New house, new dish project

[Captain Jack]

Well, with my dish parked on 5E with 11.2dB showing on the meter (11919H frequency), I decided to try the CM feedhorn with the Black Ultra C120 conversion. Disappointingly I couldn't get it above 10.1dB with the single and 10.6dB with the twin. I've only tried it for 5 minutes after which the heavens opened, stopping play.

 

[Captain Jack]

Reception reports:

Everything from 45W (possibly further) to 19.2E is receivable. Signal degrades from around 13E but not an issue as these satellites are so strong. 23.5 and 26E are missing completely. Very odd as 23.5E is a strong spot. 28E to 42E are receivable with reduced levels - nothing beyond that.

So much better than I originally thought with the house in the way.

I like the "heavy duty" jack arm as it's super quiet and quite accurate. There's a tiny bit of play in it but will take it apart and see if I can improve that.

Plenty of fine tuning to do but most satellites are coming in within a dB of what I expect them to be.

 

[Lazarus]

Sounds like a pretty respectable outcome - and with all the rain around at present you've done well to make such good progress with installation and alignment.

 

[Captain Jack]

Not connected, or even tried, yet but I've attached a C band LNB. There's no loss in Ku-band like I thought there would be. I have the design for declination adjustment ready (on paper) so will get to it when I can - probably on my return from my holidays.

View attachment 56598

 

[Huevos]

You need to insert the LNB further into the feed horn so it looks like a 4th scalar ring.

 

[Captain Jack]

You need to insert the LNB further into the feed horn so it looks like a 4th scalar ring.

Ah, gotcha - will do!

 

[RimaNTSS]

Nice job CJ! Are those nuts and bolts INOX made? I am not sure whether vertical multifeed is better than horizontal. Are you sure you do not have place for another antenna for C-band?

 

[Huevos]

Here's a picture of mine. The LNB is pushed to around 32 on the depth scale for best reception. Maybe Nelson could confirm from his depth scales.

 

[Huevos]

Nice job CJ! Are those nuts and bolts INOX made? I am not sure whether vertical multifeed is better than horizontal. Are you sure you do not have place for another antenna for C-band?

I'd say horizontal is better from a control point of view because it just means adding another DiSEqC position on the V-box, anything else means you need 2 axis control which means user intervention when changing band. Also the satellites.xml is written as 2 satellites (well the ones from my site are anyway).

 

[Captain Jack]

In terms of control, horizontal is better as you only need 1 jack but vertical arrangement means that you can have two lnbs in main focus...though obviously not at the same time. I would have thought that with offset arrangement you'd still need another position on the vbox to account for the LNB not being in focus but maybe C band isn't as sensitive to such things.

The main reason for having it vertically is because of those stupid support arms which are in the way for huge feedhorn..though I could have created a different bracket like nelson_b's.

Not going to have another dish as I just don't have the space in the garden and the Mrs is already giving me looks. I am mainly interested in 49e but that's not visible from the garden anyway so I'll have to settle for 11w which is stronger than 49e and is visible! The bolts are zinc treated I think. Not a big deal if they rust as I have a bag of them!

 

[RimaNTSS]

because of those stupid support arms which are in the way for huge feedhorn..though I could have created a different bracket

Perhaps it is easier to make proper support arms than create vertical control to antenna. And once you start to use INOX that is not so sexy to go back to galvanized

 

[nelson_b]

Here's a picture of mine. The LNB is pushed to around 32 on the depth scale for best reception. Maybe Nelson could confirm from his depth scales.

hi --
yes much the same with mine - best results around this position .

i like the look of the arrangement on the 1.2 -- C.J.
i may give that a try on mine sometime - as i have got elevation control already on my 1.2 -- and an l.n.b and feed lying around un-used .
side arrangement of a C band setup on the 1.2 channel master is particularly difficult as the side arms can,t be lowered or widened like they can on the 1.8 because of the way they are fastened at the dish ( through the dish rather than bolted to the side )
cheers --

 

[Captain Jack]

Nelson, can you take a picture of your elevation control mechanism?

My idea on paper is to get two steel plates and hinge them so that they open and close like a book. One plate would be bolted to the polar mount where the dish is currently situated and the other plate bolts to the dish. The opening and closing of these two plates would then be controlled by a 10" jack.

 

[Huevos]

vertical arrangement means that you can have two lnbs in main focus

That is not true. The dish has one focal point. Whether you move the second LNB vertically or horizontally you will be just as many degrees from the focal point and the dish efficiency will drop by the same amount.

 

[nelson_b]

hi -
if i,m picturing what you describe correctly - you will be altering the declination - yes- ?
sounds o.k.

mine is just a very basic change of the polar mount elevation -- a picture below
i,v recently changed the jack to a more substantial one --a picture below -- i was using the mini jack that you saw in the jack restoring thread , its,done the job for the last 2 or 3 years but it always looked a bit flimsy .


cheers --

 

[Huevos]

My idea on paper is to get two steel plates and hinge them so that they open and close like a book. One plate would be bolted to the polar mount where the dish is currently situated and the other plate bolts to the dish. The opening and closing of these two plates would then be controlled by a 10" jack.

This is pretty much what I did with the Fibo 90. And used spherical joints as the hinge.

 

[RimaNTSS]

In one of our shops they sell 90cm PFA with 2 jack's control
_http://intersat.lv/?128,antenna-sat-d.90-cm-parabola-prime-focus-mount-az-el

 

[Captain Jack]

Played about with C band with LNB positioned as per post 44 and got some signals so my plan should work out alright. The dish was very loosely aligned and no real adjustments but managed signal generally around 1-2dB weaker than what I had with my Fibo. I need to create a T plate depolariser as I am using an offset feedhorn (whereas I wasn't on the Fibo).

Nevertheless, if you want to have a go at C band in UK, the absolutely strongest transponder is on Express AM44 14W - 4013R. It's booming in at 15dB! You could probably get it with an 80cm dish. Lucky, as that's the transponder I wanted the most!

 

[Huevos]

Wow, that is so powerful it scans in on CL as well as CR.

 

[Captain Jack]

Got my bracket done for declination control! Just need a second Vbox, some cable, which I have been waiting for since before I went on holiday and attach some brackets for actuator.

View attachment 56997