Welcome to

SFARC Home

Portable HF Antennas

By Fred Maas, KT5X

We operated the FYBO (Freeze Your Buns Off) QRP activity from a hill-top near Santa Fe. Such hilltops are a good place to put out a signal, but invariably are devoid of tall trees. First step was to bring our own trees. This was a telescoping fiberglass pole that collapses to under four feet, weighs two and half pounds, and pushes up to 33 feet.


Van-camper gave us refuge from the wind, clouds from the front can be seen to the north. Wind turning antenna into pretzel.

Operating low power from the field takes some preparation, perhaps, especially with antennas. There are so many trade-offs to consider! Higher and bigger is better, especially when running low power. I don't see much sense in operating five watts into a low efficiency radiator!

33 feet is plenty of height for 10-20 meters and can be adequate on 40 meters, but now we need an efficient antenna, one antenna for all these bands, that is light! We have two. both are made with 22 gauge woven wire, insulated for further strength and so if it brushes a branch, there won't be any detuning as a result. Make no mistake, they require a tuner on all bands. Don't leave home without one!

One antenna is a homemade G5RV. The flat top is 51 feet long. The stub is 16 feet of twin lead, with a female BNC connector mounted on the bottom. Loops are attached to the twin lead with hot glue so the line is controlled by the mast. The flat-top is pulled out by light weight mason's line fitted with fishing swivels and snaps. I used no observable insulator which will be fine at five watts if it doesn't rain on the mason's line. This antenna is a dipole on 40 meters, almost a double zepp on 20 meters and exhibits broadside gain on all the higher bands.

The other antenna is a triangular loop, top open and attached to 16 feet of twin lead, also controlled with attached loops. This antenna is a full wave loop on 40 meters, but a bi-square gain antenna on 20 meters. It exhibits broadside gain on 10-20 meters. We fed it at the bottom of the loop through a homemade current balun mounted inside a one inch diameter short piece of pvc.

Each antenna weighs only ounces, cost only a few dollars to build, and goes up in about ten minutes. Later reports from other participants in the FYBO QRP activity were that we had among the strongest signals on all bands all day long.

Lest there be any doubts about the usefullness of CW, we made 120 CW contacts during the few hours of the activity, and five SSB contacts. When running portable low power, CW will get through much more readily. It is an investment that pays big dividends.

73,

Fred KT5X


 

Site by TelActive, Inc. Contact W5SFZ