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Author Topic: 5 watts vs 3 watts  (Read 28696 times)

Posts: 491

« Reply #15 on: February 12, 2014, 06:01:57 PM »

The FIRST "amplifier" to consider improving is the antenna.

73 de Ray
W7ASA ..._  ._

Posts: 86

« Reply #16 on: February 18, 2014, 03:51:07 PM »

 Thanks for all the feedback. We finally warmed up ALOT here in SW Oklahoma so i went to a local lake and set up to run both 12.5 volt internal battery for 3watts and an external 12 volt battery (elec start self propelled mower sealed lead acid) which is a really small battery and i added a d cell in its own holder at 1.5volts in series and had a total of 13.5 volts at 5 watts. My ants were two Par End fed half waves on 40 and 20 meters both resonant in the cw portion of the bands. All on the same day, descent conds and mid afternoon till dark. Swr on all contacts was flat. No tuner. I had plenty of contacts at both 3 and 5 watts. However, my reports on my sig seemed to be better when i was using 5 watts. Especially on fourty meters mid afternoon. 20 meters was probably as expected. Conds were good and alot less effected by the 5 watt to 3 watt switch. 20 meters seemed pretty easy either way. I know this is not a great test to prove anything but it settled some kind of doubt that i was fussing with. If i had an internal 13.5 volt battery i would pack it but no such animal. But the 12.5 volt internal battery will make plenty of contacts. I had both ants in the inv fashion. Hung about 25 feet at the apex. Sorry, meant inv vee fashion. Great fun was had by all. Thanks, hold in there nice weather.

Oh worth mentioning. I did some qrp fishing while there. Fishing with ultra light tackle. Bought my first ultra light rod and tackle about 14 years ago and ive never looked back. Sure ive lost a few nice fish on the four pound test line but ive landed alot more than ive lost. You must be a very good fisherman to land a three plus pound bass on light tackle. The sand bass were bighting pretty well the day i did the qrp radio checks. The rods and tackle weigh practically nothing, and you can carry a full day supply of jigs in a altoid size tackle box. What a great day it was.
« Last Edit: February 18, 2014, 04:27:31 PM by KI5WW » Logged

Posts: 38


« Reply #17 on: February 18, 2014, 08:38:50 PM »

My ants were two Par End fed half waves on 40 and 20 meters both resonant in the cw portion of the bands.

You should check out the PAR 10/40/20 trail version.. I use that wire with a EFHW tuner and it works great. I also have the regular PAR 10/40/20.. Awesome antennas. Use a slingshot with a fishing weight and line and aim for a high branch. I think the PAR works better vertical. I wouldn't worry about 3W vs. 5W. Keep it small and light.


Posts: 322

« Reply #18 on: February 27, 2014, 02:15:35 PM »

After nearly 60 years of QRP CW experience, I strongly believe that a 3 dB increase in TX power will seldom make a significant difference in your results, especially on 7 MHZ and higher frequencies.  Usually your signal will be either much stronger than QRN and QRM or buried so that a 3 db increase will still not make a productive QSO possible.  That is why on my trips to Europe, the UK, and backpacking trips I seldom carry an external battery pack for my KX1 to increase its power from approximately 1.5 watts to 3 watts.  However on 80 and especially 160 meters, where I think my QRP signal is often near the noise floor, I believe my results are improved with even a 3 dB or 6 dB increase in signal.  I live in Alaska and my nearest contacts are usually 1500 miles away but if you have good local (within a few hundred miles) activity the increase may not even help you.  During one 160 meter contest I could just not seem to make QSO's with 25 watts, but with 100 watts I immediately began to make QSO's.  I was hesitant to post this since it is based only my very un scientific observations.  For sure future QRP transmitters will run a full 5 watts on 160 meters where every bit of power, filtering, antenna gain, experience, and luck helps.
               Rick  KL7CW   Palmer, Alaska

Posts: 86

« Reply #19 on: February 28, 2014, 08:52:52 AM »

Wow, qrp on 160. Id have to be backpacking for that just to have room. Thanks, i agree. Some times i have to touch the stove just to see if its still hot. Then its out of my mind.

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