Re: [IRCA] Greetings from Florence

[Guy Atkins <dx@xxxxxxxxxxxxx>]

>
> âHi Michael,
>

âWow, you've certainly moved a long distance away from your Vancouver BC
home where I visited you in the late 1980s or early 90s! âThe new place in
Firenze sounds very nice from every perspective except potential RFI  :^(

âSadly, I had no success in making the FSL design both broadband *and* as
sensitive/selective as it is when inductively coupled to a receiver for
"single frequency" usage.â I had excellent input and ideas from Gary and
especially Chuck Hutton, but we could not overcome major losses when trying
to make a broadband FSL. The best approach was to remove the capacitor and
connect the FSL's coil ends to a Wellbrook FLG100LN module's wire inputs,
and power the FLG100LN in its normal fashion. Using this component was on
the suggestion of Wellbrook's owner Andy Ikin, based on his knowledge of
the input impedance for the module. Using this setup I was initially
excited to hear (weakly) 738 kHz RFO Tahiti from my inland home of
Puyallup, WA, but later discovered that the "broadband" FSL's sensitivity
was FAR below useful levels.

With an appropriate coupling link to a FSL antenna, it should be possible
to get a low-loss connection between a FSL and the 50 ohms input of a SDR
or other communications receiver. Everett Sharp experimented with coupling
coils on a FSL and he reported that the best results were with a 64:1
impedance transformation ratio (step-down). This will still require the air
variable capacitor be tuned for single-frequency reception.

I personally think it's highly unlikely a FSL antenna can be made
broadband, as the tuned L-C circuit--peaked on one frequency for major
gains in selectivity and sensitivity--is the key to its high performance.

If you can get out to the Tuscan countryside and away from RFI sources, the
Bonito Boni Whip would be a very compact, useful antenna to try with SDRs.
One of my articles on *The SWLing Post* is about the Boni Whip:
https://swling.com/blog/2017/07/portable-powerhouses-comparing-the-bonito-boni-whip-and-wellbrook-ala1530lnp-antennas/

âGood DXing in your new location,

Guy Atkins
Puyallup, WAâ


---------- Forwarded message ----------
> From: Michael Yule <michaeldyule@xxxxxxxxx>
> To: "irca@xxxxxxxxxxxxxxxx" <irca@xxxxxxxxxxxxxxxx>
> Cc:
> Bcc:
> Date: Mon, 27 Nov 2017 16:07:41 +0000
> Subject: [IRCA] Greetings from Florence
>
> â<snip>â
>
> So the next steps are going to be to review all the literature on FSL
> construction, decide how big I want to go, and start assembling materials..
> I dont know if Guy Atkins ever published anything on making the FSL
> broadband, but if he did could someone send me a link? And if anyone has
> one for sale, please let me know as well!
>
> Thanks very much everyone, I'll let you know as things progress. I might
> be able to help a bit on TA identification once I get going since I will be
> closer to the source as well!
>
> Kind regards,
>
> Michael Yule
> Firenze, Italia
>
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