ZL1RS - Antennas

Beverage RX Antennas

 

The Beverage Antenna - for weak signal HF reception

Single wire Beverage receiving antennas are used here and they work very well. On-air A/B comparison receive tests against dipoles, Vee Beams, Flags and wire colinears all gave results in favour of the Beverage ... sometimes by as much as 15dB better Signal to Noise Ratio (SNR or S/N)! Even a single wire Beverage that is just 1 wavelength long is better than most of those other antennas when it comes to receive performance. Search on "beverage antenna comparisons" and read the notes from K7TJR, W8JI and others to find out why ... but essentially, for receiving, it all comes back to "RDF" - Receive Directivity Factor.


The Single Wire Beverage Antenna at ZL1RS:


Easy to make, easy to erect, great RX performance.

Keep in mind that this antenna is for receiving weak signals from one geographic area on frequencies between 7 and 22 MHz, and has been designed, sized and erected accordingly.

Beverage wire size - 0.5 to 2 mm diameter (not critical, just physically strong enough). I use 0.7mm dia because I have plenty
Beverage wire length - between 1 WL and 4 WL long (not critical)
Beverage wire height - 60 to 90cm (not critical), supported by tread-in electric fence posts (I have used wooden tomato stakes)
Feed point transformer - 1:9 impedance ratio on an HF rated binocular ferrite core or ferrite toroid (not a powdered iron toroid)
Common mode choke - e.g. 25 or so HF rated ferrite sleeves slipped over the coax jacket near the feedpoint
Termination - 400 to 500 ohms (not critical) ... I used 3 x 1.2K ohms 0.5W carbon resistors in parallel because I had them
Preamp (optional, usually not required) - I sometimes use a home made W7IUV preamp (the "13Sep09" version)
Feedline to shack - 50 ohm 'radio' coax or 75 ohm 'TV' coax (not critical)

You may have noticed a liberal use of "not critical". All the Beverages tried here have been made from materials laying about the shed and from the junk box ... total monetary investment = zero! However, a quiet countryside location with several acres of space to erect long wires helps immensely.

Beverage construction
The important part is to not earth the feed point end of the coax and use a common-mode choke

Beverage feed point
The feed point end

Beverage feed point
The view from the feed point towards the termination

Beverage termination
The termination end

Beverage termination

View back towards feed pont
One of the tread-in electric fence stakes and a view back towards the feed point

View to 100 degrees azimuth
The view across 10km of rolling farmland to some low hills 30km away, and on towards the southern Pacific Ocean & South America


A single wire Beverage works very well ... but a pair of phased Beverages works even better!


Beverage comparison
Comparison of a single wire Beverage with a phased pair of Beverages.

The single wire Beverage antenna is a very good antenna, but a pair provides more signal on the 'nose' of the radiation pattern and less noise from other directions thus improving the SNR (S/N).


The Phased Beverage Array at ZL1RS:


This antenna is no longer in use. While it performed extremely well, it was a lot of work to shift when changing direction or when the cattle came through the paddock to graze the grass. Keep in mind this system is for receiving weak signals from one geographic area on frequencies between 7 and 14 MHz and thus has been designed, sized and erected accordingly.

Beverage wire size - 0.5 to 2 mm diameter (not critical, just physically strong enough. I use 0.7mm dia because I have plenty)
Beverage wire lengths - approximately 60 meters each (not critical)
Beverage wire height - 60 to 90cm (not critical), supported by tread-in electric fence posts
Beverage wire spacing - 15 meters (not critical)
(spacings between 0.5 and 0.75 WL are 'good' ... 15m spacing is 0.5WL at 30m and 0.75 WL at 20m)
Feed point transformers - 1:9 impedance ratio on a binocular ferrite core
Terminations - 400 ohms (not critical) ... 3 x 1.2K ohms 0.5W carbon resistors in parallel
Coax phasing harness - equal lengths (critical) of 75 ohm coax (not critical)
(for my purposes, 2 x 10m lengths are about 0.5WL including VF at 30m where it is used the most)
Preamp (not essential) - home made W7IUV preamp (the "13Sep09" version)
Feedline to shack - 50 ohm 'radio' coax or 75 ohm 'TV' coax.

You may have noticed a liberal use of "not critical". All the Beverages tried here have been made from materials laying about the shed and from the junk box ... total monetary investment = zero! However, a quiet countryside location with several acres of space to erect long wires helps immensely.


Beverage feed point 1
Feed point of Beverage 1

Beverage feedpoint 2 Feed point of Beverage 2

Beverage termination
One of the Beverage terminations ... 3 x 1.2K ohms 0.5W carbon resistors in parallel = 400 ohms


The following screen shots are of QRPp "Part 15" HiFER transmitters from the USA (between 9,000 and 11,000 km away). They are typically 5mW transmitters between 13.555 and 13.558 MHz working into a 1/4 WL vertical or 1/2 WL dipole antenna and operating 24/7. The screenshots were taken on 08 December 2015 at the UTC times shown along the bottom of the images (about my sunset time).

EH
Transmitter "EH" 5mW QRSS FSK CW from FN31nh East Haven, CT

EH
Transmitter "WM" 5mW(?) QRSS FSK CW from EM68es Lawrenceville, IL

EH
Transmitter "PBJ" 1.8mW QRSS CW from EM78cf Tracy City, TN

EH
Transmitter "RY" ?mW QRSS CW from FN43sv Raymond, ME
(The waterfall scroll interval rate was changed part way through).

EH
Multiple transmitters decoded

 


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