[ARRL-OK] ZS6BKW Simple Multi-band HF Antenna

[D C _Mac_ Macdonald]

 The following was sent by Norm, W7CK (kl7rs at yahoo.com)
 
Here is info to build a ZS6BKW (from South Africa) antenna. 
 
It is simple to build, gives you 5 bands without a tuner and is very quiet compared to a vertical and some other dipoles. 
 
It is similar to a G5RV except the dimentions are totally different;  93' across the top fed with 40.5' of 450 ohm ladder line. 
 
Connect 50 ohm coax (any length) to the ladder line either directly or using an optional 1:1 Current Balun. 
 
Get the antenna up in the air as high as you can.  Connect an analyzer to the coax and trim the ladder line in 1-2" increments for the lowest SWR on 20 meters focusing on the portion of the bands that you like operating the most. 
 
In other words if you mostly operate CW or Digital modes, trim the ladder line for the lowest SWR for around say 14.080. 
 
Once your done with that, scan the rest of the bands and you should have fairly low SWR on the low end of 10m, all of 17, 12 and most of 20. 
 
You'll also have fairly low SWR on the low end of 40.  With an internal tuner you should be able to use all of the bands between 40-10 except 30.  30 just won't work. 
 
Even though the antenna is a bit short, most people also get good results on 80.  The high end of 75 might be a bit of a stretch without a good tuner.

Norm, W7CK uses 25 feet of LMR400 into the shack and can work everything from 80-6 (excluding 30) with the internal tuner and he claims great results.  Norm stated that It outperforms his 1/4 wave vertical on 40m most of the time.  It almost always hears better than the vertical because it is just so darn quiet. 
 
He lives in an HOA and made his from plastic coated number 28 copper clad steel.  It is extremely thin and hard to see. 
 
He soldered it directly to the ladder line with shrink wrap for protection.  He's had contacts all over the world with this simple antenna.  
 
Norm stated that he's not sure why more people don't use it.  He used the OCF and still had to use a tuner most of the time and he had RFI issues.
 
Try it and let me know how it works for you.  Takes all of an hour to build one.
 
Norm - W7CK