Sorry I don't know you name, but if you want to get lower down band, you
might want to consider one of the Russian varicaps, as with both gangs in
parallel you would have 985 pf. The cost for 2 of them delivered to your door
is less than the cost for one-N-50. Here is the eBay listing.
_http://www.ebay.com/itm/Dual-Air-Variable-Capacitor-505pF-480pF-QTY-2-/3006
67726639?pt=LH_DefaultDomain_0&hash=item4601316b2f_
(http://www.ebay.com/itm/Dual-Air-Variable-Capacitor-505pF-480pF-QTY-2-/300667726639?pt=LH_DefaultDo
main_0&hash=item4601316b2f)

Also based on test by me, Steve R and Kevin S the Litz 330/46 wire looks
to perform as well as the more expensive 660/46. So for the same cost you
can wind a dual coil FSL using the 330/46 and have twice the gain on MW,
over that of a single coil with 660/46 wire and be able to cover all of the LW
band, using a Radio Shack DPDT switch and one of the lower cost Russian
varicaps and have one varicap left over for another project, or sell the extra
varicap to a friend.

73's Everett


In a message dated 2/21/2012 10:15:57 P.M. Central Standard Time,
d4g7johnson@... writes:




After doing some computations with the one of the inductance values
that Everett came up with (385uH tuning with 10-381pf, tunes 400KHz to
1715KHz), I see that my idea is not going to be much good for
just 1 MW-sized coil, because the more fixed capacitance is added
the less tuning range you get. For example to start at 400KHz and
tune down you could add about 371pf fixed capacitance, but then the
lower range is then only about 293KHz. Adding more fixed capacitance
to make that the highest frequency then lets you tune down only to
about 242KHz, etc. A much-larger variable capacitor would alleviate
this problem but then its physical size would cause other problems.


--- In _ultralightdx@... (mailto:ultralightdx@...)
, D1028Gary@ wrote:

Hello,

Thanks for your interest in the 5" FSL antenna.

<<< Since Litz wire cost is significant, has anybody experimented with
a dual-use sleeve antenna using only one coil, but with switchable
fixed capacitor(s)? The idea is to use the MW coil plus 1 or 2
fixed capacitors to tune LW without the expense of more Litz wire.
How much would that degrade performance relative to building a full
LW coil instead? >>>

To my knowledge, this method has been tried by Steve, Kevin and Everett
to create dual-band (AM & LW) FSL systems with ferrite bar models,
although not with the 140mm x 8mm ferrite rods used in the 5" FSL. As
for performance relative to a fully resonant 660/46 Litz wire Longwave
coil 5" FSL (which has already been built here), nobody has ever
compared the two systems, to my knowledge. A fully resonant LW coil
uses a lot of the expensive 660/46 Litz wire, so I'm sure that less
expensive alternatives will become popular for those interested in
economy Longwave FSL models (less expensive Litz wire, higher tuning
capacitance, etc.). For my own objectives in creating the AM-only
Mini-FSL models, following the "KISS" principle (simple, effective and
inexpensive) was most important.

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





-----Original Message-----
From: d4g7johnson <d4g7johnson@>
To: ultralightdx <_ultralightdx@...

(mailto:ultralightdx@...) >

Sent: Sun, Feb 19, 2012 10:14 pm
Subject: [ultralightdx] Re: 5" Mini-FSL Antenna- "Heathkit"
Construction Article







Since Litz wire cost is significant, has anybody experimented with
a dual-use sleeve antenna using only one coil, but with switchable
fixed capacitor(s)? The idea is to use the MW coil plus 1 or 2
fixed capacitors to tune LW without the expense of more Litz wire.
How much would that degrade performance relative to building a full
LW coil instead?

--- In _ultralightdx@...

(mailto:ultralightdx@...) , D1028Gary@ wrote:

Hello All,

> The 5" Mini-FSL was the first of several compact, AM-only antennas
that

were developed for those DXers who thought that FSL models were

either

too expensive, too complicated, or both. It was designed to be

simple,

effective, easy to build-- and cost only about $90 in part purchases

> (photo attached). After having been tested against various air core

loops in an outdoor environment, the tiny model really exceeded
expectations-- deadlocking in weak-signal performance with a

full-sized

4-foot air core box loop (the antenna of the August 2010 Oregon coast
DXpedition).

> In an effort to make assembly of the tiny FSL antenna as simple as

possible, a special, 10-page construction manual has been prepared,
patterned after the famous Heathkit assembly manuals of the last
century. In a step going beyond the Heathkit manuals, multiple
Photoshop-enhanced assembly pictures are included in the article,
showing each assembly step in a clear way. Assembly of the model has
also been made as simple as possible-- all of the parts are readily
available on the open market, and most of them have been stockpiled
here. Pre-cut kits of the PVC frame parts have been prepared, which

are

available at cost (along with the other parts, as long as supplies
last). The tiny FSL was designed to be a DXing thriller, and for

those

still "on the fence" about giving new antenna design a try, the

perfect
> introduction to a exciting new DXing experience

_http://www.mediafire.com/?9ze98h293s85p86_

(http://www.mediafire.com/?9ze98h293s85p86)

>

Thanks very much to Rob Ross of London, Ontario for his generous gift
of 140mm x 8mm ferrite rods to develop this (and other) mini-FSL
models, and to Dave Kellmer of Portland, OR, for providing a generous
supply of the Funnoodle (soft) inner core material. Hopefully this
compact new antenna will provide a major boost in each builder's

hobby

excitement!

>

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)