Re: No Joy with Tecsun PL310 Antenna Mod
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Hello Gregory,
Thanks for your interest in the external loopstick modification for the
Tecsun models, and I hope that we can optimize the sensitivity of your PL-310 to
obtain great sensitivity on all MW and LW frequencies.
In the experimentation here, identical material (7.5" type 61 ferrite bar
wound with a single coil of 81 turns of 40/44 Litz wire starting 43 mm from one
end of the bar) was used, except for the adhesive tape holding the Litz wire in
place. With these experimental parameters, the loopstick transplant in the
PL-310 did provide a very sizable performance boost on all LW and MW frequencies
over the stock PL-310, although it did not provide the average 20 dBu MW boost
observed in the PL-380 (it was more like 15 dBu in the PL-310, presumably
because of the larger stock loopstick in the PL-310 which is naturally more
sensitive than the PL-380 stock loopstick).
By experience I know that the electrical insulating properties of the
adhesive tape used to wrap a loopstick coil are critical to proper
coil performance, and if the tape adhesive has a slight deviation from
being a perfect insulator, it can really upset the coil performance. During the
development of the E100 Slider models (explained at http://www.mediafire.com/?nqggfm2jymc )
we did a lot of testing to eliminate a hand capacitance issue at the higher
frequencies, and discovered that most of the masking tape commonly sold
was useless for coils. The Johnson & Johnson 2" wide Waterproof tape
(shown below in an E100 Slider coil construction photo) was found to be an ideal
insulator, and is the tape used here for all experiments. It was obtained from
http://www.medicalsupply.com two
years ago, although they do require quite a sizable purchase as a minimum order.
If you need some of this ideal tape to use in your
loopstick experiments and have trouble tracking it down, I would be
happy to send you a smaller amount sufficient to meet your needs.
73 and Good Luck,
Gary
In a message dated 12/28/2009 2:52:28 P.M. Pacific Standard Time,
gmosherat@... writes:
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