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Dish Feeds
Posted: Sun Dec 16, 2018 6:44 pm
by g0mjw
This afternoons project was a dual band feed based on DJ7GP design.
- Dual_Band_Feed.jpg (829.99 KiB) Viewed 7701 times
I am pleased with the match.
I won't know how well it actually works until I try it of course.
Re: Dish Feeds
Posted: Sun Dec 16, 2018 7:03 pm
by m0eyt
Here is my effort.
- 20181216_173725.jpg (80.77 KiB) Viewed 7695 times
Response is pretty much identical to Mikes.
regards,
Paul EYT.
BTW I have the CAD files for this so its literally a 10 minute job to cut out the reflector / driven element.
Re: Dish Feeds
Posted: Sun Dec 16, 2018 8:20 pm
by radiogareth
CAD files, yes please. Any interest in a few blanks, I could arrange some laser or waterjet cut discs.
Gareth
Re: Dish Feeds
Posted: Mon Dec 17, 2018 11:50 am
by dh2va
You are aware, that the plastic cap is not a rain protection but should be a dielectric concentrator?
Re: Dish Feeds
Posted: Mon Dec 17, 2018 12:43 pm
by g0mjw
dh2va wrote: ↑Mon Dec 17, 2018 11:50 am
You are aware, that the plastic cap is not a rain protection but should be a dielectric concentrator?
Yes - that's why it's there. I wish there was an easy way to get them without cannibalising a rocket LNB. Apparently some of these rocket LNBs have PLLs but not the ones I have received.
It seems to work - not too badly.
- Feed_In_Place.jpg (747.99 KiB) Viewed 7576 times
Re: Dish Feeds
Posted: Mon Dec 17, 2018 1:50 pm
by radiogareth
A simple job for 3-D printing assuming we could work out how either PLA, PETG or ABS would behave. Other plastics possible too, like nylon. Happy to CAD and print something to experiment with if it helps.
Gareth, G4XAT
Re: Dish Feeds
Posted: Mon Dec 17, 2018 6:45 pm
by dh2va
g0mjw wrote: ↑Mon Dec 17, 2018 12:43 pm
Yes - that's why it's there. I wish there was an easy way to get them without cannibalising a rocket LNB. Apparently some of these rocket LNBs have PLLs but not the ones I have received.
It seems to work - not too badly.Feed_In_Place.jpg
Just asking.. it looks completely different to the original design by DJ7GP. But he would know the details.
Re: Dish Feeds
Posted: Mon Dec 17, 2018 6:54 pm
by g0mjw
How does it look different? It is the same design. He had a different dielectric lens I think but that's all.
Mike
Re: Dish Feeds
Posted: Tue Dec 18, 2018 8:23 am
by radiogareth
A bit of goggling found this article:
https://ieeexplore.ieee.org/stamp/stamp ... er=7637125
I understand all the 3-D printer speak and have a printer equal/better than the Replicator 2x mentioned. If someone can work the maths and provide dimensions, I'll happily CAD it and make some.
LMK
Gareth, G4XAT
Re: Dish Feeds
Posted: Tue Dec 18, 2018 4:35 pm
by dh2va
Sorry to be unclear:with 'different' I mean 'not identical' . I would assume that shape and material are critical for the resulting beamwidth, just like in optics.
https://www.darc.de/der-club/distrikte/ ... 24-10-ghz/
But comparing its G/T to a standard LNB by checking the Astra 2C beacon (as example) should confirm its performance. It would be certainly one of the nicest designs I have seen and my personal favourite.