Date   

Re: New Parts for FSL and Air Core PVC Loop Antennas

Chuck
 

Hello Gary and all,

First, a huge thank you to Gary and the community of people who worked on this body of knowledge. The FSL is exactly what I've been looking for to complement my Tecsun PL-660 utralight.

To follow on to Todd's question, I am gathering parts to construct the 3.5" Frequent Flyer FSL and have obtained 
27 140mm x 8mm ferrite rods (instead of the specified 160mm x 8mm)
45 feet of 1162/46 Litz wire (instead of the specified 35 feet)
1 higher Q 8:1 variable capacitor from Mike's Electronic Parts (instead of the specified 365mm variable cap)

I could imagine the unit will perform fairly well simply by substituting the variable cap and ferrite rods but are there any simple "rules of thumb" about the number of turns of wire for the circuit factoring in the 140mm rods and superior var cap? 
Or are these undefined, meaning I'll just need to experiment for myself to optimize performance?

If this has been covered before, I'd appreciate a pointer towards the earlier post.
Thanks so much for the help!

Best,
Chuck


Re: New Parts for FSL and Air Core PVC Loop Antennas

Gary DeBock
 

Hi Again Todd,

<<<   Recently an Australian DXer constructed a 135 mm diameter MW FSL using forty one Jaycar LF1010 (9 x 100 mm) ferrite rods. These rods are more affordable than anything else available on Australian eBay [1].   >>>

It would be very helpful if that Australian DXer could post a design photo showing the number of coil turns, type of Litz wire, type of variable cap, type of frame, etc. Then I could simply use math to decide how to make larger and smaller sizes of that same type of FSL, using the Jaycar 9 x 100mm ferrite rods.

Using the longer 9 x 180mm ferrite rods will give more inductance for a given coil size, slightly reducing the number of Litz wire turns required to tune the same frequencies as the 9 x 100mm ferrite rod design coil.

<<<   Also, how are the number of Litz wire turns calculated to provide 520 to 1750 KHz coverage for a given number of rods?   >>>

Since I've never used the Jaycar rods I can't give you an exact formula, but the number of rods is related to the coil diameter, and if 41 rods results in a 135mm coil diameter for the Jaycar rods, you do have enough information to design a new FSL, but ONLY if you use the exact same components as the Australian DXer used (ferrite rods, wire type, variable cap type, etc.). This assumes that he was able to get 530-1701 kHz coverage with his design. You can use the math formula that I described in an earlier post, and it should get you within one coil turn of being exactly the right length. Like Steve said, you shouldn't use expensive Litz wire for rough testing; only use expensive Litz if you are sure of the number of coil turns necessary for full MW band coverage with the Jaycar variable cap (if that's what you plan to use). Any components different from what the OZ DXer used will throw off the math calculation formula for coil turns.

<<<  Any thoughts on the theory behind why certain variable capacitors offer higher Q?    >>>

Like Steve said, the phenolic insulator type of variable cap is not the highest Q type available, but for my own FSL designs (which require rugged construction to survive rough travel, and weather extremes) they make good sense. The discovery of superior performance with the "384P" variable cap (from Mike's Electronic Parts, with Oren Elliot Products being the OEM) was completely by accident. Apparently they have made some type of substitution which provides significantly higher "Q", and better gain performance. How and why this happened is a mystery, but the difference in DXing performance is pretty astonishing. All of my recently constructed FSL's use this variable cap, as well as the models given to Craig and Chris prior to the recent Kauai DXpedition.

73, Gary

 


August 2019 Rockwork Cliff DXpedition Article

Gary DeBock
 

Because it was sandwiched in between major Ultralight "Frequent Flyer" DXpeditions to Hong Kong and Kauai last year, my own results from the August 2019 Rockwork Cliff DXpedition have never been written up in article form (although DXpedition partner Tom Rothlisberger has an excellent writeup of his own results, posted at https://www.qsl.net/k7wv/RockworkDX6.htm

With the Pandemic there is extra time for everything, though, so a new article with photos, DXpedition loggings and MP3 recording links has been posted at https://dreamcrafts.box.com/s/eems0nk7i6a89syif08iix0hhi3357l5
This DXpedition brought exceptional Longwave South Pacific NDB results to both Tom and I, and we will never forget the awesome experience of tracking down so many long range, low powered beacons all across the South Pacific at the plunging cliff. Medium Wave results were also memorable, with both 531-More FM and the new 1107-Magic Talk routinely hitting S9 levels almost every morning. DXpedition partner Craig Barnes honed his skills on his 5" Frequent Flyer FSL antenna, becoming quite an expert in preparation for Kauai in November. We all had a blast, and are looking forward to August at the plunging cliff (Pandemic permitting)!

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)


Re: FSL Antenna Tuning Course Video

Chris Rogers
 

Thanks Gary. The FSL is very easy to master on radios like the 2010, 803A, 880 etc and similar. The later DSP chip radios like the Skywave etc requires some skill to hear the "peak" as they are quite slow to react to the increase in signal level and can be quite frustrating to those who are used to the older style radios.


Re: FSL Antenna Tuning Course Video

Les Rayburn
 

Thank you for taking the time to produce this training course for the use of FSL’s. Very helpful! 

One question I have that would only apply to DSP ultralights like the CC Skywave. Does the effect of narrowing the bandwidth of the receiver have any impact on tuning the antenna? What bandwidth setting were you using in the video? I assume the stock 6 KHz setting. 

Your craftsmanship is something to behold. 


73,

Les Rayburn, N1LF
121 Mayfair Park
Maylene, AL 35114
EM63nf

NRC & IRCA Courtesy Program Committee Chairman
Member WTFDA, MWC

Perseus SDR, Elad FDM-S2 SDR, AirSpy + Discovery, SDRPlay RSP-2 Pro, Sony XDR-F1HD [XDR Guy Modified], Dennon TU-1500RD, Sangean HDT-1X, Ray Dees RDS Decoders, Korner 9.2 Antenna, FM-6 Antenna, Kitz Technologies KT-501 Pre-amps, Quantum Phaser, Wellbrook ALA1530 Loop, Wellbrook Flag, Clifton Labs Active Whip. 

“Nothing but blues and Elvis, and somebody else’s favorite song…” 

On May 25, 2020, at 12:39 AM, Gary DeBock via groups.io <D1028Gary@...> wrote:

For the benefit of Todd, Paul, Chris or any other Oz (or worldwide) DXers who wish to try out a compact FSL antenna to track down exciting DX, a video showing detailed the tuning procedures for the getting the best inductively coupled gain boost from any FSL has been posted at  https://youtu.be/uIvNdYdbxg4

Three daytime DX fringe stations (on 620, 1070 and 1700 kHz) are tuned in on a stock CC Skywave and 3" Baby FSL, while the fanatical instructor shows you how to track down the best gain boost every time. The FSL antenna does have a reputation for being somewhat tricky and mysterious, but hopefully this tuning course will dispel some of the mystery, and prepare some DXers for an exciting new way to enjoy the hobby! Once you get past the Yankee accent the rest should be easy...

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)



FSL Antenna Tuning Course Video

Gary DeBock
 

For the benefit of Todd, Paul, Chris or any other Oz (or worldwide) DXers who wish to try out a compact FSL antenna to track down exciting DX, a video showing detailed the tuning procedures for the getting the best inductively coupled gain boost from any FSL has been posted at  https://youtu.be/uIvNdYdbxg4

Three daytime DX fringe stations (on 620, 1070 and 1700 kHz) are tuned in on a stock CC Skywave and 3" Baby FSL, while the fanatical instructor shows you how to track down the best gain boost every time. The FSL antenna does have a reputation for being somewhat tricky and mysterious, but hopefully this tuning course will dispel some of the mystery, and prepare some DXers for an exciting new way to enjoy the hobby! Once you get past the Yankee accent the rest should be easy...

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)


Re: Sony SRF-59 alignment

Gary DeBock
 

Hi Keith (and Marc),

The original SRF-59 alignment instructions to the Ultralight group (in early 2008) are posted at  http://www.hard-core-dx.com/archive/irca/msg43730.html

Gary


Re: Sony SRF-59 alignment

Marc Coevoet
 

Op 25/05/2020 om 06:42 schreef keith beesley via groups.io:
alignment of the SRF-59
Out of several google results, this is the best documented, text and graphics!

http://earmark.net/gesr/srf59.htm


Marc

--
The "Penguin" has arrived - and he's not going away - ever.
For former Apple users: Xubuntu.org (menu's up left)
For former Windows users: Lubuntu.org (menu's down left)


Sony SRF-59 alignment

keith beesley
 

Gary, 

Sometime ago, probably in the old ultralight group, I think you posted some detailed instructions for alignment of the SRF-59 for better dial accuracy and better performance. I know you've since moved on to other receivers and other antenna designs, but I wonder if you still have them? If you do, would you mind sharing them again here? I recently found a couple of SRF-59s that I'd forgotten I had, and they both work, 
but the tuning is way off. 


Thanks,

Keith Beesley
Seattle WA USA


Re: New Parts for FSL and Air Core PVC Loop Antennas

Gary DeBock
 

Hi Todd,

Sorry for the delayed response. Steve's detailed information is of course very accurate and helpful, and I appreciate him stepping in to comment. We have been experimental partners for over 10 years, and by coincidence, have exactly the same technical training from the US Navy.

<<<   In terms of optimal FSL signal gain and Q, what is the preferable ferrite rod size to use among the two Jaycar available options? Also, how are the number of Litz wire turns calculated to provide 520 to 1750 KHz coverage for a given number of rods? A new article would be instructive factoring in the more recently available rod dimensions, and improved lower resistance Litz wire.   >>>

Like Steve says, the number of Litz wire turns for a new FSL design will always require some final adjustment, but if you have an existing FSL design covering the MW band with exactly the same components as the proposed design (same length and permeability of ferrite rods, same type of Litz wire and the same tuning capacitor), then you can calculate the number of required Litz wire turns prior to construction by using math, and usually be within one turn of the actual number. You accurately measure the coil diameter of the existing design, and write down the number of Litz wire turns in the existing design. Then you use the math formula where the length of one turn of wire is the coil diameter x Pi (3.141) and then multiply this by the number of turns, which gives you the total length of wire of the existing design. The total length of wire of the new design should be roughly the same, so you then use a proportion where this total length of wire is divided down by the product of the proposed coil diameter and Pi (3.141). This will give you a fairly accurate estimate of the required number of Litz wire turns in the new design. Like Steve says, with very expensive Litz wire it is a Cardinal Sin to cut an FSL coil too short, because splicing Litz wire degrades its performance. So the best option is to either play around with cheap wire as Steve suggests, or to cut an expensive Litz wire coil with an extra turn, in order to make sure that you don't end up with a coil that won't tune down to 530 kHz.

I'll try to answer your other questions later tonight, Todd. Good luck in your experimentation!

73, Gary
 




Re: New Parts for FSL and Air Core PVC Loop Antennas

Todd
 
Edited

Some updated information was kindly supplied by Steve Ratzlaff.

The current batch of available Russian ferrite rods are 400 permeability. But the desired permeability for MW is ~ 125. Fortunately, according to Steve, The Australian Jaycar ferrite rod's UI = 120 specification corresponds to the more optimal ~ 125 permeability. Hence this requires more turns of Litz wire.

These FSL antennas are more difficult to construct when factoring in the optimal number of rods, and Litz wire turns for desired ~ 520 to 1750 KHz coverage. There are many factors involved that need to be considered before purchasing materials. Kevin Schanilec's FSL optimization paper is essential reading before undertaking construction.

Regards,

Todd

AA7U wrote:

Use cheap magnet wire at first to find out the turns needed, before going to the expensive Litz wire. That will still be just an approximation not an exact thing. Big Litz of course is wider and for a given coil width will have fewer turns than wire that is thinner. All that factors into the final coil inductance. As noted, almost all FSL coils require experimenting with the actual number of turns for the variable cap being used. Main thing is to have enough inductance to tune to the bottom of the MW band.

Longer ferrite rods are always preferable to shorter rods, given a choice. The current batch of Russian rods on eBay are all 400 permeability, which is pretty high. Desirable permeability for MW is 125. If the Jaycar rods are similar to 400, then fewer turns would be needed for a given inductance than for rods with lower permeability. If they are 125, more turns are required. So once again it's all about experimenting to figure out what the Jaycar rods do.

Gary discovered a formula for FSL sensitivity relating FSL coil diameter to FSL coil width with larger diameter and longer coil length giving greater sensitivity. Generally you want the largest diameter FSL your pocketbook can afford to buy ferrite rods for.

You mention Q, but generally Q is related to the size of the Litz wire, and if the variable capacitor has good Q. Generally coil Q sets the limit as generally coil Q is lower than cap Q, if the cap is decent quality. Variable caps with phenolic insulation are always lower Q than other types of insulation; the caps Gary now prefers have phenolic insulation but apparently the manufacturing process somehow makes these with a higher Q than previously.

More turns of Litz wire gives greater sensitivity compared to fewer turns of the same size Litz for a given diameter coil. This is good. Ferrite rod coil Q is in my experience (I have an HP 4342A Q meter) much lower Q than an air coil using the same Litz. More turns of Litz may theoretically have lower Q than fewer turns of the same Litz but you are not going to notice the difference.


New Parts for FSL and Air Core PVC Loop Antennas

Todd
 

Hi Gary, and All.

Recently an Australian DXer constructed a 135 mm diameter MW FSL using forty one Jaycar LF1010 (9 x 100 mm) ferrite rods. These rods are more affordable than anything else available on Australian eBay [1].

Jaycar Electronics Australia also sell a larger (9 x 180 mm) ferrite rod [2].

In terms of optimal FSL signal gain and Q, what is the preferable ferrite rod size to use among the two Jaycar available options? Also, how are the number of Litz wire turns calculated to provide 520 to 1750 KHz coverage for a given number of rods? A new article would be instructive factoring in the more recently available rod dimensions, and improved lower resistance Litz wire.

When I built your 40" PVC tabletop box loop design using 9 turns of wire, I fortunately chose the higher Q 8:1 reduction drive variable capacitor from Mike's Electronic Parts [3].

Any thoughts on the theory behind why certain variable capacitors offer higher Q?

Regards,

Todd

1. https://www.jaycar.com.au/9mm-x-100mm-inanimate-ferrite-rod/p/LF1010

2. https://www.jaycar.com.au/180mm-x-9mm-ferrite-rod/p/LF1012

3. https://www.mikeselectronicparts.com/product/384pf-air-variable-capacitor-with-81-planetary-reduction-drive/


Re: Tecsun PL-310 vs PL-380

dwight richardson
 

Thanks Gary.  Excellent information. For domestic MW fans like myself, the Traveler III is looking good. 
--
Bob Richardson


My Ultralight Radios for Sale

Paul Blundell
 

https://www.ebay.com.au/itm/293583454547

Please email me directly: tanger32au@...
--
Paul - Moderator
UltralightDX


Re: Tecsun PL-310 vs PL-380

dwight richardson
 

Thanks Gary. I happened across your excellent discussion of ultralights a few weeks back. Reading again just now, I might have to rethink the Tecsun only agenda. Or have some fun finding an original 310 (non-et) on eBay and compare against the Skywave. Or just try them all. Runner ups might make nice gifts for my cronies. But the Traveller III might need more consideration. At any rate, I am reminded of the folly of trying to pick “the best” of anything. After all - beauty is in the eye. Thanks again. This group is great. I imagine myself as a rookie kid who has happened On to a good bunch of radio guys to learn from. At 66 I’m good with that. I might have something to offer one day. But for now I’m a sponge. 
--
Bob Richardson


Re: PL-606 sticky buns ...

Peter Laws
 

On Mon, May 18, 2020 at 8:07 AM Ron Layton via groups.io
<micron327=zoho.com@groups.io> wrote:

It seems I have made a great error. It was not my PL-600 but my venerable RS DX-440 which has the rubbery push buttons.that developed the gummy decomposition. I
Lol! No "great errors" in hobby radio unless you are operating a transmitter.

I did exercise the buttons on my '606 and they seem better (20 or so
pushes apiece). I do note that, despite the exercise, some buttons
feel different. I suppose more exercise will help that. Alas, it's
morning work Zoom so that will have to wait.



--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


Re: Tecsun PL-310 vs PL-380

Richard Allen <dx747j@...>
 


From: "Richard N. Allen" <dx747j@...>
Date: May 18, 2020 at 08:50:44 CDT
To: "Gary DeBock via groups.io" <D1028Gary@...>
Subject: Re: [UltralightDX] Tecsun PL-310 vs PL-380

I still occasionally use my PL-310 and PL-380.  Both are of the originally incarnation of the receivers.  When new the PL-310 was unbeatable for receiving Asian stations barefoot.  It offered selectivity not seen in earlier handheld receivers, and had a slight edge over the PL-380 in receiving weak signals.  However, when used in conjunction with a FSL antenna the PL-380 shined.  The evidence is my reception of station 3LO at 14592 km (9067 miles) on a PL-380 with an 8-inch FSL in 2016.  

But, because the controls on the Tecsun receivers became trickier to use over time I turned to using a Skywave receiver.  It is every bit as good as the Tecsuns with fewer of their problems.   It works well when coupled to a FSL or Wellbrook ALA1530LNP antenna.  Last winter I was able to add three new Japanese stations to my log and again hear 2BL on the Skywave.  Overall, it’s the best URL presently available.

Good DX all.

Richard Allen,
near Perry OK USA

_,_._,_


Re: PL-606 sticky buns ...

Steve Nichols
 

I had a pair of binoculars that went the same way. I rubbed the sticky plastic with Armoural, a car interior treatment, and that did the trick.

Steve


Re: Tecsun PL-310 vs PL-380

dwight richardson
 

Thanks for the input. I like the antenna jack on the PL-310. But a simple induction loop would do the same. Non recessed tuning knob sounds good too. 
--
Bob Richardson


Re: Tecsun PL-310 vs PL-380

jcfontario
 

Thanks Gary, that's good to know for the future (not that I am planning to do any travelling for a while, due to COVID).

j


On 05/18/20, "Gary DeBock via groups.io" <D1028Gary@...> wrote:
On Sun, May 17, 2020 at 03:09 PM, jcfontario wrote:
I have a CC Skywave portable radio, but I am not familiar with what a "supercharged" Skywave receiver has that I don't have. What do I need to add to my travel portable?
Hi John,

A "supercharged" Skywave refers to a model with a 7.5 inch transplanted loopstick. This modification greatly increases MW band sensitivity compared to the stock CC Skywave, transforming the radio into something like a dream travel portable.

Unfortunately, the technical procedure for creating this "dream travel portable" is somewhat of a nightmare. The Skywave portable is extremely compact, and crammed with components which fit together like a twisted puzzle. In addition, the RF circuit board connections for the loopstick Litz wire leads are in the worst possible place for this type of modification, making the entire procedure a very demanding test of close-order soldering, sharp eyesight and steady nerves. For this reason the modification procedure has never been written up in article form, although about 5 of these models have been constructed and given to friends in the US, Japan and Australia.

Gary DeBock (in Puyallup, WA, USA)  

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