Saturday 15 April 2017

The JK BevFlex-4 Antenna



This past week, comments regarding an interesting new low-noise directionally-switched receive antenna popped-up on both the Topband reflector and the IRCA (BCB DXers) reflector.

The new JK BevFlex-4 is reported to work very well without requiring a lot of real estate for deployment. The antenna was designed by Geoff Mendenhall, W8GNM, and Ned Mountain, WC4X.

There are several things that make this package a little different. The antenna can be configured in four basic forms: CLASSIC BEVERAGE, BEVERAGE ON GROUND (BOG) / BEVERAGE IN SOD (BIS), INVERTED EWE, or as a FLAG. What is quite different however is its flexible feedpoint allowing the antenna to be fed at any point along its length when used in the BOG or BEVERAGE configuration. The antenna is completely passive and requires no preamplification although, in some configurations, it is suggested for use above 7MHz.

Full details can be found at the JK Antennas website, as well as the manual and a FAQ page.

The FAQ sheet indicates that it will perform from LW through to 10m but the most dramatic improvement in reception from users has been noted on the lower bands. It sounds like it might make an interesting antenna for NDB DXing as well.

In the BOG form, the antenna can lay right on the ground or be buried (BIS) just below the surface using RG-6 for the actual antenna element. Other configurations allow much smaller, stealth-sized wire to be employed.

An interesting YouTube video of the antenna in action as well as an in-depth description may be viewed here:


Here is one comment from an east coast topbander:

I also bought one this year....deployed it as an EWE, as that’s all the room
I have, small lot in a subdivision.....in order to work them you need to
hear them, and once I put that up, I could hear !!! first put up as EU/VK-ZL
and worked several in the DX contest, but when the african dxpedetions were on, moved it to due east/west., and worked all of them, S01, etc.....front to back is remarkable on 160, it works ok on 80, (mine was 10ft high and 38 ft long) but really rocks on 160 !!!!, and really cuts down the line noise/static I normally hear on my transmit Inv L.

Perhaps this may be your answer for a small effective receive antenna for LW and above but even if not, their website description makes for interesting reading.

1 comment:

Greoff W8GNM said...

The Bevflex-4X is new version of this antenna which is now available at Unified Microsystems.

https://www.unifiedmicro.com/bevflex4x.html

73,
Geoff - W8GNM