[RTTY] Signal Link USB

Kok Chen chen at mac.com
Wed Feb 9 13:04:40 PST 2011


On Feb 9, 2011, at 12:32 PM, Tom Horton wrote:

> I am about to order a Signal Link USB to use with my old FT-1000MP. Just to make sure, what connector do I want for hookup to the radio? 8 pin round mic plug or ????

The SignaLink USB is an AFSK device.  Use the rear panel 5-pin DIN (PACKET) connector to bypass the voice processor.  Do not use the RTTY connector, which is for FSK.

Turn RF PWR to max, and adjust the RF output power you desire by using MIC GAIN (which will change the line input gain from the PKT connector also).  I know it is counter intuitive to use MIC GAIN to adjust RF output, but it is the way to avoid ALC from kicking in.  Adjust the MIC GAIN for the desired RF output power, but in all cases, make sure there is no ALC reading on the meter.  None, zilch, nada.

The PKT mode of the 1000MP uses LSB, so be sure to tell your sound card software to use LSB if you run QPSK31.  BPSK31 will work with either LSB or USB, so no need to worry if you don't use QPSK31.  Tell your sound card to use AFSK LSB (I think most of them default to LSB anyway).

There is a Menu item (6-5) in the FT-1000MP to choose the Packet tonepair.  If your software is using the 2125/2295 Hz pair, choose the 2110/2310 pair in Menu 6-5 so your receive IF filters will center properly (yes, you can use narrow IF filter in the FT-1000MP Packet mode).  There is a typo in the operating manual -- it list that tonepair as 2110/3130 (yeah right, 20 Hz shift).  They also list the 2025/2225 pair as 2025/2125 (100 Hz shift :-) :-).

If you want to use the Packetcluster spots, be sure to also change the Packet frequency display menu (6-4).  If you are using the 2125/2295 Hz tone pair, dial in -2125 (note the minus sign, in LSB, your Mark tone is below the suppressed carrier) and your VFO dial will red out the RTTY mark frequency.

73
Chen, W7AY



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