It's my own darn fault
May. 18th, 2012 12:02 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
banjoplayinnerdOh wait, that title is kind of a spoiler, isn't it?
For several days since I got the computer back up and running I had been having trouble making contacts on JT65, my current favorite digital mode. I wasn't showing up on the reverse beacon page when I called CQ and I wasn't seeing anyone on the waterfall (the scrolling signal display).
I couldn't figure out what was going on. I was sure I had transmit power. The audio was working OK, at least to make contacts on the local repeaters. I could hear Morse code signals. Everything was connected properly. I was starting to wonder if someone had taken down my antenna and replaced it with a dummy load - basically a big resistor used for testing that acts like an antenna except it doesn't radiate.
Then last night I looked down at the waterfall and saw a signal. I don't know who he was because the software hadn't decoded the message. I took a closer look and saw that the transmission had apparently started several seconds after the beginning of that minute.
It was then that a bit of enlightenment burst through the fog banks of my mind. Everything I had read about JT65 said you need to have absolutely accurate time because JT65 uses the current time as part of the decoding mechanism. If your time is off by up to about a second you're probably OK, but any higher delta can be a problem. The emphasis was on setting up a time synchronization program like Dimension4 in Windows, because Linux has the ntp protocol to keep machines on time.
Could it be that simple? This was a freshly installed Linux machine, and I thought Linux always installed ntp (the Linux time sync program) by default. Maybe I was wrong about that. Sure enough, "sudo install ntp" installed a new program instead of telling me I already had one running, and "ntpdate time.nist.gov" told me it was updating the clock, setting it back seven seconds. That's probably about how much the signal had lagged behind the start of the minute.
So that explains why signals weren't decoding, and conversely, why no one else was able to decode me. As for not seeing any signals, I chalk that up to a combination of the time differential and fairly poor band conditions the last few days. That's my story and I'm stickin' with it.
Last night I made two contacts, one with Michael in Plymouth, MI (a new state for me on JT65) and one with Richard in Vancouver, WA, who I've worked before. And I was very happy to have both contacts.
Now if that South African station would just reappear . . .
For several days since I got the computer back up and running I had been having trouble making contacts on JT65, my current favorite digital mode. I wasn't showing up on the reverse beacon page when I called CQ and I wasn't seeing anyone on the waterfall (the scrolling signal display).
I couldn't figure out what was going on. I was sure I had transmit power. The audio was working OK, at least to make contacts on the local repeaters. I could hear Morse code signals. Everything was connected properly. I was starting to wonder if someone had taken down my antenna and replaced it with a dummy load - basically a big resistor used for testing that acts like an antenna except it doesn't radiate.
Then last night I looked down at the waterfall and saw a signal. I don't know who he was because the software hadn't decoded the message. I took a closer look and saw that the transmission had apparently started several seconds after the beginning of that minute.
It was then that a bit of enlightenment burst through the fog banks of my mind. Everything I had read about JT65 said you need to have absolutely accurate time because JT65 uses the current time as part of the decoding mechanism. If your time is off by up to about a second you're probably OK, but any higher delta can be a problem. The emphasis was on setting up a time synchronization program like Dimension4 in Windows, because Linux has the ntp protocol to keep machines on time.
Could it be that simple? This was a freshly installed Linux machine, and I thought Linux always installed ntp (the Linux time sync program) by default. Maybe I was wrong about that. Sure enough, "sudo install ntp" installed a new program instead of telling me I already had one running, and "ntpdate time.nist.gov" told me it was updating the clock, setting it back seven seconds. That's probably about how much the signal had lagged behind the start of the minute.
So that explains why signals weren't decoding, and conversely, why no one else was able to decode me. As for not seeing any signals, I chalk that up to a combination of the time differential and fairly poor band conditions the last few days. That's my story and I'm stickin' with it.
Last night I made two contacts, one with Michael in Plymouth, MI (a new state for me on JT65) and one with Richard in Vancouver, WA, who I've worked before. And I was very happy to have both contacts.
Now if that South African station would just reappear . . .
