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MFJ-1278B MULTI-MODE ADVANCED OPERATION
The adjustment is very easy to perform. Simply tune the radio to a channel which has only
noise (no signals whatsoever), then adjust the threshold control so that the DCD LED just
flickers occasionally. Set it so that the DCD duty cycle is between 10 and 20 percent. DO
NOT set the threshold control so that the DCD LED never comes on even when receiving a
signal!
If your radio has a bandwidth which is wide compared to the packet signal spectrum, the
DCD LED may not flicker at ANY setting of the threshold control when monitoring only
noise. In this case, set the threshold control to its maximum clockwise rotation. The data
carrier detector will function normally when monitoring a signal in this case.
Tuning in a signal is relatively easy to do once you get the hang of it. You must wait until the
other station is sending a packet, and then tune the transceiver so that the tuning indicator
LED is centered. If the DCD LED is not lit, the tuning indicator information is NOT valid.
Each bar on the tuning indicator represents about 10 Hz. Thus, if a packet comes through
and you are 4 bars off, re-tune your transceiver 40 Hz in the indicated direction. The
direction depends on the sideband you selected and the manner in which you have the tuning
indicator oriented. One or two tries will quickly tell you which way to go! Bars to the left of
center indicate you should tune higher, while the other side of center means to tune lower.
Once you have the other station tuned in, you may initiate a connect request just as you would
on VHF.
Many BBS stations forward traffic on HF at the above frequencies. Call CQ a couple KHz
away from such channels. If you can't raise anyone, call CQ on one of the above frequencies,
but QSY immediately after establishing contact! Be careful on 20 meters especially that
you don't operate +/- 2KHz around 14.100 MHz (you will cause interference to propagation
beacons and give packet a bad name...)
Calling CQ on HF is a bit different than on VHF. One technique which has proven effective
when NOT operating on one of the congested calling frequencies is to do the following:
1. Find a clear frequency and monitor it for long enough to make sure it really is clear.
2. Set "UNProto" to CQ if it isn't already. This is the default field for this parameter.
3. Command the MFJ-1278B into converse mode by typing either:
K<CR>
or