This past week I was eventually able to mate my W1VD frequency doubler with my 630m FET amplifier and run some higher powered tests on 630m WSPR and JT9 modes.
Up until this time, I have been limited to about 1/2 W EIRP but using the amplifier allows me to get to the 5W EIRP limit. I have been using the VK4YB transverter's 475kHz reduced output of 1W and driving the doubler previously built as part of a transverter project. The doubler produces a nice 950kHz squarewave to drive my amplifier's divide-by-two flip-flop input circuit which in turn produces the dual antiphase outputs needed to drive the push-pull switching FETs in the final amplifier. Being a linear transverter, when used alone at 70W, it will run any mode that the IC756 ProIII will produce such as SSB, WSPR etc, but my switching FET amplifier is class-D, non-linear, which limits it to non-linear modes such as CW, WSPR and JT-9, the most popular modes on 630m.
A few days ago, VK4YB and I ran our first 630m sked on JT9 as conditions looked favorable. Unfortunately, this was before I had my transverter / antenna switching system completed so I was limited to the barefoot transverter at ~ 1/2W EIRP. Using a transverter to drive an external amplifier means the antenna must be switched between the amplifier output and the transverter input in addition to switching the transverter's output between the antenna and the amplifiers input. I'll post details of my switching system, and inexpensive but power-capable relays, in an upcoming blog as there are probably many 630m operators planning on doing something similar.
Thanks to Roger's huge antenna, his 90W signal was making it through well enough on this end but he was not able to decode anything from me.
1109 -26 0.3 1098 @ VE7SL VK4YB QG62
1111 -28 0.3 1098 @ VE7SL VK4YB QG62
1147 -24 0.1 1100 @ VE7SL VK4YB QG62
1149 -27 0.1 1100 @ VE7SL VK4YB QG62
1153 -27 0.1 1100 @ VE7SL VK4YB QG62
1159 -26 0.1 1100 @ VE7SL VK4YB QG62
1209 -26 0.0 1100 @ VE7SL VK4YB QG62
1225 -25 0.1 1100 @ VE7SL VK4YB QG62
1227 -26 -0.0 1100 @ VE7SL VK4YB QG62
1229 -24 0.1 1100 @ VE7SL VK4YB QG62
1239 -23 0.1 1100 @ VE7SL VK4YB QG62
1247 -26 0.0 1100 @ VE7SL VK4YB QG62
1249 -26 0.1 1100 @ VE7SL VK4YB QG62
1253 -23 0.1 1100 @ VE7SL VK4YB QG62
1255 -28 0.1 1100 @ VE7SL VK4YB QG62
1257 -26 0.1 1100 @ VE7SL VK4YB QG62
1303 -27 0.2 1100 @ VE7SL VK4YB QG62
1305 -23 -0.1 1100 @ VE7SL VK4YB QG62
1307 -25 -0.1 1100 @ VE7SL VK4YB QG62
1309 -23 -0.1 1100 @ VE7SL VK4YB QG62
1313 -25 0.0 1100 @ VE7SL VK4YB QG62
1319 -27 0.0 1100 @ VE7SL VK4YB QG62
1323 -22 0.1 1100 @ VE7SL VK4YB QG62
1325 -25 -0.1 1100 @ VE7SL VK4YB QG62
1327 -24 0.0 1100 @ VE7SL VK4YB QG62
1329 -25 0.0 1100 @ VE7SL VK4YB QG62
My location on the 'wrong' side of Mayne Island requires me to fire directly into a very nearby 600' hilltop, directly in Roger's path.
|I'm at the base of the hill on the far right.|
The large mountains are on Vancouver Island and then open Pacfic.
With the antenna / transverter / amplifier switching unit complete, Roger and I will continue to watch band conditions favorable to the Trans-Pacific path and hopefully exchange signals sometime this fall before the path disappears until next spring. For Roger, near Brisbane, the path peaks for him in the late evening while for me, it means crawling out of bed at 0330 local time to check the prop, hoping to find good signals from down under ... working VK on 630m would be well worth losing a few hours of nightly sleep!