630m Band Exploration
June 17, 2016: New.
Encouraged by my friend Steve, VE7SL I recently built a tranmitter for our new Canadian amateur radio band, 630 Meters. Check Steve's blog out for some interesting experimenting: ve7sl.blogspot.ca/
I used GW3EUP's design for the transmitter . Here is his URL,
The following picture is my 9 MHz CMOS VFO which is divided down providing a tuning range of 472 to 490 KHz. The transmitter is build in an old Northern Electric AM exciter chassic which has a nice reduction gear for the VFO.
The amplifier is composed of two parallel IRF510's run in class E followed by a low pass filter. At +12 Volts it puts out 14 watts.
The following photo is a combined 160 Meter and 630 meter matching system. The 630 meter loading coil is tuned with a variometer and it allows tuning to resonance my 70 feet of 450 ohm twin lead feeding a 40 meter quad that acts as a top hat. We are allowed to run 5 watts ERP on 630 meters but my meager 14 watts power output and inefficient antenna likely produces only 0.5 watts ERP. Amazingly I worked K7CW crossband. He was transmitting on 160 meters and I on 630 Meters. He is located near Seattle WA. When either 160 or 630 meters are selected one relay shorts the feedline together and the other relay selects the correct matching network for either 160 or 630 meters.