PERFORMANCE!

QUALITY!

DURABILITY!

PERSONAL SERVICE!

The DX – Low-Band Vertical (DX – LBV) is a new-concept vertical antenna system. Now launched on the Amateur Radio market, it is a system incorporating techniques and facilities not normally found in commercially-available antennas, to provide high performance for long-distance communication in the lower HF spectrum. The DX – low-band Vertical system is switched, tuned and controlled, in real-time, by the operator using a remote-control box at the operating position.

The 18 metre (60 feet) long DX – LBV covers the five normal Amateur Radio bands from 160m to 20m. (User-choice of one extra band, between 1.4 MHz and 7 MHz, may be available to customer request; for example 5 MHz (60m) or a portion of the top-end of the Medium-Wave broadcast band, for use as a low-angle receiving system). The DX – LBV design can be scaled for use on non-amateur bands – to discuss versions for professional applications, please enquire via the contact page.

Significant advantages are:

• Remotely-controlled tuning and band-switching by in-shack control box Tune for low feedline SWR for every operating frequency; maintain efficiency
  
• Elevated feed, on the upper three bands, but:
• No separate/elevated feeder
  
• No earth radials required for upper three bands
  
• High wind-speed resilience
  
• “Silent-tune” technique using built-in RX noise bridge; tune for 50 Ohm match, to feedline, on receive
  
• No moving elements; the only moving parts are a servo-controlled capacitor, and switching relays.
  
• High quality components for durability
  
• Outdoor boxes and ports environmentally protected to IP68
  
• Single-person erection and installation
  
• Spot-tuning, on 160m, 80m and 30m, can enhance receiver strong-signal handling, as compared with broad-match antennas

System Overview

The system comprises a base-fed wire and co-axial radiator of overall length around 20 metres, run along the support mast which is a telescoping, guyed fibre-glass mast, with two switching/tuning boxes towards the base of the mast, incorporating an on-mast tuning coil for 160m and 80m. The indoor control box, at the operating position, comprises a band-switch and single tune knob.

Operation on 160m and 80m is intended to be with a comprehensive ground system comprising, typically, at least (i) twenty 18 metre long wire radials for 80m, and (ii) twenty 30 metre long wire radials for 160m. However, experiments have suggested that operation with two short, loaded, elevated radials is achievable, with reduced performance. (Dimensions will be available, to enquirers, to fit individual site constraints).

The three upper bands (40m, 30m and 20m) do not rely on drawing earth current, and use an elevated-feed technique, without the need for a separate elevated feeder. Efficiency on 40m and 30m is believed to be especially high.

Another unusual feature is the built-in RX noise bridge, at the antenna, activated by a push-button on the control unit, which allows setting the tune control, for 50 Ohm match, without any need to transmit to find SWR dip. Apart from the convenience, and speed in tuning, this might set a trend to reduce the number of intermittent carriers appearing on the bands! The tune control-voltage, to the mast-base tune-box, is shown on an LCD display on the control box. If desired, users can produce a look-up tables unique for their installation, for favourite frequencies, thus further expediting QSYs.

Now is the time to get to enjoy what are now probably the best low-band DX seasons for the next ten years!

Final adjustments to guys!

Tim Stanley, designer; B. Sc. Communication Engineering,

G4DBL

www.g4dbl.com

DBLAntennas@yahoo.co.uk (Include "DX - LBV" in the subject line).

Patent application is pending.

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