Channel master frankensteined

[Captain Jack]

I tried it with 1.2 Fibo somewhere in 2016

View attachment 154493

How was the result compared to without the feedhorn?

 

[Trust]

I made a smaller TRF with the size of the Fibo KU horn , there was no difference in signal just have to move the lnb closer in one of the matters .
Dont know exacly , tried already to find the topics from those days .
Searching for pictures seen a date of febr 2013

 

[anto@]

I found this object in a friend's warehouse, and having seen a topic in this section that talks about it, I could install it on my rotor feed.
at the moment it has been removed for extraordinary maintenance and is therefore within reach.
question?
Where should the sub reflector be installed?
in the point where the lnb was originally located?
I have a laminas 180 with at the moment 2 lnb of C - 1 Ku - 1 KAl in the center I should have a free space hoping that it will fit
I accept advice
then maybe I won't succeed but I want to try I don't know when!!!!

 

[RimaNTSS]

Where should the sub reflector be installed?

Fibo SUB has 2 focal points. The phase center of the Fibo feedhorn co-located with one focal point. And the second SUB focal point must be co-located with the antenna's focal point.

 

[anto@]

Fibo SUB has 2 focal points. The phase center of the Fibo feedhorn co-located with one focal point. And the second SUB focal point must be co-located with the antenna's focal point.

I understand your theory but in practice?
What measurements should be used?
laminas 180

 

[RimaNTSS]

laminas 180

It is your antenna Do not you know where it's focal point is?

 

[anto@]

It is your antenna Do not you know where it's focal point is?

I think that's where the LNB is!!
so the center of the sub will be the center of the LNB cap
or am I wrong!!!

 

[RimaNTSS]

in practice?

The simplest way IMHO is:
- point your antenna to your due-south satellite ;
- remove original feedarms and LNB-holder;
- install new feedarms with Fibo SUB and feedhorn;
- adjust the SUB and feedhorn till you get maximum signal on due-south satellite.

 

[anto@]

ok in the next few months I'll try to do some tests for now it's cold and time is short
having 1 lnb on the side in the exact position I will be able to make comparisons and find the best point
for now I thank you

 

[a33]

so the center of the sub will be the center of the LNB cap
or am I wrong!!!

Here is a picture with the co-located focal point, in the circle:

Channel Master 1,2m issue

And this is my Channel Master 1,2m Frankensteined to Gregory-type :shh

www.satelliteguys.us

It shows the path of the signal very well.

Greetz,
A33

 

[scopus]

After some tweaking and adjustments, I finally have C Band at optimal position, with a healthy 199 channels off 40W..

 

[anto@]

I see what you are saying but would using the sub reflector remove the need for the conical scaler as the sub reflector is managing the ilumination of the main reflector? I see the original Fibo ku feed is just a conical horn not a corrugated feed horn.

the Fibo feed inside is wavy like any KU feed
today I shot a video that confirms that it is corrugated inside

 

[anto@]

I wonder if C band would also benefit from a dual reflector set up though, even without a full feedhorn.

That's right, it's wavy

 

[RimaNTSS]

A friend of mine got Fibo 90 with broken feedhorn (upper part was missing). I lent him the original feedhorn and his father made a copy of it and attached to the original lower part. I liked this piece of art so much that exchanged my original fibo feedhorn to it.

 

[scopus]

This picture isn't going to win awards but here was my thinking...

View attachment 154479

Following on from this..I have tweaked the original design to what CJ has suggested in this drawing. Indeed after testing,I did find over a half a dB drop in signal with the C band signal looking over the sub reflector. Quite a big job but worth if for the gain..

 

[Captain Jack]

Patent pending obvs.

 

[scopus]

Mk2 version, everything made more compact..

 

[John]

Mk2 version, everything made more compact..View attachment 156670View attachment 156671

Educational & Inspirational to fellow tinkerers, backed up with full size hi res pictures .

 

[scopus]

Educational & Inspirational to fellow tinkerers, backed up with full size hi res pictures .

New phone explains the pictures

 

[John]

New phone explains the pictures

Doing a fabulous job ..... re: the 'inspirational' reference , who can spot the rain cover ? and who can give me the original use and make for the item. Tinkering at it's best here folks.