40.5W SES6 & NSS806

[amdade]

Interesting Nelson thanks for that. Im using a very old Chaparral dielectric plate inside the LNBF using the set of grooves provided, its located as far back as it will go. I find it works slightly better than the plate provided with the titanium.

The ESPN TP will not even lock using the plate in the "normal" position for me. I have no idea why this would be, tried different plates, different skew angles of the LNB itself, different LNB's same result. In the "reversed" position mine is at 90 degrees roughly to how yours is setup.

Its annoying as I cant find an option in the mut@ant to reverse the polarisation as default. I have to manually scan each TP

There is clearly a reason the manufacturers fit those two sets of grooves in the LNBF, would be interesting to know why...

 

[suedschwede]

I have had the best experiences with this wedge-shaped dielectric, but you could forget about the small rectangular plates that came with the LNB.
The shape comes from a circular KU band LNB which I then only converted to the C band.
I am enclosing a sketch and picture of the plate I used.
The material I use is Plexiglas with a thickness of 8mm.

 

[amdade]

Comparing the two plates I have both of course are 60mm wide to match the feedhorn.

Chaparral (1990's vintage) 35mm x 7mm, very light green
Titanium 40mm x 6mm, off yellow colour, looks laminated

I note the Chaparral almost matches the B dimension in @suedschwede 's plans (35.9)

The Titanium is not so "transparent" when you hold it up to the light

Just swapped them couple of times not much in it, the Chaparral is going back in though :-)

 

[moonbase]

Interesting Nelson thanks for that. Im using a very old Chaparral dielectric plate inside the LNBF using the set of grooves provided, its located as far back as it will go. I find it works slightly better than the plate provided with the titanium.

The ESPN TP will not even lock using the plate in the "normal" position for me. I have no idea why this would be, tried different plates, different skew angles of the LNB itself, different LNB's same result. In the "reversed" position mine is at 90 degrees roughly to how yours is setup.

Its annoying as I cant find an option in the mut@ant to reverse the polarisation as default. I have to manually scan each TP

There is clearly a reason the manufacturers fit those two sets of grooves in the LNBF, would be interesting to know why...

Several forum members have done away with the dielectric plate and gone for a polo pipe option.
It seems to give better performance on circular polarity than a dielectric plate.

 

[suedschwede]

The polo pipe variant is not bad, unfortunately it is too selective and does not work optimally over the entire frequency range.
Some forum members have attached servo motors for this, for example. to be able to control the LNB immersion depth in the polo pipe, LNB rotation in the polo pipe and feed immersion depth of the entire construction.

 

[nelson_b]

The polo pipe variant is not bad, unfortunately it is too selective and does not work optimally over the entire frequency range.
Some forum members have attached servo motors for this, for example. to be able to control the LNB immersion depth in the polo pipe, LNB rotation in the polo pipe and feed immersion depth of the entire construction.

I have found the same with the AVcom - polo pipe ... constant adjustment of depth and rotation of the l.n.b. for different - weak frequencies .... at least that is ... on my Channel master offset dishes ... which i dont seem to get with my "Vipersan" style T plate .

The polo pipe perfomed much better - on limited tests - on a 3meter Prodelin - prime focus dish ... i could not devise a T plate to even equal a standard dielectric plate on this dish - experiments are still ongoing with this dish - as and when i get the time.

edit
@suedschwede .... your 8.mm plexyglas method looks interesting and i think will be worth a try on my 3 m Prodelin

 

[amdade]

The AVcom pipes look interesting, wonder where I can get one of those...

 

[John]

The polo pipe variant is not bad, unfortunately it is too selective and does not work optimally over the entire frequency range.
Some forum members have attached servo motors for this, for example. to be able to control the LNB immersion depth in the polo pipe, LNB rotation in the polo pipe and feed immersion depth of the entire construction.

Here's the ultimate Cband feed that leaves no stone un-turned - i need that but he won't let me have it
The owner should appear in the vid info

 

[nelson_b]

Re - ESPN and FS1 on 1.8 c.m. offset experiments .....

The only other plate that will lock these transponders here at my location is a plate supplied to me by member @pride21 some years ago .... it is copper foil on thin perspex ... and is very critical to depth positioning

Pic here of the two plates that do the job here ..... so very different in every way - l.o.l.

 

[dreamsat]

i have this two-axis device.

 

[scopus]

ESPN 9.5dB on the Dreambox this morning, better for reception this morning, cooler here today.

 

[amdade]

Wow very impressed with the various feed control systems you guys have, makes my equipment seem very inadequate !

Much nicer here today so far 23C

ESPN 10.2 / 9.8 db
FS 9.5 db

08.46 BST

 

[nelson_b]

The AVcom pipes look interesting, wonder where I can get one of those...

Imported mine from the manufacturer in Australia, had to then have it machined out to accept my l.n.b.f,s

Spent all yesterday evening tinkering with the AVcom and various l.n.b,s on the c.m. 1.8 - re those two sports transponders - will report my findings later.

 

[moonbase]

Imported mine from the manufacturer in Australia, had to then have it machined out to accept my l.n.b.f,s

Spent all yesterday evening tinkering with the AVcom and various l.n.b,s on the c.m. 1.8 - re those two sports transponders - will report my findings later.

@nelson_b

Looking forward to see how the LNB's fared, I expect the BSC model will be up there close to the top?


If I recally correctly from a small group buy that we did, we ordered the AV-COMM polo pipes pre-machined internally to accept insertion of a Zinwell C-Band LNBF at one end and skimmed externally on the outside at the other end to accept a scalar. The mini group buy included the Zinwell LNBF and the scalar.

I think that AV-COMM may also sell the unmachined version of the polo pipe on its own that the end user can setup according to their needs?

 

[amdade]

Apologies if Im not allowed to post links :-)

This one @moonbase ?

C Band Dual Polarity Circular Polarisation Kit - STEP Electronics

Our C Band Dual Polarity Circular Polarisation Kit is designed to provide an economic yet high performance solution for the reception of circularly polarised C Band satellite signals. C Band Dual Polarity Circular Polarisation Kit consists of our Av-Comm C Band Waveguide Polariser and a Zinwell...

www.stepelectronics.com.au

 

[moonbase]

Apologies if Im not allowed to post links :-)

This one @moonbase ?

C Band Dual Polarity Circular Polarisation Kit - STEP Electronics

Our C Band Dual Polarity Circular Polarisation Kit is designed to provide an economic yet high performance solution for the reception of circularly polarised C Band satellite signals. C Band Dual Polarity Circular Polarisation Kit consists of our Av-Comm C Band Waveguide Polariser and a Zinwell...

www.stepelectronics.com.au

Yes that is the unit we bought for the mini group buy, pre-machined at both ends.

If you have access to a lathe or a contact with a lathe you can probably save on cost by buying just the unmachined barrel excluding Zinwell LNBF and scalar.
You could then get it machined to match any LNBF's and scalars you might wish to use with it.

 

[nelson_b]

Yes that is the unit we bought for the mini group buy, pre-machined at both ends.

If you have access to a lathe or a contact with a lathe you can probably save on cost by buying just the unmachined barrel excluding Zinwell LNBF and scalar.
You could then get it machined to match any LNBF's and scalars you might wish to use with it.

I bought the unmachined one and had it cut to 65.8 mm to take the largest of my l.n.b.f,s - the zinwell is the smallest i have at 65.0 mm .... the feed end i,v left un machined as i manged to file enough metal from the inner of both my spare flat and coned feeds for them to fit o.k.

Just been repeating the l.n.b / av-com tests that i did yesterday ... in case the results had been affected by the extreme heat ... it seems that there were not significantly affected ... will post results shortly.

 

[amdade]

My scalar is an old Chaparral with one screw tightener which works way better than the ones shipped with the Titanium.

 

[nelson_b]

My scalar is an old Chaparral with one screw tightener which works way better than the ones shipped with the Titanium.

Yes i,m using the same on the Prodelin - prime focus dish ...... Much better than the Titanium one - i agree.

I had another "similar" Chaparral one that i enlarged the center hole on ... so that it would fit onto the av- com
the unmachined av-com barrel is 71.0 mm

 

[amdade]

The throat of the titanium is about 65mm which just clears the Chaparral scalar by a mm or so...