Channel Master 1.2m Dish

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
radiogareth
Posts: 294
Joined: Wed Jan 06, 2016 9:46 am

Re: comments on this dish from ebay

Post by radiogareth » Mon Apr 15, 2019 2:39 pm

Overkill but very nice, try rod-end joints like this... https://www.ebay.co.uk/itm/M6-x-1mm-Fem ... ctupt=true

RimaNTSS
Posts: 19
Joined: Fri Apr 12, 2019 9:29 am

Re: comments on this dish from ebay

Post by RimaNTSS » Mon Apr 15, 2019 3:01 pm

g8vpg wrote:
Mon Apr 15, 2019 1:32 pm
You can buy 1m lengths of threaded steel bar in 6, 8, 10 & 12mm sizes very cheaply
73 Shaun.
You are right, threaded rods are available and not so expensive, and not only in 1m sizes but also 2m are available. Unfortunately threaded rods are bending easily at 1m lengths even if they are 8mm.
For CM 1.2m antenna, to be able properly install dualfeed LNB sidearms >than 1m are needed (something like 1.2m).

G4WIM
Posts: 227
Joined: Thu Jan 29, 2015 8:36 pm

Re: comments on this dish from ebay

Post by G4WIM » Mon Apr 15, 2019 4:20 pm

Hi RimaNTSS,

My C band mount for my 1.2M CM dish arrived today - thanks for the prompt shipping !

As for replacement arms I suspect tubing would be preferable if only for weight reasons, plus tubing might be more rigid ?

Just got to make the dual feed plus a collar so it fits the 42mm clamp.

73 Tim

RimaNTSS
Posts: 19
Joined: Fri Apr 12, 2019 9:29 am

Re: comments on this dish from ebay

Post by RimaNTSS » Mon Apr 15, 2019 4:29 pm

@G4WIM Yes, tubed feedarms are lighter and more rigid as well. Comparing to original feedarms and holder, feedarms made of 10mm tube plus all fittings weight is almost 200 grams less. ImageImage
G4WIM wrote:
Mon Apr 15, 2019 4:20 pm
Just got to make the dual feed plus a collar so it fits the 42mm clamp.
Could you please post couple of pictures?

G4FRE
Posts: 86
Joined: Fri May 26, 2017 6:57 am

Re: comments on this dish from ebay

Post by G4FRE » Tue Apr 16, 2019 11:17 am

I used the tube approach on my winegard dish for eme , which proved strong enough to support a twt at the feedpoint!
Dave
G4FRE
Attachments
winegard_support.jpg
winegard_support.jpg (223.26 KiB) Viewed 578 times

RimaNTSS
Posts: 19
Joined: Fri Apr 12, 2019 9:29 am

Re: Channel Master 1.25m Dish

Post by RimaNTSS » Tue Apr 16, 2019 11:55 am

@G4FRE any solution is good when it gives acceptable final performance.
Guys, where I can find simple drawing of the dual-LNB you all use? I wish to find out the length of the feedarms for CM 1.2m to be able install LNB properly.

P.S. Thanks mods for separating this thread. Would be nice if you change 1.25m to 1.2m (the dish is exactly 120cm wide) :)

G4WIM
Posts: 227
Joined: Thu Jan 29, 2015 8:36 pm

Re: Channel Master 1.2m Dish

Post by G4WIM » Tue Apr 16, 2019 8:24 pm

I change the title of my original post to 1.2M

RimaNTSS
Posts: 19
Joined: Fri Apr 12, 2019 9:29 am

Re: Channel Master 1.2m Dish

Post by RimaNTSS » Tue Apr 16, 2019 9:13 pm

Speaking about sizes and dimensions of Channel Master antennas... I have made this collage where you can find some data about CM antennas in different sizes (I did not include .35m and .75m antennas though). Position of the focal point is very important parameter. All antennas have 22.6* offset angle. Image
Man, I like CM :D

RimaNTSS
Posts: 19
Joined: Fri Apr 12, 2019 9:29 am

Re: Channel Master 1.2m Dish

Post by RimaNTSS » Wed Apr 17, 2019 6:35 pm

Am I right that something like this should be inserted in front of antenna? Yes, I know it should be made out of copper, but this is just a dummy which I will use for tests (not real reception or transmitting). Image

G4WIM
Posts: 227
Joined: Thu Jan 29, 2015 8:36 pm

Re: Channel Master 1.2m Dish

Post by G4WIM » Wed Apr 17, 2019 8:47 pm

something like that, but not quite.

The LNB has a small horn or dielectric lens on the end of the 22mm pipe / wave guide and the pipe only protudes about 5mm in front of the 105mm disk.

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