开云体育

Hi I'd like to know if the receiver module can be modified for use with the quadrature VFO after the divider chip as already been soldered in without having to first remove the chip again.

-Justin N2TOH

Hi Justin,
I just cut the necessary tracks on the underside of the pcb and added link wires. I did this with the divider chip in situ.

73 Ken G4APB

Ken,

Ah very good and thank you for such a quick reply! another question if I may, do you have a suggested pin on the connector strip for injecting the I and Q signals? I'm entertaining a notion of a carrier board with a preamp and maybe a mixer for some higher still bands.

Justin N2TOH

Hi Justin,
the I and Q signals are outputs, if you really mean the additional CLK1 LO input signal, yes I used the spare connector holes next to the 'TX input/Rx Mute' pin to fit more connector pins (CLK1 and Gnd), and hardwired them on the underside of the Rx board to the appropriate cut tracks feeding IC1.

I dont use the I/Q output system as it is not supported in the later versions of WSJT-X, I have a Polyphase board fitted for SSB output, but I linked the two output transformers so I have an isolated output to my PC soundcard and another feeding an external audio amp for audible monitoring.

A preamp and a mixer for the higher bands sounds a good idea as despite all the mods, my 4m U3 Rx with its preamp suffers noise from the QLG1 GPs unit and is not as sensitive as my Yupiteri scanner radio.

73 Ken G4APB

Hi Ken,

yes I was talking about the additional CLK1 LO input signal, I plan to run a 2nd poly phase board to play with Independent side band operation just for fun.

in reference to the noise from the QLG1 unit, OK I'll try the mixer method first then. from what I recall the softrock ensemble uses an 80% LO frequency,? for example to listen to 144.200MHz the LO wold be tuned to 115.36MHZ as that plus 1/4 of that frequency is the desired frequency on 2 meters. 144.2 == 115.36 + 28.84MHz? with the 10 meters frequency being the IF used by the Taylor detector. what you end up with is a sliding IF frequency.

50 MHz = 40 + 10 MHz
70 MHz = 56 + 14 MHz
225 MHz = 180 + 45 MHz
432 MHz == interesting solution needed, perhaps using another CLK output followed by a multiplier stage and filter.

-Justin N2TOH