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AB3FN

Joined: Tue, Jun 5th 2007, 14:11 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
calculation of PEP ? Mar 20th, 10:04 5 1,017 on 27/3/19
question re FTDX 1200 clock Oct 26th 2017, 12:47 1 1,308 on 26/10/17
CW for stroke victim ? Jun 17th 2017, 13:45 1 2,912 on 17/6/17
power loss in tuner ? Jul 17th 2016, 00:37 3 1,153 on 18/7/16
questions about AM broadcast band images Aug 24th 2015, 13:20 2 1,329 on 24/8/15
Use of old laptop power packs ? Dec 28th 2014, 15:30 1 1,714 on 28/12/14
Strange RFI on 10 meters and 6 meters Jun 19th 2014, 17:12 4 2,587 on 6/2/19
Two important functions missing in new radios ? Feb 4th 2013, 15:16 5 2,755 on 28/2/13

Latest Posts

Topic Author Posted On
calculation of PEP ? AB3FN on 21/3/19
Thanks, Zak, but I still don't grasp this.

Let's suppose that the modulating signal was not speech, but a constant amplitude single tone. The SSB waveform would be a clean sine. Would we still use the RMS value to calculate PEP ? I understand that average envelope power may generally be a more useful figure for us, so perhaps calling it peak envelope power is just a misnomer ? And if we're designing a circuit to handle true peak power, regardless of the waveform or duty cycle, then shouldn't we be concerned with the true peak voltage ? For signals other than speech modulated SSB, e.g. FM, is PEP normally calculated from true PEV or RMS ?

My apologies for belaboring this, but thanks in advance for the education.
calculation of PEP ? AB3FN on 20/3/19
I'm missing something basic here, and hope somebody can educate me.

Consider a typical SSB speech waveform. If we have PEV (peak envelope voltage) and want to calculate PEP (peak envelope power), we first convert the PEV into an RMS value. Then the RMS value is squared and divided by R to get PEP. So PEP really refers to the average power, and not to the true peak power.

Is this simply a peculiarity with terminology, or am I missing something fundamental about the calculation?

A quick search finds references to PEP calculations based on both the PEV and on the RMS value. Both cannot be correct.

Thanks in advance for your response.

over the air antenna failure AE9DE on 22/8/18
Many over-the-air TV stations are changing frequencies, as a result of spectrum changes. I'm not sure, but believe this process has already started and will continue for the next couple of years. Perhaps there is no problem with your antenna or cable, and you just need to rescan to receive on the new frequencies.
Open Letter AD8DT on 13/3/18
For at least the past few years, similar bad behavior has occurred regularly on 7200. The offenders do not identify, they play music and transmit on top of each other, believe that they own the frequency, and use a lot of profanity.

I have reported this to the League's OO, other League officials, and the FCC. So far, there has been an acknowledgement that the problem exists, but no action to clean it up. I appreciate the challenges in identifying the offenders, but surely something can be done.

I am most concerned that as we try to get new people involved with ham radio, especially youngsters, the problem will only serve to alienate them.

Any suggestions ?

Allan, AB3FN
a rig for the blind? maybe SDR? Alexa? KJ6BQM on 27/12/17
The Yaesu FT-450 has some type of voice announcement built in. I believe it can be set to announce frequency, mode, etc., but you should look at the specs for details. Although the radio has many features and capabilities, its relatively straightforward to operate, and I suspect the small number of buttons / knobs would be easy to memorize. Best wishes for your brother.

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