Basically the same as the G Maynard "Spiral Loop with Q Multiplier" from the 1980's, with ferrites added. :^)

His design was balanced, with a centre tap half way up the windings which went to the ground of the capacitor, with two gangs of the capacitor used - one going to the top exit winding and the other to the bottom.

Q multiplier on that main balanced loop winding and then a MUCH SMALLER DIAMETER pick up turn further in towards the centre of the antenna, to reduce dampening. Made for very sharp tuning - I could peak it on one or other sideband of a station, and you could hear the peak track across the audio bandwidth of the station as you tuned the loop.

Hello Dean (and Bill),

Thanks for your interesting experimental contribution, Dean, which certainly breaks new ground in FSL antenna design.

As a veteran of multiple FSL design controversies after Graham Maynard introduced his breakthrough "ferrite sleeve antenna" in February of 2011 (for which he was relentlessly slammed by antenna "experts" at the time) the best advice I can give is to be respectful of other's experimental efforts, and keep an open mind about new design directions until you personally test them out. In my own efforts I concentrate on direct A/B testing of different FSL designs and construction components, using actual weak signal reception tests under controlled conditions. FSL antennas developed under such a concept have the potential to be astonishing performers for their size.

Another important factor in FSL antenna design is to have a definite mission for the antenna you are creating. An FSL designed to provide massive gain while surviving gale storms at an ocean side cliff will have a different design than a lightweight "airport friendly" model built to provide gain boosts on exotic salt water beaches. Of course, theory-based antennas simply designed for maximum "Q" in a shack can use flimsy components and frame designs that wouldn't survive a single session out in adverse weather, but if that is the designer's goal for the antenna, who am I to criticize it? My own opinion is that every antenna needs a definite mission before construction starts-- not only as a way to focus on design objectives, but also as a guideline for success or failure. You need a definite destination before you can have any hope of making a successful trip!

73, Gary DeBock (in Puyallup, WA, USA)
        

Hi :
Sry i cant be more help here ? The number of winding's will depend on the value of capacitor you use and what Frequencies it will tune.

Dean W.

Hi Bill;
Nope the nulls are very sharp, in fact much sharper than my regularly wound FSL's . as far as a distorted pattern I haven't seen that . These loops have a figure -of -eight pattern ,gain is in line with  the loop and nulls to the side . So in other words the front edge of the loop points directly at the station being received .
I don't know if i can explain this part ? ...but  the Flux which the loop generates is concentrated on the inside and outside edge of the windings not on the ferrite  itself . I found a very detailed article on this but have lost it . look around the net maybe it will pop up ?

Dean W.

Hi takane2,

Your ICF-S14 indeed looks like ultralight size. To me it looks about the size of my Sony ICF S10 MK2.

Welcome to the group.

Happy DXing!

Bill
Arizona

How many feet of litz wire did it take to wind this antenna?  How many times around the form did you wind?
Thank you!

Shoot, I meant ICF-S14 not SRF. Sorry I got the model numbers mixed up with the Sonys.

People keep upgrading their PC monitors, and a lot of monitor cables are being thrown away. First  VGA, and now DVI. Many of them have EMI suppression ferrite cores of various sizes.
They come essentially for free if you know where to look. I accumulated a dozen or so of these, planned to use them for common mode suppression chokes. The material is unknown, but seems to work well on HF frequencies.
Have anybody in this group tried to use these cores in a loopstick antenna? They can be glued together to form a "rod" of sorts.

73, Mike AF7KR

I am not an expert in ferrite antennas, just have a gut feeling: shouldn't the rods be moved more to the center, so that they are not sticking outside of the coil?
Intuitively, the magnetic material should be in the desired path of the magnetic field lines - inside the coil, not outside. The ferrite outside of the coil may actually "short circuit" the field lines and reduce the antenna effective height.
I am sure it still concentrates the field in the vicinity of the coil, but maybe not in the most efficient way.

Mike AF7KR

This is another mystery recording from last month's Poipu, Hawaii DXpedition, featuring Australian English on 531 kHz at 1503 UTC during a sunrise session on November 5th. There is apparently a weather report in the first part of the recording, foillowed by a lady presenter at 49 seconds saying something like, "More to come, from Radio Australia" (?). Other than this strange statement it would seem like the format is similar to 4KZ in Innisfail, but if any Australians or Kiwis can listen to the recording I'm sure that the identity mystery would be solved-- help!  https://dreamcrafts.box.com/s/m70q721ltlwwa0m23wxd5h8vp0csahnv

73, Gary DeBock (DXing in Poipu, Hawaii from November 2-8)
 

Dean,

Are the nulls sharp on the main loop? Like a loop which is edge-wound? I'm imagining all that ferrite stuck through the loop sideways distorting the pattern. Maybe it doesn't effect it that way.

Just curious.

Bill

It would be interesting to see how you align the two loops and the
directions of the received and the offending station/noise.
Even just a quick sketch would be very helpful, as I'm not understanding
this.

                        Thanks, Mikek

TP reception was down from that yesterday.

567 JOIK fair at 1322; barely audible at 1342 (LSR 1330).

594 JOAK fair at 1316; poor at 1321; poor at 1328-1340 with unID co-channel QRM; barely audible before fading out at 1344.

774 JOUB fading in at 0730; poor at 0851; fair signal at 1206; good at 1313.

972 HLCA heterodyne noted from 0745 until past LSR.

1287 JOHR barely audible Japanese talk at 1325.

1566 HLAZ poor at 1231.

Receiver: Skywave with ALA1530LNP aerial.

Richard Allen, near Perry OK USA.

The idea of using two separate loops to produce phase cancellation can be applied to either QRM, QRN, and/or unwanted medium wave signals.

Two signals of equal amplitude and 180 degrees out of phase with reference to each other will cancel. This can be easily demonstrated mathematically, or even with a CRO. In the real world, especially with varying evening amplitude from E layer skywave signals, the phase relationships do not usually correspond to a perfect null. Nevertheless, useful signal nulls can still be obtained.

I can use my home-constructed 40 inch side length PVC box loop in conjunction with a 25.6 inch (65 cm) diameter PK circular loop for nulling QRM, QRN, or unwanted MW signals. The large 40 inch loop is the DX antenna, while the smaller 25.6 inch loop is the noise pickup antenna. Both antennas introduce phasing via inductive coupling.

The late Joseph J. Carr wrote a paper detailing the advantages of using two loops to introduce phase cancellation [1].

Regards,

Todd
Sydney, AU

1. https://www.dxing.com/tnotes/tnote09.pdf

Hi:
By drilling a hole in the center of the ring (that's why i used plastic) and if needed a little glue.
Dean W.

Dean, The design looks relatively easy to construct, but how do you secure the ferrite rods to the pipe?  Jim

Using the smaller loop as a noise antenna completely gets rid of the house noise /hash.




This is a Huge advantage for me as I can DX in my home again :P

Dean W.