Mobile hamsticks as a portable antenna

Every year in April, on International Amateur Radio Day, I try not to miss an opportunity to make a few new contacts. Luckily, this year was no exception to the tradition.

However, my options were limited as my present QTH explicitly restricts any aerials, poles, etc.

First, I tried loading a downspout (and it even came resonant on somewhat 30m) but the losses were too high as the wall is steel-reinforced concrete.

Next, I tried a couple of 20m/40m MFJ hamsticks I bought earlier for a mobile install. The design was simple: a piece of a steel 2×4 stud laying on the grass for the antenna base and a radial wire cut to somewhat like 5 meters. A couple of landscaping paver stones kept the stud from rolling. The grounding left to be desired.

All in all, it took may be 5 minutes to set up and so the experiment started. It was surprisingly easy to tune the vertical element to SWR<1.5 on the entire (!) 20m band using portable miniVNA.

Then, just before the sundown, a quick CQ was sent out:

As seen from the results above, the signal was heard in the north as far as Quebec (VE2WU – 1,360miles; 14°  azimuth) with the SNR up to 18db (!). Not bad for a 6′ stick at ground plane with a single radial and no proper ground! Also I think I ran just 10 or 20W into the antenna.

It’s also clear that only stations located in the North/East direction did copy the signal. Perhaps, the

It’s also clear that only stations located 1250-1350miles in the North-NorthEast direction (MS, NH, QB) could hear me. This tells the skip distance and that the building wall behind the antenna fully blocking South/East directions.

Also, as the sun was setting down, the SNR started dropped quickly from 18db to 9db in less than 20 minutes. On the receiving side, I also noticed the band fading quickly with less and less signals compared to when I started.

As darkness fell, I switched to 40m hamstick and quickly tuned the vertical element. Mosquitoes helped to speed up the process so I was back on air in no time. The 40m band was very lively with CQMM contest running in full speed and VE9RAC booming on 7.038. However, my calls and CQs on 40m went completely unnoticed – even by the reversebeacon network.

While no QSOs were made that night, the experience was still satisfactory. Both practical experience and the learnings made were worth the time spent.

All in all, expectedly, the short length of a hamstick presents a major disadvantage (for a base antenna) – especially on lower frequencies. Also, surrounding buildings, lush vegetation, and low height of the antenna further compromise operating conditions.

A taller 1/4-wave antenna on a more open area would provide a far more satisfactory results.


About va3paw
Ham radio enthusiast, software developer

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