Rube Goldburg and I are good friends. Cascade, Im not sure the internal Ku waveguide idea is worth persuing, 3/4" copper was fairly easy to work with, square stock converted to round Invacom sounds tricky. Spindoctor, today I talked with a localy well respected machinest/machanic. He felt that I souldnt have to aneal the back of the ASC421 in order to safely remove the back of it. I just get this sinking feeling in my stomac to think of putting a perfectly good 421 in my lathe and removing the back. Is the photo of a home built conversion or manufactered unit ? Any comments on it performance ? I notice the Ku seems to have a flat scaler just before it , looks that way. I dont notice a polarizer for the C band probes. I dont know if I should remove the vane at the back of my 421 or leave it and add another 6" of C band wave guide before adding Ku. The Russians have commented about removing the polarizer and going to TP edit and switching H to V or vise versa.
120cm dish with C-Band performance - Now with HD!
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ALEC
that is a manufactured model it sells for 55.00 dollars
there are 3 companies that i know that make such product
reception is good ....there is also one on EBAY used of course
the way they made this combo is little different, thats why think it works well.
i will inquire with a company to find out more
john
that is a manufactured model it sells for 55.00 dollars
there are 3 companies that i know that make such product
reception is good ....there is also one on EBAY used of course
the way they made this combo is little different, thats why think it works well.
i will inquire with a company to find out more
john
I have been following this thread and just got my 1.2m CM dish setup. I have everything but the lnb and I just want to get everyon's opinion on this lnb feed. It is made by Channel Master and is featured on their Type 120TX dish. It has every feature that you guys have been takling about. Give me your input.
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That looks just like the assembly I'm playing with on my Starband dish, filter and all. The 'stubby' lnb mount takes the transmitter and the longer one (the extention is a filter) is where the LNB would go. I believe this is / was for a Satellite Internet setup. Judging by the size of the waveguides I'd say they are Ku only.Dishpointer said:
On mine I put the LNB where the transmitter was and am limited to Vertical polarity.
The second pic is how it came on the dish - transmitter and all.
Specifically reguarding the feed though - I'd guess it's for Ku only and uses a C120 flange.
Shawn
The Dish specification manual states, "Available with C-Band or Ku-Band feeds." Here is a link to that manual: http://www.andrew.com/search/docviewer.aspx?docid=6834
Alec:
Any more thoughts on the design where you just chop the back off an Astrotel or 421, and insert a Ku lnb? Since I now have a spare 0.6 DMS Universal Ku lnb, and a spare Astrotel C-band lnb, I'm seriously considering chopping the back off and trying it for myself. The only thing stopping me is that I don't think a dremel tool will cut it very well
Ironicly, both lnb's have the exact same design inside- both use the silver rod in between H and V elements. Also, neither have wedges or "rudders" in the rear, just a flat blank wall. The Ku lnb's rings also nearly perfectly line up to the Astrotel's back end; should slide right in with barely a mm of clearance.
Any more thoughts on the design where you just chop the back off an Astrotel or 421, and insert a Ku lnb? Since I now have a spare 0.6 DMS Universal Ku lnb, and a spare Astrotel C-band lnb, I'm seriously considering chopping the back off and trying it for myself. The only thing stopping me is that I don't think a dremel tool will cut it very well
Ironicly, both lnb's have the exact same design inside- both use the silver rod in between H and V elements. Also, neither have wedges or "rudders" in the rear, just a flat blank wall. The Ku lnb's rings also nearly perfectly line up to the Astrotel's back end; should slide right in with barely a mm of clearance.not quite...
That andrew spec sheet has 1 clue on it:
"available with C-Band OR KU-band"
the keyword is OR, not AND.... plus, that assembly is really designed for 2 way satellite applications in EITHER C-Band or KU-Band.. not both.
It's designed to have a transmitter on 1 port, and and LNB on the other port... In other words, both ports would be used for C-Band OR KU-band
(transmit/receive), not both bands...
Mitch
That andrew spec sheet has 1 clue on it:
"available with C-Band OR KU-band"
the keyword is OR, not AND.... plus, that assembly is really designed for 2 way satellite applications in EITHER C-Band or KU-Band.. not both.
It's designed to have a transmitter on 1 port, and and LNB on the other port... In other words, both ports would be used for C-Band OR KU-band
(transmit/receive), not both bands...
Mitch
You sure know how to keep us in suspense, Alec!
Now, saying this works, how much do you charge for this combo service if I ship you my 421 and Invacom?
Now, saying this works, how much do you charge for this combo service if I ship you my 421 and Invacom?
Wow Alec! I believe you could build anything. That looks awesome. I hope the tests are promising. If this works then we will all be in business. Let us know your results.
Alec said:
Yeah, I've found some of those manufactured units on ebay... REALLY expensive, and I already own the C and Ku lnb
c/ku combo lnbf (no servo)
check out this link if it is still good. It worked a few minutes ago
http://shop.store.yahoo.com/hightech/eagckucomlnb.html
check out this link if it is still good. It worked a few minutes ago
http://shop.store.yahoo.com/hightech/eagckucomlnb.html
truckracer said:
Link is good, except it lists Availability as "Not in stock, discontinued"
Could be why all the ebay ones are so high-priced...
home built combo
Today is overcast, low signals. Ive only been able to get 3 ch on G10 this morn, running 50-75%, with this combo. Anik F1 is doing ok, but not as well as unmodified lnb. Would be nice to get some results from some of the manufactured combos. I should have the "black cone" next week. I'll fully disect it, remove foam and run metal detector over everything.
Today is overcast, low signals. Ive only been able to get 3 ch on G10 this morn, running 50-75%, with this combo. Anik F1 is doing ok, but not as well as unmodified lnb. Would be nice to get some results from some of the manufactured combos. I should have the "black cone" next week. I'll fully disect it, remove foam and run metal detector over everything.
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Alec:
Were these pictures obtained with the "chopped and Siamesed" 421?.
If so, you may be able to improve on it with two 4-40 screws into the waveguide after the C Band probes. The problem may be waves being reflected inside the waveguide. The new probes would need to be slightly longer than the existing probes and you would adjust them in and out until you got the best signal level. One for verticle and one for horizontal. They would act as "shorts to ground" for any spurious C Band waves. The screws act to tune the waveguide for exact SWR'S. Tuning could be done with lots of expensive test gear but adjusting for "best picture" works for us "poor people".
Man, I'm inpressed with you experimenters attitude. Keep up the good work.
Harold
Were these pictures obtained with the "chopped and Siamesed" 421?.
If so, you may be able to improve on it with two 4-40 screws into the waveguide after the C Band probes. The problem may be waves being reflected inside the waveguide. The new probes would need to be slightly longer than the existing probes and you would adjust them in and out until you got the best signal level. One for verticle and one for horizontal. They would act as "shorts to ground" for any spurious C Band waves. The screws act to tune the waveguide for exact SWR'S. Tuning could be done with lots of expensive test gear but adjusting for "best picture" works for us "poor people".
Man, I'm inpressed with you experimenters attitude. Keep up the good work.
Harold
C/Ku combo
Caddata, all my comments or test reuslts, lately, are relative to recent placement of 03 behind 421. I continued later this morn and into afternoon. I had only picked up 3 ch this morn., discouraging. I believe that after removing polarizing plate at end of 421, I needed to install stainless wire to polarize V probe for C band. Continued testing found that 03 became Freq responsive. While trying to optimize for Fox, 12114 V 4.444 @ 90%, WMQF @ 11799 V 27.660, was only at 10-15%. Elevating LNB, more or less would tend to reverse the signals ! I some how beleive its related to the polarizing wire I had installed. Look at photo of manufactured combo submited by spindoctor, interior void of polarizer, but yet to sidewall, seems to be a lobe( polarizing lobe? ) . Wire was needed to pick up V transponders on Anick F1. The combo unit I have built has some unstable behavior. While trying to optimize for Ku, C band quality becomes less. I had made a cone from a plastic funnel, lined with aluminum tape ( great stuff ! ) , it was an attempt to improve Ku signal, has helped a bit over flat scaler. I had removed all from back of cut out back of 421,(open ended), 0 ! quality, no resonate cavity, just courious. While I had cut out back of 421, needed to grind internaly to smooth edges from flat polarizer that was removed. Thought grinding would for sure damage 421, but it still lives !!!!! Tough unit !! Interest continues. Oh, photo of stainless polarizing wire not clear, tried 3 times, was best of 3. Thanks
Caddata, all my comments or test reuslts, lately, are relative to recent placement of 03 behind 421. I continued later this morn and into afternoon. I had only picked up 3 ch this morn., discouraging. I believe that after removing polarizing plate at end of 421, I needed to install stainless wire to polarize V probe for C band. Continued testing found that 03 became Freq responsive. While trying to optimize for Fox, 12114 V 4.444 @ 90%, WMQF @ 11799 V 27.660, was only at 10-15%. Elevating LNB, more or less would tend to reverse the signals ! I some how beleive its related to the polarizing wire I had installed. Look at photo of manufactured combo submited by spindoctor, interior void of polarizer, but yet to sidewall, seems to be a lobe( polarizing lobe? ) . Wire was needed to pick up V transponders on Anick F1. The combo unit I have built has some unstable behavior. While trying to optimize for Ku, C band quality becomes less. I had made a cone from a plastic funnel, lined with aluminum tape ( great stuff ! ) , it was an attempt to improve Ku signal, has helped a bit over flat scaler. I had removed all from back of cut out back of 421,(open ended), 0 ! quality, no resonate cavity, just courious. While I had cut out back of 421, needed to grind internaly to smooth edges from flat polarizer that was removed. Thought grinding would for sure damage 421, but it still lives !!!!! Tough unit !! Interest continues. Oh, photo of stainless polarizing wire not clear, tried 3 times, was best of 3. Thanks
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