Thursday, May 3, 2012

Testing a new antenna

My first HF yagi

After talking to Paul, MM0ZBH at the beginning of this year I became interested in a yagi he uses in a portable setup. I cannot put up a large antenna at my home QTH, so I am frequently working /P with my tried and trusted end fed verticals.

A 4 element yagi however is in a different league. The yagi Paul uses is a 4 element lightweight (6kg) yagi originally built for 11m. However, with minor changes it is very usable on 10m as well. Paul told me about the results he got with the antenna and that it was easy to use /P. I was intrigued as my yagi reference is a 10 element 2m yagi that I have used in the past. It is still lying in my garage but I would not consider it a very portable antenna (bulky even disassembled, heavy and takes quite a bit of time to assemble).

After a disappointing /P afternoon this week when I did not manage to break any of the pileups that I encountered, I decided to buy the yagi. The yagi is known as Sirio SY27-4 and sells for around 130 euro's.

I picked it up today, assembled it (very simple) and did a little testing using a couple of fibre glass extension tubes of my Spieth mast to support the yagi (they actually carried the yagi quite well to my surprise).
I was careful not to push my luck so the mast was not too high. I guess the antenna was at a little under half a wave length (<5m / <15ft) high.
Sirio SY27-4 on Spieth extensions

I configured the antenna (elements and gamma match) roughly according to Paul's specs and found that the SWR was flat over 28.3 - 28.5 Mhz (not even one segment on my FT857 SWR meter). So bandwidth is not an issue with this antenna. You can find more data about the antenna performance on my projects page.

The disappointment came when I found out that 10m had already gone dead. In the phone segment I could hear one whisper and white noise, all below S1. On the PSK frequency (28.120) I heard a faint signal and on the cluster I saw some activity in South America. I decided to hook up my MicroHam interface and I turned the beam towards SA.

After calling a few times I was greeted by an Ukrainian OM who was /MM in the South Atlantic sea, south of St Helena (8700km) and by a CX OM (11.500km). Both gave me 599.
This is promising as they are not my every day type of contact and the band was really in a terrible shape.

Now I have to find some /P operating time at the right moment when 10m is open.
I think it will be fun.

Lars / PH0NO/P


  1. Hallo Lars,

    Nou ik ben benieuwd naar de verdere resultaten van je beam, maar ik denk dat hij best wel goed zal werken, ondanks zijn beperkte hoogte.
    Veel succes ermee. Ik blijf je volgen!
    73 Hans, PE1BVQ

  2. Bedankt Hans! Ik zal zeker de info updaten. Toevallig net zitten modelleren en gekke dingen gevonden. Zal mijn projectpagina erover updaten.
    Zie je over 3 weken.
    73, Lars.