[Premium-Rx] Radios and High RF powers

[George Georgevits]

Guys,

The standard impulse shape used to simulate lightning surges in cable has 8
microsecond rise time (10% to 90% of peak value) and 40 microsecond fall
time to half value - hardly microwave stuff!

Regards,
George Georgevits
Power and Digital Instruments Pty Ltd


-----Original Message-----
From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org]On Behalf Of J. Forster
Sent: Tuesday, 3 June 2003 7:21 AM
To: larry at gadallah.com
Cc: premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] Radios and High RF powers


Larry Gadallah wrote:

> Hello all:
>
> I've heard of schemes to deal with this that use some sort of conductive
> conduit ....

> The term I've seen used is "waveguide beyond cutoff", which I think refers
to
> the fact
> that below (or above) a certain frequency (again, based on the geometry),
> a waveguide will not propagate signals.

Actually "waveguide below cutoff"....  If you try to propagate a wavelength
longer than a WG can support down the guide it becomes a strong, and very
predictable, attenuator.

AIL (Eaton) uses this trick in their super precision 60 MHz variable
attenuators. A few inches of 1" pipe will effectively not pass an radiation
frm
a microwave oven out of the interior space.

-John


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