Just Sharing This AV-Comm Polariser + Zinwell lnbf

[moonbase]

Hi,

On a slightly related topic, the AV-COMM barrel is quite similar in external appearance to the ADL C Band barrel. The internals are altogether different though. Externally, the ADL has slightly more scope for scalar adjustment by having a 51mm skimmed collar versus the 40mm skimmed collar on the AV-COMM. I need to get some spare time and get on with testing this lot out.

I have attached a comparison picture of the AV-COMM and the ADL side by side.

 

[moonbase]

Hi,

Would any of the AV-Comm guys who are up and testing please be able to carry out a test using the AV-COMM / Zinwell and compare it against a Titanium C Band LNBF for linear H/V signals? There are a few linear polarity C Band satellites out West but not much out East. A test on an 8PSK signal would be preferred rather than QPSK if that is possible?

No worries if you are all busy testing other stuff, fully understand the excitement and the need to get on with your own tests. I will try to rig something up ASAP.


Rgds

 

[John]

You were quick out of the starting stalls in getting that up and running. I have got the horn and the KY, all I need now is the time to get it setup and begin testing.


Rgds

Disgusting!

 

[John]

Hi,

Would any of the AV-Comm guys who are up and testing please be able to carry out a test using the AV-COMM / Zinwell and compare it against a Titanium C Band LNBF for linear H/V signals? There are a few linear polarity C Band satellites out West but not much out East. A test on an 8PSK signal would be preferred rather than QPSK if that is possible?

No worries if you are all busy testing other stuff, fully understand the excitement and the need to get on with your own tests. I will try to rig something up ASAP.


Rgds

Iv'e got an unmodded TiT with which i can do that MB, but not straight away

 

[scopus]

You were quick out of the starting stalls in getting that up and running. I have got the horn and the KY, all I need now is the time to get it setup and begin testing.


Rgds

Got to do the Servo Motor next...

 

[John]

Hi,

On a slightly related topic, the AV-COMM barrel is quite similar in external appearance to the ADL C Band barrel. The internals are altogether different though. Externally, the ADL has slightly more scope for scalar adjustment by having a 51mm skimmed collar versus the 40mm skimmed collar on the AV-COMM. I need to get some spare time and get on with testing this lot out.

I have attached a comparison picture of the AV-COMM and the ADL side by side.

Iv'e a feeling that a few mm have been took off the front of the AV-Comm because you can feel the burr left by the mech saw

 

[John]

I can either use a second scalar as the fixing point to the dish feed support arms or I can use the Precision fixing head that attaches to the feed support arms then insert the AV-COMM barrel/Zinwell/Flat Scalar into this. I have attached a picture of the Precision feed support arm fixing head unit.

Rgds

Ohh, never seen one of those before ..... look forward to how you do it.

 

[moonbase]

Iv'e got an unmodded TiT with which i can do that MB, but not straight away

John,

If you can test when you get the opportunity that would be great.

Thx

 

[John]

Got to do the Servo Motor next...

Forgot to mention to you when i saw you .... check the 9volt power supply that came with the controller ......... mine was 120volt primary only, had to get a UK one.

 

[scopus]

Forgot to mention to you when i saw you .... check the 9volt power supply that came with the controller ......... mine was 120volt primary only, had to get a UK one.

Yep, seen that dear....

 

[moonbase]

Hi,

Can anyone please tell me why the AV-COMM barrel has been skimmed at both ends? I can see the reason for one end to allow the scalar to fit but cannot see why the other end that the Zinwell LNB slides into was skimmed? Is there a use for the LNB end being skimmed that we are not aware of?

Thx

 

[John]

Hi,

Can anyone please tell me why the AV-COMM barrel has been skimmed at both ends? I can see the reason for one end to allow the scalar to fit but cannot see why the other end that the Zinwell LNB slides into was skimmed? Is there a use for the LNB end being skimmed that we are not aware of?

Thx

Good question, i noticed that. All the 5 have been done so it's not as if a boll*ck has been dropped on just one of them ?.... Ermmmm i'm going to go into think tank mode and try and think of an answer. All welcome to participate.

 

[John]

Good question, i noticed that. All the 5 have been done so it's not as if a boll*ck has been dropped on just one of them ?.... Ermmmm i'm going to go into think tank mode and try and think of an answer. All welcome to participate.

I'm out of think tank mode now and have asked AV-Comm for the official reason. Would still like to hear theories though.

 

[blademedia]

It does state the dimensions I can only presume the measurements make it do what it does ?

 

[moonbase]

I'm out of think tank mode now and have asked AV-Comm for the official reason. Would still like to hear theories though.

Could the LNB skimmed end of the AV-COMM barrel be to allow a single port or dual port waveguide adapter to slide over it so that an LNB such as a Norsat can connect to it? Commercial LNB's such as Norsat have the rectangular waveguide port on them that bolts to the feed. With the AV-COMM barrel some type of adapter would be required to connect a Norsat LNB to the barrel. I have attached a couple of pics of a Norsat LNB and and ADL waveguide adapter that show how a commercial LNB such as a Norsat connects to a barrel.

Rgds

 

[cardiff]

Hello,

For over 2 years I had left out the LNB Zinwell and AV-COMM polarizer, on this, adaptation of the 2 diameters has not been made, the two products have been ordered separately, the LNB Zimwell comes from the United States.

Someone-one could give me the lengths and measures of reduction / increase for diameters of the polariser AV-COMM ?

Rgds

Cardiff

 

[moonbase]

Hello,

For over 2 years I had left out the LNB Zinwell and AV-COMM polarizer, on this, adaptation of the 2 diameters has not been made, the two products have been ordered separately, the LNB Zimwell comes from the United States.

Someone-one could give me the lengths and measures of reduction / increase for diameters of the polariser AV-COMM ?

Rgds

Cardiff

Hi Cardiff,

At the scalar end of the AV-COMM barrel, I measure the outer diameter as 66mm, this is after it has been machined down to reduce the outer diameter. This reduction is only done to allow the scalar to slide onto the AV-COMM barrel. The length of this outer diameter reduction is 40mm.

At the LNB end of the AV-COMM barrel, I measure the outer diameter as 70mm and the inner diameter as 65mm after the reduction. The length of the internal reduction at the LNB end is 40mm and the length of the external reduction at the LNB end is 20mm.

I hope the above info helps?


Rgds

 

[cardiff]

Hello Moonbase,

Thank you for these very precise measurements.

I do not know why there is a reduction of the external diameter for the LNB ?

Best Regards

Cardiff

 

[moonbase]

Hello Moonbase,

Thank you for these very precise measurements.

I do not know why there is a reduction of the external diameter for the LNB ?

Best Regards

Cardiff

Cardiff,

We are talking about this reduction of the external diameter of the LNB end of the AV-COMM in this forum topic, see posts 71 to 75 for our chat on this point.


Rgds

 

[Captain Jack]

This AV Comm + Zinwell LNB combination is impressive. I have removed the LNB rotator for now and stuck the C band LNB on top of the Ku, so essentially it's not at focus (using my declination jack for adjustment). Even so, I am getting some very impressive signals even on a crappy, cloudy day across the board. BBC Africa on 1W is pushing over 9dB and AFN TP is 7.7dB (F15 readings).

This is without any sort of fine tuning - just stuck the LNB into the barrel and barrel on the dish...



One thing that's annoying is that the LNB cover is costing me around 0.5dB, which is a lot considering how every tenth of a dB counts here. Any suggestions on a more "transparent" cover? Apart from cling film....



Now just need that skew control....