Channel master frankensteined

Doing a fabulous job ..... re: the 'inspirational' reference , who can spot the rain cover ? and who can give me the original use and make for the item. Tinkering at it's best here folks.
Amazing what you can make out of an old milk bottle..lol
 
I have a 2.4 m Channel Master antenna with dual reflector (Gregorian) design. I’d like to try C-band — does anyone know which feedhorn would be compatible with this system? Also, any recommendations for a best LNB? Thanks.
 
Start with any C-band LNB and conical scalar ring
 
Start with any C-band LNB and conical scalar ring
Currently, I have a Chinese LNB and a Titanium C1 LNB, but neither is compatible with the mounting bracket located on the sub-reflector of my antenna.


I would like to know if the Skyware model 6110041C42631 feedhorn assembly (or similar) would be compatible with the mounting system?
I do not want to modify (the mounting), because I want the best possible results. My dream is to receive 55°W, but my position is not ideal.
 

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would be compatible with the mounting system?
I do not think any LNB models will be compatible in your case. You will probably need to think out of the box and make a custom mounting system. Could you show a couple of pictures of your antenna?
 
The smaller sub-reflector is currently removed because I was testing the Inverto Black Ultra, positioned directly facing the main reflector. In any case, I would like to try using an original or similar C-band feedhorn.
 

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I would like to try using an original or similar C-band feedhorn.
You are doing correctly with that custom LNB-holder for Ku-band LNB. Do similarly to mount C-band LNB. Make sure LNB's phase center is co-located with antenna's focal point. Do you have possibility to measure the length of 2 yellow lines? And also the leaning of the face of the antenna?Where in Europe are you located? CM240feed.webp
 
I can't measure the yellow lines at the moment, but I will do it when I get the chance. Location: Serbia south-east.
Do you think that a combination of a C-band feedhorn and, for example, a Norsat C-band LNB would give better results than pointing the LNB directly at the main dish?
For Ku-band, for example, when I attach the sub-reflector, I can receive channels from 30.5°E, which are well outside the beam footprint. Without the sub-reflector, I can still see 30.5°E, but with fewer channels and a weaker signal. That tells me the sub-reflector does play an important role.
 
That tells me the sub-reflector does play an important role.
The SUB, of course, plays an important role in the reception, but not so radical, it is more important for X-pol and side-lobes elimination. But LNB proper placement plays an even more important role in the reception. For perfect antenna tuning, you better use your due-south satellite, which is EUTELSAT 21B @21,5E with elevation for Belgrad 38,4*, so, the leaning of the face of the antenna must be ~15*. And when you have perfectly placed LNB, then you can move to other satellites, just do not forget to adjust LNB-skew accordingly.
 
Hi ... @janixxx .... I can agree with RimaNTSS here - with correct elevation and a perfectly place l.n.b there should be very little difference ..
I have the same 2.4 CM as you with sub reflector and its feed ... i also have some genuine non sub reflector channel master 2.4 arms and regular l.n.b holder ... i,v done comparisons between them in the past using a black ultra l.n.b.f. on the regular arms .. and the results were to all intents comparable ... On the sub reflector setup i use an Invacom quad - and it possibly had the edge on some sat frequencies ... but it was very marginal ...
 
Hi ... @janixxx .... I can agree with RimaNTSS here - with correct elevation and a perfectly place l.n.b there should be very little difference ..
I have the same 2.4 CM as you with sub reflector and its feed ... i also have some genuine non sub reflector channel master 2.4 arms and regular l.n.b holder ... i,v done comparisons between them in the past using a black ultra l.n.b.f. on the regular arms .. and the results were to all intents comparable ... On the sub reflector setup i use an Invacom quad - and it possibly had the edge on some sat frequencies ... but it was very marginal ...
Hi Nelson, do you have a C-band feedhorn for the CM? I'm wondering if the one in the picture above would fit mine. First of all, I’m not sure if it would fit into the mount on the sub-reflector.
I've done a lot of testing with a C120 flange and the sub-reflector, as well as with the Inverto Black Ultra pointed directly at the main reflector. I even tested the IBU facing the sub-reflector. The results were quite strange. For example, with the sub-reflector, it feels like you’re seeing only a partial satellite — 7E works perfectly at maximum signal, but certain channels or feeds are either completely missing or barely detectable. At the same time, smaller dishes pick them up without any issue. And this didn’t just happen once.
Of course, the signal is stronger on the CM, but it still feels like there’s some kind of limitation..
 
Hi Nelson, do you have a C-band feedhorn for the CM? I'm wondering if the one in the picture above would fit mine. First of all, I’m not sure if it would fit into the mount on the sub-reflector.
I've done a lot of testing with a C120 flange and the sub-reflector, as well as with the Inverto Black Ultra pointed directly at the main reflector. I even tested the IBU facing the sub-reflector. The results were quite strange. For example, with the sub-reflector, it feels like you’re seeing only a partial satellite — 7E works perfectly at maximum signal, but certain channels or feeds are either completely missing or barely detectable. At the same time, smaller dishes pick them up without any issue. And this didn’t just happen once.
Of course, the signal is stronger on the CM, but it still feels like there’s some kind of limitation..
Hi - The C band feeds i,v used are just the - Blue - stepped / cone feeds that can be bought various places online ... but i,v not used them together with the sub - reflector - as it would mean cutting the original k/u holder assembly ( something i did not want to do ) ....I,v not had the opportunity to experiment much over the past few years unfortunately, for a number of reasons .. I,m currently using the sub and and an Invacom quad l.n.b.

I will dig out and post some pics later of some of the arrangements i,v tried .. for C band.
 
I saw this on eBay — it looks like the mount might be compatible with our sub-reflector. However, I don’t really understand the design of the feedhorn head. Is that black part supposed to be the actual feedhorn? Hmmm
 

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Hi ... @janixxx .... I can agree with RimaNTSS here - with correct elevation and a perfectly place l.n.b there should be very little difference ..
I have the same 2.4 CM as you with sub reflector and its feed ... i also have some genuine non sub reflector channel master 2.4 arms and regular l.n.b holder ... i,v done comparisons between them in the past using a black ultra l.n.b.f. on the regular arms .. and the results were to all intents comparable ... On the sub reflector setup i use an Invacom quad - and it possibly had the edge on some sat frequencies ... but it was very marginal ...
I'd agree with Nelson, I had a sub on a Channel Master 1.8, little if any difference than pointing the LNB directly at the dish.
 
I'd agree with Nelson, I had a sub on a Channel Master 1.8, little if any difference than pointing the LNB directly at the dish.

Wow, your LNB mount is stunning! Did you make it yourself?
I'm struggling with a movable polar mount — no one around here seems to know how to design it properly, and there are no sketches online that I could give to a metalworker for fabrication. I'm not skilled enough to make one myself...
In any case, this mount looks absolutely fascinating!

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Wow, your LNB mount is stunning! Did you make it yourself?
I'm struggling with a movable polar mount — no one around here seems to know how to design it properly, and there are no sketches online that I could give to a metalworker for fabrication. I'm not skilled enough to make one myself...
In any case, this mount looks absolutely fascinating!

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Wow, your LNB mount is stunning! Did you make it yourself?
I'm struggling with a movable polar mount — no one around here seems to know how to design it properly, and there are no sketches online that I could give to a metalworker for fabrication. I'm not skilled enough to make one myself...
In any case, this mount looks absolutely fascinating!

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The wheel was made by another member some time back, but yes, the other bits of it were my own concoction..
 
I saw this on eBay — it looks like the mount might be compatible with our sub-reflector. However, I don’t really understand the design of the feedhorn head. Is that black part supposed to be the actual feedhorn? Hmmm

Hi - Not sure about that ? - Is it for k/u or C band ..... it looks like it is to fit onto a genuine Fibo bottom arm ?




Hi Nelson, do you have a C-band feedhorn for the CM? I'm wondering if the one in the picture above would fit mine. First of all, I’m not sure if it would fit into the mount on the sub-reflector.
I've done a lot of testing with a C120 flange and the sub-reflector, as well as with the Inverto Black Ultra pointed directly at the main reflector. I even tested the IBU facing the sub-reflector. The results were quite strange. For example, with the sub-reflector, it feels like you’re seeing only a partial satellite — 7E works perfectly at maximum signal, but certain channels or feeds are either completely missing or barely detectable. At the same time, smaller dishes pick them up without any issue. And this didn’t just happen once.
Of course, the signal is stronger on the CM, but it still feels like there’s some kind of limitation..
I,v never had the type of unusual results you describe ... except when i was experimenting with a AV- comm polariser for C band ... Had issues like that with the AV - comm that never got resolved AV-Com.webp

No issues using C band l.n.b and feed as in the picture above .... but without using the AV- comm - and using various dielectric plates as needed instead.


Used this arrangement for a while DSC00760-Optimized.webp DSC03124-Optimized.webp but the wide spacing of the c band l.n.b,s reduced performance in C band to that of a 1.8 m dish .... plus it was a bit fiddly re the receiver positioning between linear or circular satellites ... and quite a bit of elevation adjustment (motorized ) was needed at the arc extremes . other wise it worked well despite the C band limitations .

The next step was / is to remove the sub assembly and replace it with some kind of motorized l.n.b. changer ... just not had enough spare time available unfortunately, to do that in recent times .
 
Hi - Not sure about that ? - Is it for k/u or C band ..... it looks like it is to fit onto a genuine Fibo bottom arm ?





I,v never had the type of unusual results you describe ... except when i was experimenting with a AV- comm polariser for C band ... Had issues like that with the AV - comm that never got resolved View attachment 164035

No issues using C band l.n.b and feed as in the picture above .... but without using the AV- comm - and using various dielectric plates as needed instead.


Used this arrangement for a while View attachment 164036 View attachment 164037 but the wide spacing of the c band l.n.b,s reduced performance in C band to that of a 1.8 m dish .... plus it was a bit fiddly re the receiver positioning between linear or circular satellites ... and quite a bit of elevation adjustment (motorized ) was needed at the arc extremes . other wise it worked well despite the C band limitations .

The next step was / is to remove the sub assembly and replace it with some kind of motorized l.n.b. changer ... just not had enough spare time available unfortunately, to do that in recent times
Great solution, I’ll do the same for the C band. I’ll post pictures soon. Thanks for the idea. Could you take detailed pictures of the movable mount, since we have the same antennas, so I can use them to make a similar polar mount?
 
Great solution, I’ll do the same for the C band. I’ll post pictures soon. Thanks for the idea. Could you take detailed pictures of the movable mount, since we have the same antennas, so I can use them to make a similar polar mount?
You could if budget is tight, fit any C band LNBF at the true focal point of the reflector, and work out a way (motor or manual), of dropping the subreflector out of the way when Ku is not viewed.
 
Great solution, I’ll do the same for the C band. I’ll post pictures soon. Thanks for the idea. Could you take detailed pictures of the movable mount, since we have the same antennas, so I can use them to make a similar polar mount?
Hi - janixxx:
I,m not sure they will be of much use to you .. As i already had an original motorized Channel Master 1.8 setup i decided to lengthen the support pole and strengthen the mount ... so that i could cl.amp the 2.4 support metal and dish to it .. it involved a lot of cutting and drilling of clamping brackets etc . .. all in all it was many hours of work .. and its not something i would particularly recommend doing .
Although it works ok .. i don,t feel its substantial enough to be honest. It is in a partially sheltered location - but i still lock it with tension-ed chains in stormy weather .... 2.4 C.M. polar mounts can still be bought but they are "expensive"

Here is an original Channel Master style - i think the supplier is "Orbita"polar-mount-for-240cm-antennas-andrews-channel-master-skyware.webp


This "primesat" one - is - in my view - a better all round design .... and if i was to make one would follow a similar pattern .

raven2400inclinedpm6.webpraven2400inclinedpm3.webp


I can post pics of what i did with my 1.8 mount if you wish? ... just let me know here.
 
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