On Sun, Jun 21, 2009 at 8:04 AM, Gary Strong <[email protected]>
wrote:
I went through the driver control panel and set buffer size to 512 and
sampling rate to 48K. Also, set mode to "Normal". This done, I was
able to raise one PMBO, but couldn't hold the connection. The receive
signal was quite weak, and the PMBO eventually dropped me. Probably I
should try another time when propagation is better. I still don't
have
a good fix on how to set the receive signal for the PTC modem and
whether or not the Flex should operate in DIGU or USB. The
connection I
made was USB, but in DIGU mode, I have to crank up the TX gain to 35
or
above to get the drive needed for ALC to be near 0. What is your
experience?
Well, if you want to reduce latency you need to decrease buffer size
AND/OR you want to increase sample rate. If you cut the buffer size in
half but then drop the sampling rate in half you keep the latency the
same. Being able to run smaller buffers at a higher sampling rate
means more time spent by the computer transferring buffers (this
requires more CPU as the CPU is busy transferring buffers). So try
reducing buffer size but keep the sample rate where it was, i.e.
96KHz.
As for setting up TX levels, you want to select the "mic" option on
the TX Meter. The PTC-II has a test signal it can generate. Use that
for setting up levels. You want to adjust the level out of the PTC-II
and the input level on the FxK to produce as close as possible to 0dB
on the Mic level meter without going over. I normally shoot for -1dB
for my peak signal. That will produce about 75W-80W output.
73 de Brian, WB6RQN/J79BPL
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