Feedhorn for Prime Focus 11.7 to 12.2 ghz

canofan

I have been searching unsuccessfully for a DBS feedhorn to use on a prime focus dish.
This is to be used with a single polarity LNB covering only the DBS-11.7 to 12.2ghz band.
They do exist in offset versions but cannot be used because of the different f/d ratio.
My quest is motivated by the belief that it would yield a better performance with such LNB than my wideband feedhorn.
Any ideas? Thanks.

Steamgauge

Try _www.Satellitesuperstore.co.uk --- LNB or feedhorn pages

canofan

I have already looked there.
They have only universal feedhorns.
I need the equivalent of a Channelmaster 611-6060-10 but for prime focus dishes.
Thank you for responding.

aba

try here
h**p://www.satellitesuperstore.co.uk/feedhorn.htm

just found several feed horn conversions kits for prim focus dishes

canofan

Thank you. I rechecked.
I have many feedhorns for prime focus.
They are all designed for universal LNBs from 10.9 to 12.75 GHZ.
What I need is a narrow band feedhorn specialised in the 11.7 to 12.2 GHZ just the same spec as a Channelmaster 611-6060-10 but for prime focus.
I think, for me, it is the pot of gold at the end of the rainbow.
This is why I removed my triax140 prime focus for the lack of the adequate feedhorn and replaced it by an offset triax110 with a CM feed+ Norsat 7706A for verticals and it works fine.

Steamgauge

Have a look at SPC, It is a Japanese company but they have an American subsidery SPCAmerica. They do professional LNB's and feedhorns and they might be able to advise.

Tsiklon

SeaveyAntenna have a huge range of feedhorns - but be prepared to pay well!

Turok

only have the incacom prescision feed horn,in gold,and cheap silver vesion,you can adjust the f/d ratio,it works on all freqancy range,buy tihis and your problem should be away,when you find no other,i think,its the only solutiuon!

canofan

Yes Turok I have the Invacom feedhorns but they are Universal.
I still have to find a feedhorn for PF in the range of 11.7 to 12.2 exclusively.
Thanks you guys for the Seavey and The SPC, but nothing there either.

Tsiklon

h**p://www.seaveyantenna.com/catalog/p80/pg80-83_85.htm
"Standard feed tuning is 11.7 - 12.2 GHz."

See ESA-120.

canofan

I shall have to figure out the F/D for my Triax 140 PF.
This is required before moving ahead.
Thank you again.

Trust1

F/D calculation (Att.)

Attached Images

fd berekening.jpg (57.8 KB, 40 views)

__________________
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Gr. Trust1

Channel Hopper

I have a few Chaparrall feeds here which are with the blue cap marked with a '12'. The only difference appears to be the neck is 1mm smaller in diameter

Try sleeving the throat with a piece of copper piping.

__________________
There is a very fine line between "hobby" and "mental illness"

canofan

So
f/D=D/16d
Thank you mate

@channelhopper
Very interesting.
But surely there must be more difference hidden inside.
If the rings are similar, the waveguide inside must be profiled differently.
I discovered that such feedhorns could be tuned to the frequency range required.
PS: I just measured the D and d of my Triax 140 pf.
I have got D=144cm d=26cm
so my f/D=144/(16x26) ==0.346

Turok

hello,does anyone have a orginal datasheet of trax 1,40m antenna,they dont reply to my mails..
when you have a 11 to 12 ghz feedhorn,is then the signal performance better,how much?
and what channels,you want espasely reveive with it?
please post picutures,when you get the feedhorn,you looking for !thx

canofan

I see that you want to revive your Triax140PF.
I do not have the data sheet and nobody was able to supply it. The f/d is 0.34. I know though that it is a relic from the analog era. Mine was probably reaffected to digital later. I obtained it equipped with an SMW WDL1000E (two outputs one for high and one for low, and does not therefore respond to 22khz) and a feedhorn with a transition. The problem is the boss which also allows you to skew the LNB, very rudimentary and awkward to use, with too small an angle for tweaking. The output side of the feedhorn is rectangular WR75 and so is the transition.
I was not happy with the combination and removed it.
My fringe area is Nilesat with Showtime rain or shine. Since I know nothing about the feedhorn used, I decided to do it right and find a proper feedhorn for its intended usage: 11.7 to 12.2ghz, give it another try, and use it with a Norsat 4206A, for the verticals in Nilesat initially. If I succeed I shall try using it for the horizontals in a bid to improve further on the Channelmaster/Norsat combination. This combination gave me 3.5 db increase making my CM120 the equivalent of an 180cm dish.

Turok

sounds realy great!
thx,for your report!

my triax system is a little bit complex to install, it has a 130 kg ground foot with dual axis extensions,@ the moment i dont find the lnb holders,in my garage,maybe my grandma throw it away haha we wil see,if i dont find it imidatly,i need the exact size of the iron streps,to make new one!

i wondering,why this triax antenna,is so light,in weight,and so good in performace!

after testing nearly 10 difrent flange lnbs,norsat i dont have,my final favorite is the inverto white tech series 0.3 db,performs realy great on nilesat h,i post pictures in the nilesat topic,but it crashed ,with the gegroy lnb holder,and then i cant fix it corectly and must fix ist ,with nylon for water protection,best,thing,you write me a mail,other wise we will going offtipic here,what i dont want!

okay,back to the feeds, i have the gold invacom prescision feed from usa,but it would be very intresting,how many gains,i can realy win,with this one,then,i have a silver feedhorn,that looks a little bit smaler,but technicaly the same,bought last year on Ebay germany,but when i look on incacom website,i only see gold versions,that means,maybe i have a self made feed made by an amateuer,or what ever !?
when you want,to optimeized 12 GHZ the humax 0,4 db performs very well in 12 ghz range,no lnb,performs good over the complete freqency spectrum,some better in 11 ghz the other on 12,like mti not good in 12 ghz but very well for bbc on the lower 10 ghz range!

also,an orf technican told me,they designed special 12 ghz lnbs,that are specialy made and optimeized for 12 ghz only,the reason is,in cable operatpr systemes,are a lot of meters of satelite cables,and transmitters,to the normal vhf range/dvb c or what ever,so longer the cable,so lower,the signal in the highest range,in 12 ghz,when the lnb is good and high quality,you can compare this a little bit,to get better results,it always depents,how good is the quality of sat cable,and how long!
good luck!

for nilesat h,you can contact charly 20 here on board,he is also from belgin maybe,he can help your good luck!!!!!

koansrc

canofan, could you explain this Channelmaster/Norsat combination in more detail ?

canofan

It is an aluminium dish.. but Turok, I am not sure that it is so good.
This is what I am trying to find out.
Once I am able to set it up properly, I should be able to tell. Perhaps it could behave as well as an old CM140.
The boss is certainly inadequate. I am thinking of getting the universal prime focus feedhorn from sarellitesuperstore in order to use its boss, which seems adequate. This will allow me to adjust the feedhorn which came with the triax140 and also to give the SMW WDL1000-E a proper evaluation.
I shall be posting pictures of the actual boss, feedhorn and SMW lnb that came with the dish.
Perhaps then, someone could shed more light on the matter.

@koansrc
I shall address your request later, as I have to go now.

canofan

@koansrc
I am preparing a digest about this subject.
In the meantime the following threads may be useful browsing.

Nilesat: Narrower Band LNB's and Gain.
Evaluation of Invacom's QPF-31 LNB for use in Nilesat's fringe areas..
Norsat LNB Whats Wrong ? pics

koansrc

oh yes... I have tried to follow those threads. I can't

BombedOne

check shop (dot) unitorg (dot) com

This is Russian online store, they do have C120 Feedhorn for prime focus dishes with adjustable F/D.

canofan

Difficult for me Cyrillic languages.
But thank you anyway

BombedOne

They do have english version of website - just click on small flag in the middle. Price for that feedhorn is $19.

SatFreak101

Invacom makes a c-120 prime focus feedhorn (#ADF-120) and they have several models of lnb's for it but none are exclusively 11.7-12.2. They have universals that are single, twin, quad and quatro. They also have one that has 11.7-12.2 linear(two outputs) and circular 12.2-12.7(two outputs). These latter ones are used in North America.