[ARC5] 60m band and SCR274 transmitters

[Bill Cromwell]

Hi Neil,

If you are using a transmitter that actually has SSB and you use CW mode 
the carrier is shifted into the filter passband and the modulator is 
unbalanced. The carrier is no longer suppressed and the signal is offset 
from what used to be the suppressed carrier. So there will be no 
'residual' suppressed carrier to interfere. If you feed an audio tone 
into the balanced modulator to produce the tone you might have that 
problem. Nobody makes any commercial rig that does that now. There were 
too many problems with that method. I have two commercial transmitters 
with USB and LSB from the end of the 60s into the early 70s. Both of 
them move the carrier into the filter passband and unbalance the 
modulator for CW. I would just put my TX in CW mode, set in on the 
required frequency and go. Digital is mostly done in audio to the 
modulator and is a piece of cake. If yours does straight FSK then it is 
straightforward.

Moving closer to 60 meters.

73,

Bill  KU8H

On 07/22/2017 06:24 PM, AKLDGUY . wrote:
>> But the way that the rules were explained was that you could only or had to to be legal generate the signal using the USB
>> channel of a SSB or ISB transmitter.  If the FSK signal is generated by feeding AFSK into an SSB transmitter, and receive
>> it with an USB receiver, you will get the same results if you feed the normal AFSK into the USB transmitter or feed the
>> inverted AFSK into the LSB channel.
>
>> And absent residual carrier to give it away, no one would be the wiser.
>
> And therein lies the problem. No amateur transceiver on the market
> perfectly suppresses the carrier. If you're using LSB to generate a CW
> or digital signal, you're certainly radiating the suppressed carrier at
> some level, albeit low, and it may be on or very close to, the assigned
> channel carrier of some other service.
>
> Depending on your choice of frequencies, it may even be in the passband
> of that adjacent service.
>
> 73 de Neil ZL1ANM
>
>
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