeBock
 

Hello David,
 
<<<   Just to add that I had a surprise visit from this station on 28 February 2016 at 22:31 UTC here in Aberdeen, Scotland. I have been testing my new SANGEAN DT-250 and I was sitting on a very busy 1575 kHz in the late evening when suddenly in the midst of the mayhem came the familiar VOA 'Yankee Doodle' sig tune, followed by the VOA voice ID in English. A new programme then started in an UNID language and then quickly faded down never to return. I was assuming it would have been from the Sao Thome transmitter, but Allen Willie pointed out that on 1575 it is from Thailand! Pretty amazing for barefoot!   >>>
 
Wow, congratulations on your reception of 1575-VOA with your new, barefoot Sangean DT-250! That is an amazing reception, not only because of your distance from Thailand but also because most of it s over a land path.
 
Because of its powerful transmitter 1575-VOA is a fairly common catch on west coast ocean beaches here in North America, although the challenge goes up dramatically as you try for it at inland locations with a small portable.
 
<<<   So far, I am really liking the DT-250. Selectivity could be better, but it is streets ahead of my SONY SRF T-615 in that respect and it has given me a heap more pest-free channels.   >>>
 
Yes, selectivity is certainly not a strong point of the SRF-T615. Once I was pretty sure that I had received the Korean language 1566-HLAZ with it-- until I investigated a little further and found that it actually was splatter from my local Korean pest on 1450 :-)
 
73, Gary DeBock (in Puyallup, WA, USA)
 
 

    
 
 

-----Original Message-----
From: davidhenry02@... [ultralightdx]
To: ultralightdx
Sent: Fri, Mar 4, 2016 6:45 am
Subject: [ultralightdx] Re: Thai Score

 
Hi Gary,

Great stuff!!

Just to add that I had a surprise visit from this station on 28 February 2016 at 22:31 UTC here in Aberdeen, Scotland. I have been testing my new SANGEAN DT-250 and I was sitting on a very busy 1575 kHz in the late evening when suddenly in the midst of the mayhem came the familiar VOA 'Yankee Doodle' sig tune, followed by the VOA voice ID in English. A new programme then started in an UNID language and then quickly faded down never to return. I was assuming it would have been from the Sao Thome transmitter, but Allen Willie pointed out that on 1575 it is from Thailand! Pretty amazing for barefoot!

So far, I am really liking the DT-250. Selectivity could be better, but it is streets ahead of my SONY SRF T-615 in that respect and it has given me a heap more pest-free channels.

Cheers,
David Henry
Aberdeen, Scotland.


Gary DeBock
 

<<<  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. If someone is unable to track this material down and seriously wants to build the model, I'm very willing to send an Oatey foam pack for the cost of postage. 
 
73, Gary DeBock (in Puyallup, WA, USA)
 
 
 
 

-----Original Message-----
From: jga747@... [ultralightdx]
To: ultralightdx
Sent: Fri, Mar 4, 2016 7:22 am
Subject: [ultralightdx] Re: Thai Score

 
Gary,

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?


Michael <michael.setaazul@...>
 

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@aol.com [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.


Gary DeBock
 

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]
To: 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.


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.


Gary DeBock
 

Everett,
 
You are certainly entitled to your opinions regarding the foam, and any other parts of the FSL antenna. Having been through all of the FSL design controversies since Graham Maynard's introductory article in February of 2011, I have learned that the best possible approach is to respect the opinions of others, and concentrate on A/B testing of my own designs to maximize their effectiveness in actual weak-signal DXing. Most DXers pay far more attention to actual DXing results (MP3's and/ or videos) than grandiose claims about antenna performance, and as long as an antenna is successful by that standard it is a meaningful contribution to our hobby community, regardless of the designer.
 
73, Gary DeBock (in Puyallup, WA)
 
 
 
 

-----Original Message-----
From: Everett Sharp everettsharp@... [ultralightdx]
To: ultralightdx
Sent: Mon, Mar 7, 2016 3:53 am
Subject: Re: [ultralightdx] Re: Thai Score

 
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.


Joe
 

Gary,

         I've looked at several local Home Depots and Lowe's for the foam closet spacers and have had no luck, I've even checked the website and they only list the 4x82 foot sections. So I may have to take you up on your offer. Please let me know your email address and we can coordinate.

Thanks,

Joe


Gary DeBock
 

Hi Joe,
 
<<<      I've looked at several local Home Depots and Lowe's for the foam closet spacers and have had no luck, I've even checked the website and they only list the 4x82 foot sections. So I may have to take you up on your offer. Please let me know your email address and we can coordinate.  >>>
 
No problem. My email address is d1028gary@... , and I can send you a pack of the Oatey foam ASAP if you give me your shipping address privately, along with a $5 PayPal payment (I assume that you are in the U.S.). For those outside of the U.S. who really want to build the 3" FSL Tecsun PL-380 but who can't find the Oatey foam, please send me an email, and I'll try to help out.
 
73, Gary DeBock (in Puyallup, WA, USA)
 
 
 
 

-----Original Message-----
From: jga747@... [ultralightdx]
To: ultralightdx
Sent: Mon, Mar 7, 2016 3:47 pm
Subject: Re: [ultralightdx] Re: Thai Score

 
Gary,

         I've looked at several local Home Depots and Lowe's for the foam closet spacers and have had no luck, I've even checked the website and they only list the 4x82 foot sections. So I may have to take you up on your offer. Please let me know your email address and we can coordinate.

Thanks,

Joe


Jerry Rappel <ww0e@...>
 

I am going to use Sill Seal, 5 1/2" width found at
Menard's, by Plymouth Foam Co. 

 http://www.menards.com/main/building-materials/insulation/insulation-accessories/plymouth-foam-5-1-2-x-50-standard-foam-sill-sealer/p-1444451015061.htm


Jerry  WWØE


From: "jga747@... [ultralightdx]"
To: ultralightdx@...
Sent: Monday, March 7, 2016 5:47:26 PM
Subject: Re: [ultralightdx] Re: Thai Score

 

Gary,


         I've looked at several local Home Depots and Lowe's for the foam closet spacers and have had no luck, I've even checked the website and they only list the 4x82 foot sections. So I may have to take you up on your offer. Please let me know your email address and we can coordinate.

Thanks,

Joe





Gary DeBock
 

Hi Jerry,
 
<<<   I am going to use Sill Seal, 5 1/2" width found at
Menard's, by Plymouth Foam Co.    >>>
 
You are of course welcome to use any type of foam that you wish, but already one DXer tried using window sill foam instead of the Oatey foam, and ended up with seriously reduced MW sensitivity as a result. The model's MW sensitivity was fully restored when the window sill foam was replaced with the Oatey foam.
 
73, Gary DeBock (in Puyallup, WA, USA)

  
 
 

-----Original Message-----
From: Jerry Rappel ww0e@q.com [ultralightdx]
To: ultralightdx
Sent: Mon, Mar 7, 2016 6:16 pm
Subject: Re: [ultralightdx] Re: Thai Score

 
I am going to use Sill Seal, 5 1/2" width found at


Jerry  WWØE


From: "jga747@... [ultralightdx]" <ultralightdx@...>
To: ultralightdx@...
Sent: Monday, March 7, 2016 5:47:26 PM
Subject: Re: [ultralightdx] Re: Thai Score

 
Gary,

         I've looked at several local Home Depots and Lowe's for the foam closet spacers and have had no luck, I've even checked the website and they only list the 4x82 foot sections. So I may have to take you up on your offer. Please let me know your email address and we can coordinate.

Thanks,

Joe




jerry popiel
 

Jerry, there is another option re the foam tape to try. I used “Aerotape Self-Adhesive  Insulation Foam Tape for 3 of my FSL projects including the latest 3” FSL.  The tape comes in rolls of 1/8” X 2” X 30ft. So you need to double it up to get the required 1/4” spacing. It works well and holds the 100mm Ferrite Bars in as a bonus.
You can find it on Amazon.com

Amazon.com: Itp Aerotape Self Adhering Foam Tape 1/8 " X  2 “  X  30FT

See picture below. 
Jerry 

  


Michael <michael.setaazul@...>
 

Thanks for the clarification, Gary. It is curious that there can
be such a difference with different foam. Material composition
may be significant, but is thickness and spacing more critical
than quality or composition of the foam?

Has anyone in the Old World experimented with locally
available materials - including hoarded packaging stuff?

With the rods recovered from old hotel radios, I might give
it a try. However without comparison with an optimised design,
I would never know how well my knock-up was performing :-)

Michael

On 07.03.16 02:35, D1028Gary@aol.com [ultralightdx] wrote:
. . .
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.
. . .


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.
 


Everett N4CY
 

All PE, polyethylene foam, is basically the same. Some is open cell and some 
is closed cell. The cell size determines the density, the listed density is in pounds 
per cubic. In some cases PE foam is cross linked with other materials that are added to improve the strength. 

Everett N4CY


On Mar 8, 2016, at 12:36 PM, dx@... [ultralightdx] <ultralightdx@...> wrote:

 

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@..., 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.
 


josephrot
 

RE: <<  All PE, polyethylene foam, is basically the same. Some is open cell and some 
is closed cell. The cell size determines the density, the listed density is in pounds 
per cubic. In some cases PE foam is cross linked with other materials that are added to improve the strength.  >>
 
Keep in mind that open-cell foam can be an amazing moisture-and-dirt trap where you might not dare want that to happen.

Also, open cell COULD potentially catch a lot more wind in storms, making whatever is using open-cell to blow down / collapse, etc.
 
Closed cell might be a better overall choice, based on ones needs, the job and materials at hand, and the expected lifetime of your results.

Joe Rotello / Knoxville, TN / USA