Posted: 1/29/2012 5:53:26 AM EDT
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I finally broke down and bought an SWR/Wattmeter. While my HF/6M radio does have a built in SWR meter, I decided an honesty check would be in a good idea to be safe, and I like the idea of a large analog gauge to read.
Also needing to read 2M SWR and output for antenna building and fiddling with older Motorolas, I purchased a Diawa 101 for 1.8 through 150mhz. Although the meter has a switch for average or peak readings, I think they are both average, as it reads the same in both and is not sold as a true RMS peak wattmeter. This is OK, as most of my operation is digital on HF and phone on FM. My TS-480 has an internal tuner, so the meter is placed between the rig output and the antenna. Testing the meter, it seems to only be accurate on 100% or near 100% duty cycle modes. On FM and HF digital, it is consistently within 5% of stated manufacturer ouput levels and readings are linear as I switch watt ranges. I feel that this is 'on the money' for a <$100 consumer grade meter. On SSB phone, however, I can get the rig output at 100watts, adjust settings so that ALC is overdriven, and it will still read only 20 or so watts on voice peaks. I understand a passive RMS meter is too slow to keep up with voice peaks, and will read consistently low on SSB phone. Is there some type of ratio or conversion calculation needed to figure out what I am actually putting out, or do I just need a true peak meter to measure that accurately? |
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NOTHING wrong with either your radio or meter. That is typical.
The meter cannot respond fast enough to peaks to show a true reading. And the meter tends to average out. And your voice peaks are not necessarily full power, either. They may only be in the 70-80 w range–– which is good. If over 100% modulation you would have splatter on the peaks. Remember, in SSB there is no carrier, only the voice modulation. For example, last night was net night on 75 meters. My amp is tuned and adjusted for 600 w out with a carrier wave, but on SSB, the needle is only showing 100-150 w on peaks. And that is normal. If you adjust your radio with a carrier wave, FM, RTTY or other continuous signal for 100 w out, and ALC is adjusted (mic gain - ALC) you will be fine. |
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Quoted: I finally broke down and bought an SWR/Wattmeter. While my HF/6M radio does have a built in SWR meter, I decided an honesty check would be in a good idea to be safe, and I like the idea of a large analog gauge to read. Also needing to read 2M SWR and output for antenna building and fiddling with older Motorolas, I purchased a Diawa 101 for 1.8 through 150mhz. Although the meter has a switch for average or peak readings, I think they are both average, as it reads the same in both and is not sold as a true RMS peak wattmeter. This is OK, as most of my operation is digital on HF and phone on FM. My TS-480 has an internal tuner, so the meter is placed between the rig output and the antenna. Testing the meter, it seems to only be accurate on 100% or near 100% duty cycle modes. On FM and HF digital, it is consistently within 5% of stated manufacturer ouput levels and readings are linear as I switch watt ranges. I feel that this is 'on the money' for a <$100 consumer grade meter. On SSB phone, however, I can get the rig output at 100watts, adjust settings so that ALC is overdriven, and it will still read only 20 or so watts on voice peaks. I understand a passive RMS meter is too slow to keep up with voice peaks, and will read consistently low on SSB phone. Is there some type of ratio or conversion calculation needed to figure out what I am actually putting out, or do I just need a true peak meter to measure that accurately? Never mind |