Monthly Archives: February 2011

Added band by band antenna descriptions

I just wanted to let you know that now you can check the Equipment tab and browse through each of the bands antennas. On each one of these pages at the bottom there are links to the posts which show when we built the antenna systems, so there is a lot of fun stuff to see if you haven’t followed the project from the start.

I will try to gather the posts of all tower construction work as well, but not tonight so stay tuned for that.

More done on the 2x4CX1500B amplifier

Today I did some more work on the amplifier. I milled out a sensor card, which will be used to sense the control and screen grid currents. It can also measure the voltage of the screen and all this is fed into the controller boards A/D converter. I also milled a couple of couplings, which will connect the stepper motors to the potentiometers that measures the position of each vacuum capacitor. While milling the sensor board I also milled out the high voltage pickup board, used to measure the voltage from the 2.5kV HV transformer for the anode. I also mounted some of the control electronics.

Now the next step will be to start adding the control cables for the vacuum relays to the proper positions of the control system. I will also soon mount the potentiometers which will make it possible for me to start testing the stepper motors, which will be a blast.

TJ9PF JA pileup on 160m

SM2LIY recorded this listening remote with SJ2W beverage antennas. The antenna was a 700m long beverage facing towards Japan and the time was around 21z.

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PI-tank almost done

I’ve almost gotten the PI-tank completed now on the 2x4CX1500B amplifier. I also added some padding capacitors for the C2 cap, so we can get up to 4200 pF of total capacitance on the C2. I also added feed-through capacitors to all the vacuum relays and the stepper motors.

The next step is to mount the potentiometers for the stepper motors, so we can know exactly the position of the capacitors, and no need to count steps of the motors. I also ordered some current sensor transformers which will be used to sense the current to the control and screen grid. For measuring the current from the anode I will just use a resistor and measure the voltage drop over it (at the cathode side).