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Packet on 20 Meters

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Fred McKenzie

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May 5, 2014, 6:20:18 PM5/5/14
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It was fairly easy to get my old PK-232 working on VHF. However, HF
packet seems to be more critical. So far, the only band I've heard what
sounds like packet, is 20 Meters. According to on-line articles, there
should be packet on 14.105 MHz with the radio set for LSB. I could hear
packet-like sounds there, but nothing would decode.

While tuning around the frequency, I noticed that the PK-232 tuning
indicator suddenly sprang to life when tuning higher, and data started
appearing on the computer screen. There were numerous stations there,
including some nodes. It looks like the ideal dial setting is 14.10546
MHz. I was able to connect to myself via one of the other stations.

Can someone enlighten me about tuning in packet on 20 Meters? I found a
mention on the web of a 2100 Hz offset for LSB, but 14,105,460 minus
2,100 is 14.10336 MHz, also an odd frequency. (The radio appears to be
about 20 Hz off at 20 MHz.)

Fred
K4DII

mitch...@gmail.com

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May 6, 2014, 6:27:53 PM5/6/14
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Fred,

HF packet is done with a 200 Hz shift and if you are using a soundcard modem, use 900 Hz and 1100 Hz as your two values. These are audio modulation shifts like RTTY, not a input/output frequency split like a repeater.

Keep tuning about until you read clear text as you have done. Lock your VFO and see if anyone is actually chatting or if it's just traffic. Likely the latter.

Most chatting is done on PSK these days. It's much more useful for that type of activity. Google "PSK31 frequencies" to find the hangouts. Good ops and some FB DX to be had most any time of day or night.

Mitch
AC4IY

Fred McKenzie

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May 7, 2014, 1:42:46 AM5/7/14
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In article <f7114461-6dac-4c2c...@googlegroups.com>,
Mitch-

The articles that mentioned an offset referred to the center of the mark
and space frequencies for a particular modem. The center for your sound
card would be 1000 Hz. In the PK-232 manual I see that on HF Packet it
uses 2110 and 2310 tones, for a center frequency of 2210 Hz.

Reading about the offset, I understood the objective was to add the
center audio frequency to the radio's dial frequency for Lower Sideband.
So a 14.105 center frequency would require the receiver to be tuned to
14.106 for your sound card modem, or 14.10721 for a PK-232.

Working backwards, the stations I heard when tuned to 14.10546 should
have been centered at 14.10325. I suspect they were actually centered
at 14.10300. The combined error in my receiver and the very old
PK-232's tones may account for the difference. Trying a different
receiver and calibrating the PK-232 may be good ideas. For now I will
follow your advice and tune for best reception.

I would like to learn more about PSK31, but that is not one of the modes
of my old PK-232 modem.

Fred
K4DII
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