Wednesday, 16 May 2018

"Your Delta sure is low"

If there's one thing I enjoy, it's proving prejudiced people wrong.  Not in an angry sort of way, but with evidence, plain and simple.

During QSOs with folk, almost invariably from America, it is a frequent irritation to hear the dismissive assertion that my delta loop, which has its base (its inbuilt 'radials') at 'only' 1.8m above local ground, is "way too low" for it to be effective.  Apparently, I should be raising the base to '30 feet' (the US has yet to drag itself out of Imperial measurements).

Well, there is plenty written on this blog to show that is simply a failure to take all factors, including the highly unusual ground, into account in reaching a conclusion. Most of them think that only 'big' antennas and amplifiers are what makes ham radio work.  That, of course, from the country that generates nearly three times more carbon dioxide per capita than the UK.

So the latest poke in the eye to my more machoistic American bretheren is this: the past 24 hours of reception reports for party balloon WSPR station, ZL1RS.  It's sending just 10mW.


My "way too low" delta is one of only two stations in Europe (I am not a Brexit supporter!) that is receiving ZL1RS, at a fairly good -24dB SNR.  Even more satisfying is that there are no reception reports from America at all.  And there are some very good stations there, some with directional antennas.  
Beaming America...
So for those of you who are just stuck in a trench about antennas and how high they should be, please remember: it depends on ground characteristics, both near and far field, and having a low noise floor.  After all, how many stations have an old copper mine underneath their antennas?

On an associated note, the now fairly constant balloon transmitter launches provides interesting WSPR tracking. But use of amateur radio from any airborne vehicle is not permitted in the UK. 

This is quite odd, because it seems to be perfectly legal in many countries.  The safety risk for those balloons that fly above most aviation traffic seems to be negligible, and I'm not aware of any incidents reported about small balloons conflicting with aircraft.  It seems to be a legal conflict between licensing ham radio and licensing aviation radio that causes the problem for balloon-borne WSPR in the UK.  Rather perversely, we can, with prior notification to the CAA, launch balloons, but not balloons with transmitters!  Even as a holder of a CAA pilot's radio licence, I still can't launch a WSPR beacon into the air.  How silly!




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