Everything you need to know about Wolf River Coils antennas.

I have a SB-1000 and 102" whip mounted on my truck. It has been there for over 2 years now and I spend a lot of time off road in the trees. I have successfully bent the mount several times and the coil looks as it did when I bought it from them. I also have the smaller 40-6 coil that I have not yet used. I bought these from Wolf River at Dayton(Xenia) on the last day and they only had the display ones left. I have never had any tuning issues and pretty much hang out on 40 and 80. I run 100 watts on Phone from an Icom IC-706 and turn down to 25 watts when in digital operation. I have experienced no melting or burn spots. I have made many hundreds of contacts in rain, freezing rain and snow with no issues.

 

These are great antennas. I am actually doing a comparison and contrast written review between WRC and super antenna since they are really similar. That will be posted on my website.

 

Weight would be another important factoid, especially for SOTA types.

 

Great point -- it's intended for portable ops, and those with a vertical ascent will feel the weight all the more.

 

Someone needs to shout to the rooftops that you cannot expect to run gobs of power through any compromise antenna using digital modes. Don't care who makes it.

 

I agree with your submission

 

Great video! I have made a bunch of FT8/4 contacts with my SB1000 TIA and just yesterday made a contact from Arizona to Spain with 20 watts and my G90. Great antennas for the price. When I am able to take it to a mountain top and actually spread out enough radials, the antenna really comes alive. Took me 10 minutes with a cheap nanovna to make a quick chart, I go by number of whip segments collapsed, and number of coil "clicks" for each band. No sharpie marks, no ruler measuring, and after a few days I had it all memorized. I do use the WRC extended whip, which works great without the coil mounted to an nmo to 3/8x24 adaptor on my truck roof mount as well.

 

Check this out: fresh from the interwebs...
Picture says 1000 words...



Wolf River coils -- garbage.

 

Do your comparison with a real antenna -- like a bug catcher coil. Or a webster mobile coil.
Comparing junk to junk is a waste of time...

 

Looks cheap with the white PVC pipe.

Why do hams love using white PVC?

 

PVC not such an issue but the issue with the WRC is the stainless steel coil material. Lossy and heat generating.
Eventually it melts the PVC from the wire's heat. Silver coated copper is much less lossy.

Most tank coils, inductors, air tappable coils and roller inductors are made with copper coated wire (silver, sometimes tin).
None are made from stainless steel. There's a reason for that.



Table of Resistivity and Conductivity at 20°C
Material ρ (Ω•m) at 20 °C
Resistivity σ (S/m) at 20 °C
Conductivity
Silver 1.59×10−8 6.30×107
Copper 1.68×10−8 5.96×107
Annealed copper 1.72×10−8 5.80×107
Gold 2.44×10−8 4.10×107
Aluminum 2.82×10−8 3.5×107
Calcium 3.36×10−8 2.98×107
Tungsten 5.60×10−8 1.79×107
Zinc 5.90×10−8 1.69×107
Nickel 6.99×10−8 1.43×107
Lithium 9.28×10−8 1.08×107
Iron 1.0×10−7 1.00×107
Platinum 1.06×10−7 9.43×106
Tin 1.09×10−7 9.17×106
Carbon steel (1010) 1.43×10−7
Lead 2.2×10−7 4.55×106
Titanium 4.20×10−7 2.38×106
Grain oriented electrical steel 4.60×10−7 2.17×106
Manganin 4.82×10−7 2.07×106
Constantan 4.9×10−7 2.04×106
Stainless steel 6.9×10−7 1.45×106
Mercury 9.8×10−7 1.02×106
Nichrome 1.10×10−6 9.09×105
GaAs 5×10−7 to 10×10−3 5×10−8 to 103
Carbon (amorphous) 5×10−4 to 8×10−4 1.25 to 2×103
Carbon (graphite) 2.5×10−6 to 5.0×10−6 //basal plane
3.0×10−3 ⊥basal plane 2 to 3×105 //basal plane
3.3×102 ⊥basal plane
Carbon (diamond) 1×1012 ~10−13
Germanium 4.6×10−1 2.17
Sea water 2×10−1 4.8
Drinking water 2×101 to 2×103 5×10−4 to 5×10−2
Silicon 6.40×102 1.56×10−3
Wood (damp) 1×103 to 4 10−4 to 10-3
Deionized water 1.8×105 5.5×10−6
Glass 10×1010 to 10×1014 10−11 to 10−15
Hard rubber 1×1013 10−14
Wood (oven dry) 1×1014 to 16 10−16 to 10-14
Sulfur 1×1015 10−16
Air 1.3×1016 to 3.3×1016 3×10−15 to 8×10−15
Paraffin wax 1×1017 10−18
Fused quartz 7.5×1017 1.3×10−18
PET 10×1020 10−21
Teflon 10×1022 to 10×1024 10−25 to 10−23

 

I'm sorry you feel the way you do. None the less, it won't stop me from doing what we hams do best. Experimentation!

 

interesting video there Mike, i have seen you other video with the Dx Commander Expedition, how do them 2 compare ?? , granted the Commander takes slightly longer to setup, but the ability to swap bands with no adjustment is a plus, regards the wolf river i see the potential for snapping at the joints and/or bending of the telescopic whips ,knowing the lack of mfj quality control is the reason i would never buy the mfj whip extension, your thoughts ??

 

Just for a data point, I've been using this vertical as one of my antennas on the last several outings (other is inverted-v on 12m pole at about 10.5m). I am using the larger tripod, and the two extensions under the coil. I put a fender washer there, and throw on some paracord guys to keep it from tipping over in the breeze. I built it using 8x 50' radials and have used it at three fields so far.

It takes some tuning to get the best SWR over the band. Antenna analyzer necessary IMHO. It is sensitive to both the coil setting and the length of the whip. On 40m with enough fiddling, I can get the entire band under 1.3:1. This uses the long whip with a few inches retracted, and appropriate setting of the coil. The SWR will not be better than 1.5:1 at resonance without shortening the whip a little, at least with my ground plane. When tuning if you look at a wide range on the analyzer, you might see two resonances. One is broad and so-so, and one is sharp. Tune the coil to bring the sharp one into the band and tune the length to get the broad one on the band. Then the SWR drops and flattens. I'm not going to claim it will work for you but I've done it a few times on 40m. It is touchy! I think I'm seeing that if vegetation holds the radials off the ground like on my last outing ("grass" etc nearly to my waist), the SWR at the band edges will be slightly higher and tuning gets real touchy.

On 20m with the long whip retracted approximately 4 1/3 segments and a little bit of the coil used, I've getten the SWR down to just a hair over 1.2:1 at the edges of the band.

I'm measuring at the end of 100' of LMR-400 ultra-flex with an AA-600.

Currently I'm building a DX Commander Expedition. I'm curious to see if it will work as well, and how long it will take at the field for setup / teardown. Not having to tune to change bands is a big plus. And, the shorter radials will be easier to deal with. Whether the shorter radials will work as well over my various fields is something to test. IF it works well I plan to get a second one to set up as a parasitic beam for DX rather than POTA. I work a decent bit of DX at fields with the vertical or with an inverted v.

 

The article in the link refers to mobile antennas, but the laws of physics apply to short "portable" antennas as well: http://www.k0bg.com/eff.html
Note that "antenna efficiency" is the main concern, NOT SWR! Look at the efficiency on the various HF bands, maybe you will realize why the inductors get hot enough to melt the plastic. That heat comes from energy that was NOT radiated, instead it was wasted due to the antenna being a poor radiator of RF. The losses are the same when receiving a signal, but the induced power is extremely low, so there is no noticeable heating of the antenna. The antenna will perform as inefficiently on receive as it does on transmit.