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[IRCA] Craig Barnes' 3.5 inch Baby FSL Rocks at Rockwork



Hi Rick,

<<< Has anyone done any experiments with an inductive secondary coupling loop on an FSL or a high-impedance unity gain preamp with an unbalanced low impedance output across the loop winding? I.e. what would be needed to couple to a receiver or an SDR? >>>

Local buddy Guy Atkins (also living here in Puyallup) has performed multiple experiments attempting to match the compact gain performance of the FSL antenna with the Perseus-SDR receiver, and back in 2013 Guy tried almost every conceivable interface (low-noise Wellbrook preamps, sensing coils, direct connections, etc.) in order to somehow match the single-optimized-frequency performance of the FSL with the state-of-the-art Perseus-SDR receiver. Because of intense interest among local broadband DXers over $1K was used in these experiments, which unfortunately ran into the stark reality that a high-Q, single-optimized-frequency antenna with razor-sharp tuning peaks is not very compatible with a spectrum capture receiver requiring a broadband antenna to record all MW frequencies simultaneously. That's not to say that the FSL antenna couldn't be used on single frequencies to provide exceptional gain for the Perseus-SDR (or other 50 ohm antenna input receivers) once an impedance-matching system is devised, and I'm pretty sure that Guy experimented with those type of matching systems, and how to get good performance on narrow frequency ranges with a Perseus + FSL combination. But the essential fact remains that almost all Perseus-SDR DXers are oriented toward spectrum capture of the entire MW frequency range, and will not be satisfied with exceptional antenna performance on one single frequency.

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

> On August 22, 2018 at 8:01 AM 'Rick Kunath' via NRC-AM <nrc-am@xxxxxxxxxxxxxxxx mailto:nrc-am@xxxxxxxxxxxxxxxx > wrote:
>
>
> Gary,
>
> Has anyone done any experiments with an inductive secondary coupling loop on an FSL or a high-impedance unity gain preamp with an unbalanced low impedance output across the loop winding? I.e. what would be needed to couple to a receiver or an SDR?
>
> My thinking is about whether this might replace a 4-foot box loop thatâs got an FET preamp across the main loop winding with an unbalanced output to 50 ohms. It would sure be a lot easier to tilt and rotate and a lot easier to use remote away from RFI. Iâm thinking especially about my proximity to salt water and South American and Latin American targets.
>
> Thanks in advance,
>
> Rick Kunath
> Tampa Bay Area Florida
>
> Sent from my iPhone
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