Tests of 120cm antennas

[RimaNTSS]

i was planning to remove the standard lnb holder on my 120cm CM and fit something different to suit a Ka band set-up

So, John, when you fabricate new holder, where you will be pointing your new LNB?

 

[John]

Well .... bearing in mind that the weather here in the last week or so has been very very cold, wet & snowing and playing outside has not been very pleasant but the other week i was outside doing a bit of evaluating with a XMW Ka band lnb, loosely attached on the Channel Master's original feed holder feeding into my Televes meter. I did seem to find that slightly tilting the lnb upwards did give me nearly a 2dBuV signal increase. Can't remember what the C/N reading was exactly, i was more interested in getting back inside.

 

[RimaNTSS]

@John I would advice you to make your new LNB holder adjustable, to be able to move LNB in all directions.

 

[RimaNTSS]

I think it is possible to get rid of 2 side support feedarms, by making one but powerful feedarm. That feedarm's position could be adjusted by bolt (green). From back dish would look like on second picture. And, to make polar mechanism work better, it should be connected to place with number "1", so that will prevent mechanism from flopping.

 

[Archived-1]

I think it is possible to get rid of 2 side support feedarms

I will probably do mine like the TX dish arms, with support from the bottom arm connected to the rear of the dish,

This one would be a good test if not already mentioned sorry if so.

https://www.satellites.co.uk/forums...-to-my-channel-master-1-8.163568/#post-908192

 

[timo_w2s]

I think it is possible to get rid of 2 side support feedarms, by making one but powerful feedarm. That feedarm's position could be adjusted by bolt (green). From back dish would look like on second picture. And, to make polar mechanism work better, it should be connected to place with number "1", so that will prevent mechanism from flopping.
View attachment 72990 View attachment 72991

What is the pony used for?

 

[archive10]

What is the pony used for?

It's a *magic* my little pony... brings all kinds of good reception improvements to the the dish.
In fact, I think the inclusion of the pony gives an unfair advantage to the NSC dish.
I demand my little ponies for the other dishes too!

 

[timo_w2s]

It's a *magic* my little pony... brings all kinds of good reception improvements to the the dish.
In fact, I think the inclusion of the pony gives an unfair advantage to the NSC dish.
I demand my little ponies for the other dishes too!

Maybe I'll try and borrow one from my niece and test the theory. I must admit I prefer the 80s original ones but perhaps that's a topic for another thread or forum...

 

[RimaNTSS]

I think Monster High dolls will improve performance of SAT system even more. Will test them one day.

 

[sonnetpete]

I think Monster High dolls will improve performance of SAT system even more. Will test them one day.

Think I have one here that I could test with the Laminas.....need to find the foot pump first though...

 

[hairybadger]

I suspect Action Man would be more effective (older versions, before the modern antimilitary makeover)..... Alas mine (80s vintage) are languishing in a box in my parents' loft on a different landmass. I'll try and retrieve them next time I'm in Blighty

 

[RimaNTSS]

We spoke about mesh inside plastic dishes another day. And we were unsure what kind of mesh and how big area of the dish it covers.
So, from my last Echostar I see that metal net is bended all over the edges of the dish and eyes are about 1,5mm (maybe little bit less).

 

[Captain Jack]

Actually I saw the mesh inside the CM 120 dish the other day. It was almost like one of those sieves that you use to drain your pasta.

 

[archive10]

Now that I see that you are trying to exhaust all possibilities, I just wanted to point out another 120 cm plastic dish:

The Swedish Microwave SMW-OA1200.

This is (purportedly) a 120cm plastich dish (although not an SMC dish!) that performs really well.
I have an SMW-OA1050, which is (as you probably guessed) and 105 cm dish. It has an f/D of about 0.5, so slightly different to the other plastic-fantastic SMC dishes out there.
The 1200 I have never seen, but I assume they still exist here and there...

So - Rimants, I dare you find an SMW-OA1200 in the Belgian used-dish market!

 

[Captain Jack]

Didn't @Llew or @Tivu have an SMW? Also I know @pride21 had a 1.4m version but not sure what its construction is.

 

[archive10]

Didn't @Llew or @Tivu have an SMW? Also I know @pride21 had a 1.4m version but not sure what its construction is.

@Llew has the an OA1050 similar to the one that I have.
The 1.4 version is a multifocus dish (like the Wave Frontier) made of metal.

 

[RimaNTSS]

Hi! I could not prove today that proper placement of LNB is improving performance of system, and I think it is because we do not have proper measurement equipment, I mean receiver or sat-meter.
Yes, I was was at Wim's place and grateful he spent all day with me playing with sat toys. Unfortunately all day is, at always, not enough!
But I have some conclusions already made: LNB placed in antenna's focus illuminates dish better than LNB placed out of focus and pointed somewhere towards the dish. This video clearly shows that, it is actually only one video we took today. We did not take any videos when LNB is placed where original CM120cm feedarms hold it, but I can assure you it was awful . At Wim's there are lots of toys to play with, but that Visiosat 120cm is mine (dirtiest dish I ever had!)
So, we also made experimental feedarm for CM 120 without back-support tubes. It is good, but, of course, not perfect (nothing is perfect and nobody of us is perfect as well). And, BTW, weather was not perfect today as well, about +3*C and drizzling.
I have one query to all of you lads: Please do not suggest any new dishes for me.... I promised to wife that Visiosat is my last dish! With hoorror I counted today, and found out I already have about 11 plastic dishes at my disposal, and those are only plastic ones. So, I am serious, NO MORE! But, at the same time.... if I see some dish at real bargain somewhere nearby, I will probably not be able to resist That is the dilemma

 

[Captain Jack]

Very nice, Rimant. I like the makeshift LNB arm for the CM!

As for your dish warehouse, perhaps you could get rid of some of them? (once you're done with testing)

 

[archive10]

I have one query to all of you lads: Please do not suggest any new dishes for me.... I promised to wife that Visiosat is my last dish! With hoorror I counted today, and found out I already have about 11 plastic dishes at my disposal, and those are only plastic ones. So, I am serious, NO MORE! But, at the same time.... if I see some dish at real bargain somewhere nearby, I will probably not be able to resist That is the dilemma

Well, there's always the Hughes dishes that you would need NOT to look at.
They've been used by car dealerships here in DK, but are now being thrown away as the internet provides vastly superior price/performance rates.
I (stupidly) rejected getting one off a skip 3 years ago at a Fiat car dealership.
At the time, 1.8 meter was a must for 28.2E, and so I let the hughes dish go...
So don't look at getting one of those... 8)

 

[RimaNTSS]

So don't look at getting one of those... 8)

You bet I will not..... if only it is available near me and at almost no price!
Actually, what I miss is 2,4meter dish, for that I could still be ready to go, but also depending on place and $$$