Re: Ferrite rod quality- Question for Gary DeBock, and favouri...
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Hello Laurie,
Greetings from western Washington, and we are certainly pleased
to have another dedicated loopstick enthusiast in our Ultralightdx
group! (especially one from Australia, the source of many fine AM signals
that cooperated to make my recent Ultralight DXpedition so much fun
:-)
Thanks also for your comments on the ferrite bar experimentation,
which are much appreciated. Loopsticks are the natural antennas of
Ultralight radios, and I'm very happy to work together with other enthusiasts to
create some effective upgrade antennas, to replace the semi-deaf Chinese factory
designs. Unlike the Japanese companies like Sony and Panasonic, Tecsun has
no extended experience in making sensitive AM loopsticks, so they are
certainly finding it a challenge to balance performance and cost.
Regarding the complaints that the current type 61 ferrite mix sold by
Amidon in the 7.5" x .5" bars may be of lesser quality than in previous years, I
have heard similar comments from enthusiasts here, Laurie. My own detailed
experience with these Amidon bars started about two years ago, when the
accidental development of the "Slider" loopstick (a single, shifting coil design
of 40/44 Litz wire on the type 61 7.5" bar) was found to boost the AM
sensitivity of the Eton E100 (Tecsun PL-200) model up to an extremely high
level. At that time I made about 15 of these "Slider" loopstick E100 models for
myself and others, using the Amidon type 61 bars, and found them all to be
of uniformly high quality in providing the excellent sensitivity.
For the past two years many other loopstick antenna designs have been
created and tested here using the Amidon type 61 bars, and I haven't noticed any
quality drop off during this time. Recently the type 61 mix was changed by
Amidon's Fair-Rite supplier to a type which has a significantly rougher
surface appearance, making it a challenge to create new Slider
loopsticks because of the increased friction. However the A/B signal tests have
always confirmed that the AM sensitivity performance of the two type 61 mixes is
the same.
As you may have noticed, there is an extremely great demand in our group
for 7.5" upgrade loopstick antennas, especially those of the plug-in
variety. It was my pleasure to create and send out over twenty 7.5"
plug-in loopsticks for owners of the PL-360 model, many of whom should be
enjoying DXing thrills this coming season. Current efforts are focused on
adapting these plug-in loopsticks to the PL-380 and PL-310 model cabinets, and
refining the current LW plug-in loopstick design (a 2000 uh center-wound coil of
40/44 Litz on the type 33 ferrite bar).
Welcome again, Laurie, and I can assure you that you have come to a group
where your talents will be greatly appreciated!
73, Gary DeBock (N7EKX), in Puyallup, WA,
USA
In a message dated 8/7/2010 10:18:28 P.M. Pacific Daylight Time,
lmann98@... writes:
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