Friday, October 12, 2018

Unsuccessful HF5B installation

Up side down...
It is not always a success story on my blog and today was very frustrating! I had high hopes from this butternut HF5B butterfly antenna. PB7Z Bernard does well with it and is confident the HF5B is a good antenna. However when I measured SWR at sunday I was not really happy with it. Unfortunately it went dark and I had no time to fiddle with the antenna anymore. So I took the thursday afternoon off from work to fiddle again and tune the antenna to finally place it in my tower.

Small insects also on the antenna
The weather was good, though a little too good as there were a lot of insects flying around which kept flying in my eyes when working on the antenna. I already noticed I mounted the antenna up-side-down so first thing was to turn it around. After that I tried to tune the antenna at the 20m band first as advertised in the manual. Well, the trouble was already there....there was no real SWR dip. Best SWR was 1:3 at 13,8 MHz. Moving the 20m hairpin moved it to 14.2 MHz but still 1:3 is much too high. The strange thing was that whatever I tried nothing had a real effect. Moving the antenna up higher, no effect.

Well, the manual tells that you should tune only the director about 2m above the ground horizontally. The ground will act as a reflector So, I mounted only the director on a pole. But still SWR was and stayed 1:3 at the best "dip". Not good. Could it be the coax cable? Another coax cable was connected, still 1:3. Could it be the wires from the boom to the ends of the tubes, I measured all wires separatly but all were ok. Could it be a loose connection, there are so many! I checked all connections for 20m and  cleaned everything with sandpaper, still no change! Could it be the "hairpin"? Removed it cleaned it, mounted it again. No change! I tried a choke balun in the cable, any change? Nothing at all, still best dip 1:3. Then I decided to mount everything again but now with the distances given in the manual. That should at least give me a kind of factory setting. Any change? No still 1:3 again but now again on 13,5 MHz. Moving the hairpin again moved the SWR dip to 14,2 MHz. I suspected one of the capacitors then (what else could I do) and removed the 20m one to inspect, but nothing was wrong! Still best SWR 1:3. Really, I have seen a lot of antennas and most of them were made by myself. I know how a gammamatch works and what a hairpin does. But this time I'm out of ideas. Very frustrating!

At the end of the day I decided not to dismantle the antenna but place it in the tower. I tuned the other bands as far as I could. 17m was 1:1,8, 15m was 1:1 near 21MHz, 24MHz was 1:2,5 and at 28,5 was about 1:1,5.  Hoped for a better SWRwhen mounted in the tower high up in the air. However when I tested it this evening it was even worse. Actually I could hardly see any SWR dip on any band. And receive was far worse compared to my inverted-V. This HF5B till now is absolutely no success. So if any antenna expert does have any idea what to check? How to get this antenna working? Please make a comment! I would really like to know what I'm doing wrong?


  1. Hallo Bas, jammer dat het niet lukt met die antenne. Ik heb te weinig ervaring met dat soort hf antennes dus kan je geen goede adviezen geven. Het enigste wat ik kan doen is mijn RigExpert 520 naar je opsturen zodat je een grafisch beeld kunt krijgen hoe de antenne zich gedraagt. Wel zou ik, als ik jou was, PA0FRI benaderen. Die weet veel over hf antennes.
    Heel veel succes met het oplossen van het probleem. Sterkte man! 73 Hans, PE1BVQ.

    1. Nee stuur dat dure apparaat maar niet op Hans. Ik heb een analyser. Ik kan het prima zien met de MFJ259. Ik denk dat hij ergens toch geen goed contact maakt. Ik probeer hem morgen er weer af te halen. Dan haal ik hem echt helemaal uit elkaar en maak ik alles apart schoon komende week. Dan zet ik alles weer in elkaar volgens fabrieks instelling. Als het dan nog niet goed is gaat hij naar PB7Z Bernard die ook met zo een antenne werkt. Die heeft hem bij de vorige eigenaar ook afgesteld en goed gekregen. Toch bedankt! 73, Bas

    2. OK Bas, ja, demonteren en alles per onderdeel schoonmaken en inspecteren is een goede zaak. Ik hoop dat het een goed resultaat geeft. Succes! 73 Hans, PE1BVQ


Thanks for your comment. Bedankt voor je reactie. 73, Bas