djinni442 (callsign?) wrote...
> I have one of the FC-301 boxes w/ integrated tracker2. Curious about
> constraints with the setpower command. More specifically, is there any
> info out there on xmit duty cycle versus setpower? Ie if "42" would
> allow for x seconds per minute, "99" would allow for 1 second a
> minute etc.
Straight from the FC301D service manual...
Operation Rating... Intermittent 5:5:90 ( TX: RX: Standby)
In the case of the T2-301, the "receive time" will depend on how busy
the frequency is and I assume will be insignificant as far as heating of
the whole unit. Assuming the above is in seconds, APRS transmissions
aren't 5 seconds long... more like half a second. With SmartBeaconing,
you probably won't be beaconing more than every 60 to 90 seconds
when going in a straight line, and only then at highway speeds. I use
60 seconds for the fast rate, but where I live, I can only drive at
highway speeds for 2-3 minutes at the most. Only if you continually
drove in circles would it be a problem, depending on the turn angle and
minimum time between transmissions... e.g. you might have it set to
beacon when it turns 25 degrees but no more than every 10 seconds.
Unless you are burning doughnuts in a parking lot, most turns will only
be a 10-30 seconds in duration. If you continually drove in circles with
"normal" SmartBeaconing settings, you could exceed the transmit duty
My observations with SETPOWER... with the lid off the T2-301 I've had it
go on continuous transmit with SETPOWER 99 when I was experimenting with
it. I've also had that happen when the antenna had a high SWR. My normal
setting is SETPOWER 42, but do have mine set at 60 right now. I should
measure the output power. Don't assume your antenna is good. Measure the
SWR. I discovered a problem when the T2-301 went mobile for the first
time. The antenna was checked and the SWR was low. When it was all
buttoned up when it went for a drive, it was only heard until it was
about (less than) 1 km away. On the second test, it wasn't heard at all.
Listening on another radio, the tones were rough and distorted, They
couldn't be decoded. It was shut down and torn apart. The BNC connector
on the end of the cable was bad. The final determination was that the
center conductor wasn't making good contact. The fix was to grab the
center pin and pull it further into the BNC shell. It "clicked" into
place and passed the "wiggle" test afterwards with a low SWR.
It hasn't been mobile again yet though.
73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!"