Topband: AS / EU QRM - The Cocktail Party Effect

[David Olean]

OK I guess the problem is QRM levels in EU.  The CQ WW weekend is a big 
difference from a typical Wednesday or Thursday evening. I was just 
getting paranoid when many stations in a row could not copy me while I 
was hearing them with great signals and 559 to 589.  I am thinking that 
maybe my Europe beverage is working very well. It is long at about 
1100-1200 ft (350M) and consists of two sets of wires spaced 400 ft 
apart. (120M)  We had terrific winds on Friday night and I was not QRV 
but wondered if any trees had fallen in the woods due to the high winds. 
I had just fixed all my receive wires two weeks ago. I walked along my 
beverage wires today, and found a huge tree had fallen across my South 
beverage and broken the wire. It also ripped the termination off the far 
end.  Next I found another tree that managed to fall across both the 
South beverage as well as one of my Europe beverages. I had to get the 
chainsaw out and now I have a full pickup truck load of firewood and the 
two antennas are working well again. I also had a tree across the JA 
beverage.  My East, Southwest, and West wires all were OK. There are a 
few more I have not gotten to yet. Maintaining wires in the woods is 
never ending!

On Saturday night, I saw no problem with the EU wires or the JA wire (It 
works well towards Hawaii and CA) even though they had problems. I did 
sense that my South wire was not so hot. No wonder, it was broken in 
half and laying on the ground with no termination on the southern end.  
The EU wire seemed OK to me even with a tree across it. Same with the JA 
wire.  Oh well, at least I got some firewood out of the deal.

73

Dave K1WHS

On 11/25/2019 3:08 PM, Fred Kleber wrote:

> Hi Top Banders,
> Having operated from the other end on a number of continents, I offer the following explanations of why NA hams may wonder why they can't work distant stations:
> SE Asia - The amount of non-ham QRM in the ham bands is unbelievable.  Most notable are the Indonesian (and probably other countries) fisherman who populate wide swaths of spectrum and have little to no regard for spectrum allocations.  They just go buy a cheap ham rig, make it general coverage, and off they go.  Additionally the beacons on fishing nets can also create quite a racket.  Oh yes, the commercial power suppliers in poorer countries most likely don't even care about repairing line nose.  One other challenge is the echo from NA stations which is frequently present on the low bands.  Pileups particularly exacerbate this phenomenon.
> Europe - Here's the cocktail party analogy.  When a cocktail party starts, a few people come in the door, grab a drink and start talking to each other.  As more people join the party, the room fills up and the ambient noise (QRM) rises.  In order to be communicate, guests talk louder.  More people join the party and the audible QRM noise floor rises.  In the radio world parallel, equate guest's speech with RF and talking louder with running more power.  Then consider that many countries don't effectively regulate TX power output, and you have a real mess.  Most north american's can't understand when I tell them that if you're not at least S-9 on 80-20 meters, you're most likely not going to be heard.
> I hope you find this information useful.
> 73 & good DX,Fred, NP2X / K9VV et al.
> _________________
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