Antennas

The main station antenna is a Mosely CL-33-M which is a heavy duty, stainless steel, 3-element beam for 20, 15 and 10 meters on a 5.5 meter (18 foot) boom.

Forward Gain: 10 M
15 M
20 M
8.5 dBd
8.1 dBd
7.3 dBd
cl33m
Front-to-Back: 10 M
15 M
20 M
20 dB
23 dB
23 dB
Power Rating: CW
SSB
Digital
1500 W
2500 W
600 W

The Mosley “Classic” match gives the antenna excellent bandwidth while maintaining a high ‘Q’ throughout all three bands.

yaesu_g1000dxa

The Yaesu G-1000DXA Antenna Rotator and Controller are used to rotate the tri-band beam antenna through 450° of beam heading rotation under remote control from the station operating position.  The clamshell rotator design utilises dual-stacked circumferential ball bearings to distribute load over the full diameter of the housing to minimise stress and wear.

RemoteQTHControllerThere is an optional Yaesu GS-232B Computer Control Unit available that allows rotation of the antenna by personal computer software via an RS-232 serial interface.  Unfortunately Yaesu have set the price of this unit at a very high amount. Instead, I chose to use a RemoteQTH Rotator Interface as the interface between the station desktop computer and the Yaesu G-1000DXA Controller.  In addition to being a much cheaper solution, it has the added advantages of using opensource hardware and software and connecting to the computer via a standard USB cable instead of requiring an RS-232 port on the computer.

g5rvThe G5RV antenna measures 31 meters (102 feet) across the top for 80 meter – 6 meter operation, and is fed at the center through a low loss 450 ohm twin lead feed-stub.  The interaction between the radiating section and the feed-stub allows the G5RV to be matched on all-bands from 80 meters through 6 meters using a good antenna matching tuner.

For VHF and UHF operation I use a Maldol VT-120D dual-band antenna with a gain of 2.15 dBi on 2m and a gain of 5.5 dBi on 70cm.  The VT-120D is 1.19m meter tall vertical with a maximum power handling capability of 100W and does not require radials.

mfj269The MFJ-269 RF analyzer is a compact battery powered RF impedance analyzer.  This unit combines a variable oscillator, frequency counter, frequency multiplier, 50 Ω RF bridge, a 12-bit A-D converter and microcontroller.  This device performs a wide variety of useful antenna and RF impedance measurements, including SWR, impedance, impedance phase angle, reactance, resistance, capacitance, inductance, resonant frequency, bandwidth, coaxial cable loss, return loss and electrical distance (in feet or degrees) to an open or short circuit.

Primarily designed for analyzing 50 Ω antenna and transmission line systems, the MFJ-269 measures RF impedances between a few ohms and several hundred ohms.  The MFJ-269 also functions as a non-precision signal source and frequency counter.  The operating frequency range extends from 1.8 to 170 MHz in six overlapping bands, and includes SWR measurements on 415 to 470 MHz.


HarnessWhenever I go climbing up on rooftops and antenna masts, I wear a SpanSet Ergo harness with an energy absorber connected to the rear D-ring using a screwgate karabiner.  The other end of the energy absorber is connected to the eyelet of a sliding adjuster on the 15m anchorage line.  This adjuster is used to keep the line taut between me and the end fitted with a double action safety hook attached to a suitable anchorage point.

AnchorageThis combination has a fall arrest rating designed to limit both the distance and force of a fall.  However, the sliding adjuster automatically locks under tension at any selected position along the line and as such this setup becomes a continuous work restraint that helps to prevent a person from falling in the first place.  These safety items are not cheap, but I like to have some control over when, how, and at what speed, I return to the ground.