Prodelin Antenna

[EmilK]

Created to clean up the AERO topic

 

[Channel Hopper]

Your profile still shows a 1.8m

 

[EmilK]

s-band "If you take the SDR and laptop out to the dish you can tweak it in real time."
That's not a problem, my observatory is near my antenna and using the magnifier option in wi(n)dows I can fine tune the system, This way I've done the settings for the Eutelsat 10°.

Second point.
I've have upgraded the sat system at home (parents) they have an 1.4 m prime dish antenna. The system was installed in 1991-1992, the LNB is an Sharp Carat but there are no papers anymore about it, antenna was pointed at Astra 19°E.(at that time the recommended size for Romania was about 1.6 - 2.0 m) .
Has anyone an idea what that LNB can do? IT has to be an analog one, I tried to open it but 4 screws are stuck and can't be moved without using excessive power.

 

[Channel Hopper]

Sharp probably had a badged unit such as MTI.

Take a picture

 

[EmilK]

You're funny people, all you need are pictures, so long you dont request nudes its fine for me
So here you have, on the feed horn the inner cylinder is missing, I forgot to put it back.

 

[archive10]

Second point.
I've have upgraded the sat system at home (parents) they have an 1.4 m prime dish antenna. The system was installed in 1991-1992, the LNB is an Sharp Carat but there are no papers anymore about it, antenna was pointed at Astra 19°E.(at that time the recommended size for Romania was about 1.6 - 2.0 m) .
Has anyone an idea what that LNB can do? IT has to be an analog one, I tried to open it but 4 screws are stuck and can't be moved without using excessive power.

Since you ask - there are no digital LNBs. They're all analog. The digital bit happens in the receiver, where the analog signal gets sampled (A/D'd), and converted into a string of bits, which is then interpreted as digital. The LNB doesn't know the difference.
If the LNB is that old, it may be a single band one. In modern consumer-type "unvisersal" Ku-band LNBs, there is "High" and "Low" which used slightly different LO (Local Oscillator) settings (LOF Low 9.750 GHz, LOF High 10.750 GHz) to heterodyne the signal down to the intermediate frequency, which is then sampled by your receiver to generate a signal to decode.
So... if it's a prime-focus dish, you can buy a new, universal Ku-band LNB for less than EUR25, and you can connect any modern receiver and have great reception.

 

[archive10]

Ah - posts crossed.

So here you have, on the feed horn the inner cylinder is missing, I forgot to put it back.

That is a normal universal LNB. Throw it away, and buy new one - it's bound to be better.
LNBs for 15 EUR is likely to outperform that one.

[snip] ...they have an 1.4 m prime dish antenna.

...But. The question then is: Is the dish a Prime Focus, or an offset one?
(Is the LNB held slightly in front of the lower half of the dish face, or is it smack in the middle of the dish?)

Offset dish:



Prime focus (and notably with a normal "universal" LNB attached - the LNB does not match this type of dish)



If it's a prime focus one, you need to get a different type of LNB which has a feed-horn that matches the dish...
This will guve much better reception.
Mind you, 19.2 is one of the strongest sats in the sky, and you can probably receive that on a 40cm dish, no need for 140 cm dishes...

 

[EmilK]

No is no offset dish, has 3 arms :-) I know the differences mate (here is not that hard as in astronomy optics: frauenhofer, half-achromatic, apochromatic, schmidt-cassegrain, gregorian, schmidt-newton, newton etc)
The antenna is from 1991-1992 so no need for a new one, visual inspection showed no problems, no paint failures and no deformation even after egg-sized "ice blocks falling from the sky" so quality side is really good. Just keep in mind that in that time in eastern Europe I guess nobody had the knowledge about sat equipment and what for what, they selled systems with max win ratio.
I was thinking that maybe I can use the old LNB for some experiments using the Airspy R2 that I use. I'm not into consumer society always try to reuse old hardware (specially because of my education as environmental engineer).

 

[archive10]

No is no offset dish, has 3 arms :-)

(Ahem. Both dishes pictured have three arms...)

I know the differences mate (here is not that hard as in astronomy optics: frauenhofer, half-achromatic, apochromatic, schmidt-cassegrain, gregorian, schmidt-newton, newton etc)

Sorry, just wasn't clear of what you meant with a "prime dish".
Could be a dish not divisible by anything by 1 and itself... Or a Prime-sat dish.
Or even a prime focus offset feed dish, as Prodelin actually labels some of their dishes:


So now that we've established that it's a prime focus dish, please read the part about LNB mismatch again.
(hint: you need a different feed-horn).

 

[Channel Hopper]

You're funny people, all you need are pictures, so long you dont request nudes its fine for me
So here you have, on the feed horn the inner cylinder is missing, I forgot to put it back.

There is nothing there relating to the 90s.

Do you parents have a receipt of the install, or any service arrangement with replacement of the satellite equipment at any time in the past 15 years ?

 

[EmilK]

As I sad the system was installed in early 90´s and that's sure because I was there. And no, they don't have the papers anymore, we are speaking about something installed almost 30 years ago something that was working until Astra moved to digital transmission.
In autumn Ive changed the LNB and got a new LG TV with sat receiver build-in (that was my birthday present to my father). The LNB was changes after asking what I have to do to make the system work again and the answer was LNB+Receiver....
The only part that I have here is the LNB and I've asked my mother to take a picture of the dish.

 

[EmilK]

I just phoned my mom and nope, negative for papers, but she will take a picture of the antenna, dont shoot me if the quality isn't that great (phone camera).

 

[EmilK]

The best she could do.

 

[EmilK]

A second image done today, she wasn't happy with the first one

 

[archive10]

As I sad the system was installed in early 90´s and that's sure because I was there. And no, they don't have the papers anymore, we are speaking about something installed almost 30 years ago something that was working until Astra moved to digital transmission.
In autumn Ive changed the LNB and got a new LG TV with sat receiver build-in (that was my birthday present to my father). The LNB was changes after asking what I have to do to make the system work again and the answer was LNB+Receiver....
The only part that I have here is the LNB and I've asked my mother to take a picture of the dish.

Your parents do seem to have a nice 1.2 or 1.4 metre PF dish.
Ideally, you would need a Ku-band LNB with a flat scalar that matches the reflector curvature of the PF dish.
There are not many of these, but the Golden Interstar GI-209P is an example of low-cost universal Ku-band LNB suitable for PF dishes.
You will also want someone with a sat-meter to optimise the antenna for whatever you want it to be pointing at.

However...
If you are looking to receive 19.2E in all it's contemporary digital glory, you can slap pretty much any standard universal LNB on the dish (if you can make the LNB holder fit around the somewhat smaller throat of a typical 40mm LNB ), and get 19.2E fine.
It's a really strong satellite in the European skies. The big dish is somewhat overkill for that sat position. Even using the wrong LNB will still provide enough signal to give you most channels of 19.2E

And you will get similar results by putting up a modern 60cm offset dish with a standard universal LNB, and pointing it at 19.2E.
Much less visual impact, and works really well.

So what would your parents like the most - resurrection of old equipment for the hell of it, or just a modern installation for 19.2E-reception on that new LG TV?

 

[Channel Hopper]

A second image done today, she wasn't happy with the first one

The smallest prime focus antenna from Prodelin is a 2.4m.

 

[EmilK]

Actually they aren't sure about the antena if is 1.2 or 1.4....
In September I have installed an Triax LNB (my mother wanted to pay the LNB so I had to look for something financially convenient for her - she had only a very limited budget).
The positioning and orientation was checked and tuned with a Easy SatFinder - DUR-line SF 4000 BT and to my surprise the antenna - after all this years - holded almost perfectly the position.

And yes I know this topic seems to deviate quite much from the original title. Please modify the title name into "Unknown antenna" or something representative for this topic. Thank you