Channel Master arms length

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Chr0nik

Chr0nik

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My Satellite Setup
GTMEDIA V8X - 110cm Triax on a Dark motor (34.5w to 70.5e)
My Location
Grays, Essex
Hi,

Unfortunately, the arms of my CM dish disappeared during a house move a few months ago and I would like to re-build them using aluminium tubing from B&Q. What are the lengths of the 3 arms on a 1.2m Channelmaster dish?

Thanks
 
Chr0nik said:
Hi,

Unfortunately, the arms of my CM dish disappeared during a house move a few months ago and I would like to re-build them using aluminium tubing from B&Q. What are the lengths of the 3 arms on a 1.2m Channelmaster dish?

Thanks
Click to expand...

Do let us know how you propose to make them ! Very interested in how you go about it.

I am considering doing the same for my Prodelin
 
For feedarms I would advise using 10-12x1mm INOX pipe with welded M6 nuts at the ends. And also to use M6 rods at one end to get feedarms length-adjustable.
 
Mr. Rimants has already made quite a number of them. He also made them for me at my request for the Chanel master 120 and I can say that for me personally they are better than the original ones. Precisely because of the way they are made and the possibility of adjustable feeding arms with the possibility of manipulation and setting the antenna to perfection.
 
RimaNTSS said:
For feedarms I would advise using 10-12x1mm INOX pipe with welded M6 nuts at the ends. And also to use M6 rods at one end to get feedarms length-adjustable.
Click to expand...

Would they fit a Prodelin 1.2m? The arms look very very similar
 
RimaNTSS and anyone who can assist. I have a 5 meter comtech prime focus dish. I found it without lnb arms and I know its focal length. My question is, is there the possibility of the lnb arms being of different lengths or because its a prime focus dish the arms will automatically be of same length?
 
ymttt said:
My question is, is there the possibility of the lnb arms being of different lengths or because its a prime focus dish the arms will automatically be of same length?
Click to expand...
The length of feedarms on prime-focus antenna must be all the same. How many feedarms you have, 3 or 4?
 
RimaNTSS said:
The length of feedarms on prime-focus antenna must be all the same. How many feedarms you have, 3 or 4?
Click to expand...
I have 3. Then my issue with signal is about dish alignment, which I must correct. Thanks.
 
ymttt said:
I have 3. Then my issue with signal is about dish alignment, which I must correct. Thanks.
Click to expand...
If you don't have the arms fitted, how do you know it is about alignment ?

For larger PF reflectors a boresight tool might be worth looking into, though you must first ensure the panels have not distorted, either under their own weight, bad installation practice or bad weather.
 
Channel Hopper said:
If you don't have the arms fitted, how do you know it is about alignment ?

For larger PF reflectors a boresight tool might be worth looking into, though you must first ensure the panels have not distorted, either under their own weight, bad installation practice or bad weather.
Click to expand...
Channel Hopper said:
If you don't have the arms fitted, how do you know it is about alignment ?

For larger PF reflectors a boresight tool might be worth looking into, though you must first ensure the panels have not distorted, either under their own weight, bad installation practice or bad weather.
Click to expand...
I have installed the dish with a 3 armed lnb holder, but the signal is not very good. This morning I tried to check how straight my mounting pole was and I found it not straight. Check the attached picture if it is enough to weaken the signal.
 

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The pole will make no difference to the signal.
 
Channel Hopper said:
The pole will make no difference to the signal.
Click to expand...

@Channel Hopper : He seems to be using his dish as a motorized one.
In that case, finding dish angle settings to optimally following the Clarke Belt and optimally receiving channels, might definitely be a problem, with an east/west-wise non-plumb pole. (North/south non-plumb would be no trouble at all.)
See:
ymttt said:
Mine is a motorized prime focus dish. The dish elevations change with lnb adjustments. Is this bad, can it impact signals and how do I fix this?
Click to expand...



@ymttt :
The information about your setup and about your question is now in three separate topics, when I am correct, so rather fragmented.
Y

Post in thread 'My dishes collection'

Guys, I have been following your discussions on dish installation and i think you can be of immense help to me. Mine is a motorized prime focus dish. The dish elevations change with lnb adjustments. Is this bad, can it impact signals and how do I fix this?
Y

Post in thread 'Need prime focus LNB replacement (Costa Blanca)'

scopus said:
Looks like a Famaval dish to me. I have a 1.8m version
Click to expand...
Thanks. I asked because, I have a 5 meter comtech dish which I found without all 3 lnb arms. It hasn't given good signal and the information I have been trying to find is whether or not all 3 lnb arms measure same length? Anyone with the info may assist.
  • Like
and here in this thread: Channel Master arms length

Might I again ("rudely"?) suggest that you open your own thread for the questions about your setup? It will make it easier for us, to see "the whole picture", and to advise you better.


Greetz,
A33
 
a33 said:
@Channel Hopper : He seems to be using his dish as a motorized one.
In that case, finding dish angle settings to optimally following the Clarke Belt and optimally receiving channels, might definitely be a problem, with an east/west-wise non-plumb pole. (North/south non-plumb would be no trouble at all.)
See:




@ymttt :
The information about your setup and about your question is now in three separate topics, when I am correct, so rather fragmented.
Y

Post in thread 'My dishes collection'

Guys, I have been following your discussions on dish installation and i think you can be of immense help to me. Mine is a motorized prime focus dish. The dish elevations change with lnb adjustments. Is this bad, can it impact signals and how do I fix this?
Y

Post in thread 'Need prime focus LNB replacement (Costa Blanca)'

scopus said:
Looks like a Famaval dish to me. I have a 1.8m version
Click to expand...
Thanks. I asked because, I have a 5 meter comtech dish which I found without all 3 lnb arms. It hasn't given good signal and the information I have been trying to find is whether or not all 3 lnb arms measure same length? Anyone with the info may assist.
  • Like
and here in this thread: Channel Master arms length

Might I again ("rudely"?) suggest that you open your own thread for the questions about your setup? It will make it easier for us, to see "the whole picture", and to advise you better.


Greetz,
A33
Click to expand...
It's a question of priorities.
If you look at the first image of the spirit level you will see there is barely one degree of misalignment on the pole and currently there is no indication which side of the pole is out. It may be in the direction of true south in which case elevation adjustment will correct the error.
The type of polarmount clamping (three or four locknuts on the post) allows shimming within the gap to correct such a small error without resorting to dish disassembly.

Since the reflector is also assembled on the mount I would also be inclined (sic) to optimise the feed system and string/align the reflector panels for the best performanxce before attempting disassembly to fix a pole error, which may or may not cause loss of satellite signal at the extreme ends of the arc.

Rather than submit the same arc alignment detail for steerable satellites, here is a link to the astronomical version which will make the need, or not to adjust clearer.

1742119534516.webp

RASC Calgary Centre - Right Ascension and Declination

RASC Calgary Centre - Right Ascension and Declination
calgary.rasc.ca

Finally the location of Ghana means a declination of around 8 degrees, the curve of the mechanical arc required to maintain the Clark belt is therefore not far off a straight line. A minor change of North/South on the pole may be all that is required should the small shift in the pole not be in the direction of true south. But I refer you to the first paragraph of this post to shim the dish mount before complete disassembly.

(I did earlier mention derailing the original thread)
 
Guys, pardon me for appearing to derail the course of this thread. The thread started with a lnb arms issue which, at the time, I thought I had a similar concern, but it turned out mine wasn't such. However, the gentleman who begun the thread has his issues resolved thanks to some experts here.
 
I have resolved, I will find time to mount a new pole and reset the dish. I used it at a previous location with a makeshift neck which worked well. The permanent neck which was put together appears to be fraught with a number of challenges. I have to be more accurate with measurements this time. Most grateful guys. I appreciate your valuable contributions.
 
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