Astra 2F: Iberia & Balearics Discussion

[Huevos]

I managed to tune in my friends 1.35M offset

Have you measured the dish yourself? Could you post the sizes for the vertical and horizontal dimensions please?

 

[madridman]

Hello everyone!
This is my first post but I've been following the 2F threads with interest for the past few weeks. I haven't posted a report yet because I've been away for the past week but tomorrow I'll send in a report from where I live (45km north east of Madrid)

@ bonou2: I appreciate your regular updates from Madrid

@ davidcmadrid: I'd be interested to know what type/size of dish you decide on in the end, as I'll probably have to buy a bigger dish soon as well.

 

[Andy_Madrid]

i am 30km north of Madrid (Torrelaguna) and my 1N signal is great on a 60cm - not a sniff on the 2F tests for the BBC channels.

not had chance to try my 1.25 (recently moved house) - but i am aiming to do it if i can loose the wife for a day

 

[buckshee]

Have you measured the dish yourself? Could you post the sizes for the vertical and horizontal dimensions please?

Facing the front of the dish, and measuring the catchment area 1.39M x 1.23 M approx.
Sold as a 1.35 around these parts.

 

[timo_w2s]

Facing the front of the dish, and measuring the catchment area 1.39M x 1.23 M approx.
Sold as a 1.35 around these parts.

...but 1.2m everywhere else. ;) I think these exaggerations in dish sizes are skewing the results somewhat.

 

[buckshee]

...but 1.2m everywhere else. ;) I think these exaggerations in dish sizes are skewing the results somewhat.

Where is the correct position to measure? Is it the outer rim, or the front face of the dish. This dish is certainly sold throughout Murcia as a 1.35M offset.

 

[Chazz]

I've not come across a standard legal definition of how to measure your dish, but 1.39 * 1.23 elliptical is clearly a larger surface area than that of a circular 1.2m dish.
A conservative estimate would be 1.3m and a salesman's estimate would be 1.35m ;)

 

[Cala d'or]

A Gibertini OP125L facts and figures

Reflector size 124.5 cm x 133.5 cm
Reflector effective area 121.0 cm x 130.0cm

This is their 125 model , it could be called anything between 120 and 135 !

It's no wonder there is confusion !

I used this model briefly in Mallorca on 2D , it was never big enough.

It got stolen from the roof this summer !

I have a 1.8m Prodelin now , much much better !

By the way it measures 178.00 cm x 194.00 cm . I will report some figures early feb when I go back , it's to be hoped that 2F is all ok by then .

I don't like all this waiting.

Regards to everyone , it's been interesting reading all the posts.

 

[PaulR]

The effective size of an off-set dish (except for specials like the Sly, Raven and Wavefrontier dishes) is the horizontal measurement. If you look at the dish from the LNB's point of view then the vertical measurement shrinks and the diah becomes almost circular.

Strictly speaking the measurement should only be of its effective curved area so shouldn't include any of a rolled off edge for instance. Calling a 1.78m dish a 1.8m is marketing. Calling a 1.2m dish a 1.35m is, unfortunately, the Spanish (and Portuguese) way but is fundamentally wrong.

 

[hairybadger]

I've not come across a standard legal definition of how to measure your dish, but 1.39 * 1.23 elliptical is clearly a larger surface area than that of a circular 1.2m dish.
A conservative estimate would be 1.3m and a salesman's estimate would be 1.35m ;)

Well - the area of a circle is easy enough to measure pi.r[sup]2[/sup] . The area of a perfect ellipse is pi.(a.b)/2 ( a and b being half of width and height). If we eliminate pi we can calculate the equivalent diameter of a circular dish by taking the square root of A.B (A and B being the width and height), so if width and height are 1.39 and 1.23, this gives us an effective diameter of 1.31 (or near enough).

 

[trevortronix]

I have just tried my Dark Box on a customer's 2.4m prime focus and 11024H showing nothing. Near Faro, Algarve.

 

[trevortronix]

Where is the correct position to measure? Is it the outer rim, or the front face of the dish. This dish is certainly sold throughout Murcia as a 1.35M offset.

These dishes are sold locally as 133cm. And those spindly little 50mm brackets don't stand up to the wind very well.....

 

[davidcmadrid]

@andy_madrid look forward to your report , getting an idea of whats possible / needed is valuable. So knowing if a 1.25 is good enough will be interesting as it will be a report an antenna smaller than bonou2. Based on everything i have read , I suspect it will catch a signal but may have little weather margin ,, if it does it will be a nice surprise

@madridman Yes having bonou2s reports is valuable and a further report from Andy will help me a lot in my decision because it will give an idea if there is margin at 1.35 .. I suspect a min of 1.4 or even 1.5 will give me total margin but im still open minded. Apparently the lower freqs /Psk likely to be used are a bit harder to get and we dont know the power of the TP when all the stations switch over .. signal is being reported in some ways as " almost too strong " in the UK , so its possible there will be lower power when all is live on 2F. I will have a 50 meter cable run so will prob need to compensate for the loss associated with that. finding a reasonable supplier here close to MAdrid is a bit hard but i found one place that seels a Gibertini 1.5m for 400 euros.

 

[madridman]

@davidcmadrid Yes, I'm looking forward to andy_madrid's report too.
I'll be looking into the possibility of a gibertini 1.25 or 1.50 as well. I've also seen a 1.5m FTE Maximal dish (150x163cm or thereabouts) for 220 euros, but don't know if it's any good.

 

[buckshee]

These dishes are sold locally as 133cm. And those spindly little 50mm brackets don't stand up to the wind very well.....

Not had many blow off line yet. Blowing off the wall altogether - well thats another story.
I have taken my final look at this dish, as I now have it pointing a 7W for the footy not 28.2E. Plenty of these dishes going begging when the old 2D was around. Only too pleased for me to take it away when I fitted them a 1.9M

 

[PaulR]

...we can calculate the equivalent diameter of a circular dish by taking the square root of A.B (A and B being the width and height), so if width and height are 1.39 and 1.23, this gives us an effective diameter of 1.31 (or near enough).

Maybe if you're looking straight on at it but, as my post above says, you have to look at it from the LNB's direction.

 

[Huevos]

I have just tried my Dark Box on a customer's 2.4m prime focus and 11024H showing nothing. Near Faro, Algarve.

Tuners are not too sensitive in those receivers. Also it doesn't prove the dish is correctly aligned

 

[Huevos]

If we eliminate pi we can calculate the equivalent diameter of a circular dish by taking the square root of A.B (A and B being the width and height), so if width and height are 1.39 and 1.23, this gives us an effective diameter of 1.31 (or near enough).

The only thing we are interested in is how big the dish is electrically, and that is measured horizontally, and can be directly compared with a PF dish. Seen from the satellite the cross section of an offset dish is circular not elliptical.

 

[Huevos]

@davidcmadrid Yes, I'm looking forward to andy_madrid's report too.
I'll be looking into the possibility of a gibertini 1.25 or 1.50 as well. I've also seen a 1.5m FTE Maximal dish (150x163cm or thereabouts) for 220 euros, but don't know if it's any good.

The FTE dish is steel, whereas the Gibertini is aluminium. The Gibertini is much easier on a motor, but if you are running fixed there's not going to be much difference between the two once they are set up. Personally I really like my Gibertini (165x155cm).

 

[buckshee]

The only thing we are interested in is how big the dish is electrically, and that is measured horizontally, and can be directly compared with a PF dish. Seen from the satellite the cross section of an offset dish is circular not elliptical.

Huevos - As you asked originally for the dimensions of my dish, what do you deduce from the figures. Were they of any help ?