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Re: Ferrite Sleeve Loop (FSL) antenna tests

Chris Trask - N7ZWY/WDX3HLB
 


Any guesses on how this approach might work:

A Litz wire solenoid coil, with ferrite rods both on the inside and
outside
of the wire coil.

I other words, it's a standard FSL (Ferrite Sleeve Loop), with additioanl
ferrite rods added to the outside of the Litz coil. The Litz solenoid coil
becomes sandwiched between two ferrite "sleeves".
That's an interesting idea, sort of a ferrite sandwich loop.


Any downsides in RF performance that anyone can think of? (Cost and weight
aside.)
I've narrowed my choices down to using ferrite bars, and to start with
just a single layer of the bars with one solenoid along the inside and one
along the outside. I have five different sizes of Litz wire to play with,
and I'll simply choose one of them for now. I just need to free up some
funds to buy some of the bars, a piece of PVC pipe or a coupler, and some
double-sided carpet tape.

This sounds like a fun project. First order of business will be to
measure the terminal impedance and see where the first resonance occurs, as
well as see how the real part of the impedance behaves. Those two will
dictate the frequency limits.

Chris
Re: Ferrite Sleeve Loop (FSL) antenna tests

Chris Trask - N7ZWY/WDX3HLB
 


I have not seen all the posts here so I am not aware of Paul's suggestion,
but two windings with currents passing oppositely will cancel whether
there
is a ferrite sleeve between them or not.
I never said that the currents would be passing oppositely. The
solenoid on the inside of the sleeve and the solenoid on the outside of the
sleeve are connected in seies so that their voltages are summed.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
Re: Ferrite Sleeve Loop (FSL) antenna tests

Christopher Wendling
 

Any guesses on how this approach might work:

A Litz wire solenoid coil, with ferrite rods both on the inside and outside of the wire coil.

I other words, it's a standard FSL (Ferrite Sleeve Loop), with additioanl ferrite rods added to the outside of the Litz coil.  The Litz solenoid coil becomes sandwiched between two ferrite "sleeves". 

I don't foresee any "electron spin" problems with this approach, and it surely puts the coil in even closer proximity to more ferrite than a standard FSL, to some advantage

Any downsides in  RF performance that anyone can think of?  (Cost and weight aside.)

Tnx es 73


--- On Tue, 3/1/11, graham.maynard1 wrote:

From: graham.maynard1
Subject: [ultralightdx] Re: Ferrite Sleeve Loop (FSL) antenna tests
To: ultralightdx@...
Date: Tuesday, March 1, 2011, 3:19 PM

 

Hi Chris.

I have not seen all the posts here so I am not aware of Paul's suggestion, but two windings with currents passing oppositely will cancel whether there is a ferrite sleeve between them or not.

Cheers ......... Graham.

--- In ultralightdx@..., "Chris Trask" wrote:
>
> >
> > >
> > > Basket weave through the rods won't work because coil induction will set
> > > up opposite electron orbit spin directions in the ferrite if passing
> > > inside a rod on one turn and outside on another.
> > >
> >
> > I would have to disagree here. The magnetic flux along the surface of
> > the rod should be uniform, or at least in the same direction. And the
> > current passing through the conductors is also in the same direction
> whether
> > it is along the outside or inside. It's as though we were winding turns
> > around a single rod.
> >
>
> Ooops! Graham is correct here. With the currents in the two windings
> being in the same direction they will cancel out. This being the case,
> Paul's idea of two solenoids, one along the inside and the other on the
> outside, would be a suitable method to improve the performance. The two
> windings would need to be constructed so that their currents are in opposite
> directions.
>
> Chris
>
Re: Ferrite Sleeve Loop (FSL) antenna tests

graham.maynard1
 

Hi Chris.

I have not seen all the posts here so I am not aware of Paul's suggestion, but two windings with currents passing oppositely will cancel whether there is a ferrite sleeve between them or not.

Cheers ......... Graham.

--- In ultralightdx@yahoogroups.com, "Chris Trask" <christrask@...> wrote:



Basket weave through the rods won't work because coil induction will set
up opposite electron orbit spin directions in the ferrite if passing
inside a rod on one turn and outside on another.
I would have to disagree here. The magnetic flux along the surface of
the rod should be uniform, or at least in the same direction. And the
current passing through the conductors is also in the same direction
whether
it is along the outside or inside. It's as though we were winding turns
around a single rod.
Ooops! Graham is correct here. With the currents in the two windings
being in the same direction they will cancel out. This being the case,
Paul's idea of two solenoids, one along the inside and the other on the
outside, would be a suitable method to improve the performance. The two
windings would need to be constructed so that their currents are in opposite
directions.

Chris
Re: Ferrite Sleeve Loop (FSL) antenna tests

Chris Trask - N7ZWY/WDX3HLB
 



Basket weave through the rods won't work because coil induction will set
up opposite electron orbit spin directions in the ferrite if passing
inside a rod on one turn and outside on another.
I would have to disagree here. The magnetic flux along the surface of
the rod should be uniform, or at least in the same direction. And the
current passing through the conductors is also in the same direction
whether
it is along the outside or inside. It's as though we were winding turns
around a single rod.
Ooops! Graham is correct here. With the currents in the two windings
being in the same direction they will cancel out. This being the case,
Paul's idea of two solenoids, one along the inside and the other on the
outside, would be a suitable method to improve the performance. The two
windings would need to be constructed so that their currents are in opposite
directions.

Chris
Re: Ferrite Sleeve Loop (FSL) antenna tests

Chris Trask - N7ZWY/WDX3HLB
 


Basket weave through the rods won't work because coil induction will set
up opposite electron orbit spin directions in the ferrite if passing
inside a rod on one turn and outside on another.
I would have to disagree here. The magnetic flux along the surface of
the rod should be uniform, or at least in the same direction. And the
current passing through the conductors is also in the same direction whether
it is along the outside or inside. It's as though we were winding turns
around a single rod.


The gap between wire and rods is essential to resonance.
I had 1/4" on the 8.5" dia FS Loop. 5mm on smaller sizes.
For a given number of turns, by changing the gap you're changing the
inductance of the loop, which is what is causing the resonance to change.


I suggest to not have too high a Q for broadcast listening, but high Q for
DXing beacons.
Yes, you need to have sufficient Q so that you couple the entire signal
(carrier plus sidebands) to the receiver.

Chris
Re: Additional source of Litz wire

Kevin Schanilec
 

Hi Chris:

Thus far I have only used passive coupling to a portable receiver's internal ferrite, so no direct connection to a receiver.

Graham Maynard's article mentions that he connected one leg of the FSL to the retracted whip antenna for SW reception. The whip connection presumably had a fairly low impedance - it sounds like it worked quite well, and he didn't report any loss of tuning sharpness due to that load. That might work at MW/LW freqs too, with perhaps something like a 16:1 xfmr helping out. I plan to open up the FSL to tinker with it a bit, and can report how it works.

Regards - Kevin

--- In ultralightdx@yahoogroups.com, "Chris Trask" <christrask@...> wrote:


Something that I've been meaning to ask is how you are coupling
the FSL to the receiver?
Using the PL-380 or other DSP set, an FSL this small generally has to
be right up next to the antenna on LW in order for the antenna to take
over the front end, since these are not as sensitive on LW - the Q is
not noticeably spoiled. The Tecsun PL-210, on the other hand, does
not have a tuned front end and is more sensitive, so the distance from
the antenna can be larger on LW. On MW, the DSP receivers can be some
distance away.
Let me rephrase the question: How are you connecting the FSL loop to
the cable or receiver?

Chris
Re: Ferrite Sleeve Loop (FSL) antenna tests

graham.maynard1
 

Hi Chris,

Basket weave through the rods won't work because coil induction will set up opposite electron orbit spin directions in the ferrite if passing inside a rod on one turn and outside on another.

It is essential to imagine ferrite as being full of electron spin gyros and not magnetic domains.

The design is for maximum spin-field alignment within and shared equally between rods (hence circular and not square) and also not spaced rods.

The gap between wire and rods is essential to resonance.
I had 1/4" on the 8.5" dia FS Loop. 5mm on smaller sizes.
I suggest to not have too high a Q for broadcast listening, but high Q for DXing beacons.

Cheers .......... Graham.

http://www.gmweb2.net/The%20FS%20Loop.htm

--- In ultralightdx@yahoogroups.com, Chris Trask <christrask@...> wrote:

<<SNIP>>



If it worked, it would get much more of the wire close to
the surface of round ferrite rods. - FARMERIK
Yes, you would be coupling more flux into the windings
and therefore have a higher signal current/voltage.

Interesting conundrum. Could be a good RF engineering exam
question!

I wonder about the sections of a weave "outside" the ferrite
sleeve, which by contributing less inductivity result in less
sensitivity to "incoming" RF. The extra windings required to
make up the total uH required would compensate this "loss"
to some degree. So, overall, sensitivity might be more, less
or similar to a straightforward outer winding, but the Q
factor improved as with an old-style basket-weaved inductor.

Chris, your IEEE background probably makes you the most
learned in the group. Any further ideas? I do find the concept
of the FSL fascinating.
This is indeed something that is worthy of experimentation. I don't have the funds at the moment to purchase any of the rods, but they are at the top of the list for next month. A side-by-side comparison should be made between a single-layer solenoid version and a basket-weave version, plus Paul has proposed a version having a single-layer solenoid on the inside and outside, which may be more practical from a construction standpoint.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
Re: Additional source of Litz wire

Chris Trask - N7ZWY/WDX3HLB
 


Something that I've been meaning to ask is how you are coupling
the FSL to the receiver?
Using the PL-380 or other DSP set, an FSL this small generally has to
be right up next to the antenna on LW in order for the antenna to take
over the front end, since these are not as sensitive on LW - the Q is
not noticeably spoiled. The Tecsun PL-210, on the other hand, does
not have a tuned front end and is more sensitive, so the distance from
the antenna can be larger on LW. On MW, the DSP receivers can be some
distance away.
Let me rephrase the question: How are you connecting the FSL loop to
the cable or receiver?

Chris
One New XE Logged

kirk74601 <kirk74601@...>
 

I finally found some time to DX from my new QTH here in Ponca City. This new location is great, with one exception....electrical noise. Nevertheless one new station was added to the ULR log this morning. Logged this one on my T615. I compared the reception on the Sony and my E-100 Slider. The T615 was far better...much better audio, and superb nulling of the relog stations there. I was also using a SAT with both rigs.

1260, XESA, Culiacan, Sinaloa, 1103-1245 UTC, 3/1/11, Noted this one at a very weak lvl at t/in and then just hung around in hopes of a sig increase, and it certainly did. Playing ranchera mx and some mellow standards in SS...the type I can't pin a style name to. Very slick production complete with various sta promo jingles. M ancr w/ a full ID at 1230 UTC, "Aqui....en Culiacan, Sinaloa, eqees-eh-esse-ah, La Mexicana." Faded up to a good lvl by 1230 UTC. Sometimes patience pays off! ULR #741, LAm # 142.

Wishing you all the best of DX!

Kirk Allen
Ponca City, OK
Ultralight Longwave DX- 4 New NDB's (and State #11)

Gary DeBock
 

Hello All,

The LW band certainly was back to normal here last night, and maybe
even a little exceptional. I knew something was ujp when I tuned in to
413 kHz around 0600 UTC (10 PM local time), and found YHD in
Dryden, Ontario (1,350 miles) with an almost nuclear-level signal
(http://www.mediafire.com/?lt4w1pn0646pbk7).

After searching around for a while, I found a much weaker 365-AA in
Minnesota (across the border from Fargo, ND) for state #11 here
(headphones recommended: http://www.mediafire.com/?b1k6mjkpt57k261).

Besides 365-AA, 302-QW (SK), 295-8C (AB) and 365-DPY (WA) were heard
for new beacons on the 7.5" LW Loopstick PL-380 model here last night.
Total NDB's are now 143 stations in 11 States, 7 Provinces, and 4 DX
"Countries" (including Alaska and Hawaii). I'm currently testing out a
new, hard-wired 7.5" LW loopstick PL-380 model (photo posted at
http://www.mediafire.com/i/?wncdzuorogdq11n ), which is significantly
more sensitive than the plug-in loopstick model (as if I needed more
reason to go out into the cold to chase beacons :-)

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)
Re: Additional source of Litz wire

Kevin Schanilec
 

Using the PL-380 or other DSP set, an FSL this small generally has to be right up next to the antenna on LW in order for the antenna to take over the front end, since these are not as sensitive on LW - the Q is not noticeably spoiled. The Tecsun PL-210, on the other hand, does not have a tuned front end and is more sensitive, so the distance from the antenna can be larger on LW. On MW, the DSP receivers can be some distance away.

Kevin

--- In ultralightdx@yahoogroups.com, "Chris Trask" <christrask@...> wrote:


Something that I've been meaning to ask is how you are coupling the FSL to the receiver?
Re: Additional source of Litz wire

Chris Trask - N7ZWY/WDX3HLB
 


I have #46 currently on my FSL, and it does a good job on LW, although it
has 175 strands, which may be helping quite a bit. This Litz from Xizi
seems to have a higher/broader range for a given grade than the standard
tables from Kerrigan-Lewis would indicate. For instance, Q for the #44
peaks at around 700 khz, staying above 1000 between the range of 400-1200
khz (and Q=680 at 200 and 1700 khz), whereas the K-L table recommends a
range of only 350 to 850 khz.

Not sure about 16/38 for MW, though. I haven't seen any Q meter data for
this, but I suspect that the performance on the MW band would be only
so-so, with the Q peaking somewhere in the LW band.
Something that I've been meaning to ask is how you are coupling the FSL
to the receiver? I've been looking at the FSL as being suitable as a higher
performing substitute for a ferrite rod antenna, which is usually used as
parallel-resonant connected to a JFET input amplifier. I used that approach
here:

http://www.home.earthlink.net/~christrask/Paper006.html

and I've taken that design a few steps further to improve the performance,
in particular using a balanced tuner and amplifier to reduce the distortion.
And I won't have the remote tuning as I want to use a mechanical dual
variable capacitor to further reduce the chance of distortion.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
Re: Additional source of Litz wire

Kevin Schanilec
 

Hi Chris/all:

I have #46 currently on my FSL, and it does a good job on LW, although it has 175 strands, which may be helping quite a bit. This Litz from Xizi seems to have a higher/broader range for a given grade than the standard tables from Kerrigan-Lewis would indicate. For instance, Q for the #44 peaks at around 700 khz, staying above 1000 between the range of 400-1200 khz (and Q=680 at 200 and 1700 khz), whereas the K-L table recommends a range of only 350 to 850 khz.

Not sure about 16/38 for MW, though. I haven't seen any Q meter data for this, but I suspect that the performance on the MW band would be only so-so, with the Q peaking somewhere in the LW band.

Regards - Kevin

--- In ultralightdx@yahoogroups.com, "Chris Trask" <christrask@...> wrote:

That's quite a variety of Litz wire that he has. The 10-44 and 10-46
(maybe the 16-38) would be very nice for MW antennas while the 20-44 and
20-46 would be better for LW. The higher strand count offerings are better
suited for rewinding motors.

Chris
Re: Additional source of Litz wire

Chris Trask - N7ZWY/WDX3HLB
 


For those who are thinking of getting some Litz wire, there is now
another vendor on eBay, seller "zlowe7", who is Scott Lowe who lives
in Middletown, Ohio. He stocks a variety of grades of Litz made by
Xizi in China. He also sells the little two-section variable
capacitors that I have frequently used for this and that, which is
how I learned of his Litz offerings. In my experience he ships very
quickly. I have no financial stake or interest in this - just
letting folks know.
That's quite a variety of Litz wire that he has. The 10-44 and 10-46
(maybe the 16-38) would be very nice for MW antennas while the 20-44 and
20-46 would be better for LW. The higher strand count offerings are better
suited for rewinding motors.

He also has MVAM108 and MVAM109 varactors at relatively low prices. I
use the MVAM109 quite a bit in my receiving antenna designs.

Chris
NE Oregon ULR NDB DX, Monday night

Steve Ratzlaff <steveratz@...>
 

Despite some static, conditions were decent. 245 total.
Steve
NE Oregon
PL380, FSL

242 EL TX 1135 MI 335 YLD ON CAN 1629 MI 344 YC AB CAN 420 MI 356 ODX NE 986 MI 361 E3 AB CAN 736 MI 376 YAG ON CAN 1161 MI 417 IY IA 1251 MI 420 FQ MN 1166 MI
Re: Took the plunge

David Alpert
 

Welcome to the group, Chris.

I'm DXing from the Valley on PL310, PL380 (with 7.5" plug-in loopstick) and Sony SRF-59 (still my favorite ULR).  Logged some TP stations last Fall even from here in Studio City, but find it makes all the difference in the world to drive to a quiet spot near the ocean and let these little radios really show their stuff. 

73,
- DRA
KB2LUM


At 10:20 PM 2/28/2011, you wrote:
 

MW DX in the LA/OC Basin is a bit tough as virtually every channel slot is occupied and ground wave propagation over the mountains is nil. Still, along the coast, I am able to receive up to San Francisco and down to Tijuana with little effort for the higher powered stations. Santa Barbara is tough to hear as many stations in LA/OC seem not to reduce power or shutdown at night. KTAR in Phoenix also comes in pretty well as on a hop, skip, and jump as the signal wavers a bit.

I am using a Grundig G6 and a Sangean ATS-909 with a Terk Advantage; no other antennas at the moment. Haven't tried the Tecsun so I do not know how it will perform in the environment.

73,
kevin
kc6pob

--- On Mon, 2/28/11, cap_cstorey wrote:

From: cap_cstorey
Subject: [ultralightdx] Took the plunge
To: ultralightdx@...
Date: Monday, February 28, 2011, 10:20 AM

 

After reading this group for a few weeks and researching LW and MW on various sites, I finally took the plunge and ordered a Tecsun PL380. I am excited to see what I can hear on this radio from Southern California (Los Angeles area). Are there any others in this area willing to share their local knowledge with a newcomer to ULDX¡¦ing? Too many fun looking antenna choices though¡K.. can¡¦t decide ƒº

Chris
KA6WNK
Re: Took the plunge

kevin asato <kc6pob@...>
 

MW DX in the LA/OC Basin is a bit tough as virtually every channel slot is occupied and ground wave propagation over the mountains is nil. Still, along the coast, I am able to receive up to San Francisco and down to Tijuana with little effort for the higher powered stations. Santa Barbara is tough to hear as many stations in LA/OC seem not to reduce power or shutdown at night. KTAR in Phoenix also comes in pretty well as on a hop, skip, and jump as the signal wavers a bit.

I am using a Grundig G6 and a Sangean ATS-909 with a Terk Advantage; no other antennas at the moment. Haven't tried the Tecsun so I do not know how it will perform in the environment. 

73,
kevin
kc6pob


--- On Mon, 2/28/11, cap_cstorey wrote:

From: cap_cstorey
Subject: [ultralightdx] Took the plunge
To: ultralightdx@...
Date: Monday, February 28, 2011, 10:20 AM

 

After reading this group for a few weeks and researching LW and MW on various sites, I finally took the plunge and ordered a Tecsun PL380. I am excited to see what I can hear on this radio from Southern California (Los Angeles area). Are there any others in this area willing to share their local knowledge with a newcomer to ULDX¡¦ing? Too many fun looking antenna choices though¡K.. can¡¦t decide ƒº

Chris
KA6WNK
Additional source of Litz wire

Kevin Schanilec
 

Hi all:

For those who are thinking of getting some Litz wire, there is now another vendor on eBay, seller "zlowe7", who is Scott Lowe who lives in Middletown, Ohio. He stocks a variety of grades of Litz made by Xizi in China. He also sells the little two-section variable capacitors that I have frequently used for this and that, which is how I learned of his Litz offerings. In my experience he ships very quickly. I have no financial stake or interest in this - just letting folks know.

The #44 Litz I received from him has very good Q, and seems well suited for general products, in that the Q is the same at 200 khz as it is at 1700 khz (Q=680 on a polystyrene coil). His prices appear to be similar to those of another vendor of Xizi Litz wire, "mkmak222" in the SF Bay Area, who also gives sterling service in my experience.

Kevin S
Bainbridge Island, WA
ULR DX.....BEACONS......One New Beacon Tonight........

robert ross
 

HI Guys:

Conditions have been Bad here the past 3-4 Days...and I've not heard much of anything lately!! Both the AM BCB and NDB Band have been miserable. Nothing here on BCB @ Sunset again tonight.

However....Conditions on NDB Band seem a little better this evening...and I did hear one New Beacon. They're making me work for each new one lately!!!

RADIO USED.................TECSUN PL-380 ULR With DeBock 7.5 Inch Ferrite Antenna.

ULR LOG TOTALS are now....................76 Beacons Heard


73.................ROB VA3SW

Robert S. Ross
London, Ontario CANADA

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248 UL Montreal, QUEBEC Mar/01/11 0230 UTC 1 KW 418 Miles

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