Harris FlexStar Issue
I mentioned awhile back that we were having mysterious outages, or off-air events, with our HTHD+ transmitter. This began May or June last year and we’ve spent much time working with Harris to determine where the problem was. Each time we would try or look into something as they suggested. The events were random and quite annoying. Obviously the station PD was becoming quite annoyed. Random issues are the worst.
As we followed suggestions, we connected the remote control to various status and metering locations to determine what and where our RF mute was occurring. We ended up metering the FlexStar exciter forward power. We connected a status monitor to the RF Mute status. Was it the transmitter telling the exciter to mute? Was the exciter muting on its own? More questions and no answers. Was the APC circuit cutting out? Nope. We began to catch events that ruled out the transmitter and APC. The exciter forward power muted without any mute status. Now what?
Next became a look at the HD data network. Could the data cause an RF mute? It seemed a reasonable question as the exciter does lock its PLL to the 10MHz clock that is derived via the Exporter and GPS. We began to gather PLL logs. We did discover some latency that could affect the PLL, but it did not explain why or how it could mute the RF. As we are running in hybrid mode, we really do not want anything that messes with the HD to mess with our analog. We continued to gather more logs and information, but an no point were we able to tie anything together.
Harris decided they wanted the exciter for bench testing. After nearly two weeks of bench testing we did receive an email stating that they captured an RF mute situation and it had nothing to do with the HD data or network. Now we wait to hear what internal issue is causing the random mutes. This whole thing has become quite an interesting ordeal. Sometimes you learn more than your really wanted or needed to know. Stay tune for the final word!
Tech Notes from the Field 
We are having the same problem with loss-of-rf from our Flexstar. We also have a limited path to the tower site (double-hop Starlink and one path over some water) which can take hits in the summer. We had two outages in the past couple weeks but none for several months before which I find interesting. I really thought is was releted to RTAC but maybe not. We lost RF about 30 minutes after a couple misaligned packets today. I must say this problem and one other has made this installation a real bear.
Was your RF loss attributed to the packet loss? Did you lose analog or just digital? There seems to be a couple issues being worked on. If it is a packet/digital carrier Harris has a release to hopefully alleviate this. If analog RF is going away we are trying to capture the event that causes it.
If you wish, I can forward your issues to Harris and see what they say. You definitely have a “tough” path!
BE
We believe so. We lose ANA and Dig every time. We’ve been working with Harris on this problem for a while but not much recently, we had several months of no trouble. When I called yesterday they were quick to suggest the patch which I installed and hoping for the best. Symptoms: RF loss for several minutes (8-10) and recovers. Another error we experience is the Flexstar exciter rebooting about once a month (this I can handle) but it clears the Exgine logs. I didn’t see where it was due to packet loss until it was mentioned that Exgine failure may be a period of time after the packet loss. Our jitter is also slightly higher then Harris would like (Max Buffer 19-26% and buffer used 20%) but I don’t know the solution to this. Bottom line, the exciter needs to handle errors better, we’ve had zero problems like this with two other big names over the years. Thanks for posting your experience, it’s satisfying to see we are not the only ones.