C-band parts search

[bubby-joe]

I started with 2 astrotel scale rings identical including peeling paint, 5 minutes with a bandsaw and a sanding belt and not bad looking very close fit. The back will be a little more fun but I don't expect to many problems. I intend to bolt the two pieces to the backing plate then warp into working order then maybe visit a friend with a tig welder so I can practice my skills. After it's all working a coat of paint and presto a new one. I think I'll go with the last pictures bolt pattern for easier mounting to the dish, gives me 4 wide spaced mount legs and keeps the lnb's at 3 and 9 oclock. I do nice work but only when I work. One of the perks to being SEMI retired.

 

[bubby-joe]

I thought a little update was in order, the parts have started to come in I'm just waiting for the aluminum brazing rod (early next week) I used an LNBF from a Canadian *choice 75e dish setup 1 LNBF dual outlet but any linear LNBF would do. I started with 2 astrotel rings, one I cut to join the other. The whole one got the center ring cut out to insert the commercial Andrews scale ring. If this LNBF works with any success then I may opt for a QPF-031 flange mount linear and circular LNBF for the prime focus dish. The adapter I had built had to be modified as there was no way to fine tune the LNBF skew. A little work with a small hobby lathe and presto it should work just fine. It was harder to build a small boring bar than to enlarge the inside bore of the adapter. Any how here's some pic's so I'm not so long winded.

 

[Turok]

Hello!
how many signal lost,do you have in cband,on the signal meter,on the 2. lnb,on the site,when is not directly in focus?
you lost more then one db?

most older call amp cband,has a very big case,the newer kuband lnbs,espasaly the smart titanium are very small,my idea,was to implementad,the electronic of a new kuband lnb,in a bigger cband lnb,together,make a 2.hole ,then you have your selfmade solution ku and cband in one lnb,and you dont loose any signal,when both are directly in focus!
on strong cband signals,this solution is okay,but when signal is hard on the limit,you lost,on the nabour satellite to much,and that result often no signal!

 

[bubby-joe]

Hello!
how many signal lost,do you have in cband,on the signal meter,on the 2. lnb,on the site,when is not directly in focus?
you lost more then one db?

most older call amp cband,has a very big case,the newer kuband lnbs,espasaly the smart titanium are very small,my idea,was to implementad,the electronic of a new kuband lnb,in a bigger cband lnb,together,make a 2.hole ,then you have your selfmade solution ku and cband in one lnb,and you dont loose any signal,when both are directly in focus!
on strong cband signals,this solution is okay,but when signal is hard on the limit,you lost,on the nabour satellite to much,and that result often no signal!

I tried a BSC-621 C/Ku all in one, that's KU behind C-band and one feedhorn but with very limited success 98 to 100 for signal quality on C-band but no KU, KU lnbf spun internally using a 10 ft mesh dish that's in poor shape and due to be replaced. Most receivers can no longer use a Corotor to control polarity and fine tune. When I'm finished I'll post some quality readings across the arc compared to my 1 meter with a QPH-031 LNBF but whatever I get has to be better than my offset 1 meter motorized KU only setup. The C-band Cal amp in the picture is a 25 K and works very well here. The object is to get C,KU linear and KU circular on one dish in the end, right now I'll settle for C and KU linear to test the homemade part. To get Ku circular I need to change to a QPF-031. If the dish adjusts E/W a small bit to lock signal quality on C or KU that's OK. All motor adjustments will be controlled by USALS commands from the receiver. I'm not trying to get 2 satellites at the same time but 1 satellite with all 3 bands at one time.

 

[BombedOne]

Such scalar rings, generally sold bundled with 2LNBs are quite popular on chinese and indian market. For example, indians use it for simultaneous reception of 83E+93E positions.

 

[bubby-joe]

Such scalar rings, generally sold bundled with 2LNBs are quite popular on chinese and indian market. For example, indians use it for simultaneous reception of 83E+93E positions.

Yes I know that's where the idea for this twined LNBF mount was born, I saw it in satellite international magazine and yes mostly in asia is where it's found but it only uses 2 C-band lnbf's and your right used to receive 2 satellites at the same time from a stationary dish, So why not 1 C-band and 1 KU band lnbf with C and KU scale rings on one motorized dish. My intent was to improve a solid 6 ft Andrews prime focus to do C and KU to get both bands on one satellite at a time with better performance than my 1 meter offset, using an offset LNBF it only see's 1/3rd of the dish also explained in satellite international and a prime focus LNBF with the right scale ring see's the whole dish so my 6ft dish with an offset LNBF seeing only 1/3 of the dish and will performs no better than an 18 inch dish, not enough to receive KU linear signal here but with the proper scale ring and LNBF combination it sees the whole 6ft of the dish giving better performance . With the rings on the KU band ring having 3 times as many rings on it I'm hoping for optimum performance from my Andrews dish for both C-Band digital and KU linear for now, to later expand the KU to include both linear and circular with a different LNBF a QPF-031 flange mount linear and circular LNBF meant for use on a prime focus dish with the optional ADF-120 scale ring which by the way has very widely spaced rings from the pictures of it, in my case this part will be no longer necessary.

 

[BombedOne]

Unfortunately you aren't right.

C band scalar ring won't help in Ku band, in fact, it will even lower signal strength. For ku band, you need ku band scalar ring.

 

[bubby-joe]

Unfortunately you aren't right.

C band scalar ring won't help in Ku band, in fact, it will even lower signal strength. For ku band, you need ku band scalar ring.

I'm not using 2 C-band rings but a modified set of rings. Take a good close look at all the pictures in post 22, there is C-band rings on one side and Ku band rings that came with the dish on the other. This is a work in progress, it's not set in stone yet, I always leave room to modify the modification. And I appreciate any thoughts to improve what I'm trying to do here.

 

[bubby-joe]

Well I finally got around to testing the modified Ku scale ring with the (Eagle 270KU lnbf) off of a Starchoice twin lnbf setup meant for an offset elliptical dish and I must say the results were more than pleasing, my true south (linear) satellite on a 1 meter dish with a QPH-031 lnbf tops at 50-60 for signal quality, minimum size for my location listed as 1.2 meter.

Tested on a 6 ft or 180cm Andrews commercial solid spun aluminum dish, modified scale ring mounts all on a non penetrating stationary ground mount final tuning to steady 97 quality on true south ku-band satellite and solid 90 quality on c-band satellite next door to true south.
Impressed enough with the dish and lnbf setup to now move to replace my aging 10ft very out of tune dish... I'm not sure if I will use the BSC-621, I'll test it on the weekend then decide.

 

[patmos]

Good Job bubby-joe. How do you calculate the distance of the two LNB. How many degrees separation between your sats?

 

[bubby-joe]

Good Job bubby-joe. How do you calculate the distance of the two LNB. How many degrees separation between your sats?

TRIAL and ERROR mostly if you haven't got something and can't find it MAKE IT

All tuning was done with the receivers built in meter, at the dish with all of the following:
Coolsat 6100 private receiver FTA ONLY
dvd portable monitor
short length of rg-6 cable with compression fittings ONLY way to go.

All setup adjustments were followed with a 30-50 second wait for the downloaded information to show on the meter.
True south linear is 129.0W and next door C-band is 125.0W so the spread is 4 degrees. But is not critical
Overall performance is far better than I expected especially from the Ku side, c-band was normal for a 6ft solid prime focus dish.

(All digital signal is GOOD)

The Ku LNBF was removed from a Canadian Starchoice elliptical offset satellite dish and really should not have worked as well as it did theoretical mismatch and all.... on a prime focus dish

This whole thing was never to get both C and Ku at the same time so the motor moves the dish to the sweet spot for the satellite selected. But to merely get 3 bands from the same dish with 2 lnbf's....using just one dish and motor.
C-band
Ku Linear
Ku Circular

Ku linear and circular will be covered with a new QPF-031 flange mount lnbf. (ORDERED)
QPH-031 gets sent to the (work shop) Satellite TV setup