[HBR] Dissipation factor of materials

[Brian Burns]

Hi Brian,

Most of the tubular items, extension pieces, tail pieces, p traps, etc are
made from polystyrene.  They are all no pressure items and are not used for
pressure.  PVC drainage on the other hand is made of PVC and is not as
suitable for coil forms.  

JamesF


Hello James,

Well dog my cats! Not only did I not know that, I never would have suspected
it! I've always thought of polystyrene as being good for packing-peanuts,
carry-out food containers, and coffee cups---of course there was the
occasional piece of lab equipment.... (;->).

On mature consideration, I think increased Q of the RF and mixer coils is
not going to make much difference in adjacent channel selectivity. It seems
that it would take something a good deal more radical than changing to a
lower loss coil form, to make any significant improvement in that. 

My obsession with selectivity comes from using a couple of receivers that
were as broad as a barn door, back in the day. At age 74 I'm looking for
"arm-chair copy", even with a strong signal right along side. In reading the
first part of Jay Helm's e-book he says that Ted never did come up with a
solution to the problem of a strong signal in an adjacent channel. 

Cheers,

Brian







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