[Moon] DL0SHF 24GHz beacon results

Charles g3wdg at moon-net.eu
Sat Oct 10 19:33:51 CEST 2020


Hi John

Re flexi guide at 24G, better than nothing might be a single length of 
141 semirigid.  Yes its lossy but might get you started.

Or, a length of solid WG20 with short semirigids to accomodate difficult 
angles.  Again, better than nothing and even with 10W at the feed you 
should be able to make some QSOs.

For power measurement, I used a homebuilt WG20 three hole cross 
coupler.  Needs calibrating of course.   Think there are some designs in 
the Microwave Manual. Load are easily made out of tapered lossy rubber 
glued to broadwall, at least for low power. They don't like too much 
power....

73

Charlie

On 10/10/2020 17:39, g4bao wrote:
> That's great stuff Charlie,
> Inspired me to do more on my 24GHz EME system build.
> I now have all the parts and yesterday was metal bashing to put the 
> 1127 TWT on to a heatsink and into the feed tray. I've worked out a 
> way to get it all on my standard "tray" slung under the offset dish 
> arm with the TWT PSU behind the dish. I'm a little scared of the EHT 
> but I think I can at least "showerproof" it and remove it pretty 
> quickly to change bands to 10GHz.
> On target for a QSO next Spring at the latest.
> That's assuming the TWT is OK but I'm assured by ian 'KQW that "it 
> worked when he last used it." :-)
> The only thing I need to find now is a length of flexible waveguide to 
> get to the feed, so I'm searching EBay. I can get away with coax on 
> receive as I have an LNA and relay right at the feed.
> Hopefully I can find some "new old stock" WR24. I found some WG16 for 
> my 10GHz system, but at 24GHz, flexi is notorious for ageing 
> especially at 24GHz.
> Power measurement at the 25W level might be challenging, but I'm going 
> to look at the return loss of my 18GHz HP 30W (precision N type) 
> attenuator and see if I can bodge that somehow.
> Wonder what others out there use as a load/attenuator?
>
> 73 from the Fen Edge
>
> John
>
> John
>
> On Sat, 10 Oct 2020 at 04:25, Charles via Moon <moon at moonbounce.info 
> <mailto:moon at moonbounce.info>> wrote:
>
>     Hi All
>
>     We have been carrying out some receiving tests in the last days
>     with the
>     new DL0SHF 24GHz beacon.
>
>     I've posted some results here:
>
>     https://drive.google.com/file/d/1u8wFi0RQ3pHAREWIS9N8B7FGo67xfitz/view?usp=sharing
>
>     The beacon is available on request to DK7LJ at
>
>     per at per-dudek.de <mailto:per at per-dudek.de>
>     <mailto:per at per-dudek.de <mailto:per at per-dudek.de>>
>
>
>     Please send wave files of the QRA64D sequences to me (recorded with
>     WSJT-X) , as we are trying to estimate the level of the beacon with
>     different systems.
>
>     With a 1.2m  receiving dish, we have been seeing a signal margin of
>     10-14dB depending on conditions.
>
>     73
>
>     Charlie G3WDG
>
>
>
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