RadioBanter - View Single Post - WR-90 X-Band aperature attenuator question??

January 29th 05, 09:02 PM

On 28 Jan 2005 19:01:02 GMT, unicate (Fred McKenzie)
wrote:

I needed to produce some referance power levels that were 'down' from
my calibrated 0DbM generator. (It's output power is auto leveled, and
non-adjustable) 9445mhz, center of one of the maritine radar bands.

I've never worked in this band, but recall that some lower-frequency signal
generators use a "waveguide beyond cutoff" attenuator. If you can find some
waveguide sections designed for a sufficiently higher band, the attenuation
will be proportional to their length.

This doesn't address impedance mismatch, but neither does your method.

73, Fred, K4DII

but another case is that while normal attenuation may be 0.15dB/m for
a waveguide within the specified band, it may become 0.1dB/m below the
cutoff frequency, it seems that the lower limit is not for
attenuation, but for phase relationship, so it may be difficult to
predict phase along the cable and it is a question of narrowband
contra wideband applications

73, LA8AK
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm