Member Input, Band Usage
QRP With K3WWP - Column # 77 - I always like to share feedback I get from these columns with you so here's something I received from Mike N9JIY.
"John, ...always enjoy your items in Keynote, & thot I'd pass this along.
I like to build/operate QRP stuff, too, & used to worry abt tuners for the little xmtrs. Now I don't think this necessarily has to be a worry for (say) sub-500mW rigs.
I recently built a RockMite-40. Final amp is a little metal-cased 2N2222. I put a heatsink on mine. Before putting it into an enclosure I tested it by running key down for a minute with the ant conex wide open. Then did the same with a dead short across the ant conex. 2N2222 got hot, but didnt fry. Listened to signal & sounded fine in both cases. So I operate it w no tuner at all.
It's now in a plastic soap dish, and ant conex is just a banana socket for the 20' single-wire feed to a classic Windom I use portable.
Maybe not all xmtr designs could stand this strss. Maybe some would wander off freq, chirp, etc. Dunno, but if final transistor is cheep & easy to replace, it's worth a try.
Keep up the good writings & 73 de Mike/N9JIY/1282/1107."
That's a good point. With 500mW you would have to have a pretty bad mis-match with your antenna to get enough reflected power to burn out a final transistor. There are other considerations involved in using or not using a tuner besides destroying a final transistor though.
With a tuner, the loss in the components might be worse than a loss from a mis-match between xmtr and antenna. In that case, it's best not to use one.
However, I still would make sure the antenna is matched well enough to the xmtr output to give you an SWR close to 1:1 to give you the best results. If you can't achieve that good a match with no tuner, I'd consider using one.
Folks like me who use just a hunk of wire for an antenna with no idea of the antenna impedance are better off using a tuner. That way we can get an SWR of 1:1 on several different bands with the same non-resonant hunk of wire.
I'm not sure what the impedance of your Windom is, but since it is such a popular antenna I imagine it would be in the 50-75 ohm range which is what most good transmitter final circuits are designed for so you should be in fine shape without a tuner.
Let's change gears now. How are you doing with your QRP during these down days of the sunspot cycle as we wait for the wonderful conditions to return in a few years when the Sun becomes spotted again?
While the DX may be harder to work and less abundant now, it is still there for the taking. Especially on the bands from 80-20 meters. In fact you may be surprised to know that 17-10 meters are still good for DX from time to time, although few hams operate those bands during a sunspot minimum simply because they believe those bands completely die during such a period.
I've said this before and I'll probably say it again. Get on 17-10 and don't just listen, but try calling CQ. You might be surprised at who answers you. The bands definitely will be 'dead' if everyone listens and doesn't transmit.
Talking about a different band, I often will listen to 30M and find it devoid of signals, yet when I call CQ, I get an answer, and now and then it's from some DX station. Those who answer will be quite strong and give me a good report as well. So propagation conditions are definitely good, it's just a lack of hams transmitting making the band sound dead. The same is often true on the higher bands although at times during the sunspot minimum the bands are actually propagationally dead except perhaps for stations running KW's and huge antennas who can communicate virtually any time. It's interesting how 15 and even 10 can come 'alive' during a major contest.
Incidentally a good indicator of propagation on 30M is a German meteorological station that seems to transmit 24/7 sending RTTY at the very low edge of the band. If that station is strong, you know that conditions are good to Europe.
Remember if we don't use the CW bands, we will lose them just like we are losing a large chunk of CW room on 80M because of a lack of CW activity. It's all well and good to talk about preserving CW, but the bottom line is if we use up too much time talking about it, and not getting on the air and using CW, we are going to continue to lose CW frequencies. So get on the bands, and stop just talking about it.
Need some incentive to get on the bands? I'll talk about some in the next column. Visit my web site, email or write me in the meantime, but don't waste too much time doing it - get on the air with CW! -30-