Sunday, December 6, 2009
Clipperton L on ARRL 160 Contest
ARRL 160M Summary
1.8 122 Q's 247 Points 43 Sections 10,621 Score
After working fifty or so stations barefoot in the 160 contest yesterday evening. I decided to put the Clipperton back online for a while even though it still has the Ip at turn on issue. Wait though I do have that used capacitor board I wanted to try so I opened it up and changed the HV filter board. I had already checked all the caps with my Heathkit magic eye tester they were replaced onec from the original with nice (but still a bit old) Sprauge metal can 150uf 500V units. I checked all the resistors decided to leave them as they were all right on the money as far as I could tell with my meter. I pulled all the diodes as they looked original and replaced them with modern HV 1000v 60A high speed diodes that were on super sale at Allied so I bought 100 of them. They are made for switching power supplies and are not 5408's but look about the same and thought I'd try a set. I removed the 'equalization' by pass caps and left them out as someones paper suggests (Measures?)
While the unit was open I inspected the plate choke and found what looks like a previous hot spot on the side near the plate end where the insulation looked damaged on a few turns and the wire was loose too. Should this be rewound? What type of wire is it ? The wire has a whitish color to the insulation almost like fabric but I don't think it is. Or could the wire be 'tightned up' and revarnish to hold it down. Not sure this is the Ip at turn on problem but it looked suspicious to me.
The parasitic suppresser looked ok but are originals. I did get another used broken set of parasitic suppressor parts and anode clips so I can make some new ones at some point.
Also bought a vacuum relay off flea bay, an RJ1a (I think) to try in one of the Amps to get faster switching...
Was going to pull the two Chinese tubes I have in it now and put back in the two weaker originals to see if it is a tube causing the Ip at turn on but didn't this time.
Turned it on and did get a short 100ma Ip reading but then it was ok as before.
HV reads just a tad higher and the big difference seems to be that when switching from SSB (hi B+) to CW/Tune (lower B+) it takes much longer for the voltmeter to come down to the lower voltage. This change now takes maybe 3 sec or so where before with original caps it took maybe 1 sec or less. Both boards had the 'stock' bleeders. I am thinking this is due to the incrased total capacitance from the old original caps to somewhat newer and I think increase in value from 120-150uf.
This thing has 160m on the bandswitch but it really does not 'tune 160' in my opinion, it is however putting out 400 plus watts if you can keep it tuned up so I was able to get back on the contest and make a few more contacts with a bit more power. I really need to reread the 160m mods for this and do some of them. It really does not matter much where the knobs are on 160 so I just leave the Load and Tune on max cap and go.
The antenna is basically a 'rubber duck' for 160m, a Alpha Delta twin sloper thrown out the window of my 3rd floor shack and tied on to my hedgerow in the side yard. With this rig I did manage the west coast and a few VE's and Caribbean stations for 135 or so contacts.
Next week the Raytrack is going back online and the Clipperton will get opened up yet again for the Ip at turn on issue and maybe 160 tuning and possible QSK ...
In the meantime I am still reading...