There¡¯s probably some lore that perpetuates the ¡°RF is black magic¡± thing, and all sorts of myths get accepted into such lore. That¡¯s the thing about disjoint knowledge: people may say ¡°PVC is high loss¡± but they don¡¯t know what are the practical implications of it, they only may have heard it said in relation to an antenna or another ¡°incomprehensible¡± object, and the link from that bit of ¡°fact¡± to everyday life just isn¡¯t there.
There is a very nice Starlink customer terminal tear down video on YouTube (that device is a brilliant bit of engineering BTW) and a good vuunk of the comment section just goes to show that magical thinking is here to stay.
Cheers, Kuba
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5 dec. 2020 kl. 9:16 fm skrev Chuck Harris <cfharris@...>:
?Ordinary PVC is very, very low loss through low microwave frequencies, as is
easily demonstrated by putting a piece in your microwave oven.
Do you have a reference I can look at that shows your assertion?
-Chuck Harris
Andy ZL3AG via groups.io wrote:
Depending on the frequency, PVC's loss tangent will ruin your loop Q, so try to use
HDPE or LDPE instead.
Possible source of litz wire can be transformers used in high efficiency SMPS's, but
the ideal litz wire (wire thickness and qty of wires) changes, even across the MW band.
If you want to build a kick-arse receive loop for MW, I highly recommend the late
Graham Maynard's "Sprial loop with Q multiplier" as found in Practical Wireless - the
best loop I've ever used (feeding into a Racal RA17L).
