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Channel Master 1.2m Dish

Posted: Sat Apr 06, 2019 7:09 pm
by G4WIM
Stumbled across a 1.2M dish made by Andrew / Raven in the USA on Facebook Market place. Part number 3040646 mold 1.2M-1

Measures 1.2 x 1.3M and seems well made - cleaned up nicely and only cost £30 including the motorised polar mount and quad LNB which I don't need.

Hoping for an extra 2-3dB over my 70cm x 80cm dish, currently get the WB beacon with an MER of 5.5 to 6dB when its not raining - so hopefully this new dish will give me some rain margin.

Regards Tim

Re: comments on this dish from ebay

Posted: Sun Apr 07, 2019 12:44 pm
by g8gtz
Well done Tim,

That is actually the same dish as the channel master 1.2mt - original design by Andrews, sold to Raven and then to Channel Master.

Good price - they normally go for around £50 - £80.

73
Noel

Re: comments on this dish from ebay

Posted: Sun Apr 07, 2019 7:46 pm
by G1LPS Terry
Tim I get a MER9 occasional 10 on my Channel Master with Mikes duel feed and Bob Platts dielectric design (cq-tv187) combo.
Also running with a modified LNB mount to get the feed more in the focus as it fowls the arms with the standard plastic LNB holder and is too far forward.
For me this had the edge over a red rocket dielectric. Others have reported different results with machined dielectric so may be down to material used.
About time I cleaned my dish up been installed for 19 years and was parked at 26deg already as we like the Dubai One channel at that location for the movies. ;)

Re: comments on this dish from ebay

Posted: Mon Apr 08, 2019 5:44 pm
by 2W0ODS
G1LPS Terry wrote:
Sun Apr 07, 2019 7:46 pm
Tim I get a MER9 occasional 10 on my Channel Master with Mikes duel feed and Bob Platts dielectric design (cq-tv187) combo.
Also running with a modified LNB mount to get the feed more in the focus as it fowls the arms with the standard plastic LNB holder and is too far forward.
For me this had the edge over a red rocket dielectric. Others have reported different results with machined dielectric so may be down to material used.
About time I cleaned my dish up been installed for 19 years and was parked at 26deg already as we like the Dubai One channel at that location for the movies. ;)
I also have a CM 1.2m here, you cannot really get a better dish in this size, mine is on a polar mount and actuator.
I'd love the 1.8m version, if one comes up at a reasonable price I will grab it.
That LNB holder looks like one of Rimants designs?

If anyone is thinking of going below 1.2m the ally Gibertini dishes are the best I've ever used, I've got a 1m on the side of my property exposed to all kinds of weather with a STAB HH-100 rotator and that's not moved a mm in any weather.

Re: comments on this dish from ebay

Posted: Mon Apr 08, 2019 9:00 pm
by G4WIM
Looks like I got a good deal - hope to have it in place for rx testing within a day or two.

I found this link which goes into some detail about how to align the LNB - makes for interesting reading. My LNB seems to be pointing at the centre of the dish.

https://www.satelliteguys.us/xen/thread ... ue.346696/

Next step is a dual band feed ready for tx. Going to be using a PyroJo 30 watt PA right behind the dish with a zrl2400 https://ww2.minicircuits.com/pdfs/ZRL-2400LN+.pdf as a pre-driver to overcome the loss of 180 feet of coax between shack and dish ! Exciter will be either a Lime or Pluto or DATV express. Steve G0AIN is machining a 2.4GHz interdigital filter to keep unwanted stuff out of the feed.

Terry, your dual feed looks good - could you provide links as to where I could obtain one or detailed drawings to make one ?

There seems to be quite a few variants detailed on the web but not sure how well they'd illuminate this particular dish.

Lots to do and not enough time !

Re: comments on this dish from ebay

Posted: Tue Apr 09, 2019 7:55 am
by g8gtz
Hi Tim,

That's the MJW dual band patch feed described in CQ-TV 263 which "everyone", well 90% of people, are using.

Lot's of people have built them and they perform incredibly well with no need for any filtering to run duplex - apparantly someone in Germany has made over 300 parts and sold out!

But very interested in Terry's LNB mount - have to try that on mine to see if it makes any improvement.

[edit]
Terry, can you confirm yours is a 1.2mt CM dish - if so 9 - 10 dB MER is very good. If that is the case do you think it is down to the revised LNB mount? I did find them on a finished ebay listing but quite expensive ao want to make sure it's worth it before making further enquiries.
https://www.ebay.co.uk/itm/LNB-holder-f ... 7675.l2557
[edit ]

73
Noel - G8GTZ

Re: comments on this dish from ebay

Posted: Tue Apr 09, 2019 11:44 am
by G4GUO
This is what it costs from a UK supplier
https://www.satellitesuperstore.com/rav ... andbracket

- Charles

Re: comments on this dish from ebay

Posted: Tue Apr 09, 2019 3:24 pm
by G4WIM
HI guys,

got the dish installed - nobody told me how sharp a 1.2M dish is at 10GHz. Luckily I could turn the polar mount lead screw manually to get it more or less spot. Beacon at MER 9.5dB and D6 - about 3.5dB better than my 70x80cm dish.

I wish I'd put a T bar through the mounting post when I set it in concrete - 3 feet in the ground and 3 feet out surrounds by a lot of concrete, hopefully it won't act like a wind vane ! The pole is 50mm thick walled aluminium and seems quite sold.

Charles - thanks for the link to the mount, I'll order one in readiness for when I've made a dual band feed. Edit, just seen the price !!!! Me thinks I might try and fabricate one myself .....

Here are a few pictures of the dish - not much between me and the bird !

73 Tim

Re: comments on this dish from ebay

Posted: Wed Apr 10, 2019 9:02 pm
by 2W0ODS
For the LNB Mount I cannot recommend this seller enough, he's on all the satellite forums and has an incredible satellite farm including a 4.8m Andrews dish!
Really nice guy to deal with, I've bought lots of bits from him personally outside of eBay.
https://www.ebay.co.uk/itm/LNB-holder-f ... ctupt=true

Re: comments on this dish from ebay

Posted: Thu Apr 11, 2019 4:53 pm
by G4WIM
Thanks for the link to the mount - not cheap but better than £99 elsewhere !

Just ordered one - cost 50% more than the dish but saves me the trouble of making one.

73 Tim