Just Sharing This AV-Comm Polariser + Zinwell lnbf

[Captain Jack]

How much weight do you have sitting on that arm? Must be quite substantial!

 

[John]

How much weight do you have sitting on that arm? Must be quite substantial!

I bet it is CJ, and thats the reason why the installation is so heavily braced, reinforced & counterbalanced at the back. It's at it's limit now mainly due to how much the drop-dowm mast equipment can stand before it bends in the middle when lowering it down. The dish still has the stringing in place and it still shows them just kissing still. For data sake i'll try and do a fairly accurate weight assumption at the end of the arm when i get chance.

 

[John]

.. A short Youtube vid of the 433 MHz RC switch in use and also showing how useful and important it is to get lnb skewing maximised to eliminate x-polarity problems and to ensure maximum receiver performance.
Vid here:

 

[moonbase]

This shows it a little better...
View attachment 98837

John,

Would you please be able to confirm a couple of settings and wire mapping for me re the APC and the Servo motor?

1st question:
The wiring of the HJ S3315D Servo Motor to the APC looks to be as listed below, can you please confirm?

Servo...................APC
Red Wire.............(RED) +5V
Orange Wire........(WHT) Pulse
Brown Wire.........(BLK) GND

2nd question:
Is the metal flick switch on the APC set to Invert or Normal?

3rd question:
You seem to have some additional labels on the APC that were not present on the units we recently imported. Have you added these yourself?

I have just got my PSU from Maplins and am getting close to the point of flicking switches and powering up.


Rgds

 

[John]

John,

Would you please be able to confirm a couple of settings and wire mapping for me re the APC and the Servo motor?

1st question:
The wiring of the HJ S3315D Servo Motor to the APC looks to be as listed below, can you please confirm?

Servo...................APC
Red Wire.............(RED) +5V
Orange Wire........(WHT) Pulse
Brown Wire.........(BLK) GND

2nd question:
Is the metal flick switch on the APC set to Invert or Normal?

3rd question:
You seem to have some additional labels on the APC that were not present on the units we recently imported. Have you added these yourself?

I have just got my PSU from Maplins and am getting close to the point of flicking switches and powering up.


Rgds

1./ Your servo wiring is correct Dave.
2./ Re: flick switch, you need to use this in both positions to get the full 180 deg travel from the servo motor. Used only if your going to make the Zinwell do Hor & Ver as well as L & R polarisation. See pic.
3./ Added labels: Yep, added by me. Done after i had calibrated the APC to correspond with the polarity positions of the feed..... which when added were actually on another Cband feed system & not the Zinwell. Trimming of the servo travel can be fine tuned by the small trim pots on the side.
Btw .... hooked the RC2KX up to the 1.8 earlier on, set the limits etc and looking ok. Silent in operation, like the Fast/Slow function. Need to program it up a bit when iv'e got a bit more time.

 

[moonbase]

John,

I wired up the servo to the APC as confirmed and tried it out, its working but I am not sure if I am balancing the Invert/Normal switch correctly with the Skew rotation. I marked the Servo wheel that fixes to the Zinwell at the 12 o'clock position and no matter what combination of the Invert/Normal switch and the Skew rotator dial I only get 90 degrees travel anti clockwise and back. Is this adjustable via the small trip pots on the side of the APC?

When I come to setup the AV-COMM barrel with the Zinwell and the Servo I will be using in on linear H and V signals initially. Could you please tell me how I orientate the AV-COMM barrel with respect to the internal steps for linear H and V polarities and the internal probes on the Zinwell? If I can get it setup close to the theoretical orientation then the 90 degree rotation scope I have from the servo might be enough?

Thx

 

[John]

John,

I wired up the servo to the APC as confirmed and tried it out, its working but I am not sure if I am balancing the Invert/Normal switch correctly with the Skew rotation. I marked the Servo wheel that fixes to the Zinwell at the 12 o'clock position and no matter what combination of the Invert/Normal switch and the Skew rotator dial I only get 90 degrees travel anti clockwise and back. Is this adjustable via the small trip pots on the side of the APC?

When I come to setup the AV-COMM barrel with the Zinwell and the Servo I will be using in on linear H and V signals initially. Could you please tell me how I orientate the AV-COMM barrel with respect to the internal steps for linear H and V polarities and the internal probes on the Zinwell? If I can get it setup close to the theoretical orientation then the 90 degree rotation scope I have from the servo might be enough?

Thx

...as a matter of interest on mine the trim pots are set--"H ADJ" is fully CCW and the "V ADJ" is fully CW for me to get the correct rotation positions. Before joining the servo wheel to the back of the Zinwell did you do an initial set-up test by setting the top rotary pot on the APC to the central position, with toggle switch in one position, make a note / mark on the coupling wheel and then rotate the top pot fully either way so as to establish what rotation range you get. Repeat the operation with the toggle switch in the other postion and make note / mark on coupling wheel to establish the rotation range. From this you should be able to determine where to fix the coupling wheel to the rear of the Zinwell. Note that on initial set-up test the Zinwell probes / Barrel side steps must be in the position shown on the pic.

 

[John]

... is this pic any better

 

[moonbase]

John,

I have not yet attached the servo motor to the Zinwell, I am still testing out the rotational range of the APC/Servo.

My findings so far using a reference mark on the servo wheel are:

1. I need the H ADJ full counter-clockwise and the V ADJ around 2/3 clockwise to get a 90 degree separation when I flick the Invert/Normal switch.
2. I have more than 90 degree rotation with the flick switch in the Invert position.
3. I have less than 90 degree rotation with the invert switch in the Normal position.
4. The over/under 90 degree rotation from 2. and 3. above is about equal.

The rotation is a little bit jerky at times and it twitches about a bit, its not a smooth even rotation all of the time. Generally, the reference mark on the servo end up at the correct location but is sometimes quirky on route to that point. Smooth slow rotation of the Skew button lessens the twitchiness. I might try a different PSU just to see if that smooths things out a bit.

I will see if I can rig up a test dish on an Az-El fixed mount to have a look at it under operational conditions. Could you please confirm that if I align the dish on 0.8W or due south then the barrel side steps are vertical and the Zinwell has the probes at the 10 to 2 position? Is there a satellite that springs to mind that has linear C band polarity with signals capable of being received by a 1.5m dish within 45 degrees East or West of due south?

Thx

 

[Captain Jack]

Try Paksat 38e or 46e...both linear with some signals available on the 1.5m.

 

[John]

John,

I have not yet attached the servo motor to the Zinwell, I am still testing out the rotational range of the APC/Servo.

My findings so far using a reference mark on the servo wheel are:

1. I need the H ADJ full counter-clockwise and the V ADJ around 2/3 clockwise to get a 90 degree separation when I flick the Invert/Normal switch.
2. I have more than 90 degree rotation with the flick switch in the Invert position.
3. I have less than 90 degree rotation with the invert switch in the Normal position.
4. The over/under 90 degree rotation from 2. and 3. above is about equal.

The rotation is a little bit jerky at times and it twitches about a bit, its not a smooth even rotation all of the time. Generally, the reference mark on the servo end up at the correct location but is sometimes quirky on route to that point. Smooth slow rotation of the Skew button lessens the twitchiness. I might try a different PSU just to see if that smooths things out a bit.

I will see if I can rig up a test dish on an Az-El fixed mount to have a look at it under operational conditions. Could you please confirm that if I align the dish on 0.8W or due south then the barrel side steps are vertical and the Zinwell has the probes at the 10 to 2 position? Is there a satellite that springs to mind that has linear C band polarity with signals capable of being received by a 1.5m dish within 45 degrees East or West of due south?

Thx

I think both Chris (scopus) & me had similar erratic nature when we used a very short piece of cable to test, i tended to use the cable that was going to be used for the run from shack to dish position, which in my case is about 20mtrs, and found that that got rid of the erratic behaviour

 

[Archive-8]

@moonbase 46 E is linear and I can get it with the 1.5 dish and c-band offset by about 3 or 4 °.

 

[moonbase]

I think both Chris (scopus) & me had similar erratic nature when we used a very short piece of cable to test, i tended to use the cable that was going to be used for the run from shack to dish position, which in my case is about 20mtrs, and found that that got rid of the erratic behaviour

John,

Thx, very useful tip, yes I was using the short cable that came with the servo. What spec cable did you use for the long run, ie, core diameter, the condictor cores seem quite small diameter, is there a cheap off the shelf cable readily available?

Thx

 

[moonbase]

Try Paksat 38e or 46e...both linear with some signals available on the 1.5m.

Thx CJ.

@moonbase 46 E is linear and I can get it with the 1.5 dish and c-band offset by about 3 or 4 °.

Thx Chris,
What are you referring to re the offset of 3 or 4 degrees? Is the C Band LNB not at the central focus of the dish and is offset in a multi LNB arrangement?



Is there anything on 43W or 45W in C Band H/V available to a 1.5m dish?


Rgds

 

[Archive-8]

Thx Chris,
What are you referring to re the offset of 3 or 4 degrees? Is the C Band LNB not at the central focus of the dish and is offset in a multi LNB arrangement?
Rgds

On my 1.5 dish the c-band lnb is about 3or4° offset from the centre.

Centre position for me is my twin ibu.

 

[John]

John,

Thx, very useful tip, yes I was using the short cable that came with the servo. What spec cable did you use for the long run, ie, core diameter, the condictor cores seem quite small diameter, is there a cheap off the shelf cable readily available?

Thx

Me being a sparkie, i had some .75 x 3core circular flex which i used which was a bit of over-kill for a 20mtr run. .5 x 3core circular flex should be ok up to about a 30mtr run.
I was a bit unsure at first wether to use a 3core cable with one core screened for the pulse signal to help stop any induced interference on the pulse line but have found that the servo works without any issues just using standard circular flex that can be bought from B&Q etc.

 

[scopus]

I'm using 1.0mm 3 core main flex, had a roll of in the garage, no point in buying new...

 

[John]

I'm using 1.0mm 3 core main flex, had a roll of in the garage, no point in buying new...

Didn't realise you had your own channel on 53West matey

 

[scopus]

Oh yes, I'm a man of mystery

 

[John]

Years ago I already was thinking about trying to make such AV-COM barrel by myself .
Beginning this year a friend ordered one from AV-COM , from that one I took the dimentions .
A few days ago I ordered the nessasary parts for 2 polarisers , yesterday the package arrived .
The alu tube is 70/60 , thursday I will start with this project .
View attachment 98921

Bare with me Wim, I'm going to follow up on your post idea above, first picture.

Iv'e just got to chamfer the edges down to get a proper fit and then i'm going to try and get a fixing of the steps to wall by either aluminium welding.. OR, just plumbers large grade solder with a blow lamp and then mould for a good flat finish whilst the solder is still workable ??, and also "in-fill" the bottom gap with solder and mould to good finish. Might work / might not ----worth a try