>As any serious DXer will tell you, that extra 500 watts is sometimes
>the difference between QSO and no QSO. If you're not serious about
>DXing then right, you don't need it. Your call.
Think noise floor...What is the noise floor at the station to which you
are transmitting? With a big pileup, it might be a S9 +10 dB noise
floor. Then yes, the extra 500 watts would help. Yes, it can DEFINITELY
make the difference between QSO and no QSO. I agree.
However, I disagree that you can't be serious about DX without it. I
have worked stations on 100 watts and a vertical antenna faster than some
people running beams and kilowatts. I have also spent 2 hours trying to
get one station (S92SS) with the same setup. So while power helps, it
doesn't always. I've worked lots of DX running barefoot. And sometimes
it's more fun that way. To know you got the rare guy and all of the big
guns are still fighting for him!
Also, we need to think about total system performance as well. But I
repeat myself: 1000 watts with a 9 dB gain Yagi will do much better than
1500 watts into a 6 dB gain yagi. Also, keep your coax runs as short as
possible and use good quality coax and connectors. Minimize losses as
much as possible. This includes making sure you have a well tuned
antenna. Bad SWR basically causes losses as every time your RF is
reflected back and forth through the coax, there is a little additional
loss. An SWR of just 1.5:1 can reduce your power by as much as 4% (4% of
power is reflected back from antenna). At 1500 watts that is 60 watts
(some of that 60 watts does get eventually radiated after it is reflected
back from the source, travels back downt the transmission line and out to
the antenna, but there are losses with each trip through the coax). An
SWR of 1.8:1 can result in an 8.2% reflection. As well the high voltage
peaks in a condition of high SWR along the coax can cause problems if
your coax isn't high enough quality (dielectric can literally break
down). Remember that if you have 1.5 dB of total loss in all of your
feedline, connectors, etc. you can make your 1500 watts into 1000 at the
antenna! You've also done a lot to heat up the coax!
To anyone buying an amplifier, I would urge them to think in terms other
than just transmitted power. It's best to think in terms of ERP
(Effective Radiated Power). Again, what can you do to improve your
station over just adding more power. What can you do with the antenna,
the feedline, etc. It all matters quite a bit. It's an entire system
working together and it is only as good as the weakest link.
In the final analysis however, after all is said and done, I would buy an
amp that is rated continous duty at 1500 watts. If you are going to
spend the money you might as well do it right. That way you know that if
you run 1200 or 1300 watts that your amp is well within its limits.
However as another person put it, the 1000 watt amp the original poster
asked about may not even cut it at 1000 watts but more like 700 watts.
>From 700 to 1500 is a BIG difference.
I apologize for the length of this and if any was too technical for
anyone out there. I just got on a roll! :-)
Cheers to all,
"A life lived in fear is a life half lived."
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