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Stew Perry Topband Challenge   2017   Dec 30   Claimed Score

Click on a call below for a list of all the contests for which that call sign is listed as an operator. Click on the [email] link to send an e-mail to the contester who posted the claimed score.

Call: K1LT
Operator(s): K1LT
Station: K1LT

Class: Single Op HP
QTH: EM89ps
Operating Time (hrs):
Location: USA

Summary:   Compare Scores
Total:QSOs101Total Score238


Club: Mad River Radio Club

Comments:     [email]     2017-12-31 05:54:51
Jeff, K8ND, loaned me his NCC-2 antenna phasing box. I planned to see if the NCC-2 could out-perform the circuit hack that I previously used to tune a 2-element end-fire array to null out my transmitted signal. Wednesday before the contest I set up the NCC-2 and observed that it could achieve a deep null, although the tuning was a bit touchy. Thursday I intended to check to see if the NCC-2 could provide this null while transmitting 1500 watts. However, when I turned on the receiver, the bandscope was wall-to-wall with power-line impulse noise. I think I have seen this noise before intermittently. It appears when the temperature goes below about 15-20 degrees Fahrenheit, and hangs around until the temperature goes over 35 or thereabouts. The noise is sporadic, and the duty cycle increases as the temperature decreases. Thursday, the temperature was in the single digits. The weather forecast called for the temperature to remain quite low through the contest period, so I was officially worried. Friday it warmed up to the mid 20s and the noise became somewhat sparse and sporadic and it seemed like the Beverages were impacted less than the phased arrays. However, Saturday morning the temperature was again low and the noise was mostly full-time and much stronger. I gathered my noise tracking gear and made about 3 attempts to locate the noise. On Friday, a trip around the 'block' in the car showed the noise to be loudest on 1700 kHz when on my street, just east of the house. With the large loop and the KX3, walking east showed the noise peaking in the direction of the electric pole in front of the east neighbor's house when I was west of the pole on the east-west road. But when east of the pole, the loop nulled best when pointed directly at the power line. When I was east of the next pole, then the loop pointed back towards the first pole. Though not definitive, the implication was that the noise came from that single electric pole. Saturday I repeated the process with the MFJ-852 'noise receiver'. This time there appeared to be 2 noise sources, one coming from possibly that same electric pole and another coming from somewhere else. I walked a longer stretch of the road in front of my house and saw no other intensity peaks. Meanwhile, the noise seemed to affect reception on all receiving antennas by raising the noise floor about 25 db. Around 2200Z, I started operating in S&P mode to see how many contacts I could make and to see how badly the noise affected operating. I worked TM6M and OK7K and several east coast stations. I took several breaks because the noise was very frustrating. I had the noise blankers enabled on all of the receivers, but as signals got stronger and more numerous, the noise blankers became less and less effective. By about 0000Z, the blankers were decreasing the noise level by only a few db. Any strong signal splattered across the entire band. Suddenly, the transmit SWR went to infinity. Not just super-high, but 99.9:1 on the K3 meter. The amplifier wasn't happy, either. So, after 2 non-stop 20 db noise sources and a failed transmitting antenna, I decided to quit. After a while I figured I might try walking out to the splice in the transmit feedline and see if a jiggle would restore operation. However, previous splice disruptions did not cause an 'infinite' SWR (just very high) and the last 'jiggle' was actually a 're-tightening' of the connector. Nevertheless, I took a walk in the fresh 3 inches of snow under the almost full moon in 10-degree air. I roamed around in the woods where the feedline was suppose to be, but I could not find it. When I got back to the house, it occurred to me that I could use the VNA to 'TDR' the feedline to see if the break was at the splice. The TDR said that the break was a complete open circuit about 25 feet from the shack, which means it must be where coax transitions to hardline under the deck. I tuned up the 80 meter vertical for 160 with the antenna tuner. The match was not quite perfect (about 2.5:1) and the tuning was a bit critical, which means high Q which means loss and potential overheating or arcing. Nevertheless with the amplifier at about 500 watts, I was able to make another 25 QSOs to get my total over 100, including PJ7/UT6UD after numerous calls. I took another break. Then I went outside and shoveled the snow off the deck and peered underneath at the coax to hardline junction. Everything looked the same as always. I got a stick and tried rapping the connector, but it was hard to impart much impulse in the constrained space. So I wedged the stick between the connector and some other stuff to see if a little strain might make a difference. But there was no change. I took another break. Then I went outside to start taking out deck screws to lift a few boards to gain access to the connector in question, but my knees got cold. Also it was hard to find all of the screws in the dark. I abandonded that idea. I took another break. Now I am typing this report. This is the first time ever I have abandoned a 160 meter contest effort from this location, and it feels terrible. Hopefully the noise will hang around long enough to track it down for certain. I'll probably have to haul a laptop and the VNC to the basement to get a better fix on the location of the feedline fault. Once I discover the failure, then I can learn the appropriate lesson about reliable engineering. Conditions sounded decent the best I could tell through the noise. Besides working the 2 Europeans, I could hear some of OK7K's Eu callers. By 0130Z, the west coast was coming through and the noise was reduced on the phased array pointed west. Oh well. Hopefully back to a fully operational battle station by CQ WW 160.