Date   

Re: Oren Elliot latest "0219" series variable cap?

Gord Seifert
 


    Thanks again Gary,

    Those 140mm rods look great! Don't know how I missed them. Ordered 40 of them this morning. They cost only about $32 Canadian more than 30 of the 125mm rods I was considering would have. If I decide to go with the 1162 strand Litz wire, with 60 feet of it, and 40 ferrite rods, I should be able to build something somewhat larger than the 3 inch, 28 rod, 'Baby' FSL. Waste not, want not. And it will, no doubt, work better.

   Will likely order one of those caps from Mike's, but I have a brute of a dual section with about 440 in one section and 500 in the other and a three to one geared drive. Will see how that works to start.

   Thanks for the history lesson too!

   Regards, 
   Gord


Re: Review - Digitech AR-1780 Multi-band Radio Receiver

Marc Coevoet
 

Op 8/07/2020 om 12:54 schreef Paul Blundell:
<https://1.bp.blogspot.com/-SgPgkmcIVBA/XwWlUHPuZxI/AAAAAAAAMtQ/GsdRrkN6SHkk7qfrQCaRdle82b-FCD6bwCPcBGAYYCw/s1600/AR-1780%2BReview_July2020%2B%25284%2529.jpg>
The AR-1780

The buttons of the XHDATA D-808 are exactly the same!


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)


Review - Digitech AR-1780 Multi-band Radio Receiver

Paul Blundell
 

 

 

 
 
The AR-1780 is the big brother of the AR-1733 which has been my go-to ultralight DXing radio for a number of years. The AR-1780 covers the AM and FM broadcast bands along with the shortwave, long wave and air band. This includes RDS on the FM band and SSB on the shortwave band.
 
From the Jaycar website:
“This is a very compact world band radio, covering the most popular frequencies. It features rapid digital tuning, 1000 memory presets, and an easy to read display. Single Sideband Modulation (SSB) is used to listen in on 27MHz CB radio, short wave amateur radio and morse code. The large internal speaker provides clear audio, and you can connect your favourite set of headphones for personal listening. Powerful enough to receive what you want, and compact enough to take wherever you want.”

Features:
- FM/MW/SW/LW/AIR Bands
- Single Side Band (SSB)
- Telescopic Antenna
- 3.5mm socket for external antenna
- Selectable Bandwidth: 1 - 6kHz
- Radio Bands:
    FM 87.5 - 108MHz
    MW 522 - 1620kHz / 520 - 1710 kHz
    SW 1711 - 29,999kHz
    LW 150 - 450kHz
    AIR 118 - 137kHz
 
Product Dimensions
Height
95mm
Weight
0.253kg
Depth
30mm
Width
150mm
Radio Receiver
MW(AM) Frequency Range
522kHz-1710kHz
Power Source
Battery
SW Frequency Range
1711kHz-29999kHz
SW Frequency Range
150kHz-450kHz
Type of Radio
FM
FM Frequency Range
87.5MHz-108MHz
Power from disposable battery
Battery used for
Main Product
Size / Shape
AA
Battery quantity
4pc
Batteries included
No
Batteries can be replaced by user
Yes
Warranty: 12 Months
 
 
AM Band:
The performance on the AM broadcast bands is very good, in most cases better than my AR-1733, this has made the AR-1780 my current “go to” radio. It is very sensitive and tuning across the band is very enjoyable. The built-in ferrite antenna works well, and it matches up nicely with my 3” FSL aerial for long distance / serious DXing needs.
 
FM Band:
The AR-1780 features RDS which shows station names, song names and other information, this works well. Side by side testing with the AR-1733 shows a slight edge to the AR-1780 on audio quality and ability to pull in signals, a couple of community station which are iffy at best on the AR-1733, are much better and clearer on the AR-1780.

Shortwave Band:
Shortwave coverage is from 1711 kHz to 29999 kHz in 1 kHz steps. The main rotary tuning control on the side of the radio can be set to 5kHz or 1 kHz steps and there is a fine-tuning control on the right-hand side that is used for the USB and LSB modes. The radio uses the inbuilt telescopic antenna for the entire shortwave band. My experience and focus is not on this band so my experience is limited, from my limited testing it works as well as a radio of this size / price point could be expected to.

Longwave Band:
Coverage is from 150 kHz to 450 kHz. Our local beacon on 242kHz comes in well enough. Again, this band is not an area I know much about and it has very limited use here in Australia.
 
Air Band:
This covers from 118 MHz to 137 MHz in the AM mode. I have programmed in my local tower, ATC and AWIS frequencies and I find I often leave this locked on one of them while I am working, the gentle sounds of the ATC controllers and pilots are good background noise. While not a “scanner”, this does have a one-time search mode and will save any found frequencies for later review. Performance wise, it works as well as any of my scanners would and for listening over an extended period, the squelch mode is very helpful. I find around a 3 the best setting.
 
Pros:
It works well given the price and size of the unit, as a step up from the AR-1733, it fills the gap between this and the full-size radios. AM performance is an improvement on the AR-1733 and the choices of AM bandwidths really helps with hunting down stations. FM BCB is covered well. Airband is acceptable with no issues.
 
Cons:
Slight gap in audio while changing frequencies, delay in switching between USB and LSB modes. Weird charging voltage. Lack of carry case included.
 
Summary:
I am a big fan of this radio and it has taken over from my AR-1733 as my main DXing rig, for $99 on special, it is excellent value.


Re: Oren Elliot latest "0219" series variable cap?

Gary DeBock
 

On Tue, Jul 7, 2020 at 12:19 PM, Gord Seifert wrote:
   I just looked on Mike's site and can not find a part with any reference to Oren Elliot. I do see this..
 https://www.mikeselectronicparts.com/product/384pf-air-variable-capacitor-with-81-planetary-reduction-drive/   But, the price is SO much less than on the Oren Elliot site that I can hardly believe it is the same. No problem with Mike's price, but no way am I paying well over twice as much to Oren Elliot. And, in the photo, the one on Mike's does not look anywhere near as pretty. Is the Oren Elliot version really that beautiful, or is that simply a computer generated image?

Hi Gord,

     The "N50 384P" variable cap from Mike's Electronic Parts (at the link you posted above) is exactly the same as the one from Oren Elliot Products, despite the much cheaper price. Oren Elliot is the OEM for the component, and has always charged higher prices (I have ordered from both sources, in the past).

<<<    Also, I have been looking for ferrite rods. I came up with this: https://tinyurl.com/ybk5amyr   Looks to be the same material you use (same seller too) but is considerably shorter at 125mm. Also MUCH less expensive. Would this work reasonably well for someone who does not need the absolute nth degree in performance? The 10mm x 200mm version is completely out of the question due to price.   >>>

The 125mm x 8mm ferrite rods are perfectly fine for FSL use, although if you would like significantly cheaper 140mm x 8mm ferrite rods than the ones that "Alexer1" sells (which are also slightly higher in gain than the 125mm variety), try this link from my friend Dennis ("sovtube," on eBay)  https://www.ebay.ca/itm/Russian-Large-balun-ferrite-rods-8x140-mm-Lot-of-20-NEW-High-Quality/164167133643?hash=item26391fa9cb:g:PekAAOSwYaFWfwfH

I have dealt with both of these sellers multiple times on eBay, and can assure you that Dennis will always provide the best price and service, if he has the ferrite rods that you are looking for.

<<<    One other question. Did you actually test the various different ferrite mixes for suitability while designing you FSLs? Or is it just a basic, known, fact that, for this frequency range, NiZn 400 permiability works best for this application?   >>>

To be honest, the reason why I use the Russian surplus 400-permeability ferrite rods in almost all of my FSL antenna designs is because back in 2011 (when the U.K.'s Graham Maynard introduced modern FSL antennas), the cost of this Russian surplus ferrite was dirt cheap, and the early FSL experimenters like Steve Ratzlaff, Kevin Schanilec and yours truly bought up a ton of it. I still have loads of this stuff stashed away, which cost about a third of what it costs currently. Of course I have nobody to blame but myself for the explosion in ferrite price, since immediately after I publish an FSL construction article the Ukrainian eBay sellers quickly jack up the price on the ferrite type I suggest, so that some weird cases result like the 140mm x 8mm ferrite rods actually costing more than the 160mm x 8mm ferrite rods in 2016. After noticing this in 2016 I published a 3.5" FSL construction article using the 160mm x 8mm ferrite rods, and the eBay sellers promptly evened out their prices :-)

Gary
  

   


Re: Oren Elliot latest "0219" series variable cap?

daiche
 

DeOxit is not cheap here either! We use it here mostly for scratchy pots, with the F5 formula having more lubricant compared to the D5 formula. They both remove corrosion and protect the contact surfaces without leaving an oily film, which is why I tried it on the variable caps of my FSL's too, to 'freshen' them. I use both formulas on my phasers to keep them running smooth. You don't need much so it lasts a long while......

Dave Aichelman     N7NZH     Grants Pass, Oregon


Re: Oren Elliot latest "0219" series variable cap?

Gord Seifert
 


    Hi Gary,

     I just looked on Mike's site and can not find a part with any reference to Oren Elliot. I do see this..
 https://www.mikeselectronicparts.com/product/384pf-air-variable-capacitor-with-81-planetary-reduction-drive/   But, the price is SO much less than on the Oren Elliot site that I can hardly believe it is the same. No problem with Mike's price, but no way am I paying well over twice as much to Oren Elliot. And, in the photo, the one on Mike's does not look anywhere near as pretty. Is the Oren Elliot version really that beautiful, or is that simply a computer generated image?

   Also, I have been looking for ferrite rods. I came up with this: https://tinyurl.com/ybk5amyr   Looks to be the same material you use (same seller too) but is considerably shorter at 125mm. Also MUCH less expensive. Would this work reasonably well for someone who does not need the absolute nth degree in performance? The 10mm x 200mm version is completely out of the question due to price.

 One other question. Did you actually test the various different ferrite mixes for suitability while designing you FSLs? Or is it just a basic, known, fact that, for this frequency range, NiZn 400 permiability works best for this application?

   Regards, 
   Gord


Long Term DX Project - 7/07/2020

Paul Blundell
 

Date: 7/07/2020
Time: 12:30
Location: St Georges Square, Launceston Tasmania
Notes: A portable session at St Georges Square around lunch time. Some good signals were logged around the bottom of the band and the use of my 3” FSL made a real difference with it lifting a few signals from average to good signal levels. 2CA on 1053khz which is the furthest station of this project really struggled and was a very poor signal with only traces heard.
 
 
Freq
Callsign
Logged
531
3GG
AVERAGE
549
2CR
POOR
594
3WV
GOOD
621
3RN
GOOD
774
3LO
AVERAGE
1053
2CA
POOR
1179
3RPH
POOR
1341
HPON GEELONG
GOOD
1422
HPON MELBOURNE
GOOD
1503
3KND
POOR


 
 
 


Re: Oren Elliot latest "0219" series variable cap?

Gary DeBock
 

<<<   Or the one with the 8:1 drive here: 
 
 
I’d like to substitute the one on my shiny new 5” FSL and see if I can detect any difference in performance. Glad that this secret leaked out—now about those lottery numbers….   >>>

Les,

Your new 5" FSL is one of the many ones built here during the Pandemic, and almost certainly has the latest variable cap installed. You can confirm this by noting the "0219" stamp on the back of the variable cap, after the "N50 384P" stamp.

For ordering, always purchase the 8:1 drive variable cap-- otherwise you will feel like you are at a casino when you try to tune in a station.

Gary



 


Re: Oren Elliot latest "0219" series variable cap?

Tom Crosbie G6PZZ <tom@...>
 

Dave,

I looked up DeOxit D5 from Amazon UK. Almost £30.00 for 142ml. This side of the pond we pay around £10.00 for 400ml of contact cleaner, with several good brands to choose from, excluding WD40, which I class as for mechanical use only! I guess your D5 is more of a pro product. This piqued my curiosity as last year I purchased three 500+500pf airspace variables with reduction drives, described as new old stock. That’s what I got wrapped in layers of tissue. A squirt of air duster took care of disintegrating tissue but you’ve made me think about hitting them with some isopropyl. Next time I find myself looking at them again!

 

Tom | G6PZZ

Nr Chesterfield | Derbyshire |UK | IO93he

HF250 | Sentinel 4 |RSPdx | RM50 | TR2 | ATS 808

15m MLB | MTA | D707

tom@...

 

 

 

 

From: main@UltralightDX.groups.io <main@UltralightDX.groups.io> On Behalf Of daiche via groups.io
Sent: 07 July 2020 00:29
To: main@UltralightDX.groups.io
Subject: Re: [UltralightDX] Oren Elliot latest "0219" series variable cap?

 

Gary and Steve,

I had noticed a difference in older vs newer Oren caps also, although I saw no physical difference between them. I tried something on the 'older' ones that seems to work to freshen them up. I have used DeOxit D5 and/or 91-99% alcohol on them to clean the blades, keeping away from the bearings and gearing. That seems to perk them up also. So maybe it is plain old corrosion from bad city air, causing a problem, rather than a new manufacturing technique. I have always used canned air to dry them off after a treatment, as a finishing touch. You might try one or both treatments on one of your old caps to see if that helps. I'd be interested to hear if my improvement method is real or imaginary. Ha!

73's

Dave Aichelman     N7NZH     Grants Pass, Oregon


Re: Oren Elliot latest "0219" series variable cap?

Les Rayburn
 

Looking on the Mike’s Electronics Parts web site, I see three different air variable capacitors. 

Is the desired part the 384 variable capacitor here: 



Or the one with the 8:1 drive here: 


I’d like to substitute the one on my shiny new 5” FSL and see if I can detect any difference in performance. Glad that this secret leaked out—now about those lottery numbers….



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 Jul 6, 2020, at 6:29 PM, daiche via groups.io <daiche@...> wrote:

Gary and Steve,

I had noticed a difference in older vs newer Oren caps also, although I saw no physical difference between them. I tried something on the 'older' ones that seems to work to freshen them up. I have used DeOxit D5 and/or 91-99% alcohol on them to clean the blades, keeping away from the bearings and gearing. That seems to perk them up also. So maybe it is plain old corrosion from bad city air, causing a problem, rather than a new manufacturing technique. I have always used canned air to dry them off after a treatment, as a finishing touch. You might try one or both treatments on one of your old caps to see if that helps. I'd be interested to hear if my improvement method is real or imaginary. Ha!

73's

Dave Aichelman     N7NZH     Grants Pass, Oregon


Re: Oren Elliot latest "0219" series variable cap?

daiche
 

Gary and Steve,

I had noticed a difference in older vs newer Oren caps also, although I saw no physical difference between them. I tried something on the 'older' ones that seems to work to freshen them up. I have used DeOxit D5 and/or 91-99% alcohol on them to clean the blades, keeping away from the bearings and gearing. That seems to perk them up also. So maybe it is plain old corrosion from bad city air, causing a problem, rather than a new manufacturing technique. I have always used canned air to dry them off after a treatment, as a finishing touch. You might try one or both treatments on one of your old caps to see if that helps. I'd be interested to hear if my improvement method is real or imaginary. Ha!

73's

Dave Aichelman     N7NZH     Grants Pass, Oregon


Re: Oren Elliot latest "0219" series variable cap?

Gary DeBock
 

Hi Steve,

<<<   Where are you obtaining the latest 0219 variable caps--from the manufacturer or from Mike's Electronics? This is certainly a very interesting finding.
73, Steve >>>

During the Pandemic I have been doing a lot of FSL experimentation, and have been buying these new "N50 384P" variable caps from Mike's Electronic Parts in batches of 7. Around March I first noticed that one of 3" Baby FSL's recently constructed was outperforming one constructed in 2018, even though all of the components were exactly the same. The only difference was that the variable caps used in 2018 had a "0217" series number, while the new ones received in 2020 had a "0219" series number. Both of those were received from Mike's Electronic Parts, with Oren Elliott as the OEM. Kind of curious about this, I substituted another "0219" variable cap for a "0217" variable cap in another 2018 FSL design, and immediately got the same noticeable performance boost (sharper tuning, and a greater sensitivity peak when zeroed in on the radio's frequency, which only happened when you tuned the FSL to exactly the right point). This "0219" variable cap performance boost was most noticeable on the extreme low band frequencies (such as 530, 531 and 540), although it was detectable all the way up to 1700 kHz. The effect was enough to motivate this fanatical tinker to replace all the FSL variable caps headed for the Rockwork Cliff this summer, ensuring that they all have new "0219" upgrades.

This is the first time that I'm sharing this discovery with anyone, Steve-- I had actually considered keeping it a secret :-)

73, Gary



 


Re: FSL coil Q of 1162/46 and 660/46 Litz compared using HP4342A Q meter

Steve Ratzlaff
 

I just checked with Mike at https://www.mikeselectronicparts.com/ and he says his current caps are the latest version "0219" so I just ordered one to try.

Thanks for this info, Gary.

73,

Steve

On 7/5/2020 11:05 PM, Gary DeBock via groups.io wrote:
Hi Steve,
To make matters even more interesting, Oren Elliott seems to have recently improved his manufacturing process in the later "N50 384P" variable caps, so that the N50 384P caps with a "0219" series number are clearly superior to those with a "0217" series number. I don't know if he has been improving the dielectric, rotor or stator, but these newest variable caps are extremely sharp performers-- to the extent that every FSL antenna heading for the Rockwork Cliff this summer will have one of the latest variable cap upgrades.

Gary


Re: Oren Elliot latest "0219" series variable cap?

Steve Ratzlaff
 

Hi Gary,

Where are you obtaining the latest 0219 variable caps--from the manufacturer or from Mike's Electronics? This is certainly a very interesting finding.

73,

Steve

On 7/5/2020 11:05 PM, Gary DeBock via groups.io wrote:


To make matters even more interesting, Oren Elliott seems to have recently improved his manufacturing process in the later "N50 384P" variable caps, so that the N50 384P caps with a "0219" series number are clearly superior to those with a "0217" series number. I don't know if he has been improving the dielectric, rotor or stator, but these newest variable caps are extremely sharp performers-- to the extent that every FSL antenna heading for the Rockwork Cliff this summer will have one of the latest variable cap upgrades. With Hawaii and all overseas travel temporarily scratched out because of the Pandemic, the Rockwork cliff should be a dream DXing venue for both Tom R. and yours truly, who both broke our records for South Pacific NDB-DX last August. Tom told me that he's still uncovering new South Pacific NDB-DX from that trip, in addition to his record-breaking haul already posted.

Gary


Re: FSL coil Q of 1162/46 and 660/46 Litz compared using HP4342A Q meter

Gary DeBock
 

Hi Steve,

Thanks for running these detailed "Q" tests between the 1162/46 and 660/46 Liz wire at various frequencies with the HP4342A Q meter. This kind of detailed test is something which would not be my first choice for using up my hobby time, but I'm happy that somebody did it! :-)

The 1162/46 Litz wire's 'Q" advantage on the low band covers the frequencies which are typically checked first during DXpeditions and band scans, so its substitution for the 660/46 Litz wire in 2014 may have given the impression that it was superior throughout the MW range, which apparently isn't so. But to be honest the recent replacement of the old "N50 365P" variable caps with the newer "N50 384P"variable caps seemed to provide a higher "Q" boost in the newer FSL's  than the switch in Litz wire, to the extent that it was the inspiration for the miniature "Frequent Flyer' FSL's which have tracked down long range DX in Hawaii and the Cook Islands.

To make matters even more interesting, Oren Elliott seems to have recently improved his manufacturing process in the later "N50 384P" variable caps, so that the N50 384P caps with a "0219" series number are clearly superior to those with a "0217" series number. I don't know if he has been improving the dielectric, rotor or stator, but these newest variable caps are extremely sharp performers-- to the extent that every FSL antenna heading for the Rockwork Cliff this summer will have one of the latest variable cap upgrades. With Hawaii and all overseas travel temporarily scratched out because of the Pandemic, the Rockwork cliff should be a dream DXing venue for both Tom R. and yours truly, who both broke our records for South Pacific NDB-DX last August. Tom told me that he's still uncovering new South Pacific NDB-DX from that trip, in addition to his record-breaking haul already posted.

Gary
 


Re: FSL coil Q of 1162/46 and 660/46 (added 330/46) Litz compared using HP4342A Q meter

Steve Ratzlaff
 

I wound a coil using 330/46 Litz to compare with the other two. 21 turns gave 273.3 uH, quite a bit higher than the other two due to the narrower width coil. Probably 1 or 2 turns should be removed for use in an actual FSL with 385 pF tuning cap.

On 7/5/2020 3:46 PM, STEVE wrote:

This experiment compares a ferrite sleeve coil of 1162/46 Litz with a ferrite sleeve coil of 660/46, both 21 turns with final coil diameter about 6 3/8", using 140 mm ferrite rods in the ferrite sleeve. The same ferrite sleeve was used for both coils, with the coils centered on the sleeve for peak inductance. The 1162/46 coil measured 236.5 uH; the 660/46 coil measured 253 uH for the same 21 turns for each. (The fatter Litz will have a little less inductance compared to the thinner Litz for the same number of turns due to being a wider coil.)

Each ferrite sleeve coil was suspended 7" above the Q meter deck, oriented horizontally; each coil had about 12" of pigtail length. The HP4342A Q meter capacitor (very high Q) was used to resonate each coil. Solid copper lugs were used on the ends of each coil to connect the coil to the Q meter. Coil Q should directly relate to signal level coupled to the receiver with higher Q giving higher signal level. Since the Q meter's variable capacitor was used, which has much higher Q than any external variable capacitor I'm aware of, this removes the external capacitor Q effects from the experimental results, only comparing the two Litz types.

73,

Steve AA7U

                          1162/46    660/46    330/46

1700 kHz  305Q        310Q     263Q

1600 kHz  345Q        350Q     300Q

1500 kHz  385Q        395Q     340Q

1400 kHz  440Q        445Q     380Q

1300 kHz  500Q        500Q     433Q

1200 kHz  565Q        570Q     490Q

1100 kHz  643Q        645Q     555Q

1000 kHz  740Q        730Q     630Q

900 kHz   840Q        835Q     710Q

800 kHz   955Q        930Q     785Q

700 kHz   1116Q       1084Q    860Q

600 kHz   1246Q       1144Q    910Q

550 kHz   1301Q       1173Q    925Q

520 kHz   1332Q       1186Q    925Q

510 kHz---------------1188Q    928Q (340 pF for 330/46)


Re: FSL coil Q of 1162/46 and 660/46 Litz compared using HP4342A Q meter

Steve Ratzlaff
 

I should add that my 140mm ferrite rods are Chinese rods, not Russian rods, and that the results may be different using Russian rods. I don't have enough Russian rods to do the experiment using them. Gary's latest 6" FSL with Russian rods used 19 turns of the 1162/46 Litz where mine used 21 turns.

Steve AA7U

On 7/5/2020 3:46 PM, STEVE wrote:

This experiment compares a ferrite sleeve coil of 1162/46 Litz with a ferrite sleeve coil of 660/46, both 21 turns with final coil diameter about 6 3/8", using 140 mm ferrite rods in the ferrite sleeve. The same ferrite sleeve was used for both coils, with the coils centered on the sleeve for peak inductance. The 1162/46 coil measured 236.5 uH; the 660/46 coil measured 253 uH for the same 21 turns for each. (The fatter Litz will have a little less inductance compared to the thinner Litz for the same number of turns due to being a wider coil.)

Each ferrite sleeve coil was suspended 7" above the Q meter deck, oriented horizontally; each coil had about 12" of pigtail length. The HP4342A Q meter capacitor (very high Q) was used to resonate each coil. Solid copper lugs were used on the ends of each coil to connect the coil to the Q meter. Coil Q should directly relate to signal level coupled to the receiver with higher Q giving higher signal level. Since the Q meter's variable capacitor was used, which has much higher Q than any external variable capacitor I'm aware of, this removes the external capacitor Q effects from the experimental results, only comparing the two Litz types.

73,

Steve AA7U

                            1162/46    660/46

1700 kHz  305Q        310Q

1600 kHz  345Q        350Q

1500 kHz  385Q        395Q

1400 kHz  440Q        445Q

1300 kHz  500Q        500Q

1200 kHz  565Q        570Q

1100 kHz  643Q        645Q  Q's are equal at this frequency

1000 kHz  740Q        730Q  Fatter Litz begins to have better Q

900 kHz   840Q        835Q

800 kHz   955Q        930Q

700 kHz   1116Q       1084Q

600 kHz   1246Q       1144Q

550 kHz   1301Q       1173Q

520 kHz   1332Q       1186Q

1162/46 Litz--385 pF, 516 kHz, 1333Q (max capacitance of variable cap Gary uses)

510 kHz               1188Q

660/46 Litz--385 pF, 502 kHz, 1189Q (max capacitance of variable cap Gary uses)


FSL coil Q of 1162/46 and 660/46 Litz compared using HP4342A Q meter

Steve Ratzlaff
 

This experiment compares a ferrite sleeve coil of 1162/46 Litz with a ferrite sleeve coil of 660/46, both 21 turns with final coil diameter about 6 3/8", using 140 mm ferrite rods in the ferrite sleeve. The same ferrite sleeve was used for both coils, with the coils centered on the sleeve for peak inductance. The 1162/46 coil measured 236.5 uH; the 660/46 coil measured 253 uH for the same 21 turns for each. (The fatter Litz will have a little less inductance compared to the thinner Litz for the same number of turns due to being a wider coil.)

Each ferrite sleeve coil was suspended 7" above the Q meter deck, oriented horizontally; each coil had about 12" of pigtail length. The HP4342A Q meter capacitor (very high Q) was used to resonate each coil. Solid copper lugs were used on the ends of each coil to connect the coil to the Q meter. Coil Q should directly relate to signal level coupled to the receiver with higher Q giving higher signal level. Since the Q meter's variable capacitor was used, which has much higher Q than any external variable capacitor I'm aware of, this removes the external capacitor Q effects from the experimental results, only comparing the two Litz types.

73,

Steve AA7U

                            1162/46    660/46

1700 kHz  305Q        310Q

1600 kHz  345Q        350Q

1500 kHz  385Q        395Q

1400 kHz  440Q        445Q

1300 kHz  500Q        500Q

1200 kHz  565Q        570Q

1100 kHz  643Q        645Q  Q's are equal at this frequency

1000 kHz  740Q        730Q  Fatter Litz begins to have better Q

900 kHz   840Q        835Q

800 kHz   955Q        930Q

700 kHz   1116Q       1084Q

600 kHz   1246Q       1144Q

550 kHz   1301Q       1173Q

520 kHz   1332Q       1186Q

1162/46 Litz--385 pF, 516 kHz, 1333Q (max capacitance of variable cap Gary uses)

510 kHz               1188Q

660/46 Litz--385 pF, 502 kHz, 1189Q (max capacitance of variable cap Gary uses)


Re: Gary's New 6" FSL Design

Todd
 

Thanks Gary for the detailed response.

When endeavoring to obtain the highest resonant signal output at a given frequency, the Q needs to be high as practicable. The audio fidelity will be somewhat compromised, but this can be partially improved by slightly tuning the FSL antenna to peak 1 or 2 KHz above the carrier frequency. This is why the 8:1 reduction drive is essential. 

High Q FSL antennas are the only way to obtain similar RF gain and selectivity in a small package that favorably compares to large 4 - 6 foot air core box loops. This means a 6 inch FSL can be positioned pretty much anywhere within the house. A 6 ft air core box loop positioned on the kitchen bench top is not practical. But a 6" FSL would easily sit there.

The 6" FSL with 1162/46 Litz wire will likely be more expensive for DXers outside the USA and China. I estimate the total cost for me would be around AU $250 including parts postage.

For those DXers that seek weak signals only 9 or 10 KHz adjacent to very strong locals, the high Q FSL is ideal from a 3 dB bandwidth perspective. The disadvantage is no tilting provision for reducing local signals by > 60 dB. This Kiwa loop tilting mechanism was very good for obtaining the critical tilt angle for nulling a local signal.

One possibility is to video a 6" FSL comparison test against the large 9 foot air core loop. If the results are comparable, that will be an amazing achievement in itself. Interesting to see what your most distant daytime MW groundwave signal that can be obtained with both antennas.

Regards,

Todd


KGB 760

Mike Sanburn
 

Call change is logged on my little Sangean DT160. Heard spot for San Diego Honda dealers and promo for Mark Larson Show. 0800 PDT top of hour call letter ID read very quickly then into CBS news. Former KFMB for decades. 
Mike Sanburn
Lakewood CA 

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