BSC621 Ku S+Q improvement
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I hope not, but it seems that the C band lnbf won't work as well. By opening up the lnbf the back part no longer acts like a C band microwave cavity.
I made some 1/2" polycarbonate rings on yesterday. They turn out okay. I, then made the modification to the the bsc621-2. So far no difference. The c band side still works, but the ku is still not working. I think I may be a little off on my focal point on the ku side. I will do some fine tuning this weekend and try again. Pictures of my mod with 1/2" poly rings coming soon.
- give it a chance:
I don't see why moving the Ku LNB should improve performance.
Seems like it should decrease Ku reception.
HOWEVER, if you are going to give the Ku a proper test, at least read what Stogie wrote about centering his dual band LNBF.
http://www.satelliteguys.us/c-band-satellite-discussion/185240-actuator-6-footer-3.html#post2030920
I don't see why moving the Ku LNB should improve performance.
Seems like it should decrease Ku reception.
HOWEVER, if you are going to give the Ku a proper test, at least read what Stogie wrote about centering his dual band LNBF.
http://www.satelliteguys.us/c-band-satellite-discussion/185240-actuator-6-footer-3.html#post2030920
Very interesting. I apparently missed this before.
I am using a BSC621-2 on a 10 ft prime focus dish. I have tried for months to hit 97w. I hit it but only pick up 11 channels on the KU side. Maybe this will change my luck
I am using a BSC621-2 on a 10 ft prime focus dish. I have tried for months to hit 97w. I hit it but only pick up 11 channels on the KU side. Maybe this will change my luck
I'm confused as the next guy on it - but I do know that to peak the thing between C & Ku, I had to adjust the feed in the scalar in or out.
Now, why would that be if the focal point of the dish is at one particular point? It would seem that once the signal enters the feedhorn, it wouldn't make any difference where the lnb was inside...
Maybe the proximity of the C-band element interferes somehow? And by moving the Ku element away, it helps the signal???
Gaaa... it all sounds goofy...
MADD... what's yer home twenty?
Hi everyone
I have read alot of useful information onthis forum and now it's time to share my experiment
with the standard BSC-621 LNB.
One mont ago i buy a conical scalar ring and a BSC-621 C/KU lnb to experiment with my old 4
feet GI fiber oofset dish .After a week of testing and tweaking my conclusion was, on Cband
i had to much co-satellite interference !Not a big surprise but the ku side perform very
bad. Why? i dont Know... maybe the dish F/D not made for this LNB .I do it, i buy a 6 foot
prime focus dish.
A week later i start tuning the dish and lnb. Afet peaking the lnb for c Band (focal length
and F/D) now i have good signal and no more co-satellite interference on the sat i want. I
was very disappointed by the ku signal , i have lock on strong transponder only!
At that point i scratch my head!
I notice during my test on both dish , if in the bracket i tilt the lnb body at one position
quality raise to interesting number 90%. At the same time i lost the c band , this is not a
pratical solution.
After another week of thinking, i decide to separate the ku side from the lnb.I remove the
tree screw and separate them. A bit hard to separate because the rtv is very goog quality.
With my receiver beside the dish i star slowly pulling out the ku lnb until i find the best
position for maximun quality on my receiver. I find between 1/2 to 5/8 inchs was the best
distance.
To attach the lnb (ku) to it new positon i use tree 1/2" plastic standoff spacer used for
supporting pcb(printed circuit board) with longer screw.I seal the gap with a strip of
aluminum sheet and silicone RTV.
I think this lnb was desing to be used with dielectric plate in place , ku wave goes right
at the ku waveguide opening with the plate. Without the plate that chage the speed of the
wave and focus point at the same time.
The C band section of the tube act as a wave guide, for ku the wave is bounce on the wall
and then focus again and bounce again until wave focus and enter the ku waveguide .That my
theory.
If some boby try this mod post your result.
Since i made the mod i see no degradation on c band.
Any comments welcome.
Nick
I have read alot of useful information onthis forum and now it's time to share my experiment
with the standard BSC-621 LNB.
One mont ago i buy a conical scalar ring and a BSC-621 C/KU lnb to experiment with my old 4
feet GI fiber oofset dish .After a week of testing and tweaking my conclusion was, on Cband
i had to much co-satellite interference !Not a big surprise but the ku side perform very
bad. Why? i dont Know... maybe the dish F/D not made for this LNB .I do it, i buy a 6 foot
prime focus dish.
A week later i start tuning the dish and lnb. Afet peaking the lnb for c Band (focal length
and F/D) now i have good signal and no more co-satellite interference on the sat i want. I
was very disappointed by the ku signal , i have lock on strong transponder only!
At that point i scratch my head!
I notice during my test on both dish , if in the bracket i tilt the lnb body at one position
quality raise to interesting number 90%. At the same time i lost the c band , this is not a
pratical solution.
After another week of thinking, i decide to separate the ku side from the lnb.I remove the
tree screw and separate them. A bit hard to separate because the rtv is very goog quality.
With my receiver beside the dish i star slowly pulling out the ku lnb until i find the best
position for maximun quality on my receiver. I find between 1/2 to 5/8 inchs was the best
distance.
To attach the lnb (ku) to it new positon i use tree 1/2" plastic standoff spacer used for
supporting pcb(printed circuit board) with longer screw.I seal the gap with a strip of
aluminum sheet and silicone RTV.
I think this lnb was desing to be used with dielectric plate in place , ku wave goes right
at the ku waveguide opening with the plate. Without the plate that chage the speed of the
wave and focus point at the same time.
The C band section of the tube act as a wave guide, for ku the wave is bounce on the wall
and then focus again and bounce again until wave focus and enter the ku waveguide .That my
theory.
If some boby try this mod post your result.
Since i made the mod i see no degradation on c band.
Any comments welcome.
Nick
Attachments
Thank you for your very clear pictures! - :up
That LNBF has had a pretty bad reputation on Ku for the several years it's been around.
Other LNBFs, such as the Ck-1 and the DMX741 seem to work adequately on Ku, but require delicate centering on the dish to work effectively.
Hope other members will try your solution and confirm.
Thanks again -
That LNBF has had a pretty bad reputation on Ku for the several years it's been around.
Other LNBFs, such as the Ck-1 and the DMX741 seem to work adequately on Ku, but require delicate centering on the dish to work effectively.
Hope other members will try your solution and confirm.
Thanks again -
Out of sheer accident, I noticed that using this LNBF (BSC621-2) with a flat scalar ring on a mini-bud (1.2M) that you can substantially improve the reception signal quality in the C-band spectrum with another rather unique modification.
While trying to adjust the scalar ring position, I noticed that the signal quality on C-Band was substantially improved when my finger-tips were just barely over the outer scalar ring. I mentioned this to Walrus and he experimented a little with this and found that it also improved his C-band reception.
Basically, out of curiosity I guess, Walrus grabbed whatever he had on hand - a metal socket that just fit in this outer ring snugly so that it would stay in place - and found the results desirable if the socket was placed in the right spot.
It therefore appears that some sort of parasitic element, properly positioned in the outer scalar ring, will improve the signal on at least the C-Band signals for a mini-bud dish.
I thought others might like to test this out for yourselves, as well as the modification that Minimo has mentioned.
I wonder if placing a thin, short aluminum tube (same diameter as the outer ring on the rear assembly of the BSC621-2) when it is extended would help as well.
RADAR
While trying to adjust the scalar ring position, I noticed that the signal quality on C-Band was substantially improved when my finger-tips were just barely over the outer scalar ring. I mentioned this to Walrus and he experimented a little with this and found that it also improved his C-band reception.
Basically, out of curiosity I guess, Walrus grabbed whatever he had on hand - a metal socket that just fit in this outer ring snugly so that it would stay in place - and found the results desirable if the socket was placed in the right spot.
It therefore appears that some sort of parasitic element, properly positioned in the outer scalar ring, will improve the signal on at least the C-Band signals for a mini-bud dish.
I thought others might like to test this out for yourselves, as well as the modification that Minimo has mentioned.
I wonder if placing a thin, short aluminum tube (same diameter as the outer ring on the rear assembly of the BSC621-2) when it is extended would help as well.
RADAR
Nick-
This is an important contribution and your explanation sounds good. Interesting about the dielectric plate. Great pics.
Thanks!!!!
This is an important contribution and your explanation sounds good. Interesting about the dielectric plate. Great pics.
Thanks!!!!
Not new
If you look back at Satcom1 mini-BUD posts, he describes this about two years ago. what's old is new. There were pics.
If you look back at Satcom1 mini-BUD posts, he describes this about two years ago. what's old is new. There were pics.
Nice, i'll see of I can do the same on my six footer, that particular LNBF while not being as good as my old Bullseye on C-Band, has given me great results on both an 8ft and a 10 ft solid dishes on the Ku side.
M.
M.
Yes, and several years before that, the guys on the forum were making up conical scalars. -
A necessity for offset feed dishes (well, actually because of their F/D ratio)
More recently, ACradio noted critical placement of a flat scalar on an offset dish.
http://www.satelliteguys.us/c-band-...g-c-band-my-1-2-meter-dish-2.html#post1735458
Nick,
What if you skew the C band for max, then remove screws from Ku lnbf section and skew the Ku band for max. No extension just different skew positions.
Thanks Nick.
I have both a BSC621 and a DMX741. When schedule allows I'll try this on both and report back.
I have both a BSC621 and a DMX741. When schedule allows I'll try this on both and report back.
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