Question re. Ku Analog Receiver

[IA6Newspath]

Hi all.

I'm thinking about picking up a Ku analog receiver to use along with my Fortec Mercury II. I did a search and read through a number of threads regarding analog Ku reception and found some great information, but I just wanted to confirm something. If I were to hook up an analog Ku receiver (Uniden or Toshiba, for example) to the "loop through" RF output of my Mercury II, I can control whether the analog receiver is receiving horizontal or vertical polarity simply by selecting a horizontal or vertical transponder/channel on my Mercury II receiver, correct? In other words, my understanding is that the H/V control for this kind of setup lies completely with the Mercury II, and the polarity sent to the analog receiver off of the Mercury II's loop through RF output would be and based on whether a H or V channel is selected on the Mercury II.

By the way, my Ku LNBF does have a 10750 LO, so I should be ok to receive all 24 Ku analog transponders, correct?

Thanks!

 

[Mr Tony]

correct on both accounts

The polarity of the analog when slaved will be controlled by your DVB box

And since you have a standard LNB (LNB LO 10750) you can get all 24 TP's (19 on SBS6) with no issues

 

[IA6Newspath]

Thanks for the quick reply, Iceberg.

Here's another analog-related question that just came to mind. Are most Ku analog FTA receivers configurable to receive both half and full analog transponders, or are they generally capable of receiving only one or the other? Many analog Ku news feeds, for example, use half transponder transmission, so I'm curious if FTA analog Ku receivers can toggle between full and half transponder reception.

 

[Mr Tony]

I thought analog was the whole TP?

I know on my Toshiba TRX-1420, the channels go in 20k steps on KU except for SBS6 which is weird

 

[ronjohn]

On my Uniden, you can select wide or narrow band. When tuning the signals, some look better with narrow and some look better with wide. You can see the signal with either selection, but I tune up/down and wide/narrow to get the best signal.

 

[IA6Newspath]

I thought analog was the whole TP?

Not necessarily. Although I'm fairly sure that most, if not all, C-band analog transmissions use full transponders, I do know that Ku-band analog uplinks can be done using either a full transponder or half transponder. Actually, for analog Ku news feeds (which are becoming somewhat of a dying breed), half-transponder analog Ku uplinks tend to be more common than full transponder uplinks.

CBS Newspath, for example, utilizes G26 Ku transponder 3 for news feeds. Typically, transponder 3 is sub-divided into ten 5.5 Msps digital channels, 3A through 3J. However, if an affiliate who has only analog uplink capability needs to book satellite time, CBS can reserve for them the "upper" portion of the transponder (normally occupied by digital channels 3F through 3J) and allow them to perform a half-transponder analog uplink. As such, when speaking about half-transponder analog Ku uplinks, the terms "lower" and "upper" are used along with the transponder number to specify which side of the full transponder is being used. So, using the example I just cited, a half-transponder uplink on G26 3 upper would be commonly noted as G26K, 3U.

It's also worth noting that for half-transponder Ku analog uplinks, the downlink frequency differs from that of a full transponder uplink. Specifically, half-transponder frequencies are offset 15 MHz from a transponder's center frequency. Going back to the example above, the center frequency for G26K3 is 11790.5 Mhz, so the downlink frequency for 3U is 11805.5 MHz. Similarly, the downlink frequency for 3L would be 11775.5 MHz, although CBS never uses the lower portion of transponder 3 for analog - it's always configured for digital channels 3A - 3E. Also, since half-transponder uplinks must use half the amount of bandwidth as a full transponder signal, most analog uplink encoders have a "half" or "full" bandwidth setting which can be set depending on whether a half or full transponder will be used.

I knew all this useless information I've learned at work would come in handy someday

 

[turbosat]

Hey thats not useless information!! Thanks, I have always wondered what they meant by upper and lower when it comes to satellite transponders. I guess you are right about the dying breed though, in analog news uplinks. Though I did see quite a lot during the last 2-3 hurricanes.

 

[Panavision]

I'll try to help, but it sounds like you know a whole lot about this stuff. I used to work master control at a CBS affiliate. The feeds we took from NewsPath were always some fraction of a full transponder. My sat guy would call up and say he was on IA6 3H or whatever (G26 nowadays). Of course, that was using DVB. Analog sports on SBS6 would sometimes use Upper or Lower. And I always used Standard's Agile Omni IRD to get these. I believe it has an AUTO setting for IF bandwidth, or you can manually select it like ronjohn suggested. There are several of these IRDs on eBay currently. However, I never used the Omni for analog NewsPath feeds, so I'm not necessarily endorsing this method. Hope this helps.

 

[IA6Newspath]

I'll try to help, but it sounds like you know a whole lot about this stuff. I used to work master control at a CBS affiliate.

Well, I don't know if I'd call it "a whole lot", but I do work in engineering/operations at a CBS affiliate, so I'm fairly familiar with the details and nuances of CBS' satellite operations with respect to network programming/distribution and their SNG (satellite news gathering) transponder inventory. Given my background in television, I was thrilled when I discovered the world of FTA and that for a couple hundred bucks, I could put together an FTA system and tinker around with searching for feeds and other FTA content at home. I think you would agree with me, Panavision, that broadcast-grade satellite equipment is a little easier and faster to configure than consumer FTA receivers, especially when it comes to tuning in digital signals. Ironically, though, the IRDs that we use at work which cost 10+ times as much as my little Mercury II don't have anything that even resembles a blind scan feature!

 

[Tron]

What really distinguishes the broadcast gear from consumer receivers is the build quality. I'd swear I could drop a broadcast IRD and it would harm the floor before it would harm the receiver Another major difference is that EVERYTHING is manual on the broadcast gear. There are no channel lists, the IRD stays programmed on one frequency until it is manually configured for another. And as Newspath pointed out, there is no blind scan. You have to know where the feed is, as well as the details (S.R., FEC, etc.)...

 

[IA6Newspath]

Another major difference is that EVERYTHING is manual on the broadcast gear. There are no channel lists, the IRD stays programmed on one frequency until it is manually configured for another.

Exactly. When I'm using a digital IRD at work, I simply select the proper polarity, enter the downlink frequency, enter the symbol rate (FEC detection is automatic on most receivers), and the receiver then locks onto the signal. No need to "scan a transponder" as we do with the consumer receivers - PID detection is automatic and essentially instant with broadcast grade IRDs. That's one aspect of FTA receivers that I didn't quite catch onto immediately, and it led to quite a bit of confusion. I later realized that unlike the receivers I use at work, I actually have to "scan" a newly-entered transponder on an FTA receiver in order to get the receiver to establish a lock on the signal.