21500 is the symbol rate Dish uses on their turbo 8PSK transponders and out recievers can't pick them up so dont bother
I just did some testing regarding what Iceberg and I suspected. The DN signals with 21500 symbol rates are not acknowledged with a FTA receiver. Therefore, they are encrypted with Turbo 8PSK and not detectable.
Such channels are simply not available to us ITC. You will have to subscribe to DN in order to view them with their equipment. FTA receivers won't even detect their signals so that is why your signal meter drops out.
This is somewhat disappointing as at least with DN signals, even though they were encrypted, you could at least mark the satellite position and use their signal blip to help align your dish and motor (if you were using one or setting one up). This will probably all become a thing of the past in the near future.
Yes, most of the 21500 SR signals are turbo 8PSK, and you can't lock them on *MOST* FTA receivers, but if you have the right receiver, and/or add on cards, you CAN lock these signals, and there are a few viewable FTA channels that aren't encrypted, although not many at this time.
I use the Genpix Skywalker-1 for the turbo 8PSK channels, which is a USB receiver for a PC. There are also a few STB receivers that have turbo-8PSK add-on cards, but I'm not familiar with those.
There are also a few DN transponders with a 22500 SR. I can't lock these with the Genpix. Or to be more accurate, I can't get a "data lock". I DO get a "signal lock". The way this was explained to me is that a signal lock sort of means that the receiver is demodulating the signal OK, but it doesn't understand the data structure and FEC, so it can't interpret the data. My Broadlogic control app has little boxes that get checked when it gets signal and data lock, which is kind of interesting to see signal lock but no data lock on a strong signal. The Broadlogic shows a signal lock on the 22500 SR DN signals, but won't give a data lock. I have been told that these signals are Turbo QPSK. The Genpix does Turbo QPSK, but apparently doesn't do the FEC that these signals are using.
Also, it isn't quite accurate to say:
"Therefore, they are encrypted with Turbo 8PSK and not detectable."
"FTA receivers won't even detect their signals so that is why your signal meter drops out."
The turbo 8PSK is not encryption, it's just a modulation format. And they are "detectable", they will give you a signal strength reading, and even using my analog receiver coupled with a short wave receiver, I can "detect" and measure the SR. It's just that the way they do that turbo FEC thing, regular DVB-S or DVB-S2 receivers won't lock on the signals. Or at least you won't get a data lock.