How does a Viper Antenna work?

Question

Are any of you guys familiar with a "Viper" antenna? It came up in a recent discussion with club members for higher frequency bands (6m, 4m, 2m). I hadn't heard of it before and internet searches suggest it's a brand as opposed to a type.

However, it seems the one thing they have in common is the coil (large or small) somewhere along the shaft. So, how do these antennas work electrically and do they have advantages over better known antenna types - or are they just snake oil (sorry, just couldn't resist!!)

Answer 1

As far as I know Viper antenna looks like this:

Here we see an antenna for 2m band. It's well described by John, VK2ZOI and Andrew, VK1NAM.

Basically it's a vertical dipole. The inner part of the coax in the top is one arm and the shield in the bottom is a second arm. The antenna is fed from the bottom. 9 turns of the coax cable work as a balun.

I've used this antenna on 2m and it works very well. If properly tuned it also works on 70cm as a 3 lambda dipole:

Although the balun is probably not designed for 70cm band.

You can find a little more details (in Russian) and pictures here.