FreeDV---peak power vs average power

[Rick, W4XA]

Howdy all, 

I have been doing a few tests to determine power levels and have made measurements  with 3 peak reading watt meters and 2 (UN-modified) NON-peak reading Bird 43 watt meters (1 with a 1000w slug and another with a 250W slug) 

Knowing that most peak reading watt meters are really optimized for voice envelope measurement it's not surprising that the 3 peak reading meters indicate slightly more than 3 times higher than the Bird 43.

For example, Just now, I was indicating 50W on the Birds  using both the 1000W and 250W slugs.

OTOH, my  Array Solutions Power Master II indicates about 150W, the Mercury IIIs amplifier built-in (peak-reading) watt meter indicates around 150-175w and the watt meter in the Palstar HFAUTO  tuner indicates around 130-150W (all peak reading) 

It's not surprising that those peak reading watt meters would read higher than the Bird,  but I if I remember correctly, there's supposed to be  a roughly 1dB difference between average and peak power with RADE.

I could understand if I only had 1 Peak reading and 1 average reading meter (one might be inaccurate)  but with 3 different peak reading meters and 2 Birds with different slugs(but agreeing with each other) ,  it would appear that Peak power is considerably more than "1dB" (even more than 3dB) 

None of this probably matters,  but I am just wondering what the "real deal" actually is.

73/Rick

W4XA

[Peter Reichelt]

Hi Rick 

See this article from David VK5DGR https://freedv.org/david-july-2025-waspaa-paper-papr-rade-v2-snr-bbfm-otc-demo/ where he measured approx 4.5  dB when he expected about 0.8dB.

73 Peter VK5APR

[Takehiko Tsutsumi]

Hi Rick,

Thank you for sharing your work results for us.

In fact, I did the similar measurement reading David's blog pointed by Peter. Here is the result done January 21, 10 days earlier than your post.

See the table below.

1. Notes to be able to read table written in Japanese.

Title: Transmission Filter Bandwidth and Measured Peak Power 

First line: Bandwith (kHZ)

Second line: Transmitter Fiter Bandwidth (Hz). Thetis (SDR) transmitter filter setting LOW and HIGH.

Third line: Average Power (W) Measured by DAIWA Analog Meter (W). The center value of needle movement.

Fourth line: Peak Power measured by ATU-100 (antenna tuner). The value is the maximum reading of LCD for more than 10 seconds.

Fifth FPAPR and PAPR(dB) By the reason that two meters are uncorrelated, multiplied 1.25 correlation factor to average power to get PAPR and PAPR dB. The correlation factor is obtained as Peak Power is 20W and Average Power is 16W to the same unmodulated CW signal of Thetis program.

2. Comments comparing your and my measurement works.

1)  It is fairly similar values obtained between two independent works, i.e. your "slightly more than 3 times higher" and my PAPR such as 2.7 at 2.5kHz and 3.7 at 2.0kHz. 

2) Have you or are you going to measure the effects of transmitter bandwidth and the PAPR like I did?

3) I tend to agree your conclusion i.e. "None of this probably matters" if it is based on the judgment from SSB nature of PAPR characteristic saying more than 6dB (?). However, I wish to remind that it is better to set your transmitter filter as much as wide to the legal limit i.e. 3.0kHz. I believe modern transceivers supplied by radio amateur venders can offer almost 3.0kHz bandwidth values. Otherwise, you may break the legal limit of power as it is defined by peak, not average.

4) I do not know exact PAPR design target of "digital voice systems", perhaps not RADE designers one, except "smaller is better if you manage harmful things" by my measurement done.  Agree?

Regards,

I am glad to receive your reply if you are interested in to continue your thread.

take

de JS1MAV/JA5AEA

 

2026年2月1日日曜日 16:13:17 UTC+9 Peter Reichelt: