The HB9CV has been a popular antenna for decades, especially on the 2m band where it is commonly used for direction finding (foxhunt). Others create arrays of HB9CV antennas for DXing. Since I needed a simple antenna for 23cm (to uplink to the local ATV repeater PI6ATV) I thought it would be nice to use this HB9CV design.
There are several designs available, I used a description of DH2PA for no particular reason (it was simply one of the first usable designs I found). If you don’t want to build it yourself, you can buy one on some radio stores or a local radio market.
Some specifications of the HB9CV antenna (according to “Rothammels Antennenbuch”):
- Gain: 4.2 dBd (+/- 0.2)
- 3dB angle (E plane): 68 degrees
- 3dB angle (H plane): 130 degrees
- Front-to-back ratio: 20 dB
- Impedance: 50 ohm
I used thick copper wire to build the antenna itself, and thin copper wire to create the match/feeder. Everything is simply soldered together. I used to build antennas for HF and VHF, so with these small dimensions I continuously thought I was building some model. The capacitor has a range of 2-6 pF and is used to match the antenna impendance.
The antenna is a bit vulnerable to weather conditions and other external influences, so I put it into a plastic box. If you want to do this, remember that the box must be “RF friendly”. If you’re not sure, put the box into your microwave for 2 minutes along with a glass of water, the box should remain cold. The antenna itself is fixed by using a small piece of semi-rigid, connected to the HB9CV at one side, and a N flange jack at the other side which is mounted through a hole in the box.
After a final test the box is mounted to one of my antenna poles, close to the LNC which I use to receive the 3cm output of the ATV repeater.
Down here you’ll see some pictures which show you how I made this antenna.
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