Re: Wave guide dummy load.


KENT BRITAIN
 

Only, Only if there is enough Carbon to make the epoxy electrically conductive.
The particles have to be touching.       A little Carbon does nothing.    Kent

On Wednesday, March 3, 2021, 07:22:13 PM CST, Gordon REASON via groups.io <gordonj.reason@...> wrote:


would'nt some carbon powder , mixed into one part of an epoxy , such as araldite , have a good absorbtion >>>>>  just thinking !
> On 03 March 2021 at 19:18 "John E. Beech" <john@...> wrote:
>
>
> Tnx John,
>                I eventually found it on page 8.20 of the 1969 edition. No mention of it in the index under micro- or wave-
> though.
>
> de John G8SEQ
>
> >  -------Original Message-------
> >  From: John Fell <john.g0api@...>
> >  To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
> >  Subject: Re: [UKMicrowaves] microwave absorbent adhesive polymer?
> >  Sent: Mar 03 '21 10:57
> >
> >  RSGB VHF Manual - Microwave section .Wood in guide dummy load .
> >
> >  John
> >  G0API
> >
> >  On Wed, 3 Mar 2021 at 10:11, John E. Beech <john@...> wrote:
> >
> >  > Don't laugh, but has anyone tried a thin strip of balsa wood or
> >  > plywood for the absorber? ( Perhaps covered in
> >  > graphite pencil lead?) I once made an effective waveguide dummy
> >  > load for 10 GHz out of wood - a specially shaped
> >  > wedge. I don't know where the design came from but I got it from
> >  > G8MWR (SK).
> >  >
> >  > de John G8SEQ
> >  >
> >  >> -------Original Message-------
> >  >> From: Neil Smith G4DBN <neil@...>
> >  >> To: BVA-transverters-uk@groups.io
> >  > <BVA-transverters-uk@groups.io>, UKMicrowaves@groups.io
> >  > <UKMicrowaves@groups.io>
> >  >> Subject: [UKMicrowaves] microwave absorbent adhesive polymer?
> >  >> Sent: Mar 02 '21 23:27
> >  >>
> >  >> Are there any secret sources of microwave absorbant material
> >  > which will
> >  >> work from 2.5 to 10 GHz with good reflection loss and bulk loss,
> >  > around
> >  >> 1mm thick and self-adhesive?
> >  >>
> >  >> For the F6BVA 3cm to UHF transverters, we need a bit about 150 x
> >  > 50 mm.
> >  >>
> >  >> I see RF Microwave has some at around £330 for a 600 mm square
> >  > sheet of
> >  >> silicone 1mm carbonyl/iron, which makes 48 pieces at around
> >  > £8.50 per
> >  >> piece including VAT etc. The price from Mouser etc for similar
> >  > stuff
> >  >> works out about the same. Is that the right sort of price or is
> >  > there
> >  >> some low cost magic stuff of which I am unaware? The gap above
> >  > the PCB
> >  >> is only 7mm, and some of the components are a few mm tall, so
> >  > 1/16" or
> >  >> about 1.5 mm is the max I can fit in.
> >  >>
> >  >> Neil G4DBN
> >  >>
> >  >>
> >  >>
> >  >>
> >  >>
> >  >>
> >
> >
>
>
>
>
>





Join UKMicrowaves@groups.io to automatically receive all group messages.