Vortex Super J-Pole Vertical Antenna – VHF 70Mhz (4m band) Amateur



Vortex Super J-Pole Vertical Antenna - VHF 70Mhz (4m band) Amateur

Vortex Super J-Pole Vertical Antenna - VHF 70Mhz (4m band) Amateur

£230.00 — £335.00

Product Code – 70-SUPERJPOLE

A Super J-Pole Antenna for the *70Mhz (4m) Amateur band.
The Vortex ‘Super J-Pole’ Antenna consists of a five eighth wave vertical radiator, a half wave tuning section and a half wave top section.

At the base, a quarter wave matching stub forms the classic ‘J Shape’. The addition of the extra half wave top section boosts the gain over a standard J-Pole. The Super J-Pole has an added advantage that tuning can be varied over a fairly wide frequency range by moving the feed-point location up or down. This also gives the user finer control over the impedance and match.

We also include a quarter wave 75 ohm matching section of Webro WF100 coax which improves the system considerably making matching to 50 ohms much easier. The antenna is end fed and has an omni-directional radiation pattern and requires no ground plane or radials. From our modelling we can also observe that the antenna has a nice low angle of radiation, typically 8 degrees when mounted at 4m in height. This angle reduces further the higher the antenna is mounted. A typical installation with the antenna at 8 meters above ground sees the angle reduce to 5 degrees and the gain increases to 7.29dbi when ground reflections are added.

J-Poles should include a 1 to 1 ‘Choke Balun’ close to the feed-point, which prevents feed-line radiation. A simple and cost effective solution is to wind a small length of coaxial cable around a former. Vortex can also supply this if required in commercial grade ®Westflex 103 Coaxial Cable .
A Vortex Antenna Systems premium ‘Ferrite Core 3kw Choke Balun’ (Sealed to IP67 rating) is also available as an optional extra.

No Knowledge of Antennas? Our 70Mhz antenna is pre-tuned from the factory and all set-up measurements are included. However the system is fully adjustable should the user require to finely tune the system for their own requirements. We include a full set-up instruction sheet with each antenna.

All Vortex Antenna Systems Super J-Poles use heavy duty components and hardware including M10 stainless hardware, heavy duty Stauff polyamide and aluminium clamps as also used in our lower frequency base antennas. The main element section of this antenna is 5 sections of genuine VORTEX 6082-T6 or **AA6082-T6 Aluminium each section telescoping into its counterpart. We use 16mm tube for the adjacent matching section. The half wave tuning section has been recently revised and now includes a much sturdier solution. Gone is the ‘Mastrant’ support guy and we have included ‘Stauff’ clamps which totally support the horizontal rods without any additional aid.

To add even more strength to the whole structure, we include two 10mm diameter aluminium support bars which form a ‘Support Brace’ which sits over the fibreglass spacer.

See info below for mechanical and electrical details

  Vortex Super J-Pole Vertical Antenna – VHF 70Mhz (4m band) Amateur

Band(s):  4m (70Mhz)
Element Material:  6082-T6/*AA6082-T6
Bandwidth (2:1) SWR:  1.75MHz
Gain:   Freespace 4.15dbi. Typical over 6.10dbi when mounted 4m above ground
Feed:   Direct via 75 ohm matching section mounted to ‘STAUFF’ clamps (supplied)
Matching:   Quarter wave 75 ohm coaxial matching section (Webro WF100) – (supplied)
Rating:   2kw
Element Clamps:   Stauff (Germany) – heavy duty polyamide series
Antenna Weight:   4.5kg
Hardware:   304/316 stainless steel
Antenna Height:   4.80m
*If available