HB9CV  Diamond A502HB

A502HB Base Station Yagi Beam

50 - 54 MHz 2 Element Yagi Beam Antenna 32 Inch Boom 6.3 dBi Gain  

Model: A502HB A504HB Frequency MHz: 50-53 MHz 50-53 MHz Gain: 6.3 dBi 10.8 dBi Power Rating (P.E.P.): 400 W 400 W Impedance (nominal): 50 Ohms 50 Ohms Connector: UHF UHF VSWR (nominal): 1.5:1 1.5:1 Element Phasing: 2 4 Front To Back Ratio: 15 dB 12 dB Boom Length: 2.5 ft. (750mm) 10.66 ft. (3250mm) Longest Element: 9.84 ft. (3000mm) 9.84 ft. (3000mm) Driven Element diameter: Parasitic Elements diameter: Max. Mount diameter: Weight: 3.75 lbs. (1.7 kb) 7.7 lbs. (3.5 kg) Warranty: 1 Year against defects in material or workmanship. 

The 2-Element-HB9CV-Beam

Construction by DK7ZB for 2m, 6m and 10m

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The HB9CV-Beam is a 2-Element-Yagi with two driven elements and was introduced  by Rudolf Baumgartner, HB9CV, in the 1950ies. The Beam is a coax-fed version of the ZL-Special. The reflector is fed  225° out of phase. The distance between the two elements is 1/8-Lambda (45°), with the two crossed phase lines of 180° results the 225°.

It is astonishing that this antenna is not well known in many countries, the ARRL-Antenna-Book does not mention this type of antenna.

You will get the beam very easy to work, because the influence of the element-diameters is much less critical than by parasitic Yagis, where the tapering and the element diameters are very important for the mechanical length of the elements. The gain is in the range of 4,1-4,2dBd.The HB9CV has a great bandwidth and a very good F/B, which are more dependent on the phase shift and the two driven elements than on the physical lengths of the elements and their individual dimension. The mechanical construction is a little bit difficult for the phasing lines and you need a compensation-C for tuning the SWR. For tuning use a variable capacitor (max. C see below), tune for best SWR (<1,2) and use then a fixed capacitor with the same value.

Principle of the HB9CV and dimensions for 2m, 6m and 10m

For other bands use the following formulas:

Reflector (R) :  l = 150/f             Radiator (S) : l = 139/f        l (m), f (MHz)

Feeding poits for the phasing lines: RS = 0,076 x lambda (m),  SS = 0,072 x lambda (m)

The 50MHz-HB9CV

Boom 25x25mm square-Aluminium

Elements 12x1mm round Aluminium

Lengths in mm

2-Element-HB9CV for 144-146MHz 

 HB9CV Antenna 

The name HB9CV may not be familiar to you, but chances are you've seen countless in your lifetime. Now and again, a design or piece of equipment defies our modern desire to upgrade simply because it’s so effective.

This antenna has been in use since its invention in 1954. While many more complex antennas have come out since then, its reliability and performance have made it a mainstay in the ham and amateur radio community. So what is this best-kept secret, and what can you do with it? Keep reading to find out. 

What Is an HB9CV Antenna?

The HB9CV is the most popular directional antenna in the world, invented by Swiss amateur radio enthusiast Rudolf Baumgartner in the 1950s. He designed a reasonably simple antenna with two dipoles. In part because of its simplicity, it remains hugely popular, especially among ham radio users. It’s more prevalent even than the three and four-element versions that have appeared since.

It is generally used for communication between two points over a medium range with ham radios and is arranged in an H shape when constructed. Many HB9CVs are portable or are attached to a permanent point, which helps to gain better coverage.

What Is the Performance of the HB9CV Antenna?

Considering it has remained a mainstay across Europe for nearly 65 years since its introduction, it'll be no surprise to hear that the performance of the HB9CV is excellent for what it is. Its low price, portability, clear signal, and ability to pick up low-frequency transmissions ensure this antenna is still going strong after all these years.

There are a few variables that can, however, affect overall performance. The first is the length of the beams, which are the two metal rods that make up the H shape. The shortest you'll generally see is 50 cm, with the longest stretching to several metres. Typically, the longer the beams, the better the coverage, but even a small HB9CV antenna placed at the highest point around can receive and send signals between 50 and 70 miles away. 

It tends to have a gain of 3.6 to 6.5dBd, although this is extendable through modifications. Its coverage can go up substantially with adjustments or different models.

Advantages of HB9CV Antenna

The HB9CV hasn’t remained the most popular directional antenna for all these decades without having numerous advantages, so let's dive in and look at what continues to make it so popular after all these years.

Easy to Assemble & Use 

One of the best aspects of the HB9CV is how easy it is to assemble and use. You can put the antenna together in a matter of minutes, and you can easily be chatting away in less than 10 minutes if you have everything set up and ready to go.

Portable

The portability of the HB9CV has earned it the nickname of being a hand-held antenna, and some models come fit for that purpose with an ergonomic grip. You can take it out into the field to pick up a signal without struggling to hold onto it.

Many portable versions of the HB9CV fold down — or quickly disassemble — meaning they’re easy to store away quickly after use. Perfect for trips out and great if you're using public transport.

Good with Low Signals 

Where the HB9CV shines in performance is its ability to pick up low signals. Having two elements picking up signals rather than just one means it has a handy boost compared with more simplified models. Although, you should bear in mind that the two beams need to be a certain distance apart, or they begin to overlap and cause interference.

Easily Adjustable & Manoeuvrable

The whole point of a portable HB9CV is that it is easily manoeuvrable. As any ham radio enthusiast will tell you, the ability to move an antenna a metre here or a metre there or even invert the elements can make all the difference.

It's common for people to modify their HB9CV antennas by shortening or lengthening the beams. Some ham radio users will build their own from scratch. The simple design is that easy to replicate.

Limitations of HB9CV Antenna

While the HB9CV is an excellent antenna and packs a pretty sizable punch for what it is, it doesn't come without a few drawbacks.

Weather Damage

An HB9CV affixed to a roof will have a rough time if a big storm occurs. Like many antennas, its top-heavy design at the end of a long boom makes it particularly susceptible to damage in high winds, and it's probably a good idea to take it down if you know something big is approaching.

Weather damage is not an issue with portable models. It’s another reason the easy assembly and disassembly is an advantage.

assembly instructions