Project 7 of 7 for October, 2020 – projects to keep sane during Covid-19 Lockdown
Status: All work is completed.
A new Yaesu G-450ADC rotator was ordered from GigaParts. Still needed are the rotor plate, the cable, and the interface to make it remote controlled. Cable and interface are on order from DXEngineering and HRO. This project has hit a snag. Rotor plate is special order and has a November ship date. It has not even been ordered and by the time it gets here the weather could be too wintry to install it.
Universal Towers saved the day. An order was placed directly with them today and they promised a much earlier delivery date.
“The rest of the story” is this tower is decrepit. It was used 10 years to hold up wireless Internet antennas on a windy hill. It has two blow outs from being overloaded. Even though the blowouts have been repaired the concern now is it might not be able to keep the A3S in the air. Torque is the tower killer when wind makes a beam twist. An overloaded tower can fail from that twisting motion. When this tower is down for the rotor installation a torque arm will be attached in an attempt to reduce the twisting motion.
Remote Controlling The Rotator
All parts have arrived. The Yeasu G-450 rotator is the new DC version which makes absolutely no detectable difference in the operation but it makes lightning protection easier. Relays had to be used on the AC rotator because the AC voltage was too high for the 26vac/31vdc MOV’s on hand. Perfect for the 20 volts DC the new version uses. Modifying the controller for access over the Internet looks like this:
Actually the controller is not modified. A few wires are tacked onto existing terminals inside. Wires are brought out through an existing hole. The controller could be easily restored to original. In the picture above, the green thing at the bottom is the remote interface from RemoteRig.com model RCU-1216:
The interface talks to the RemoteRig 1216H Webswitch and will get mounted inside the controller. A Webswitch already exists at the remote site to provide remote access of the first rotator on the taller tower. That missed getting written up. That’s why this is being written up now. The unit has the capability of two rotators so all that was needed was this interface to the Webswitch. The installation just needs some hookup wire and a solder iron.
There is no brake release button on Yaesu control boxes so a brake release connection is not needed. Only the Pot potentiometer connection and the two motor activation buttons are needed. A data pair and a power pair connect back to the Webswitch.
For this rotator the two jumpers, P5 and P6, are opened up to accomodate the voltage on the Yaesu rotator for direction indication potentiometer. Voltage maxes at 1.3 volts on the pot. Next attach a little Blue Tack or 3M gray stickem to hold the interface in place.
Stick it to the inside of the cabinet and you’re done. It should look something like this:
Coming out of an existing hole in the back are two pairs of wires. One is for 12 volts DC. The other is the 1-wire data pair (1-wire really means 1-wire and ground). Next step is to install and test at the site.
Today the rotor plate was mounted and the rotator is mounted to the plate. A short piece of aluminum tubing was cut to go from the rotator to the mast. A hole was drilled for a bolt to keep the mast from twisting and slipping.
The tower was raised a few feet to see if it is too heavy with the rotator. It is noticeably heavier and harder to lift but not impossible. None of the gin components complained. The rotator only weighs 7 pounds and the wire is probably 2 more pounds. Another 9 pounds is apparently not overdoing it. Next the cables will be extended where needed for slack and they will be dressed. The bolt will be installed. The rotator connector will have a waterproof boot installed. The balun will be reworked to provide enough slack for turning the antenna (the balun is near the center of the picture with cable ties holding it to the tower leg). The rotator cable will be run through the cable entrance at the shed and MOV lightning protection will be provided. Inside the shed the controller will be connected to the RemoteRig Webswitch and all will be tested. It will be really nice to be able to turn this beam in the direction of the signals as they change.
Today, the balun was rebuilt by replacing the RG-58 windings with LMR-400. It is still 5 turns through a stack of 4 Mix 52 ferrite toroid cores. It looks like it can handle a lot more power now. Only the common mode current is flowing through the toroid.
Proving the balun is working is a matter of observing the signal pattern on pskreporter. In this case it is a nice flashlight beam shape in Europe indicating the balun is doing it’s job. It’s job is to keep common mode currents from generating stray radiation which distorts the pattern. No pattern distortion, the balun is working.
The rotator mounting is completed and the cables are dressed. Ready to raise the tower.
Back up in the air the rotator turns the beam perfectly with no issues. As for remote control, a relay is being used to switch between the two rotators. The other rotor turns the 203BA 20 meter beam on the big tower. One rotor at a time is accessible over the Internet.
This project is completed.