[HBR] Dissipation factor of materials

[Brian Burns]

Hello All,

 

Here are some numbers I found for dissipation factor:

 

Polystyrene-------------------------------------------.0002 to .00007

 

PVC------------------------------------------------------.016

 

Steatite--------------------------------------------------.0035 to .0008

 

It would appear from these that polystyrene is quite a bit better than even
steatite ceramic, probably what was used in old-timey coil forms. No wonder
it was so well liked for UHF stuff at Hansen Labs, where I used to work back
in the day. Not only does it melt easily, it crazes over time. The base that
I have in mind is available from National, and shouldn't have the melting
problem, as it's ceramic.

 

Next question: Does using the lowest loss coil form "make enough difference
to make a difference"? Walt's experience, as well as other builders', using
PVC seems to say "no it doesn't".

 

Cheers,

 

Brian 

 

 

 

 

 



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