Saturday, March 9, 2013

DXing from QTH near high tension voltage line

With TX5K gone QRT this morning, it was bit of disappointing for me. I was trying to follow them all over bands from 20m to 10m on SSB and CW but no sign for me other than noise.

 Just when VU3DMP was working them on Long path (around 7:30AM IST i.e 2:00 UTC), i was having 54 noise and just nothing. Obviously VU3DMP, including 2PAI, 2NKS all live on coastal area with highly conductive ground and have atleast 3 element Yagi antennas. 2PTT lives in Bangalore though. It was puzzling for me when i saw their multi band QSOs. It was not just about patience, grey line timing or power output i thought!. It is also the place you live in I concluded.

My current QTH a rented apartment 5 floors above with dense surrounding population. There is high tension overhead line going from SW to SE of my apartment at 100 ft and a cell phone tower at 200 ft in the same direction. I was observing very quite conditions when turning my 2 element Hexx beam to the south and exactly to the north( instead of higher noise levels). I had worked only handful JA stations and even less VK/ZL and ZS. Most of the stations i worked in these directions were relatively short distance like HS0, YB etc. And almost all these stations are high power one. I am starting to conclude that these are normally resultant of high angle radiation and I never caught low angle from south west, south or south east on Long path propagation.

TX5K was coming strong on long path during morning grey line as reported by some. But for me there was a suction effect for signals coming from south. Experts and grand fathers in this area of electromagnetism can clarify this better, but i recollect a theory from my college days. I remember right-hand rule for electromagnetism which says, if current is traveling in a line in the direction of your thumb, the magnetic field direction would then be in the circular direction of following your other fingers. reference link 

If i consider this principle, high tension lines are right in between low angle radiation waves from south and my antenna. This may be acting like a RF sponge limiting my ability to listen to those weak signals. By the way i have tried other techniques of small magnetic listening loops, noise cancelling devices and large delta loops for improving reception earlier. But now I am sure that all those helped in reducing some specific noise problems, but solution to this RF sponging is no other than QSYing the QTH only. Fortunately for me i am going to QSY to another location in next couple of months.

So definitely another operation from Clipperton may or may not happen in near future, my learning from this chase has made me more knowledgeable on my favorite subjects of DXing and Propagation. 

The day i work < 100watter stations from NA or SA from Bangalore, I can assume either we are at the top of propagation or all my local QRM and sponging problems are gone - which is still a dream!


Kiran VU3KPL 

Why TX5K was important for me? -  
Yeah definitely it was one most sought after DX entity for hams. More importantly, it is almost an antipodal point for India with distance on Long being 4000KM larger than Short path. This location offers an interesting observational benefit when it comes to propagation. As noted VU QSOs took place during morning greyline long path over south pole. Indicating that RF waves traveled over darker edge of the planet earth for longer distance and with enough energy to reach other side!.

3 comments:

Chetan L. Pujara said...

Kiran,

Thanks for the nice article, very well written, yes was lucky to have 2 contacts with TX5K. Location does help sometimes.

Sampanna said...

Kiran,

Very well written and very inspiring. Makes me eager to jump to HF and explore the theories.

73,
VU3OBO

Sailin Gudhka said...

QSL Kiran, excellent write up. Keep sharing.

73,
Sai, VU2SGW

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