Backup 3" FSL Tecsun PL-380 Design (with 62mm ferrite bars)


Gary DeBock
 

Hello All,
 
For those who are unable to track down the scarce 100mm x 20mm x 3mm Russian surplus ferrite bars (to make a 3" FSL Tecsun PL-380 model), an alternative design has been created using the commonly available 62mm x 12mm x 4mm ferrite bars (currently offered on eBay by two sellers).
 
Although this FSL design will not have the same sensitivity at the 3" 100mm design (see the side-by-side comparison in the attached photo), the model does have some advantages in comparison to other types of hard-wired antennas. It is far more sensitive than the stock loopstick, and still more sensitive than a 7.5" loopstick transplant.
 
The design uses 15 of the smaller 62mm x 12mm x 4mm ferrite bars, and ends up being slightly more lightweight than the 100mm ferrite bar model (see photo). Like its larger 100mm bar FSL sibling the model seems to have an exceptional nulling capability, possibly because of the unusual, stubby shape for a hard-wired antenna coil-- something which hasn't been tried in loopsticks since radios were created. This new model can put all of my Seattle semi-locals down in the noise, and most of the Tacoma semi-locals as well. Further experimentation in these short, stubby antenna coils may well breed a new class of portable radios with a breakthrough mission-- "pest control."
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)    


Everett N4CY
 

Hi Gary,
If you will remember I did many experiments using the 64 X 12 X 4 mm ferrite bars and built several stellar performing FSLs by butting the bars up to each other. I have used them 2 wide,  3 wide and 4 wide. They were wound with 1 coil, 2 coils, 3 coils and 4 coils. They worked very well in LW, MW and in the lower part of the tropical bands. I have also used the larger bars 125 X 15 X 4 mm and they too worked very well and I still have enough of them to build a very nice FSL

At the time I bought they cost less and weighted a lot less. I still have well over 1,000 of the still in inventory, but am not ready to part with any of them, as I may build a few more FSLs before I die. 
Everett N4CY


On Jan 16, 2016, at 6:58 PM, D1028Gary@... [ultralightdx] <ultralightdx@...> wrote:

 

Hello All,
 
For those who are unable to track down the scarce 100mm x 20mm x 3mm Russian surplus ferrite bars (to make a 3" FSL Tecsun PL-380 model), an alternative design has been created using the commonly available 62mm x 12mm x 4mm ferrite bars (currently offered on eBay by two sellers).
 
Although this FSL design will not have the same sensitivity at the 3" 100mm design (see the side-by-side comparison in the attached photo), the model does have some advantages in comparison to other types of hard-wired antennas. It is far more sensitive than the stock loopstick, and still more sensitive than a 7.5" loopstick transplant.
 
The design uses 15 of the smaller 62mm x 12mm x 4mm ferrite bars, and ends up being slightly more lightweight than the 100mm ferrite bar model (see photo). Like its larger 100mm bar FSL sibling the model seems to have an exceptional nulling capability, possibly because of the unusual, stubby shape for a hard-wired antenna coil-- something which hasn't been tried in loopsticks since radios were created. This new model can put all of my Seattle semi-locals down in the noise, and most of the Tacoma semi-locals as well. Further experimentation in these short, stubby antenna coils may well breed a new class of portable radios with a breakthrough mission-- "pest control."
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)    

<2016FSLantennas-052.jpg>
<2016FSLantennas-056.jpg>


Michael <michael.setaazul@...>
 

----- Original Message ----- From: Everett Sharp

If you will remember I did many experiments using the 64 X 12 X 4 mm ferrite bars and built several
stellar performing FSLs by butting the bars up to each other. I have used them 2 wide, 3 wide and 4
wide. They were wound with 1 coil, 2 coils, 3 coils and 4 coils. They worked very well in LW, MW and
in the lower part of the tropical bands. I have also used the larger bars 125 X 15 X 4 mm and they
too worked very well and I still have enough of them to build a very nice FSL
---------------------

Everett,

Is there any detail of your designs on the group website - or (The Force forefend) elsewhere?
With my snail-band, it is hard to search :-)

I have one more year of French stations on longwave, so a temp-build might be worthwhile.
Medium wave is already all but dead, except for Spain and one from Belgium.
Two MW UK masts developed a top-end bend in recent days. Digital conspiracy ???

2016 may be the year I will turn to Burbon and/or mood-enhancers...

Michael


Everett N4CY
 

Michael,
There are several articles that I have posted in the files section of URL that cover my experiments and builds.
Everett N4CY
 
In a message dated 1/17/2016 7:00:52 A.M. Central Standard Time, ultralightdx@... writes:

 


----- Original Message ----- From: Everett Sharp

If you will remember I did many experiments using the 64 X 12 X 4 mm ferrite bars and built several
stellar performing FSLs by butting the bars up to each other. I have used them 2 wide, 3 wide and 4
wide. They were wound with 1 coil, 2 coils, 3 coils and 4 coils. They worked very well in LW, MW and
in the lower part of the tropical bands. I have also used the larger bars 125 X 15 X 4 mm and they
too worked very well and I still have enough of them to build a very nice FSL
---------------------

Everett,

Is there any detail of your designs on the group website - or (The Force forefend) elsewhere?
With my snail-band, it is hard to search :-)

I have one more year of French stations on longwave, so a temp-build might be worthwhile.
Medium wave is already all but dead, except for Spain and one from Belgium.
Two MW UK masts developed a top-end bend in recent days. Digital conspiracy ???

2016 may be the year I will turn to Burbon and/or mood-enhancers...

Michael


Nick Hall-Patch
 

Your observation of superior nulling ability with the stubby FSL antenna is very interesting Gary.   One of the most intriguing aspects of the old SRF-59 in my recollection was that in spite of its tiny size, it had very good nulling capability.

Is it a rule of thumb that a stubby antenna has better nulling capabilities?  (though a single rod hasn't much signal pickup overall)

best wishes,

Nick


---In ultralightdx@..., <D1028Gary@...> wrote :

.........
 
The design uses 15 of the smaller 62mm x 12mm x 4mm ferrite bars, and ends up being slightly more lightweight than the 100mm ferrite bar model (see photo). Like its larger 100mm bar FSL sibling the model seems to have an exceptional nulling capability, possibly because of the unusual, stubby shape for a hard-wired antenna coil-- something which hasn't been tried in loopsticks since radios were created. This new model can put all of my Seattle semi-locals down in the noise, and most of the Tacoma semi-locals as well. Further experimentation in these short, stubby antenna coils may well breed a new class of portable radios with a breakthrough mission-- "pest control."
 


Gary DeBock
 

<<<   Your observation of superior nulling ability with the stubby FSL antenna is very interesting Gary.   One of the most intriguing aspects of the old SRF-59 in my recollection was that in spite of its tiny size, it had very good nulling capability.   >>>
 
Thanks for your comment, Nick.
 
Yes, in the early days of the Ultralight boom many DXers (Canadians, especially) ran wild with the nulling capabilities of radios like the SRF-59, SRF-39FP and SRF-T615. I can still remember the excitement of Rob Ross, putting his Ontario pests way down in the noise. After performing about 45 alignments on the SRF-59, I can still see the short and stubby shape of the loopstick.
 
<<<   Is it a rule of thumb that a stubby antenna has better nulling capabilities?  (though a single rod hasn't much signal pickup overall)   >>>
 
Well, with stock loopsticks there is always a practical limit how short and stubby an antenna coil can get, since the ferrite rod needs to fit inside the radio (i.e. it can't be a very large a diameter, like the 3" diameter of these FSL's), and too short a rod will limit the radio's sensitivity. These externally mounted FSL's have no such limitation, and that's probably why this bizarre nulling capability first appeared. Of course, it's now easy to design external, hard-wired FSL's that go specifically in this "short and stubby" direction-- and possibly create the ultimate nulling monster!
 
When my local graveyard pest (1450-KSUH) finally gets nulled completely down into the noise, Nick, victory will be claimed :-)
 
73, Gary DeBock (in Puyallup, WA, USA)
 
 
 
      
    
 
 

-----Original Message-----
From: nhp@... [ultralightdx] <ultralightdx@...>
To: ultralightdx
Sent: Sun, Jan 17, 2016 8:19 am
Subject: [ultralightdx] Re: Backup 3" FSL Tecsun PL-380 Design (with 62mm ferrite bars)

 
Your observation of superior nulling ability with the stubby FSL antenna is very interesting Gary.   One of the most intriguing aspects of the old SRF-59 in my recollection was that in spite of its tiny size, it had very good nulling capability.

Is it a rule of thumb that a stubby antenna has better nulling capabilities?  (though a single rod hasn't much signal pickup overall)

best wishes,

Nick


---In ultralightdx@..., wrote :

.........
 
The design uses 15 of the smaller 62mm x 12mm x 4mm ferrite bars, and ends up being slightly more lightweight than the 100mm ferrite bar model (see photo). Like its larger 100mm bar FSL sibling the model seems to have an exceptional nulling capability, possibly because of the unusual, stubby shap e for a hard-wired antenna coil-- something which hasn't been tried in loopsticks since radios were created. This new model can put all of my Seattle semi-locals down in the noise, and most of the Tacoma semi-locals as well. Further experimentation in these short, stubby antenna coils may well breed a new class of portable radios with a breakthrough mission-- "pest control."
 


Guy Atkins
 

Hi Nick,

With regard to nulling ability, I wonder if the optimum length-vs-diameter ratio for FSLs is different than for standard (solid, non-hollow) ferrite rod antennas. In the early days of the UltralightDX Yahoo Group there was some experimentation with very skinny, long ferrite antennas. In fact, group co-founder John Bryant created an unusually skinny antenna composed of six or seven 1/2" X 7.5" Amidon rods in a row. The rods were cleverly compressed "on-axis" to simulate a single long rod for RF receiving purposes (did you ever know John *not* to be the King of Clever in any of his projects? :^)

Around the same time I also experimented with the nulling ability of ferrite rod antennas using a 3/4" X 18" commercial Stormwise ferrite rod. I'm sure Gary must have tried various length-to-diameter ratios, too. The diminutive Sony SRF-T615 receiver was presumed to have excellent nulling due to its skinny (albeit small) antenna; we were just trying replicate or improve upon the length-vs-diameter ratio of our antennas in larger sizes for better sensitivity.

Now with this talk about the benefits of "stubby" Ferrite Sleeve Loop antennas, it makes me wonder if the preferred ratio works in the opposite direction if the ferrite is a hollow cylinder? Gary, can you chime in with your thoughts here?

73,

Guy Atkins
Puyallup, WA



---In ultralightdx@..., <nhp@...> wrote :

Your observation of superior nulling ability with the stubby FSL antenna is very interesting Gary.   One of the most intriguing aspects of the old SRF-59 in my recollection was that in spite of its tiny size, it had very good nulling capability.

Is it a rule of thumb that a stubby antenna has better nulling capabilities?  (though a single rod hasn't much signal pickup overall)

best wishes,

Nick




Gary DeBock
 

Hi Guy,
 
<<<   Around the same time I also experimented with the nulling ability of ferrite rod antennas using a 3/4" X 18" commercial Stormwise ferrite rod. I'm sure Gary must have tried various length-to-diameter ratios, too. The diminutive Sony SRF-T615 receiver was presumed to have excellent nulling due to its skinny (albeit small) antenna; we were just trying replicate or improve upon the length-vs-diameter ratio of our antennas in larger sizes for better sensitivity.   >>>
 
Yes, I recall John's experiments, and your 18" Stormwise bar transplants for the PL-380. John even turned his 4 foot long solid-ferrite monster over to me shortly before his accident, but unfortunately there were too many other hobby projects going on here at the time to have any chance to test it out (I guess some things never change). There never was much experimentation done here with super-long loopsticks, although a 30" composite loopstick for the ICF-2010 was made by placing 4 Amidon 7.5" ferrite rods together. To me there seemed to be a point of diminishing returns with the Stormwise and longer ferrite rods, which made the attached portables very awkward to carry around. On the other hand the 7.5" loopstick transplant has always seemed to provide a lot of "bang for the buck."
 
<<<    Now with this talk about the benefits of "stubby" Ferrite Sleeve Loop antennas, it makes me wonder if the preferred ratio works in the opposite direction if the ferrite is a hollow cylinder? Gary, can you chime in with your thoughts here?   >>>
 
Well, for some reason the hard-wired FSL's do seem to have made a breakthrough in nulling performance, possibly because they can be made extremely "short and stubby," whereas loopstick coils can never get too large in diameter because of the practical need to fit inside of a radio cabinet. In comparison to the famous SRF-T615 the 3" hard-wired FSL can get deeper nulls on pest stations, even though it was never specifically designed for this capability. The real fun will start when hard-wired FSL's are purposely created with sizes and shapes to emphasize this advantage-- at which time the design principles should be clarified. 1450-KSUH may be the final victim of this ultimate "pest control."
 
73, Gary
 
           
 
     
 
 

-----Original Message-----
From: dx@... [ultralightdx]
To: ultralightdx
Sent: Mon, Jan 18, 2016 2:31 pm
Subject: [ultralightdx] Re: Backup 3" FSL Tecsun PL-380 Design (with 62mm ferrite bars)

 
Hi Nick,

With regard to nulling ability, I wonder if the optimum length-vs-diameter ratio for FSLs is different than for standard (solid, non-hollow) ferrite rod antennas. In the early days of the UltralightDX Yahoo Group there was some experimentation with very skinny, long ferrite antennas. In fact, group co-founder John Bryant created an unusually skinny antenna composed of six or seven 1/2" X 7.5" Amidon rods in a row. The rods were cleverly compressed "on-axis" to simulate a single long rod for RF receiving purposes (did you ever know John *not* to be the King of Clever in any of his projects? :^)

Around the same time I also experimented with the nulling ability of ferrite rod antennas using a 3/4" X 18" commercial Stormwise ferrite rod. I'm sure Gary must have tried various length-to-diameter ratios, too. The diminutive Sony SRF-T615 receiver was presumed to have excellent nulling due to its skinny (albeit small) antenna; we were just trying replicate or improve upon the length-vs-diameter ratio of our antennas in larger sizes for better sensitivity.

Now with this talk about the benefits of "stubby" Ferrite Sleeve Loop antennas, it makes me wonder if the preferred ratio works in the opposite direction if the ferrite is a hollow cylinder? Gary, can you chime in with your thoughts here?

73,

Guy Atkins
Puyallup, WA



---In ultralightdx@..., wrote :

Your observation of superior nulling ability with the stubby FSL antenna is very interesting Gary.   One of the most intriguing aspects of the old SRF-59 in my recollection was that in spite of its tiny size, it had very good nulling capability.

Is it a rule of thumb that a stubby antenna has better nulling capabilities?  (though a single rod hasn't much signal pickup overall)

best wishes,

Nick