Astra 2E: Iberia & Balearics Reports

[joddle]

I would put a correctly alighned 1.45 pf against any 1.8 off-set (other than the ch master) and win the money any day of the week!

I like the optimism - but in reality if both dishes are of similar quality and set up properly with optimal LNBs there will be very little to choose betwen them. The real problems is defining "equal quality" as they are two very different products with differing manufacturing techniques and different ways of operating. Not quite like comparing bananas with oranges but more like comparing a Granny Smith with a Cox - both apples - but not the same at all but at the end of the day some people will prefer one to the other.

 

[Huevos]

All I can say is a reasonable quality PF dish is a lot cheaper than a similar quality offset.

 

[joddle]

All I can say is a reasonable quality PF dish is a lot cheaper than a similar quality offset.

Yup - I forgot to add that bit......

 

[Cala d'or]

Just came back from Mallorca where for the first time since 1N arrived I tweaked my dish.

On 2E and 2F I was getting 10.7 db on V and 11.1 on H at best

Using Prodelin 1.8m and Inverto Black Ultra quad . A decent enough result for me, I thought, being an amateur !
I can only really adjust my dish during the winter months cos of access to the dish. It means crawling over other people's terraces etc.. I don't like disturbing people !

 

[Huevos]

Tonight is the last of the spring equinox eclipses.

 

[sinbadmarino]

Funny thing.
A surface perpendicular to the beam coming from the satellite would be more effective than one that is oblique. I have problem to translate into English what I studied at the university a lot of years ago. It has to be with electric flux, electromagnetic flux… I am going to try to explain my reasons.
Offset dish is “oblique” compared to the satellite beam direction. So the effectiveness is less than the one should have according to the diameter. Exactly, it would be = diameter x cos (Ѳ).
“Prime Focus” dish is perpendicular to the beam direction. In this case, cos (Ѳ)=1 so this would be the best performance.
On the other hand, PF has a shadow, and most of you agree that offset dishes are better than Prime Focus ones.
Electric and electromagnetic Flux (from Wipipedia)
The concept of electric flux is useful in association with Gauss’ law. The electric flux through a planar area is defined as the electric field times the component of the area perpendicular to the field. If the area is not planar, then the evaluation of the flux generally requires an area integral since the angle will be continually changing.

Here, a small surface, but being perpendicular to the beam direction has the same "beam rays" passing through it.

Sorry, I can't upload the pictures.

 

[sinbadmarino]

Two pictures. No esay to draw them.

 

[altman]

true but not really pertinent because:
-lnb and arms block less than 1% of the reflector area on a 1.8m PF
-a 1.8m offset has more area compared to a 1.8m PF, but that area doesn't translate into more gain because of the offset angle

viewed from the satellite, they are both round ;)

 

[Huevos]

PF has a shadow

Along with "you mustn't use connectors" this must be one of the most overstated satellite myths.

1% difference in dish area equates to 0.04dB, too small an amount for even the best meters on the market to measure.

 

[sinbadmarino]

a 1.8m offset has more area compared to a 1.8m PF, but that area doesn't translate into more gain because of the offset angle viewed from the satellite, they are both round ;)

That's what I was trying to say. The surface in a PF is perpendicular to the satellite. In a offset there is an angle, it's a lateral surface viewed from the satellite, and that should be a reason to have less gain.

Anyway, in the end the real thing is what the signal meter says.

 

[altman]

I see what you are trying to say, but neither are perpendicular, its a curved surface on both cases, the case you used applies to flat reflector surfaces like the ones used in microwave links back in the day

as we seen on a few posts before, the most important component is: the installer ;)

 

[Archive4]

Last day = April 12th
Duration = 13 minutes

Huevos, I assume we will not see the signal drop tonight as we are now past 12 April, is because the sat will not go into shadow tonight?

Also, can we expect it to return later in the year, as with the solar eclipse?

 

[joddle]

Also the shadow of the

I see what you are trying to say, but neither are perpendicular, its a curved surface on both cases, the case you used applies to flat reflector surfaces like the ones used in microwave links back in the day

as we seen on a few posts before, the most important component is: the installer ;)

That is only sort of true - because having an inclined curve still means the actual area seen by the satellite is smaller than the actual area of the dish whereas for a PF dish it sees the whole diameter of the dish. What is in fact happening is that the offset dish uses its larger surface area to focus the same amount of signal to the LNB as would a PF dish of the same diameter as the shortest side of the offset - so in fact the argument used does still hold!

 

[Huevos]

Huevos, I assume we will not see the signal drop tonight as we are now past 12 April, is because the sat will not go into shadow tonight?

Also, can we expect it to return later in the year, as with the solar eclipse?

Yes, for about 7 weeks each equinox.

 

[Huevos]

Signal level is crap this week. At some points almost 1dB SNR lower than in February.

 

[lovelyperson]

Signal level is crap this week. At some points almost 1dB SNR lower than in February.

Yep......friend 1km soth of Torrevieja (Alicante) lost his on a 1.4m....even the normally strong 10818 V having been lost!----------but yesterday seemed to improved.

Think you will agree summer has arrived for us here. Enjoy your day.

 

[Pride Of Cucamonga]

Yep......friend 1km soth of Torrevieja (Alicante) lost his on a 1.4m....even the normally strong 10818 V having been lost!----------but yesterday seemed to improved.

Think you will agree summer has arrived for us here. Enjoy your day.

Is 2F weaker than usual too (i.e. is this environmental factors)? I haven't noticed any 2E picture breakup, but we've had clear skies most days.

 

[Huevos]

Both are weaker. Here's a graph of the last 24 hours compared to the last week in February.

 

[Archive4]

Both are weaker. Here's a graph of the last 24 hours compared to the last week in February.

Is the 19:30 drop on one txp or all?

 

[Huevos]

Just one. 11053. Probably just the receiver not locking quick enough.