stacked c band lnbf

[gabshere]

ok what i'm needing is to know how it works
it list "Voltage-Controlled H/V Switching"

i thought that the stacked took the H & stacked the V on top with a higher freq . but i don't know why the switching would still be needed if it was stacked.
what i was looking at was several receivers using this lnbf through a 3X4 switch.
thanks

[elgemcdlf]

To my knowledge C Band is not stacked nor is normal Ku. The only stacked I know of is done with DN or DTV systems. I could be completely wrong on this as my knowledge into stacked lnbf's (note lnbf's not lnb's) is extremely limited.

[gabshere]

17K B1 SAT Stack C-Band LNBF

here's a link of one
thanks

[elgemcdlf]

What would be the benefit of stacked? The range is normal for a standard feedhorn/lnb configuration. I guess what I am getting at is why are you interested in this lnbf when you can get c band with normal feedhorn/lnb or a BSC-621 without the stacking. Don't you have to unstack at the other end?

[Iceberg]

The reason stacked works really well on digital is you can hook up a satellite rated 4 way splitter and go to 4 boxes.

Since all the polarity is vertical you can watch different shows on one box with the advantage of only one cable coming into the house (instead of 2). Starchoice (Canadian satellite provider) use to have their LNB's as stacked (KU Band) so all you needed to do when adding a receiver was split the existing line.

Disadvantage of stacked would be analog as the (normally) H polarity is higher frequencies than V

LNB LO for a stacked C-Band is 5150/5750 So lets use G4 satellite as an example. World Harvest is at 4000 H...so on a stacked system its at 4600 V (take the LNB LO - the frequency and you get the IF frequency of 1150...now subtract that from 5750)....The nets at 3950 H would be 4550 V.

I thought about getting one of those just to try it out

[wejones]

Originally Posted by elgemcdlf

What would be the benefit of stacked? The range is normal for a standard feedhorn/lnb configuration. I guess what I am getting at is why are you interested in this lnbf when you can get c band with normal feedhorn/lnb or a BSC-621 without the stacking. Don't you have to unstack at the other end?

That certainly is an interesting LNBF. I had seen that listed, but never noticed that it was stacked. That's kind of weird.

I agree.

I don't know what the benefits of such an lnbf would be... perhaps it makes it cheaper? It probably wouldn't need unstacking for FTA reception, since you can just enter the shifted frequency, provided that your receiver goes that high. Ie most FTA receivers list an upper freq up around 2150, so with the other polarity shifted 600 mhz, it would put the upper tuning range at 2050. For example, my Ultra will let me enter a freq that high, however it won't do a blind scan that high, even if you try to do it in two steps. So unless you had some sort of unstacking it would make it extremely difficult to use with an FTA receiver, and impossible to use with an analog or DCII receiver. So I don't know what possible market this lnbf was aimed at. However it doesn't surprise me that something weird comes out of Eagle Aspen. The only Eagle Aspen lnb I've owned only lasted about 2 or 3 weeks. Never bought another one.

[Iceberg]

Originally Posted by wejones

Ie most FTA receivers list an upper freq up around 2150, so with the other polarity shifted 600 mhz, it would put the upper tuning range at 2050. For example, my Ultra will let me enter a freq that high, however it won't do a blind scan that high, even if you try to do it in two steps. So unless you had some sort of unstacking it would make it extremely difficult to use with an FTA receiver,

go into your menu on the Ultra...select a C-Band satellite and scroll to the LNB LO's...there is a Stacked SL and Stacked SH on C-Band

so it WOULD work with a FTA box without any 2nd steps..change the LO ot 5150/5750 and scan V only

and impossible to use with an analog or DCII receiver. So I don't know what possible market this lnbf was aimed at.

companies that maybe use FTA to broadcast and channels are on both polarities..again...one cable coming in and using a sat splitter

[wejones]

Originally Posted by Iceberg

The reason stacked works really well on digital is you can hook up a satellite rated 4 way splitter and go to 4 boxes.
......

I thought about getting one of those just to try it out

Are un-stacking boxes available, other than taking apart a Dishnet or some other proprietary system? Or were you going to just key in the shifted freqs?
I can understand the use of such a thing for a service like Dishnet or Star Choice, where you're using their equipment, but I'm still having a hard time figuring out why any FTA user would want such an LNBF, and thus not sure why they would sell one, particularly a C-band one.

[wejones]

Originally Posted by Iceberg

go into your menu on the Ultra...select a C-Band satellite and scroll to the LNB LO's...there is a Stacked SL and Stacked SH on C-Band

so it WOULD work with a FTA box without any 2nd steps..change the LO ot 5150/5750 and scan V only

Thanks. Interesting. That's good to know. I never noticed that option, or I should say that I noticed it, but never investigated what it did.
Will the blind scan work in this mode then too? Ie when I do a blind scan, the scan generally stops at about an IF of 1800 mhz, and it would have to go up to 2050 for it to work here.

[Iceberg]

Originally Posted by wejones

Will the blind scan work in this mode then too? Ie when I do a blind scan, the scan generally stops at about an IF of 1800 mhz, and it would have to go up to 2050 for it to work here.

yep. Since there are two LO frequencies it would do like a Universal does

Scan low band start to finish
then flip to high band and repeat

A KU Universal LNB scans from 950-2150 on the low side (LNB LO 9750) then "flips the switch" (turns 22k on) and rescans with LNB LO of 10600

[Iceberg]

Originally Posted by wejones

I can understand the use of such a thing for a service like Dishnet or Star Choice, where you're using their equipment, but I'm still having a hard time figuring out why any FTA user would want such an LNBF, and thus not sure why they would sell one, particularly a C-band one.

Easy setup I guess. Like I say, since its all V polarity I could run one line and put splitters on it instead of a multiswitch

[gabshere]

yeah thats what i was wanting to do i was to set up one stationary dish and have like 4 lnbf's feeding one multiswitch and send it to multiple receivers via a multi switch but the lnbf says its a 13 /18 v switching didn't know what that was saying . i thought it stacked to all one side like vertical why would it need switching power.
thanks guys

[wejones]

Originally Posted by Iceberg

yep. Since there are two LO frequencies it would do like a Universal does

Scan low band start to finish
then flip to high band and repeat

A KU Universal LNB scans from 950-2150 on the low side (LNB LO 9750) then "flips the switch" (turns 22k on) and rescans with LNB LO of 10600

Since in standard mode, my Ultra only scans from 950-1800 {actually it's 1600 not 1800}, I must admit I was skeptical of the above, but I tried it in universal mode, and sure enough, it went all the way up to 2150 on 9750, then went all the way up to 2150 on 10600, although it seemed to skip about 300 mhz at the beginning of the second scan (too fast for me to catch exactly how much it skipped).
I then tried a test scan in the stacked mode you mentioned, however it doesn't do two complete scans in this mode, it does one scan from about 1550-2150, and another scan from 950-1550, approximately. But it DOES seem to do the whole 950-2150 band, which it does NOT do in standard mode, at least with 10750 LO as the setting. I couldn't figure out why it would stop at 1800{1600} in this mode, until I thought that perhaps it didn't want to go out of the satellite band, ie past 12700 in Ku mode. So I decided to do another experiment, and that was to choose standard mode, but use 10400 as a LO freq, to see if it changes the scan range. Sure enough, in standard mode with a LO of 10400, it scanned all the way up to 2150. So then I changed the LO freq to 11250, and tried again. I was expecting it to only scan to 1450 or so, but no, again, it scanned all the way up to 2150!?!?! Now I was confused, doubting my memory about the thing stopping at 1800, even though I had observed this many dozens of times. Well it turns out I remembered wrong. It stopped scanning at 1600 , not 1800. But this is even more confusing, re WHY. However I noticed that that I didn't really have to do the scan to see the range, as the scan range was printed out on the page before you tell it to actually scan, and it said that it was scanning from 11700-12350. So I decided to see how far I could push this, ie increasing the 12350. Well it turns out that you can't enter anything in there above 12350. Ie enter 12400 as the upper limit, and it reverts to 12350 after a pause of a couple seconds.
Well I decided to try one more test. Ie I set the LO freq to 10751. Sure enough, the scan range is listed as being 11701-12901 !?!?!
Basically, the Fortec firmware seems to have the 10750 LO freq as a special case where it limits the scan range to only 650 MHz. I don't have a clue as to why this would be the case. But apparently you can get around that by just adding 1 mhz to the LO freq.

Anyway, this has been interesting, and I've learned a lot about this old receiver which has been getting closer to death every day. I think I'll take a look at my Mercury to see if it has similar limitations on standard 10750 scans.
Strange.

[wejones]

Originally Posted by gabshere

yeah thats what i was wanting to do i was to set up one stationary dish and have like 4 lnbf's feeding one multiswitch and send it to multiple receivers via a multi switch but the lnbf says its a 13 /18 v switching didn't know what that was saying . i thought it stacked to all one side like vertical why would it need switching power.
thanks guys

OH, I see, I completely missed that 13/18 thing in the specs. That makes sense now. Apparently what it does is with 13V it might put H above V, and at 18V it might put V above H (or visa versa)??? That would make this lnbf a LOT more compatable with other (analog and DCII) receivers, and still give you the stacked capability if you wanted it.

I completely missed that when I read the specs before. Ignore what I said above about not being compatable with analog/DCII.

[Iceberg]

Bill
The software of most boxes knows to stop at 1600IF frequency when using a Standard (10750+1600=12350) so thats why if you scan 91 you sometimes get Nimiq1 TP's (at least I do)

Universals go up to 12900 so thats why it needs to go up to 2150 IF frequency. Here in the US the upper (upper) KU (12.2-12.75) is DBS whereas in other countries they still plop KU feeds on that band (god wouldnt that be nice)

[Iceberg]