Improving the Wolf River Coil

by Mike Jahrig KG5P

The improved Wolf River Coil setup with ground spike and tuning clamp (Photo: KG5P)

I bought a 40-10 meter Wolf River Coil vertical antenna at the last Ham-Com about 3 years ago.  I have forgotten what I paid for it, but it was less than the current price of $130. To be truthful, I have been very disappointed with this antenna.  The tuning mechanism is a cheap stainless steel spring clip mounted inside a 2-inch slice of PVC pipe.  You are supposed to tune it by sliding the little clip up and down the coil windings, hoping you can find a low SWR somewhere.  If you are lucky and succeed, don’t sneeze!  If you do and measure again, you will find the SWR is now above 11:1. Don’t get me started on the flimsy tripod.  When you sneeze, it will be lying on the ground.

Bob Hill, KG5WRY, wrote about a low cost quick deploy portable antenna in the February 2023 Chawed Rag. So I decided to cannibalize the aforementioned Wolf River vertical and see what I had in my junk box plus whatever I could scrounge up to improve this nightmare.

I replaced the tripod with the trucker’s special CB mirror mount mentioned in the Bob Hill KG5WRY article.   I found mine on Ebay for $7.98 including shipping.  I found the 12-inch nail at Lowe’s for 98 cents.

Replacement tuning clamp for Wolf River Coil (Photo: KG5P)

The only useful stock components I see with this entire product are the stainless steel coil and the 102-inch stainless steel collapsible whip.  Stainless steel is one of the poorest conductors of electricity of all the metals.   About the best thing you can say is that it doesn’t oxidize.  Of course, neither does 24ct gold, which happens to be a great conductor, 6 times better than stainless, so I’m not faulting their use of stainless.

I bought a #4 conduit clamp and used it to replace the sliding tuning clip.  It must have cost less than 3 bucks or I would have remembered how much.  The picture shows it adjusted for the low end of the 20m CW band with perfect SWR.  I can also tune any other ham bands from 10-40m by adjusting the slider and the length of the collapsible whip.  With additional mods, I will try to tune it on 80m.

The last thing I bought was 20 meters of silicone covered 16AWG wire to make four 5-meter radials.  This is an improvement over the 22AWG hookup wire that came with the vertical.  The silicone coating is very unlikely to tangle.  I used ring lugs to attach them to the mount base.  I may replace the ring lugs with banana plugs for faster hookup.  Also I probably will replace the mild steel screws on the truck mirror mount with stainless because they have started to rust.

To tie things up, this mod is a great improvement over the stock WRC vertical.  I’m not saying to go out and buy a $130 WRC antenna just to make the mods, but if you have one laying around, go for it.  You can also buy just the necessary parts from WRC.  The Silver Bullet mini coil costs $55.  You can also buy the 102-inch collapsible whip from WRC for $25.