Eutelsat 7A Ka band test using no-name feedhorn

[Llew]

After sawing off the feedhorn from an old combined feedhorn/magnetic polariser that was attached to an SMW Ku LNB I got on fleabay, I noticed the 'bore' diameter was within a millimeter or two of a Ku circular feedhorn.
Coupling this to my upper band XMW LNB, the signal level results were to all intents and purposes the same as with the FD9000 feedhorn which is normally associated with the XMW.

No idea why the feed's diameter is smaller than a typical Ku feed, maybe something to do with it being coupled to the magnetic polariser?

Tested on an overcast 16/10/2013 on a Triax TD88 pointing to Eutelsat 7A 7E Ka TP's.

 

[Vipersan]

Nice Job Llew ..
good results..
You could try lining the feed with sticky backed aluminium tape as I did..
It did seem to help..but maybe conditions changed in the interrim.
If you do try this I'd be interested to see if you get any improvement ..and mine wasn't just a fluke.

 

[Llew]

Tried that today VS after your success with that, no observable improvement. Clear sky this morning, and the signal on CCTV has dropped about 1.5 dB. Conditions maybe alter over the day (original readings taken late afternoon).

 

[Vipersan]

Tried that today VS after your success with that, no observable improvement. Clear sky this morning, and the signal on CCTV has dropped about 1.5 dB. Conditions maybe alter over the day (original readings taken late afternoon).

It may just be that he no name feed is a better match altogether..
I'd like to get my hands on one..
any offers ?

Also ..a small sheet of opaque polycarbonate 0.75 mm thick I ordered..arrived this morning ..
I shall be cutting a disc to pop on the Gibby feed later ...
I need some weatherproofing ..and hopefully this will be more transparent than the original Gibby feed cap..
Maybe ..maybe not ..but it's worth a go.

 

[nelson_b]

It may just be hat he no name feed is a better match altogether..
I'd like to get my hands on one..
any offers ?

hi V.S. --that feedhorn looks a bit familiar --
i think i may have one -- somewhere -- i will have a search tonight ---

 

[Vipersan]

Nice one Nelson..
you realise of course ..if should turn out to be the right one ..
I'll be attacking it with a hacksaw ?

 

[Llew]

hi V.S. --that feedhorn looks a bit familiar --
i think i may have one -- somewhere -- i will have a search tonight ---

Certainly an odd one nelson. IIRC it was shown in the listing as being on a prime focus dish.

 

[Llew]

Different Triax TD88 dish, results for the usual 16E Equinox and Golfe TP's using the feedhorn (other Triax blocked to 16E by greenhouse).

 

[nelson_b]

Certainly an odd one nelson. IIRC it was shown in the listing as being on a prime focus dish.

hi - your picture is pretty much how mine originally looked -- it came with my 1.8 offset channel master many years ago .. and worked well - then i upgraded to digital and bought a correct c.m. offset feed .

@Vipersan -- its already been hacksawed from its polariser as i had it attached to a c120 l.n.b. in the past --- it won,t have been thrown away --

 

[Vipersan]

Nicely done Llew ..
I've yet to lock Equinox at my location
Golfe and LTM is all ..
doh!

 

[nelson_b]

hi - V.S.
yes - i found the feed it was the same - a feedhorn / polariser combined -
the diameter through the feedhorn is standard k/u 18.5 mm it then stepped down to 12.5 mm through the polariser which has been cut off ---
the pics show the ---- feed - -- the polariser that i cut off minus its probe/teflon insert --
and a couple of other bolt on polariser,s ---- that i,v cut up for the c120 flange with the probe/ teflon bit still in.(same sized insert) - if you think any of its of use to you - i will drop it off next time i,m in your area . or post to you if you wish

.

 

[Vipersan]

Cheers Nelson ...I'm sure I can still use it ..
Where there's a will..etc