40m OCF DIPOLE
Version 4 has the same feedpoint split and leg lengths as used in version 3.1 and 3.2.
CHANGE: I have re-designed the feed method.
New: I have built a 4:1 Guanella on two "-43" Toroids, placing one transformer on each core.
SAME: I have used the same 1:1 Guanella (CMC Choke) which is 2x 9 turns of RG-174 on a "-43" Toroied. (Total 19 turns incl. the cross-over).
LENGTH: About 66 ft.
FEEDPOINT SPLIT: 17.4% / 82.6%
WEIGHT: Unfortunately the weight has increased significantly. This version weighs 440 gr. (14 oz.), including 11m (35 ft.) of RG-174 coax. For comparison, Ver. 2 weighed 335 gr. and Ver. 3 weighed 360 gr.
RESULTS: The excellent SWR curves of Ver. 3.1 have been maintained, while eliminating the problem of the apparent resonance frequency being dependant on the length of the coax.
How do you like them apples?
- The antenna was mounted on a Spiderbeam 12m telescoping fiberglass "Spiderpole".
- The feedpoint was 10m (33 ft.) high.
- The long end was 4m (13 ft.) high at its far end.
- The short end was about 8m high at its far end.
SWR CURVES BY BAND:
[ click on image to enlarge ]
- IS RATED FOR 200 WATTS OF TYPICAL AMATEUR RADIO SSB AND CW OPERATION.
- may be used on 40/20/15/10/6m WITHOUT the need for an antenna tuner.
- may be used on 12m WITH a matchbox, but I recommend reducing power to 75w.
- has met all of my original design goals EXCEPT for weight.
- I will address the weight issue in Version 5.
- is finished.
DO NOT ATTEMPT TO USE THIS ANTENNA ON 17m
UNLESS YOU REDUCE POWER TO ABOUT 50w.
DO NOT ATTEMPT TO MATCH THIS ANTENNA ON 50m
UNDER ANY CIRCUMSTANCES;
THERE IS A VERY HIGH RISK OF BURNING UP
THE 1:1 GUANELLA CMC CHOKE IF YOU TRY TO USE THOSE BANDS!