Channel Master 1.2m Dish

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
satdxer
Posts: 20
Joined: Sat Jan 26, 2019 6:10 pm

Re: Channel Master 1.2m Dish

Post by satdxer » Fri Apr 26, 2019 9:03 am

RimaNTSS wrote:
Thu Apr 25, 2019 7:29 pm
satdxer wrote:
Wed Apr 24, 2019 4:55 pm
Hi to be honest there is no reason to make longer arms and no reason to over complicate a very simple modification, its as simple as this.
Yes, it is quite simple and well camouflaged (little bit rusted holder though :twisted: )but I do not think this solution can provide best performance of the system. Seems that LNB is located too close to the surface of the dish, so LNB's phase center could not be co-located with antenna's focal point. Reception is, of course, possible, but, again it will never be best as it could be.
P.S. looked in your link but did not find your name and any pictures of your dish. But, I am pretty sure, if you were placing LNB in proper position you would certainly have even more astonishing reception results whatever good/bad they are right now. :D
Hi Rimantts the modification was done over six years ago when you based your over complicated design around my modification it was a prototype that i never got round to doing anything else with as it worked so well yes a little bit of rust but the rust doesn't effect the signal quality,

This solution does provide the best performance anyone who knows anything about phase center knows it can not be judged from a photo ive been around a long time and know how to set a dish up, wasn't you the person to install a large channel master without a leveling system and now its stuck on 28E ?, anyhow if you only have criticism to post please refrain from posting and move along to the satellite forums where your criticism is tolerated.

satdxer
Posts: 20
Joined: Sat Jan 26, 2019 6:10 pm

Re: comments on this dish from ebay

Post by satdxer » Fri Apr 26, 2019 10:52 pm

2W0ODS wrote:
Mon Apr 08, 2019 5:44 pm
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.
Your friends dish posted elsewhere is a Andrew 123 Vsat dish off set is 16.97 degree

g8gtz
Posts: 1162
Joined: Wed Apr 07, 2010 6:26 pm

Re: Channel Master 1.2m Dish

Post by g8gtz » Tue Apr 30, 2019 7:24 pm

Along with Graham and Tim, I purchased a set of longer arms and LNB holder from Rimants.

These arrived today, with super fast delivery, and were superbly made in stainless steel. I naturally abandoned everything else and spent most of the day on it but I finally managed to find the magic 1 dB extra! Plus I now have room for an N type Tx connector which I need after I burnt out the SMA patch lead!

I went back to basics and based on the dimensions diagram on the forum used the string method to find the focus point – I then set the bottom strut to the right length to put the LNB further away than it and then set the 2 sides arms to that length - I could then slide the LNB forward in it's mount to the correct position. I also marked the focus point on the dish with black marker and viewed through the 22mm pipe to ensure the LNB would be pointing at it.
Overall, very impressed with the quality of the parts and speedy service from Rimants.

73
Noel
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G4WIM
Posts: 258
Joined: Thu Jan 29, 2015 8:36 pm

Re: Channel Master 1.2m Dish

Post by G4WIM » Tue Apr 30, 2019 7:37 pm

Hi Noel,

looks good - hopefully I'll get similar results to yours.

Even with my non optimum feed point I managed 500K S thru es'hail today (with just 25 watts) and choppy audio went away.

Out of interest what lengths did you set the rods to ?

Regards Tim
Last edited by G4WIM on Tue Apr 30, 2019 7:51 pm, edited 1 time in total.

RimaNTSS
Posts: 21
Joined: Fri Apr 12, 2019 9:29 am

Re: Channel Master 1.2m Dish

Post by RimaNTSS » Tue Apr 30, 2019 7:42 pm

Thanks Noel for this feedback!
Let me suggest one small test to make sure your LNB is properly located....
We all know that CM antenna has 22.6* offset angle. You also can find out exact elevation of the satellite your antenna pointed at. For example, if the elevation of the satellite 22.6* than the "face" of the dish should be exactly vertical. If dish is leaning forward or backwards than there is need to adust height of the LNB up or down, your LNB-holder has this possibility. To do this test you have to use digital inclinometer.
G4WIM wrote:
Tue Apr 30, 2019 7:37 pm
Could you provide some links on how to find the focus point etc ?
Tim, look couple of posts back where I've presented collage with all needed information.

G4WIM
Posts: 258
Joined: Thu Jan 29, 2015 8:36 pm

Re: Channel Master 1.2m Dish

Post by G4WIM » Tue Apr 30, 2019 7:52 pm

Thanks Rima

just edited my post as I answered the question myself !

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