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Author Topic: A couple of questions after being away from amatuer radio for 17 years.  (Read 2083 times)

Posts: 5

« on: March 25, 2013, 07:52:45 AM »

After nearly 17 yrs away from ham radio, I have finally got the time to get back into the hobby. I recently purchased a new IC-7200, Astron SS-30M PSU, LDG AT-100ProII auto tuner and a Ventenna vertical 40-6m antenna.

Setup everything per instructions (yes, after 51 yrs I have finally learned to RTFM :-) ) I am still only a tech, so have 10 meter privileges, keyed up the mic for first call in many years, and I notice while talking that the amp meter on the PSU is only pulling about 10-15amps and the meter on the radio was only showing about 30 watts out. Radio is set for 100 watts. Antenna was checked at 1.2:1 SWR, without the tuner. Checked all my connections, try calling CQ again, and low draw again.

Am I wrong in thinking that amperage pull during phone transmit that the pull on the PSU would be around 22? I switched to digital mode, trying out PSK31 for the first time, send my CQ call, and meter pulls 20 amps, and the meter on the radio shows 50 watts out, as I reduced RF down, even the meter on the LDG is showing 50 watts. A few more qso's on PSK and now the radio doesn't show any PO on the rig meter in PSK, amp pull is down to 4-8.

What has me worried is I forgot to connect radio ground to my ground rod. Hopefully I haven't blown something in the radio because of that.

I would appreciate some worthy help instead of the "if you dont know what you're doing you shouldn't be in ham radio" answers that seem to be prevalent these days.

Thanks in advance.

Dave, K8DSW

Posts: 1819

« Reply #1 on: March 25, 2013, 08:35:20 AM »

Hi Dave.  When operating SSB, where there is no carrier, the current draw at any point depends upon the volume of the voice at any point in time.  The meter movement has some inertia and isn't fast enough to follow the voice peaks, so  what you'll observe on the ammeter is an average value and will depend on your voice characteristics, the meter characteristics, etc.  So, even if you were set to run 100W output (remember, that's a PEAK value of power), you'd rarely see the ammeter jump up to the peak value, which might be 22 amps in your case.  The way to see what the current draw peak should be at 100W output would be to switch the rig to CW mode and close the key. 

I'm not familiar with that particular Icom rig, but if it's like almost all other transceivers, the wattmeter is NOT a peak reading meter and so will show you an average value just as the ammeter on the supply does.  Many external wattmeters have a "peak reading" mode where they will actually display a value close to the peak output and the meter circuit will be well damped and the needle will hover around the peak value without jumping around a lot. 

Can't say what might have been happening when you noticed the power output way down on PSK.  In PSK mode, assuming that the transceiver was adjusted for, say, 50 watts output in CW or tune mode, the actual output will depend on the audio drive reaching the mic or aux input of the transceiver.  So, if the line level from the soundcard was reduced or if the mic gain on the transceiver was reduced, the output would also be reduced.  You should be able to reduce the output to zero or nearly so by turning the audio all the way down.

73, Floyd - K8AC

Posts: 5

« Reply #2 on: March 25, 2013, 08:48:31 AM »


Thanks very much for your response.  So I'm not losing my marbles then. Smiley  I will need to go through all my settings in HRD, and the quick settings on the radio.

Thanks again.

Dave - K8DSW

Posts: 546

« Reply #3 on: March 25, 2013, 04:02:15 PM »

When working PSK, set the radio for 100 watts and adjust the audio drive to say roughly 30 watts.  If you bring the power down by the Quick set (as in my 7000) the transmitter will not run linear.  At least this is the way I was taught to do it.  Have not had any one tell me my signal was wide or causing any interference.  Have worked allot of Q's with just 30 watts.  Oh, and welcome back to the fun.

73 and good luck
de Rick  wn2c

Posts: 5

« Reply #4 on: March 25, 2013, 06:46:42 PM »

Helps to slow down, read, read and read some more.  Things are working properly.  Helps when moving from digital to phone, that I have to manual set the radio back to M A from U in quick set. 

Thanks for all the help.

Dave - K8DSW
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