X80 Vertical

Mostly written in 2011

The x80 vertical antenna is a possible replacement for my end fed Par antenna that had to come down. It is in my garage unused recently and never at this QTH.

Introduction

The X80 is a commercial version of a so-called Rybakov vertical antenna. It was manufactured in the UK by the Snowdonia Radio Company. The antenna is 5.8m long and covered 3.5-29MHz via an ATU. The antenna resembles a base loaded CB vertical in appearance, although the design is quite different. The SRC X80 base contains a 9:1 UNUN transformer rated at 150W which converts the relatively high antenna impedance at the

base of the vertical section to an impedance more easily matched by auto-ATUs found in modern radios. As with all such antennas, this is a compromise one, so do not expect remarkable results. However, when mounted in the clear it is capable of quite decent performance, even when running QRP. The SRC X80 was very reasonably priced and represented quite a bargain for a commercial HF antenna.

Packing and Delivery

The unit arrived within 3 days of ordering by Royal Mail and came in a strong cardboard carton. What surprised me was how small the package was considering the size of the erected unit. The secret was packing the 6 vertical sections of the antenna within each other to save space. All the necessary jubilee clips and brackets were supplied and nothing was missing.

Erection

This took about 30 minutes, with some of this time removing the previous antenna on the side of the house. There were no issues at all in assembly or erection. SRC recommend waterproofing the antenna joints with self-amalgamating or PVC tape if erecting permanently. When up on the back of the house, the antenna did sway about in the wind, but it looked strong enough and likely to survive.

Testing

This consisted of connecting 10m of coax back to the operating shack in the front upstairs of the house (the antenna was at the back) to my Elecraft T1 auto-ATU and connecting this to the output of my FT817 5W QRP radio. Then I set the middle of each band on the FT817 and set the match using the auto-ATU. On all bands from 80-10m I was able to match the antenna without problem. As I had the Elecraft T1's FT817 interface lead, the ATU automatically remembered band settings when changing bands on the FT817. This means you can switch to the same part of a new band without having to reset the ATU - ideal for flicking between QRP calling frequencies, PSK31 frequencies or WSPR frequencies.

Results

Within a couple of minutes of connecting up the antenna and matching it on all bands I had a couple of QRP CW QSOs in the log on 12m and 10m. I then tried WSPR beaconing on 7, 10, 14 and 28MHz to see what reports were given and received. On all bands tested I received several reports within a few minutes. As I write this, I see I've received a -27dB S/N WSPR report on 18MHz with my 5W from W8LIW some 6105km away, so it's definitely working. A little later I had a QSO on QRP CW with EI5DR on 12m.

Conclusions

Well, it's early days, but it's certainly putting a decent signal out on several bands and it's allowed me multi-band operation without adjustment with the FT817 and the T1 auto-ATU. My only concern is it's rather high and thin and does blow around a bit in the wind.