On 17/05/2013 17:42, andyfoad@... wrote:
Right then lads...Andy & Eddie,
Just done the DDS pot tweek and it sprang to life on 28Mhz!
Not done exhaustive tests yet but at least it's looking like
the RF from the DDS is being amplified by the 4 x BS170's at 9 volts.
Anyone got any confirmed power output figures yet on 28Mhz ?
Andy Cutland <gj7rwt@...> wrote:
Yes I've adjusted the blue pot so that the unit functions on 10m
but have not adjusted it for max power as the lower bands suffer.
Good show Andy's
Setting the Mark Space Ratio Pot to produce equal mark space on pin 7 of the DDS gives stable operation between the points either side where the signal collapses completely like Andy FTD's and my unit and unstable operation like Andy RWT's. In the unstable condition the filthy squiggle which is output from the DDS will cause heating of the PA device as noted by FTD.
Power level on 28MHz for me is a nice healthy 300mW as measured on the scope.
Unfortunately my U2 will not produce WSPR much above the stated problem frequency of the V2 version of the PIC. There is a WSPR data frequency missing at 28MHz and the noisy, spiky wide bandwidth signal already described.
I have appealed to Hans for a replacement PIC.
I will add captures of the missing data frequency to my folder on here.
73 Eddie G3ZJO
