SWM Transponder Signal Readings

[JACH]

Would someone tell me what the SWM transponder signal readings indicate? Out of the 9 transponders, up to 3 of them would sometimes read 0, while the rest would be at upper 90s to 100. I see this on all 3 of my receivers (2 HR21-100 and 1 D12-500.) The SWM transponders that would read 0 changes frequently. They would read 0 one minute and be at 100 moments later. I have no problems receiving channels on any receiver even when they show 0. Should I be concerned with the 0's? Thanks.

[jdspencer]

I know little of what's going on with SWM TPs. But, I've read other threads that indicate that the SWM TPs strengths move around based on the number of receivers that are connected and the channels they are requesting.

Since I don't have an SWM system, a search on this subject is in order. :)

BTW, there's a sticky thread at the top on this subject. :D

[veryoldschool]

Should I be concerned with the 0's? Thanks.
"Nope".
Each tuner will use a SWM channel, so this one will show "zero" on another receiver.
If you set all receivers to the SWM screen, you'll see no zeros [since all tuners are "free" because of being on the setup SWM screen].
Then as you exit the setup menu, each receiver/tuner will take a SWM channel and cause a zero to show on the other receivers still on the setup screen.

[pfp]

"Nope".
Each tuner will use a SWM channel, so this one will show "zero" on another receiver.
If you set all receivers to the SWM screen, you'll see no zeros [since all tuners are "free" because of being on the setup SWM screen].
Then as you exit the setup menu, each receiver/tuner will take a SWM channel and cause a zero to show on the other receivers still on the setup screen.

This makes sense to me however....

Say you have 4 HR2x receivers connected to a SWM all using both tuners. Only one receiver is looking at the SWM strength meter and 3 SWM TP's are 0. I can understand 2 (since the receiver you are vewing the meter with is not using it's two) but where is the third zero coming from?

Not really an issue just more of a curiosity.

[HoTat2]

This makes sense to me however....

Say you have 4 HR2x receivers connected to a SWM all using both tuners. Only one receiver is looking at the SWM strength meter and 3 SWM TP's are 0. I can understand 2 (since the receiver you are vewing the meter with is not using it's two) but where is the third zero coming from?

Not really an issue just more of a curiosity.

My setup is legacy at present and I don't have a SWM module installed at the moment, but I will soon. But the way I understand it is that with 4 HR2Xs installed on a SWM and only one of the DVRs on the satellite setup screen the SWM "channels" (not transponders) 1-8 should show six readings at zero, and two non-zero representing the unused SWM channels freed by the one HR2X two tuners on the setup screen. SWM channel number 9 is the program guide which always has a non-zero level.

Anyone please correct me if I'm wrong on any of this here...

[veryoldschool]

This makes sense to me however....

Say you have 4 HR2x receivers connected to a SWM all using both tuners. Only one receiver is looking at the SWM strength meter and 3 SWM TP's are 0. I can understand 2 (since the receiver you are vewing the meter with is not using it's two) but where is the third zero coming from?

Not really an issue just more of a curiosity.
So you have three DVRs not recording anything, leaving only the live buffer to be needed with each.
1 DVR is in the setup screen, so no tuners used there and the other 3 DVRs are only using one tuner each.
"Next time" go to the other DVRs, start it recording and then change channel.
"Go see" what the setup screen shows.

[HoTat2]

So you have three DVRs not recording anything, leaving only the live buffer to be needed with each.
1 DVR is in the setup screen, so no tuners used there and the other 3 DVRs are only using one tuner each.
"Next time" go to the other DVRs, start it recording and then change channel.
"Go see" what the setup screen shows.

Oh ... :o

Thanks, I stand corrected, but as I said I'm on a legacy setup at the moment :sure: So on this hypothetical setup SWM channels 1-8 would show three at zero, five at non-zero including two relinquished by the HR2X on the setup screen.

And is SWM channel 9 indeed the program guide and always non-zero?

[veryoldschool]

Oh ... :o

Thanks, I stand corrected, but as I said I'm on a legacy setup at the moment :sure: So on this hypothetical setup SWM channels 1-8 would show three at zero, five at non-zero including two relinquished by the HR2X on the setup screen.

And is SWM channel 9 indeed the program guide and always non-zero?
I don't know if it's 1 or 9. I'd have to sit down and play with it for a while.

[texasbrit]

"Nope".
Each tuner will use a SWM channel, so this one will show "zero" on another receiver.
If you set all receivers to the SWM screen, you'll see no zeros [since all tuners are "free" because of being on the setup SWM screen].
Then as you exit the setup menu, each receiver/tuner will take a SWM channel and cause a zero to show on the other receivers still on the setup screen.
I think it's more complex than that. If a tuner wants a transponder that is already available from the SWM, the SWM maps the tuner to the same (existing) SWM channel so the tuner does not use a new one. So that would mean it's possible to add a tuner without creating another "zero".

[pfp]

So I did some testing and I think I've figured this out.

Conclusion:
An SWM channel currently being used by a tuner will show 0 otherwise it will have a reading. Note: there is apparently one SWM channel never used by a tuner so at least one will have a reading other than 0. I'm also pretty sure SWM channels are not shared between tuners (even those on the same receiver)

My tesing results this morning with 4 HR2x's filling a single SWM. At the start all receivers were simply buffering live TV on just one tuner. Double play was not used recently and no programs were recorded for at least 5 hours.

I went to the SWM meter on one receiver and see three 0's. (This receiver is using no tuners and the other three receivers are eah only using one tuner leaving three channels unused)
http://www.dbstalk.com/attachment.php?attachmentid=19902&stc=1&d=1255619900


With the SWM meter still up on the first receiver I bring up the SWM meter on a second receiver.
http://www.dbstalk.com/attachment.php?attachmentid=19903&stc=1&d=1255620130


Now 3 receivers looking at the SWM meter
http://www.dbstalk.com/attachment.php?attachmentid=19904&stc=1&d=1255620296


And finally all four
http://www.dbstalk.com/attachment.php?attachmentid=19905&stc=1&d=1255620345


I then started taking reveivers off the SWM meter screen and using double play to ensure they were using both tuners.. Unfortunately I messed up on the pictures So I'll have to try this again from that point.

[veryoldschool]

^ post shows what I've seen before.
Yesterday I played a bit with this and did see that some SWM channels were being shared, as I couldn't get as many zeros as before.
You really need to get as many SATs in the mix as you can, to not have them be sharing SWM channels, since each channel is 100 MHz and carries several "channels".

[pfp]

I don't think SWM channels are shared but I can't yet offer any proof of that. I took 2 receivers off the SWM meter screen and used double play to tune to four different channels. As expected four SWM channels were in use. I then set both receivers to channel 12 and 15 - still using four SWM channels. Next I set all four tuners on these receivers to channel 12 - still using four SWM channels. Now this all occured rather quickly (a few minutes) and perhaps some time needs to pass before a receiver will release a SWM channel.

I think the aspect that make this more interesting is that without both tuners on a receiver being used the receiver is only using one SWM channel.

I also noticed immadiately after taking a receiver out of the meter screen two SWM channels were being used. I would expect only one since at this time only one tuner is buffering live TV. Perhaps there is a time persiod when both are being used even though we can't toggle between live buffers.

Also I wonder how long after recording on the background tuner is the SWM channel still being used?

[veryoldschool]

I don't think SWM channels are shared but I can't yet offer any proof of that. I took 2 receivers off the SWM meter screen and used double play to tune to four different channels. As expected four SWM channels were in use. I then set both receivers to channel 12 and 15 - still using four SWM channels. Next I set all four tuners on these receivers to channel 12 - still using four SWM channels. Now this all occured rather quickly (a few minutes) and perhaps some time needs to pass before a receiver will release a SWM channel.

I think the aspect that make this more interesting is that without both tuners on a receiver being used the receiver is only using one SWM channel.

I also noticed immadiately after taking a receiver out of the meter screen two SWM channels were being used. I would expect only one since at this time only one tuner is buffering live TV. Perhaps there is a time persiod when both are being used even though we can't toggle between live buffers.

Also I wonder how long after recording on the background tuner is the SWM channel still being used?
We don't have all the info for this.
I've done "your test" and gotten the same results.
I've also done it slightly different and gotten different results.
"It seems" by putting all receivers on the SWM screen, and then exiting each one at a time, that the zeros "match", where if you only set one receiver to the SWM screen and then try changing channels on the other receivers/tuners, more are being shared, as there are less zeros.
This may be do to the software in the SWM. When each receiver is on the setup screen, it's no longer in the sharing mode. As each one exits, it asks for a channel for each tuner. As the receiver needs to change channel, the request is handled by the SWM "as just another request", where it knows which SWM channel [if any] is carrying the requested channel, and tell the receiver to tune there.

[HoTat2]

I don't think SWM channels are shared but I can't yet offer any proof of that. I took 2 receivers off the SWM meter screen and used double play to tune to four different channels. As expected four SWM channels were in use. I then set both receivers to channel 12 and 15 - still using four SWM channels. Next I set all four tuners on these receivers to channel 12 - still using four SWM channels. Now this all occured rather quickly (a few minutes) and perhaps some time needs to pass before a receiver will release a SWM channel.

I think the aspect that make this more interesting is that without both tuners on a receiver being used the receiver is only using one SWM channel.

I also noticed immadiately after taking a receiver out of the meter screen two SWM channels were being used. I would expect only one since at this time only one tuner is buffering live TV. Perhaps there is a time persiod when both are being used even though we can't toggle between live buffers.

Also I wonder how long after recording on the background tuner is the SWM channel still being used?

Hey, interesting stuff pfp;

Please keep us posted on any further results of your experimentation. With all due respect to texasbrit's expertise in these areas (which is much greater than mines I suppose), I actually agree with you that there is most likely no sharing between SWM channels, because what would be the real advantage in doing so? I mean the bandwidth for each SWM channel is fixed and each channel carrier is always transmitted from the SWM.

If the SWM operated on a Switched Digital Video (SDV) principle, then yes there would indeed be sharing, but it doesn't that I'm aware as each receiver's tuner is assigned a SWM channel on boot-up which does not change regardless of wether the receiver's tuner is actually using that channel at any given time or not.

[veryoldschool]

Hey, interesting stuff pfp;

Please keep us posted on any further results of your experimentation. With all due respect to texasbrit's expertise in these areas (which is much greater than mines I suppose), I actually agree with you that there is most likely no sharing between SWM channels, because what would be the real advantage in doing so? I mean the bandwidth for each SWM channel is fixed and each channel carrier is always transmitted from the SWM.

If the SWM operated on a Switched Digital Video (SDV) principle, then yes there would indeed be sharing, but it doesn't that I'm aware as each receiver's tuner is assigned a SWM channel on boot-up which does not change regardless of wether the receiver's tuner is actually using that channel at any given time or not.
With seven tuners on my SWMLNB, read the post above. ;)

[HoTat2]

With seven tuners on my SWMLNB, read the post above. ;)

OK VOS;

I'm not about to dogmatically rule out the possibility of sharing among the SWM channels at times, its just that I can't imagine DirecTV engineers designing something for nothing, yet I can't see any advantage to be gained by channel sharing since all the SWM carriers seem to on all the time.

[pfp]

OK VOS;

I'm not about to dogmatically rule out the possibility of sharing among the SWM channels at times, its just that I can't imagine DirecTV engineers designing something for nothing, yet I can't see any advantage to be gained by channel sharing since all the SWM carriers seem to on all the time.

+1

[veryoldschool]

OK VOS;

I'm not about to dogmatically rule out the possibility of sharing among the SWM channels at times, its just that I can't imagine DirecTV engineers designing something for nothing, yet I can't see any advantage to be gained by channel sharing since all the SWM carriers seem to on all the time.
Since I have seen both cases [shared and not], I can only conclude that the SWM "doesn't think" it needs to use another SWM channel for a requested channel, it already is delivering on another SWM channel. I don't know that exact channel bandwidths, but OTA is 5 + 1 MHZ, so 100 MHz could carry 16-20 channels on each SWM channel.

[pfp]

Since I have seen both cases [shared and not], I can only conclude that the SWM "doesn't think" it needs to use another SWM channel for a requested channel, it already is delivering on another SWM channel.I don't know that exact channel bandwidths, but OTA is 5 + 1 MHZ, so 100 MHz could carry 16-20 channels on each SWM channel.

Does this linked doc help? (http://www.box.net/shared/f0o7xsed80)

[veryoldschool]

Does this linked doc help? (http://www.box.net/shared/f0o7xsed80)
"Old news"
Want my copy? :lol:
"Figure" each SWM channel is carrying ~ 3 transponders [say 1,3,5], so there are a fair amount of broadcast channels on each SWM channel.

[rudeney]

Personally, I think this is a case of the Heisenberg uncertainty principle. ;)

[netraa]

along those lines....
Nothing exists until it is measured.
—Neils Bohr

[Matt9876]

Did a big install today with SWM 8 LNB two HR23s and one H23, three big flat screens.

Went in smooth as silk and the HD looked awesome.:)

[cartrivision]

"Nope".
Each tuner will use a SWM channel, so this one will show "zero" on another receiver.
If you set all receivers to the SWM screen, you'll see no zeros [since all tuners are "free" because of being on the setup SWM screen].
Then as you exit the setup menu, each receiver/tuner will take a SWM channel and cause a zero to show on the other receivers still on the setup screen.

That doesn't match what I see... with 3 DVRs (6 tuners) on an SWM, I don't see 4 zeros when 2 DVRs are in normal operation and 1 DVR is on the SWM signal level screen.

[veryoldschool]

That doesn't match what I see... with 3 DVRs (6 tuners) on an SWM, I don't see 4 zeros when 2 DVRs are in normal operation and 1 DVR is on the SWM signal level screen.
You might [want to] read all the posts here. ;)

[texasbrit]

The SWM definitely allocates multiple tuners to a single SWM channel if the transponders the tuners need are already on that SWM channel. In testing, I have had as many as 11 tuners running successfully on an SWM that supports only 8 tuners. As long as the tuners are not asking for more than eight "transponder sets", this works fine. As soon as a tuner asks for the ninth "transponder set" thereby needing an ninth SWM channel, the system collapses. I seem to remember someone tried this with 20 tuners and it worked OK as long as there was not a need for more than eight "transponder sets".

This causes problems in MDUs using the MFH2 system because if a customer adds tuners to their setup without the involvement of the MDU tech support person, and the total number of tuners on a "shared" SWM-8 exceeds eight, it's not always obvious because people might be watching the same channel (or certainly the same transponder, since in most cities all HD locals are on one or at max two transponders).

I don't know how many transponders are delivered on each SWM channel, it might only be one (for simplicity). There's room in an SWM channel for two HD transponders or three SD ones.

[hombresoto]

Very interesting reading, thanks for all the sharing and testing guys!!! :-)