My HF Rig and Antenna

 
HF-station overview
HF station overview.		Overview
My HF station consists of a HF transceiver which is connected to a horizontal wire loop antenna. The automatic ATU and the 1:4 balun performs impedance matching between the coax cable and the loop antenna.

Click any picture to enlarge.
FT-920
Yaesu FT-920

HF transceiver
My HF transceiver is the Yaesu FT-920 multimode transceiver. The receiver is a double-conversion superheterodyne (IF1 = 68.985 MHz; IF2 = 8.215 MHz). Receiving range is 100 kHz - 30 MHz and 48 - 54 MHz. Transmit range is amateur bands from 1.8 MHz to 50 MHz. Maximum output power on all bands (including 6 meters) is 100 W. The weight is 11.5 kg. 

This transceiver offers a multitude of features. Full break-in, CW-reverse, CW pitch, and CW spot is provided. Computer aided tuning is also available via the RS-232 port, and an ATU is built in. 

The RF output can be reduced to 5 W QRP.
Balun and automatic antenna tuner.
Balun and ATU in a plastic box.
 ATU 
An automatic antenna tuner (SG-239 from SGC) is housed inside a weather-proof plastic box and placed close to the feed-point of the loop antenna. DC power for the ATU is supplied via the coax cable. I use a bias-tee at the radio and at the ATU (not seen in the picture). The bias-tee injects/extracts 12 VDC from the coax cable.

A broadband balun (BL2 from Elecraft) is placed between the tuner and the antenna. It is housed inside the plastic box. The balanced side of the balun is connected to the loop antenna. The balun is wired for 1:4 where the low impedance side is connected to the antenna tuner, and the high impedance side is connected to the wire loop.    

When the operating frequency is changed (or when the antenna impedance changes due to weather conditions), the antenna tuner requires RF from the transceiver to align for best match and lowest SWR. A few seconds of RF carrier at 5 W is usually enough for completing this task.                 
Loop skywire antenna.
Loop skywire antenna.

Antenna 
My loop skywire antenna is 43 meters long and erected horizontally. The loop is supported in 4 corners and the feed-line is connected to one of them. The antenna resonates in the 40 meter band but is usable on the higher bands as well. The ATU provides impedance matching between the coax cable and the antenna.

The loop is made of 1 mm enameled copper wire. The 4 insulators are made of makrolon (high tech polycarbonate) and they are connected to the support points using black 1.5 mm Dyneema rope. Insulators and rope were purchased at www.dx-wire.com


   
Latest revision: 14-Nov-2017 by OZ1BXM Lars Petersen.

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