Date   

Re: Compare Tecsun PL-606 to the PL-380

Rik
 

I had both the 390 and 310 and preferred the 310 and liked the 310ETM even better for my uses on AM FM and SW. Never had the 380 myself though. Based on Gary's reviews comparing the 310 and 380 I chose the 310 for some reason I forget. This of course is just another opinion. I do not chase 9KHz stations from my inland location in CT.  I also think the stock 310 is much better than a stock 360 or GP-5/SSB barefoot, but it is so easy to use any sort of wire or loop connected directly to those two models.- FARMERIK


Re: Compare Tecsun PL-606 to the PL-380

josephrot
 

Paul...

Thank you for bringing he PL-390 to our attention.

Although the PL-390 does not do SSB reception, I had an opportunity to handle a new one for about an hour, and I must agree with you...the performance is surprisingly sensitive and devoid of "odd-ball problems", and the unit makes a fine "good for a lot of people" LW / AM (MW) / SW and FM receiver in my humble opinion.

And yes, it certainly appears as two-speaker "version" of the PL-380, yet the 390 definitely seems improved in many performance areas over the PL-380.

It's an interesting find, and I may add one to my Tecsun PL-660 that I really like as well.

Joe Rotello / Knoxville, TN / USA
Skype; joerotello (audio / video / chat)

---In ultralightdx@..., <qa1433@...> wrote :

<<  I bought the Tecsun PL390. It is very hot on Shortwave-AM-FM. I was impressed with the way it receives. I live here in Chicago land about 5 miles away from WBBM,  WSCR, WGN and I  am about 2 miles away from a 50 kw station on 1160. I don't have any images on this radio. There are no strange DSP birdies on this radio either. There is also a way to turn off the muting and Agc circuit on the Internet. >>


Re: Compare Tecsun PL-606 to the PL-380

Paul Juarez
 

Hi Dave,
I bought the Tecsun PL390. It is very hot on Shortwave-AM-FM. I was impressed with the way it receives. I live here in Chicago land about 5 miles away from WBBM,  WSCR, WGN and I  am about 2 miles away from a 50 kw station on 1160. I don't have any images on this radio. There are no strange DSP birdies on this radio either. There is also a way to turn off the muting and Agc circuit on the Internet. It was a uTube video. Works great on AM and Shortwave. All in all is the same radio as the PL380. Only with two ✌ speakers. I like it and it performs outstandingly. Hope this helps you with your decision.
Best regards,
Paul Juarez
Sent from my HP Slate 7 Extreme Tablet

On Jan 20, 2016 10:40 AM, "Dave Hascall dhinfomedia@... [ultralightdx]" <ultralightdx@...> wrote:

 

Hello Gary and fellow ULR enthusiasts!

As some of you may remember, I purchased a Tecsun PL-606, to augment my Eton e-100 and to take advantage of the Tecsun's adjustable bandwidth.  Since I live in a bi-level home, I have one on each floor.  

Gary warned me about the freakish tuning that the Tecsun uses with no tuning knob or direct frequency entry.  While the adjustable bandwidth has netted me a few new stations, I have been frustrated by the tuning oddities of the PL-606.  The fact thatr there is no way of setting the light to stay on, is another issue.

Having read lots about the PL-380, I am considering replacing the PL-606 with the PL-380.

Here are some questions that I have (yes I downloaded a PL-380 manual but some things are not clear to me.  Maybe it's me but maybe it's the way the writer translated it):

How does the PL-380 compare to the 606 in terms of barefoot sensitivity?  And how does the 380 compare to my e-100 bf?

Is there a frequency up/down button  to advance in 10 KHz steps?  I use this on my e-100, as my main way of flipping through the band.   Tuning knobs usually deafult to 1 KHz steps until you spin it long/ fast enough

Is there a direct way of entering a frequency?  There is on my e-100 and it's the fastes way for me to hop from say 700 to 1340.

Can I make the light stay on longer than 3 seconds?  Another drawback on the 606.

Many thanks!

73,
Dave Hascall
Dave in Indy


Compare Tecsun PL-606 to the PL-380

Dave Hascall
 

Hello Gary and fellow ULR enthusiasts!

As some of you may remember, I purchased a Tecsun PL-606, to augment my Eton e-100 and to take advantage of the Tecsun's adjustable bandwidth.  Since I live in a bi-level home, I have one on each floor.  

Gary warned me about the freakish tuning that the Tecsun uses with no tuning knob or direct frequency entry.  While the adjustable bandwidth has netted me a few new stations, I have been frustrated by the tuning oddities of the PL-606.  The fact thatr there is no way of setting the light to stay on, is another issue.

Having read lots about the PL-380, I am considering replacing the PL-606 with the PL-380.

Here are some questions that I have (yes I downloaded a PL-380 manual but some things are not clear to me.  Maybe it's me but maybe it's the way the writer translated it):

How does the PL-380 compare to the 606 in terms of barefoot sensitivity?  And how does the 380 compare to my e-100 bf?

Is there a frequency up/down button  to advance in 10 KHz steps?  I use this on my e-100, as my main way of flipping through the band.   Tuning knobs usually deafult to 1 KHz steps until you spin it long/ fast enough

Is there a direct way of entering a frequency?  There is on my e-100 and it's the fastes way for me to hop from say 700 to 1340.

Can I make the light stay on longer than 3 seconds?  Another drawback on the 606.

Many thanks!

73,
Dave Hascall
Dave in Indy


Re: Hard-Wired FSL Antennas-- How Big is Too Big?

Gary DeBock
 

Hello Farmerik (and Alex and Michael),
 
Thanks for your messages.
 
It's probably best to remember that the experimentation to "smoke test" the Si4734 DSP chip to see how much RF it can handle isn't exactly the mission that Silicon Labs intended for it :-) After the "article version" hard-wired FSL worked very well, of course it was irresistible to find out how much additional RF the component could handle. As it turns out, although the Si4734 chip can handle the "article version" FSL superbly, it can't handle much more RF power. 
 
<<<   My understanding of RF theory is pretty limited. Do you think the 'fluttering' is from overloading the DSP chip? If so, would a variable resistor used to cut the signal when needed on some frequencies fix that, or am I misunderstanding what is happening?   >>>
 
There's no doubt that the "fluttering" is a sign of DSP chip overload, Farmerik, but a variable resistor would be an impractical solution to the issue. A much better idea is to determine the maximum size of hard-wired FSL that the chip can handle without such overload, and then stay within the component's parameters. The primary attraction of the hard-wired FSL design is the chance to enjoy superb DXing performance without tuning a variable cap, or adjusting a variable pot.   

<<<  Do either radios you worked with use the same  chip as the GP5/SSB or the Pl-360?   >>>
 
The PL-360 uses the same Si4734 DSP chip as the PL-380, so if someone made up a plug-in design for a 3" FSL, the PL-360 would have the same enhanced DXing performance as the PL-380. The challenge isn't that tough; it would just require some mechanical modifications to the plug-in antenna frames that were designed for the PL-360 7.5" loopsticks in 2011.
 
<<<    I think I read you to say the FSL antennas have about the same figure 8  pick up pattern as an air core loop, rather than a tighter pattern like some radios have. Is that correct? For example, my PL-600 seems very directional with a pick up pattern much tighter than 90 degrees. I looked inside my radios as much as I could, and saw no pattern to how the internal ferrite antennas looked to explain why some radios have a much narrower pick up pattern than others. For DXing it could be a huge advantage, but you could miss stations in the wide nulls for ordinary listening.   >>>
 
FSL antennas, air core (box) loops and ferrite loopsticks all have figure-8 reception patterns, Farmerik, and none of these are particularly directional (except for nulling pest stations). There are some excellent cardioid-pattern broadband loops and beverage wire systems which can be made quite directional, and have been used very successfully by DXpeditioners on ocean beaches.
 
73, Gary DeBock (in Puyallup, WA, USA)
 
   
   
 
 

-----Original Message-----
From: farmerik@... [ultralightdx]
To: ultralightdx
Sent: Tue, Jan 19, 2016 7:20 am
Subject: [ultralightdx] Re: Hard-Wired FSL Antennas-- How Big is Too Big?

 
My understanding of RF theory is pretty limited. Do you think the 'fluttering' is from overloading the DSP chip? If so, would a variable resistor used to cut the signal when needed on some frequencies fix that, or am I misunderstanding what is happening?

Do either radios you worked with use the same  chip as the GP5/SSB or the Pl-360?

I think I read you to say the FSL antennas have about the same figure 8  pick up pattern as an air core loop, rather than a tighter pattern like some radios have. Is that correct? For example, my PL-600 seems very directional with a pick up pattern much tighter than 90 degrees. I looked inside my radios as much as I could, and saw no pattern to how the internal ferrite antennas looked to explain why some radios have a much narrower pick up pattern than others. For DXing it could be a huge advantage, but you could miss stations in the wide nulls for ordinary listening.

While certainly not compact, lightweight or inexpensive, my few experiments with Polydorof windings on a toroid stack show a sharp peak with much better S/N, but ordinary nulling. I have not attempted having a  FSL  built yet, and have not been following all the advances. It sounds like you are coming up with improved designs tailored  for DSP radios. FARMERIK.


Newfoundland Ultralight Radio Log

Allen Willie
 



Hello To All



A new addition to the Ultralight Radio Logbook last night



1300 kHz - WXRL - Lancaster, New York 4:20 UTC 1/19/16 w/ numerous Classic Country songs by Sonny James, Ronnie Milsap , Waylon Jennings and others. ID " Classic Country, WXRL" by man finally after hearing this one fading in and out for the better part of an hour.


 WXRL was mixing with WGDJ and WOOD.


Also confirmed by Global Tuners Buffalo, New York audio feed



Thanks to other DXers for their suggestions initially on what this station was.


Ultralight Station # 1342


Receiver:  Sony SRF-M37W Ultralight (barefoot mode )


 Good DX


 Allen Willie VOPC1AA
 Carbonear, Newfoundland
 47'44"15N 53'11"46W


Re: Hard-Wired FSL Antennas-- How Big is Too Big?

Michael <michael.setaazul@...>
 

This explanation was the one which first came to mind.
A lot of radios struggle with too much or too little signal :-)

Michael


Original Message ----- From: Alex winston376

Sounds like AGC circuit 'pumping'. Common when too much signal
is presented to the circuit beyond what was designed for.
Could also be mixer or IF amp overload.

Alex


Re: Hard-Wired FSL Antennas-- How Big is Too Big?

Alex P
 

Sounds like AGC circuit 'pumping'.   Common when too much signal is presented to the circuit beyond what was designed for.   Could also be mixer or IF amp overload.

Alex


Re: Hard-Wired FSL Antennas-- How Big is Too Big?

Rik
 

My understanding of RF theory is pretty limited. Do you think the 'fluttering' is from overloading the DSP chip? If so, would a variable resistor used to cut the signal when needed on some frequencies fix that, or am I misunderstanding what is happening?

Do either radios you worked with use the same  chip as the GP5/SSB or the Pl-360?

I think I read you to say the FSL antennas have about the same figure 8  pick up pattern as an air core loop, rather than a tighter pattern like some radios have. Is that correct? For example, my PL-600 seems very directional with a pick up pattern much tighter than 90 degrees. I looked inside my radios as much as I could, and saw no pattern to how the internal ferrite antennas looked to explain why some radios have a much narrower pick up pattern than others. For DXing it could be a huge advantage, but you could miss stations in the wide nulls for ordinary listening.

While certainly not compact, lightweight or inexpensive, my few experiments with Polydorof windings on a toroid stack show a sharp peak with much better S/N, but ordinary nulling. I have not attempted having a  FSL  built yet, and have not been following all the advances. It sounds like you are coming up with improved designs tailored  for DSP radios. FARMERIK.


Hard-Wired FSL Antennas-- How Big is Too Big?

Gary DeBock
 

For those interested, the first signs of some limitation in the PL-380's Si4734 DSP chip's ability to handle powerful RF inputs from a hard-wired FSL have appeared.
 
In a step-by-step approach to test this out, the 3" Bar FSL composed of 8 Russian surplus 100mm x 20mm x 3mm ferrite bars (the construction article PL-380 version) was thoroughly proof-tested in this aspect, and had superb performance from 521-1700 kHz. A similar experiment with the same size of  3" FSL hard-wired into a CC Skywave had excellent performance on the frequencies up to about 1400 kHz, but showed erratic operation on the X-band frequencies (1600-1700 kHz). This erratic reception sounded similar to signal flutter, with the choppy-sounding signal dropping in and out several times a second. As such, I do not recommend any transplant of the 3" bar FSL into a CC Skywave model.
 
Tonight's experiment was to transplant a 3.25", 10-bar FSL into a PL-380. As with the CC Skywave, the low band performance was excellent, but the X-band frequencies had the same choppy-sounding reception as the CC Skywave did with the 3" FSL. Side-by-side comparisons of a 3" FSL PL-380 (the article version) and this new 3.25" FSL PL-380 on the X-band showed the former to be clearly superior, with no issue in the reception or nulling of any station up to 1700 kHz.
 
For experimenters with access to these Russian surplus 100mm ferrite bars, it is not recommended to hard-wire FSL's composed of more than 9 bars into a PL-380. I know that Steve R. has made a 9-bar FSL model, and he reported good reception across the band.
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)
 
  .


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

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




Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Gary DeBock
 

Hi Bill,
 
<<<   Thanks for posting the link to your article. In all that I've read about the FSL, I haven't seen any "directivity" comparisons given between the various implementations. Your thoughts.   >>>
 
As for "directivity," the FSL antennas have a figure-8 (non-cardiod) reception pattern, and are not very directional in the desired angle of reception. As long as the antenna bearing is with about 30 degrees of the desired DX station's bearing, there isn't very much difference in signal strength. When the angle is greater than 60 degrees the signal drops off noticeably, however. When DXing on the Oregon cliffs you generally can choose between Asian stations (around 300 degrees) and DU stations (from 210-240 degrees), but not both.
 
FSL's can be made extremely directional for nulling pest stations, however. The new 3" FSL Tecsun PL-380 models can null out almost all of my pest stations, but the null bearing must be within about 1 degree of the station's bearing in order to do this. When you get a couple of degrees off of the null bearing the pest station strength is as strong as ever. An extremely clean RF reception pattern is important for these nulls; the FSL coil must be as symmetrical as possible, and lead-in wires must be as short as possible. The hard-wired FSL's have a critical advantage in this aspect, since there is no variable capacitor to disturb the clean RF reception pattern.
 
73, Gary DeBock (in Puyallup, WA, USA)
 
 
 
 
 
 

-----Original Message-----
From: Bill bill@... [ultralightdx]
To: ultralightdx
Sent: Mon, Jan 18, 2016 2:06 pm
Subject: Re: [ultralightdx] Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

 
Gary,

Thanks for posting the link to your article. In all that I've read about the FSL, I haven't seen any "directivity" comparisons given between the various implementations. Your thoughts.

Regards...Bill

On 1/18/2016 1:46 PM, D1028Gary@... [ultralightdx] wrote:
 
Hi Farmerik,
 
<<<   Tell me more about this 'Sensitivity Rating' please.    >>>
 
The FSL "sensitivity rating" formula was determined after detailed A/B experimentation with 8 different FSL test models in 2012. The full details are contained in the article posted at  http://www.mediafire.com/view/6oyoldllrbiwf91/FSL_Antenna_Design_Optimization.doc 
 
The "coil diameter times ferrite length" sensitivity rating system only applies for true FSL antennas using the same type of Litz wire, same ferrite permeability and the same construction components. As such, there is no way to judge the sensitivity rating of your antenna compared to FSL antennas, Farmerik.
 
73, Gary deBock (in Puyallup, WA, USA)
    
 
 
-----Original Message-----
From: farmerik@... [ultralightdx]
To: ultralightdx
Sent: Mon, Jan 18, 2016 9:07 am
Subject: [ultralightdx] Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

 
Tell me more about this 'Sensitivity Rating' please. For example, my toroid stack uses  3 inch coils over a 13.5 inch long stack. What would that rate? It has very sharp peaks when pointed exactly at a station, but does not null out completely other stations a few degrees off to the sides. I hear a much improved S/N exactly at one direction on the target station though. And compared to my short 500 foot BOG most all other weak  stations on a frequency disappear, since the short BOG is not terribly directional at most AM BCB frequencies I think. - FARMERIK


Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Rik
 

Thanks Gary- FARMERIK


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

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




Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Bill <bill@...>
 

Gary,

Thanks for posting the link to your article. In all that I've read about the FSL, I haven't seen any "directivity" comparisons given between the various implementations. Your thoughts.

Regards...Bill

On 1/18/2016 1:46 PM, D1028Gary@... [ultralightdx] wrote:

 

Hi Farmerik,
 
<<<   Tell me more about this 'Sensitivity Rating' please.    >>>
 
The FSL "sensitivity rating" formula was determined after detailed A/B experimentation with 8 different FSL test models in 2012. The full details are contained in the article posted at  http://www.mediafire.com/view/6oyoldllrbiwf91/FSL_Antenna_Design_Optimization.doc 
 
The "coil diameter times ferrite length" sensitivity rating system only applies for true FSL antennas using the same type of Litz wire, same ferrite permeability and the same construction components. As such, there is no way to judge the sensitivity rating of your antenna compared to FSL antennas, Farmerik.
 
73, Gary deBock (in Puyallup, WA, USA)
    
 
 
-----Original Message-----
From: farmerik@... [ultralightdx]
To: ultralightdx
Sent: Mon, Jan 18, 2016 9:07 am
Subject: [ultralightdx] Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

 
Tell me more about this 'Sensitivity Rating' please. For example, my toroid stack uses  3 inch coils over a 13.5 inch long stack. What would that rate? It has very sharp peaks when pointed exactly at a station, but does not null out completely other stations a few degrees off to the sides. I hear a much improved S/N exactly at one direction on the target station though. And compared to my short 500 foot BOG most all other weak  stations on a frequency disappear, since the short BOG is not terribly directional at most AM BCB frequencies I think. - FARMERIK


Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Gary DeBock
 

Hi Farmerik,
 
<<<   Tell me more about this 'Sensitivity Rating' please.    >>>
 
The FSL "sensitivity rating" formula was determined after detailed A/B experimentation with 8 different FSL test models in 2012. The full details are contained in the article posted at  http://www.mediafire.com/view/6oyoldllrbiwf91/FSL_Antenna_Design_Optimization.doc 
 
The "coil diameter times ferrite length" sensitivity rating system only applies for true FSL antennas using the same type of Litz wire, same ferrite permeability and the same construction components. As such, there is no way to judge the sensitivity rating of your antenna compared to FSL antennas, Farmerik.
 
73, Gary deBock (in Puyallup, WA, USA)
    
 
 

-----Original Message-----
From: farmerik@... [ultralightdx]
To: ultralightdx
Sent: Mon, Jan 18, 2016 9:07 am
Subject: [ultralightdx] Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

 
Tell me more about this 'Sensitivity Rating' please. For example, my toroid stack uses  3 inch coils over a 13.5 inch long stack. What would that rate? It has very sharp peaks when pointed exactly at a station, but does not null out completely other stations a few degrees off to the sides. I hear a much improved S/N exactly at one direction on the target station though. And compared to my short 500 foot BOG most all other weak  stations on a frequency disappear, since the short BOG is not terribly directional at most AM BCB frequencies I think. - FARMERIK


Re: 3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Rik
 

Tell me more about this 'Sensitivity Rating' please. For example, my toroid stack uses  3 inch coils over a 13.5 inch long stack. What would that rate? It has very sharp peaks when pointed exactly at a station, but does not null out completely other stations a few degrees off to the sides. I hear a much improved S/N exactly at one direction on the target station though. And compared to my short 500 foot BOG most all other weak  stations on a frequency disappear, since the short BOG is not terribly directional at most AM BCB frequencies I think. - FARMERIK


3" FSL Tecsun PL-380 Construction Parts-- Availability Update

Gary DeBock
 

Thanks to the timely assistance of Scott Davis and my Kiwi buddy Tony King we are now "swimming" in the Funnoodle inner core material for the 3" FSL PL-380 project. If you are having trouble tracking this down, please let me know.
 
Despite the very high demand for the Russian surplus 100mm x 20mm x 3mm ferrite bars I still do have a few more sets (of 8) that I can provide at my own cost ($25, including shipping to the USA) on a first come, first served basis. Since there is an extreme demand for these bars please do not request a set unless you actually plan on building the 3" FSL PL-380 model. All of the DXers who have paid for a set of 8 bars (in both the USA and international areas) should have them shipped out by Tuesday.
 
An alternative 3" FSL PL-380 design using the commonly available 62mm x 12mm x 4mm Russian surplus bars has been created for those who cannot track down the 100mm long bars. Assembly information for this alternative design will probably be added as an addendum to the "Heathkit-like" construction article for the original model (posted at http://www.mediafire.com/download/w0gcek56f6aq7kr/3_Inch_FSL_Tecsun_PL.doc  This alternative version is not as sensitive as the original version-- the FSL's ferrite length x coil diameter "sensitivity rating" is 186, compared to 300 for the original version. However, all of the parts to construct it are readily available, and its performance is still superior to that of a 7.5" loopstick transplant.
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)       


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

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."
 


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

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."
 

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