Re: [Hamlib-developer] IC7300 output power

[<gm...@bt...>]

I realise the mistake I originally made in confirming the bug in the first place. I operated at 50% drive - which will still try and send 50W on 70 MHz. I assumed it would send 25W. All now understood and the Icom behaviour now seems consistent in returning a percentage of the OVERALL maximum power for the rig.

Phil.
________________________________
From: Philip Rose via Hamlib-developer <ham...@li...>
Sent: 30 May 2025 7:31 PM
To: ham...@li... <ham...@li...>
Subject: Re: [Hamlib-developer] IC7300 output power


Nate,


Can you please ignore the patch.


I am seeing a different behaviour now. The way the IC-7300 appears to limit power output on 50 MHz is to cap the drive at 50%. I can set 100% on the drive level setting but this is ignored and the drive level appears to be kept at 50%. Well it actually creeps up to 55% power output at 100% drive, and 50% power out at 50% drive.


After Sakari, I also looked at the current consumption. At 100% drive (55% power out) I draw 8A from the PSU with IDD about 7A on the Icom meter. So that indicates about 90W DC to the PA for 50W RF.


Until I can get hold of a power meter that handles 70 MHz (mine are either too low or too high a frequency range) I'll not be able to do further work on this.


I rushed into this earlier as I could only manage 10 minutes or so to take the measurements.


Phil GM3ZZA


On 30/05/2025 17:06, gm3zza--- via Hamlib-developer wrote:
Hi Sakari,

I saw that anomaly after I had sent the e-mail. My default drive is 50% and I do remember having to change it at one point after switching from 70 MHz to 28 MHz. I forgot the IC-7300 remembers these by band. I did read the right result, but mustn't have updated my notes.

I can't retest it right now.

73 Phil.
________________________________
From: Sakari Nylund <sak...@ni...><mailto:sak...@ni...>
Sent: 30 May 2025 4:57 PM
To: ham...@li...<mailto:ham...@li...> <ham...@li...><mailto:ham...@li...>
Subject: Re: [Hamlib-developer] IC7300 output power


That looks good, but I wonder how you get only 25W rigctld reading on 70Mhz/CW and almost the same with emergency mode?


My SX-1000 shows 55W out with ~1.5W reflected when using normal mode an my home made dummy load.

Switching emergency tuner mode 70MHz/CW shows 30W out with ~0.9W reflected with same dummy load.


SX-1000 should go from 1.8 to 160MHz with selected connectors. There are another connectors for UHF 430 to 1300MHz not used now.

I think it is not accurate, but "quite close enough" meter.


Current drain shows 12A for "normal" mode 70MHz/CW carrier, so ~144Watts DC input should produce at least the measured 55W RF output using CW.


Curious to see Hamlib readings here after the PR is in use.

--
Saku
OH1KH

gm3zza--- via Hamlib-developer kirjoitti 30.5.2025 klo 17.44:
Guys,

Just tested now with CW and AM on 28 MHz and 70 MHz: emergency mode and not.


Normal Mode
Band
Mode
Drive
Internal Meter
External Meter
Hamlib
28 MHz
AM
100%
~25%
24W
22W

CW
100%
95%
79W
94W
70 MHz
AM
100%
25%
N/A
9.6W

CW
100%
95%
N/A
25W

Emergency Mode
Band
Mode
Drive
Internal Meter
External Meter
Hamlib
28 MHz
AM
100%
25%
13W
12W

CW
100%
50%
51W
46W
70 MHz
AM
100%
15%
N/A
5W

CW
100%
50%
N/A
23W

Notes: External meter: MFJ-993C so does not read for 70 MHz

So basically with my patch hamlib is now providing the user with figures in the right ball park. At the lower power ratings there is a non-linearity between the internal meter provided by IC-7300 and to get a more accurate translation would need using different LUTs for Emergency/Normal and AM/non-AM, which I reckon would be a non-starter.

I will see if I can generate a pull request (I've never done one before!). If not I'll repost the patch file here.

73 Phil GM3ZZA

________________________________
From: Nate Bargmann <n0...@n0...><mailto:n0...@n0...>
Sent: 30 May 2025 2:36 AM
To: ham...@li...<mailto:ham...@li...> <ham...@li...><mailto:ham...@li...>
Subject: Re: [Hamlib-developer] IC7300 output power

* On 2025 29 May 10:48 -0500, gm3zza--- via Hamlib-developer wrote:
> PS. I applied that patch to the pull I took this morning.

I must have missed the patch.

When you all get it tested either post it here or create a PR on GitHub.

73, Nate

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