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Which rocket lens ?

Posted: Thu Apr 18, 2019 4:56 pm
by G4WIM
Hi Guys,

just getting ready to build my dual feed and plan on trying both a copper pipe reducer horn and a rocket lens on the end of the 22mm pipe.

Looking on Amazon there's a few reasonable priced rocket LNBs and the dielectric lens looks to be about 35mm diameter - I was wondering if there's an optimum Rocket model I should be looking for or would any one of the 35mm lens be ok ?

As ever, any guidance gratefully received.

Re: Which rocket lens ?

Posted: Thu Apr 18, 2019 5:24 pm
by g4eml
The Red Eagle Blackbuster is probably the most used one and works very well. Unfortunately like many other LNBs they are in short supply at the moment so you may struggle to find one.

Re: Which rocket lens ?

Posted: Thu Apr 18, 2019 5:49 pm
by g4eml
Another option is the Venton EXL-S. These at least seem to be available from Germany but with high postage charges.

Re: Which rocket lens ?

Posted: Fri Apr 19, 2019 8:20 am
by G1LWX
Tim I can confirm that the Rocket Black Buster Lnb lens fits
22mm copper pipe perfectly.

Re: Which rocket lens ?

Posted: Fri Apr 19, 2019 10:00 pm
by 2W0ODS
Has anyone designed lenses in CAD that can be 3D printed? a few of us on here have 3D printers and can't see why it wouldn't work.
I've been printing with CPE HG100 lately which is a modified version of PETG so should stand up to the outdoors better than PLA etc.

Re: Which rocket lens ?

Posted: Sat Apr 20, 2019 1:34 am
by G7JTT
There is one at the bottom of this page

http://www.hybridpretender.nl/

John G7JTT

Re: Which rocket lens ?

Posted: Sat Apr 20, 2019 7:01 am
by g4hiz
You may like to try the AB LNB 01 as shown below, currently available on Ebay for £4.95 + postage. I have tried the feed lens on my dual-band G0MJW feed and it works.

73
Jen

Re: Which rocket lens ?

Posted: Sat Apr 20, 2019 7:21 am
by G7JTT
That looks to be a PLL LNB ?

Re: Which rocket lens ?

Posted: Sat Apr 20, 2019 8:15 am
by g4hiz
It is a PLL type. The crystal is 25MHz.

Re: Which rocket lens ?

Posted: Sat Apr 20, 2019 9:54 am
by g4eml
3D printing could produce something that looks like a dielectric lens but almost certainly wouldn’t work like one.
The dielectric constant of the material used will be very critical so different plastics or even different batches of the same plastic could vary. Even if you managed to measure and reproduce the exact formulation used in the commercial lenses the layered structure of a 3D printed lens would most likely affect the results.
The commercial lenses are actually made in two interlocking parts. I wouldn’t be surprised if the dielectric constant of the two plastics is different and the transition between them is also part of the design.