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New style FSL Part 2

Dean wayman
 

So what's next in the project Dept. ??
Yup you guessed  it !   BIGGER   :P

Made with a ring cut from a 8 1/2 inch water pipe ,and 29 Ferrite 8x80 mm rods then wound with 1200/46 litz ;
This loop gives even more signal boost ,but the biggest advantage is using it with the smaller loop that was made before as a phasing array



I used these two loops to good affect tonight at sunset on 650 Khz to get KGAB orchard Valley Wyo. as WSM was fading in and using the smaller loop as a noise antenna I got rid of all my house  hash /qrm This should prove very useful when the weather warms and I get get some place quiet ?







Dean wayman
 

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.

Jim B
 

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

Dean wayman
 

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.

Todd
 

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

lamontcranston17
 

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

mediumwavedx
 

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

dziki64
 

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

Dean wayman
 

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.

Dean wayman
 

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.

Gary DeBock
 

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)
        

Andy ZL3AG
 

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.

On 13/12/19 3:02 pm, Dean wayman wrote:
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.

Dean wayman
 

Thanks Gary :
BTW i don't feel like anyone was giving me grief about these new loop's ,And honestly my goal was just to see if there  was any advantage to the basket weave design that I had been thinking about for some time.
Also I wish I had the time etc. to take this new loop to where you DX !  that would tell the tale about their design ,but I don't think that will ever happen .
Another thing I wanted to test was If a small loop setup could be used  in a phasing setup  .
I have a Pixel loop and a active vertical antenna  here at the house ,and I wanted to see if these loops could be as useful as that antenna setup ? So far I think they can come close to the bigger setup ,and what an improvement has been seen with my normal QRM .
There may be refinements in these loop's as time goes by ,most likely when the weather warms here, I'll be out there using them and have to make changes based on use,  etc.
Last week I gained 2 new stations in my log book which has been stagnant for a while now . Maybe as the solar min. turns the corner I can add more ?
Still, all-In-all I'm having fun doing the work .

Good DX all
Dean W.

mediumwavedx
 

Thank you for your reply Dean.

Very interesting about the flux concentration.

Keep at it. Looking forward to seeing what you find.

Bill