Re: fanatical mega-loopstick question
Garry and Guy,
All of the mega-loopsticks (7", 14" and 21") have been constructed using an LCR meter to measure inductance only, to ensure that the recycled coils (mostly salvaged from the vintage long ferrite bars) match the SRF-39 stock coils in inductance. The alignment procedure, in which the small coil is slid along the ferrite bar to peak a low-band (usually 600 kHz) signal, optimizes the match between the recycled coils and the SRF-39 circuitry, making it unnecessary to measure capacitance and resistance during the construction process. As long as the inductances match, and the 600 kHz peak is sharp, the newly recylced coils are perfect for DX reception in the SRF-59.
As for comparison of the ferrite mega-loopsticks and spider coils, I'm sorry that I have never experimented with spider coils, or air-core loops. The ferrite mega-loopsticks seem to be great for DX, relatively cheap, and still quite portable. The only drawback is that you inevitably make longer and longer ones, as you fanatically strive for the highest sensitivity level. Eventually you need to face the reality that doorways are only 30" wide.
Guy, if you wish to make some spider coils and compare them to the mega-loopsticks, you can borrow them at any time (Guy and I live in the same city). As of today, all of them will still fit through a doorway :>)
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