Amatuer Radio Blog

It has been a week since my new LA-1K amplifier came in and today was the first opportunity that I have had to test it out. Well, I can say it works, yes! It works simply great! I made a quick call to a station calling CQ from Washington state, and then another to Lou calling CQ from Barcelona, Spain. 59+10db report from Lou. Wow! I have been trying Lou (EA3JE) for over a year – he is always on 20 meters calling DX. I have never received a reply from him until now.

I also noted that in both contacts, I waltzed right in on my very first try, and there was considerable competition answering the CQs. Getting to the top of a “pile up” is exactly what I hoped for when I decided to purchase an amp – it is the edge I need to work DX just a little quicker. The one hundred watts my transceiver puts out can work fine for DX, but the boost from the new amp gets you noticed a lot quicker.

I did give myself a scare though. This one is not related to the amp, but to the new tuner. I changed frequency on the transceiver and for some reason the new tuner could not find a tuning solution. I went as far as to take the lid off the tuner to see if anything was amiss. Accidentally moving the tuner box, a little bit, must have caused the rf jumper cable between the amp and tuner to make proper contact since it started working again. I am sure that I must have bent the jumper cable near its connector, and that this was causing an intermittent connection. The jumper in question is made from LMR-400 coax which is very stiff and does not bend easily, causing the cable to pull at its crimped shield. I could use smaller diameter cable (RG8X), but the LMR-400 will handle the power from the new linear amplifier easily, and it has exceptionally low loss at HF frequencies. I ordered some new 3-foot LMR-400 jumpers and fifty feet of bulk cable from DX Engineering. Normally, I would make the jumpers myself, but I used up all the LMR-400 I had laying around.

Anyways – the tuner works fine. Gangbusters! Right now, it is reporting a 1.05:1 match at 14,250Mhz. Gosh, you really cannot ask for better than that from an auto tuner!

The power I am running with the new amplifier is 600-650 watts with about thirty watts of drive. This is right where I want to be. The amp is capable of 1200 watts or so but is conservatively rated at 1000 watts ICAS. This means you can run it at 1000w output in SSB voice mode all day long, but FM, AM, RTTY, FT8 modes will need to use a lower power level. Not a problem for me. A high-power amp beefy enough to run the high duty cycles these modes need, at full tilt, would need a special cooling system not to mention a power supply the size of a Volkswagen.

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