Add LSB is very simple.
PRC-319 By British MEL (Philips)
To add LSB to the PRC-319 is in fact very simple.
In the design with the Weaver's third method ssb generation, you only have to swap the two 90 degrees phase shifted signals.
You can find this signals on the interconnecting diagram in the manual.
At "Radio frequency unit" in the diagram you can see a RX1 and RX2 pin 1 and 20. And a TX1 and TX2 pin 3 and 18.
If you connect RX 1 to pin 20 and RX2 to pin 1, and TX1 to pin 18 and TX2 to pin 3,the weaver phase method will now genarate lower sideband.
The frequency information on the display is now incorrect with LSB.You have to tune 3.4 KHz lower for the right frequency.
This happens because this method of SSB generation needs to set the tune frequency in the middle of the audio SSB spectrum.
For the right frequency on the display in USB there must be a compensation of 1.700 KHz to show you the right frequency. If you put the set on LSB the tune singnal stay also on the same frequency in the middle of the SSB audio spectrum. The frequency now have to compensate for the right LSB frequency twice 1.700 KHz is 3.400 KHz down.
So if you want to receive 3630 KHz on 80 meter you have to tune the set to 3626.6 KHz.
The most easy place to swap the leads is in the "Radio frequency unit" just on the other side of the connector.
Weavers 3th method explained.
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