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Re: QSX
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Hi Joe,
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My first response was about what QRP *is*. It's about reduced power at the transmitter output and more recently folks think of 5 watts. It is not about the physical size of the gear. Obviously it can be smaller. You can't put 1500 pounds of baloney in a five pound sack but five pounds does fit in the smaller sack. However unfair it may seem you can also put 5 pounds of baloney in the 1500 pound sack:) The obvious question is "why would you?". The comments about my Matchboxes also address "use what you have". I have those Matchboxes. I also have higher power radios (only up to 100 watts) but those are presently collecting dust and cobwebs on the shelf. I have used the higher power transmitters at levels below 5 watts output. I did it because it was what I had at the time and participated in some QRP events that specified 5 watts or less. Of course it's not efficient. The tube heaters in the DX-100 burn up more than the output signal! At 4 watts out it is still QRP:) I agree about suitable cores. I see varying and even contradictory reports regarding what does and does not work well. Even the polyvaricons seem to work well. I am considering a slightly larger unit using air variables and maybe air core inductors. They will tolerate higher voltages - period. I suppose that would be along the line of a scaled down matchbox. Nah! I have been using the BLT for a couple of days here and I am going with that general approach. RG-174 is wonderful stuff for test leads. I use RG-58 for jumpers in the shack and twin lead, Ladder line, or direct connect to the end of the wire antenna. I currently have a long (70 foot) chunk of coax for antenna feed and it is *killing* me. I need a little bit more hardware that I will get tomorrow and change the antenna! It's going to rain tomorrow. I will just have to get wet:) 73, Bill KU8H On 4/6/19 6:46 PM, Joe Street wrote:
It is pretty funny picturing those kilowatt capable match boxes on a picnic table beside a diminutive QRP xcvr.? But food for thought:? The QRO guys build those big clunky (but low loss) boxes and run ladder line because 1% loss when running legal limit is still 10's of watts burned up in heat somewhere and things will literally melt, otherwise those QRO types probably wouldn't care about losing 1% of their power or maybe even 10% if it didn't hurt anything, but something I've always considered is when you are starting out with a few precious watts you should be as concerned about loss as the QRO crowd, but how many examples do we see of equipment used for QRP that doesn't give much consideration to loss.? Tuners using those plastic "polyvaricon" AM tuning capacitors (with a Q factor of about 30! according to W7ZOI's tests) small transformer cores or cores of unsuitable permeability (the cores don't noticably heat up because the power is low) long lossy feedlines to save weight like RG-174, etc etc.? Maybe it's just my OCD but I think as QRP operators we should consider these anciliary parts of our station with the same care and concern for loss as the QRO folks. So yeah get those Johnson matchboxes out and run some open wire line! Unless you are climbing a mountain, why not? --
bark less - wag more |
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