Maplin 180cm dish €115

Zaphod

Maplin have released a new catalogue which has quite a bit more satellite stuff than they previously had e.g. Fortec Star blindsearch and HD receivers, Diseqc switches, Metronic transparent dishes etc. However, the one item that caught my eye was a Fortec Star 180cm petalised prime focus dish for €115. You can get a tenner off with the catalogue vouchers.
http://www.maplin.co.uk/Module.aspx?ModuleNo=47165&doy=21m8

Some additional pics form a US site here:
http://www.sadoun.com/Sat/Products/Fortec-Star/Dishes/FS6D-180-CM-C-Ku-Prime-Focus-Dish-Antenna.htm

Although it has an az-el mount, it's the same construction as the 2.4m here and can be motorised with little effort.
http://www.boards.ie/vbulletin/showthread.php?t=236817&page=3&highlight=twins

Boggles

Nice, can you walk into a store in Ireland and buy it?

Zaphod

Maplin have stores in Dublin, Cork, Limerick, Galway and Belfast. The catalogue says "special delivery requirements may be required for this product" so they might not keep them in stock, but have them shipped over with next batch of stock from UK. In my experience, it takes Maplin about 1-1.5 weeks to get in stuff which isn't in stock.

Boggles

It's a very good price, will give them a ring today and order one, does the price directy translate from pounds to euro? Are you getting one?

Zaphod

No, the price doesn't compare exactly, but you have 21% VAT in Ireland + 17% in the UK - €115 is the price in the Irish catalogue. Not getting one now (I have enough stuff cluttering up the place!) but perhaps later on in the year.

Boggles

I have the Autumn/winter 2004/05 cat, is there a newer one out lately?

Zaphod

The new one is 2005/06.

Just a couple of thing to remember before you go splashing out:

The dishes are prime focus, so a standard offset LNBF will work with them, but not very efficiently.

The dishes have no holding brackets for Ku-band LNBFs but they will attach directly to a C-band LNBF. The bracket I use came with with the LNBF.
http://www.kristal.com.au/product.asp?id=11

If you're erecting the dish, make sure it's securely fitted in case of wind - see bottom of thread.
http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ru_en&trurl=http%3a%2f%2fwww.forum.alyno.ru%2fphpBB2%2fviewtopic.php%3ft%3d370%26start%3d0%26postdays%3d0%26postorder%3dasc%26highlight%3d%26sid%3d5b596528175c6682b53a9d3f97191b8d

Capt'n Midnight

Zaphod wrote:

The dishes are prime focus, so a standard offset LNBF will work with them, but not very efficiently.

Is it as simple as pointing the LNB's feed horn at the centre of the dish ?
Do you loose signal because of the way LNB's are usually designed for oval dishes ? (especially SKY minidish LNB's) - if so what would the effective size of that 1.8 dish be ?

Smeagol

A KU-Band LNB on my 180cm ChannelMaster prime focus dish is about as effective as a KU-Band LNB on my 120cm Gilbertini offset dish. Tested mostly on Sirius5°e and Thor1°w.

Zaphod

Capt'n Midnight wrote:

Is it as simple as pointing the LNB's feed horn at the centre of the dish ?
Do you loose signal because of the way LNB's are usually designed for oval dishes ? (especially SKY minidish LNB's) - if so what would the effective size of that 1.8 dish be ?

http://web.archive.org/web/20010112235900/http://www.smw.se/qa/qa10.htm

Capt'n Midnight

Ta - missed out on the need for a 120 degree feedhorn vs as low as 90 for offset

Great

My Reckoning

angle - half angle => => area
90 - sine 45 => root 2 => Area =0.5
120 - sine 60 => root 3/2 => Area =.75

so .5/.75 means you loose 1/3 of the Area
Ratio of Radius is 81% so same as a 147cm dish but at least less noise at the edges.. (100 degree feed horn would be better - could use mirrors/smaller secondary dish but not much point since they would not be better than 80% anyway.)

Other uses
Dish area is 2.54m2 - might be useful for solar panels / steam engine too. Although it doesn't have a hole in the centre for a telescope ..