Thursday, January 26, 2017

KU4XO's 2 Year Run on 160m and my current pursuit in "topband"

KU4XO two year run is shown by the chart below.  He actually started in late winter 2015 after I got into 160m in the fall of 2014.

What is notable about KU4XO's run was that he was able to do it from a small lot without any kind of a receive antenna.   He was inspired by an article written by WB6RSE in QST March 2016 Page 66-68 about the pursuit of 160m DXCC from a small city lot.   It took him  (WB6RSE) 6 years to obtain DXCC on 160m between 1998 and 2004.   He worked the 1st 60 countries with 100 watts.   His pace did step up when he added the inverted L with 3 radials.

I too, have a small lot.  My run on 160m started in 2014.  I installed an inverted L with 4 elevated radials and worked the 160m contests that winter.  After that winter I concentrated on getting to 300 DXCC and DX Marathon QRP and took a hiatus on 160m.  I took down the 160m inverted L and put up a 30m delta loop.

As one can see my 160m had a very pronounced lull from the chart below:

The run ended abruptly in the Spring of 2015.  I felt I needed more power and a better antenna.  More power came in the form of an old Clipperton L that will do KW on 160m.   I had put in a brand new set of  high voltage capacitors in the power supply.  I tested it and found that it will push 1000W with 100W of drive.  (See my post in May 2016).  I really have not had to push power past about 750W and for the most part gotten away with mostly using the KPA500 since I still had the "old reliable".  In January of 2017 I had put up a folded counterpoise (FCP) design espoused by K2AV and W0UCE (SK).  It only has a 66 foot folded counterpoise from 174 feet of solid copper wire which takes up very little space. It requires a specially designed isolation transformer.  There are many articles on this design on the net.

 I did have a good run for a few days in January but it still remains to be seen whether I can keep up this pace.   I already see that it will likely slow down.  Below is a picture of the installation of the FCP Inverted L.   The radiator is 150 feet long and I nailed the SWR without pruning.   It is reasonably  flat from 1800-1835 with SWR < 2 and then I have to add inductance above 1835.  I could remove a few inches and center the dip in the SWR to about 1.825 but fooling with the set-up might do more harm than good since the proximity of the horizontal radiator to ground might change the capacitive coupling.  I think I will leave well enough alone.  Not a big chore adding inductance through the tuner.

Here is the SWR Curve

In terms of how it plays - the stateside stations in the CQ WW 160m Contest are loud and the noise floor is about S3 during the contest.  The K9AY is down in noise about 12 dB or 2 S units.

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