Radome for your dual band patch

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
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radiogareth
Posts: 262
Joined: Wed Jan 06, 2016 9:46 am

Radome for your dual band patch

Post by radiogareth » Wed May 15, 2019 7:43 pm

I've been inspired to see the various re-purposing going on to keep the WX out of the dual band feed. Inevitably I have been thinking about a simple design for a radome that traps a sheet of polythene (or cereal packet polypropylene) as the low loss 'window. I quite liked the idea of having the outer disc of the dual band feed 'snap in' but its proving tricky to get the dimensions right. It's also putting force into the weakest plane of the 3-D print. Vile colour as this is the only PETG (fizzy drinks bottle plastic) I have ATM. PLA isn't long term WX proof but PETG is both UV and WX stable.

The radome cover retention works well but I think I'll re-design the back side to just slot in and then secure with some suitable glue (UHU etc) or maybe a couple of lugs/tabs/screws.

Technical observations and comments welcome....

Gareth
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radiogareth
Posts: 262
Joined: Wed Jan 06, 2016 9:46 am

Re: Radome for your dual band patch

Post by radiogareth » Thu May 16, 2019 8:16 pm

Well I swapped over my 1.1x1.05 TRIAX dish for my 1.2x1.15. Same LNB but a lower MER on the beacon? This new dish is easier to adjust but heavier so I still have to raise it up to the original height (+2')before I can try 'direct comparison'. I may just be squinting over the roof of the house opposite but had 8.5 early this morning but 7.7 now on the bigger dish.
Worked on a /P dish support instead to make use of a mesh dish I was given last year. It has suffered bottom arm corrosion so I braced across the weakened part. Sundry bits from my 'handy-pile', angle-grinder and MIG and its good to go. Also mounts a 65cm dish for yet to be decided use.
Surveyors tripod has been waiting for this day since 1986! A really nice bit of kit, extends to 6' plus and levelable in all axis. Both dishes can rotate 360 degrees should the need arise.
Gareth
You can just see the edge of the 1.2 dish to the right of 'Maspro'. I can raise it above that but need local assistance (wife Jayne :-))
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G7JTT
Posts: 91
Joined: Fri Jun 10, 2016 5:05 pm

Re: Radome for your dual band patch

Post by G7JTT » Wed May 22, 2019 6:17 pm

Thanks for the idea this is my take on it using a clip a seal pot I had. All I done was cut the front of the lid out and then clamp a sheet of plastic between the lid the pot.

Cheers John G7JTT
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radiogareth
Posts: 262
Joined: Wed Jan 06, 2016 9:46 am

Re: Radome for your dual band patch

Post by radiogareth » Wed May 22, 2019 7:42 pm

Happy to share :-)
What brand of plastic box? Did the MER improve with just the thin polythene?
Gareth

G7JTT
Posts: 91
Joined: Fri Jun 10, 2016 5:05 pm

Re: Radome for your dual band patch

Post by G7JTT » Wed May 22, 2019 7:58 pm

Just a generic one from "The Range" about £3, with the original lid I lost 2db on 3cm but was ok on 13cm. Once the lid was cut out I tried the LNB and was back to the normal around 8db, with the plastic stretch out and clamped in place I saw no difference in the received MER level. It looks a lot better than it did with the hi-tech bag waterproofing technique LOL.
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