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Power Transmitted vs Power Out #ft8 #FT4 #power #ic-718 #icom


Ken White
 
Edited

Enjoying FT4/8 and learning a lot from the Group. My setup appears to be working for me but I'm curious about something.
My setup includes an Icom IC-718, Signalink USB, Diamond SX-200 SWR/PWR Meter, Macbook Computer, and an OCF Dipole Antenna. I do not use Rig Control. The antenna is tuned to an SWR of 1.2:1. USB Audio Codec is set to max on the computer and the WSJT-X Power slider is set to max.
Although my setup appears to be effective I've noticed that in order to transmit a 30 watt digital signal, I have to set the 718's output at 50 watts. Is this something that I should expect or am I losing 20 watts somewhere along the way?


Chuck Adams
 

Don't control power out that way.  Set power on radio to full output and then control power with WSJT-X slide setting.



Sent from my T-Mobile 5G Device



-------- Original message --------
From: Ken White <khw210@...>
Date: 8/27/20 2:24 PM (GMT-05:00)
To: main@WSJTX.groups.io
Subject: [WSJTX] Power Transmitted vs Power Out #ft8 #FT4 #power #IC-718 #Icom #WSJTX_config #wsjt-x

Enjoying FT4/8 and learning a lot from the Group. My setup appears to be working for me but I'm curious about something.
My setup includes an Icom IC-718, Signalink USB, Diamond SX-200 SWR/PWR Meter, Macbook Computer, and an OCF Dipole Antenna. I do not use Rig Control. The antenna is tuned to an SWR of 1.2:1.
Although my setup appears to be effective I've noticed that in order to transmit a 30 watt digital signal, I have to set the 718's output at 50 watts. Is this something that I should expect or am I losing 20 watts somewhere along the way?


Bob McGraw - K4TAX
 

Since you have the USB Audio CODEC at MAX and you have the WSJT-X PWR slider set to max, I suggest and agree with Chuck, set the power on the radio to 100 watts and adjust the Line Gain on the radio for the desired power output.   Also, VERY IMPORTANT,  be sure the Speech Processing function is always OFF and that TX EQ is always set to FLAT. 

73
Bob, K4TAX


Martin G0HDB
 

Ken:

You're using a SignaLink-USB device as the interface between your MacBook and your IC-718; I assume you're connecting the SL-USB to the ACC socket on the rear of the 718.  The SL-USB has a front-panel pot that controls the level of the transmit audio going into the 718, so I'd suggest setting both the 718's RF power output and the WSJT-X power slider to maximum and then controlling the RF output power from the 718 by adjusting the 'Tx' pot on the SL-USB to give you the power output you want.

This was how I used to use an SL-USB with an IC-735, an IC-746 and an IC-756 Pro III.

Additionally, you'll need to check the MacBook's settings for the SL-USB's USB audio codec so that the audio 'Playback' level is set to 0dB - this might or might not be the maximum level.  You want to avoid having excessive digital gain (or attenuation) on the output level from the SL-USB and setting the audio output to the 0dB mark is the optimum point.

HTH,
--
Martin G0HDB


Ken White
 

Thanks Bob. I've set my 718 to 100 watts and adjusting the FT8 signal power to 30 watts via the software slider... as the 718 doesn't have a Line Gain nor TX EQ adjustments. 
As a consequence I noticed that the radio's ACL went from about 50% to zero.
Prior to this, I was hesitant to set the radio at 100% power as I tend to use only the power that I think I need.


Arnold Lausevich
 

Experience the same from time to time 



Sent from my Samsung Galaxy , an AT&T LTE smartphone


-------- Original message --------
From: Ken White <khw210@...>
Date: 8/27/20 1:32 PM (GMT-06:00)
To: main@WSJTX.groups.io
Subject: [WSJTX] Power Transmitted vs Power Out #ft8 #FT4 #power #IC-718 #Icom #WSJTX_config #wsjt-x

[Edited Message Follows]

Enjoying FT4/8 and learning a lot from the Group. My setup appears to be working for me but I'm curious about something.
My setup includes an Icom IC-718, Signalink USB, Diamond SX-200 SWR/PWR Meter, Macbook Computer, and an OCF Dipole Antenna. I do not use Rig Control. The antenna is tuned to an SWR of 1.2:1. USB Audio Codec is set to max on the computer and the WSJT-X Power slider is set to max.
Although my setup appears to be effective I've noticed that in order to transmit a 30 watt digital signal, I have to set the 718's output at 50 watts. Is this something that I should expect or am I losing 20 watts somewhere along the way?


Ken White
 

Thanks Martin. I've made the adjustments as you suggested. The 718 is set to 100 watts, the software slider set to max, and I've adjusted my signal to 30 watts via the Signalink's TX pot. 
I reviewed my Mac's SL-USB's audio codec playback setting. The level is set to 0dB - which is the maximum level. 
Time to "play radio".


Ken White
 

Thanks Chuck. I'll give it a shot. Until now, my mindset has been to use the minimum power required to get the job done...


groups@...
 

On 27/08/2020 19:24, Ken White wrote:
Enjoying FT4/8 and learning a lot from the Group. My setup appears to be working for me but I'm curious about something.
My setup includes an Icom IC-718, Signalink USB, Diamond SX-200 SWR/PWR Meter, Macbook Computer, and an OCF Dipole Antenna. I do not use Rig Control. The antenna is tuned to an SWR of 1.2:1.
Although my setup appears to be effective I've noticed that in order to transmit a 30 watt digital signal, I have to set the 718's output at 50 watts. Is this something that I should expect or am I losing 20 watts somewhere along the way?
Have a read of this post:-

https://wsjtx.groups.io/g/main/topic/setting_windows_wsjt_x_tx/75435187?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,75435187


Ken White
 

I'll have to try and relate the information in the article to my Macbook.


Martin G0HDB
 

On Thu, Aug 27, 2020 at 09:20 PM, Ken White wrote:

Thanks Martin. I've made the adjustments as you suggested. The 718 is set to 100 watts, the software slider set to max, and I've adjusted my signal to 30 watts via the Signalink's TX pot. 
I reviewed my Mac's SL-USB's audio codec playback setting. The level is set to 0dB - which is the maximum level. 
Time to "play radio".

Sounds good, Ken.

Just out of interest, when you turn up the 'Tx' pot on the SL-USB so that you get as close as you can to 100W out of the 718, what's the ALC reading on the 718?  Ideally it should be zero or as close to zero as possible.  If it is, then your signal should be acceptably clean.

FWIW, I'm currently using an IC-7610 with a G4ZLP datamodes interface; this is functionally almost identical to the SL-USB but has much better LF noise performance (on both Tx and Rx).  When I turn up the Tx drive level pot on the G4ZLP device I find that I start to see an ALC reading on the 7610's meter when the RF power output is about 85W.  However, I never need to run the 7610 at this output level because I use the 7610 to drive a KPA500 amp that gives me our legal limit of 400W out with approx 25W in from the 7610, so there's never any ALC action on the 7610.

Have fun playing radio; I hope we can have a QSO sometime!

73
--
Martin G0HDB


George J Molnar
 

When you don't use rig control, and operate away from the center of your transmitter's passband (audio response), you will transmit at lower and lower power the further you get. At 100 Hz or 2900 Hz, for example, some radios will barely put out anything, despite whatever your sound card is pumping out.

Moral of the story - Use "fake it" and rig control whenever you can. Or stay in the middle of the waterfall as best possible.


Bill Somerville
 

On 27/08/2020 19:24, Ken White wrote:
Enjoying FT4/8 and learning a lot from the Group. My setup appears to be working for me but I'm curious about something.
My setup includes an Icom IC-718, Signalink USB, Diamond SX-200 SWR/PWR Meter, Macbook Computer, and an OCF Dipole Antenna. I do not use Rig Control. The antenna is tuned to an SWR of 1.2:1.
Although my setup appears to be effective I've noticed that in order to transmit a 30 watt digital signal, I have to set the 718's output at 50 watts. Is this something that I should expect or am I losing 20 watts somewhere along the way?
Hi Ken,

I recommend using CAT control of your rig if you are operating on busy HF bands, without it you must limit your Tx audio offset to between 1500 Hz and about 2400 Hz, otherwise you will be either liable to transmit unwanted audio harmonics, or suffer reduced output because your Tx audio is outside of the passband of your rig's SSB Tx filter. With CAT control you can enable one of the WSJT-X "Preferences->Radio->Split Operating" options, that removes any Tx audio offset limitations.

There are reasonably prices CAT interfaces for Icom CI-V radios, just ensure that the device has macOS virtual serial port (VSP) drivers available.

73
Bill
G4WJS.


Don Roden
 

Bill G4WJS says :

> Hi Ken,

I recommend using CAT control of your rig if you are operating on busy HF bands, without it you must limit your Tx audio offset to between 1500 Hz and about 2400 Hz, otherwise you will be either liable to transmit unwanted audio harmonics, or suffer reduced output.
Bill,

I don't have an Icom, I use a Kenwood TS-2000 on FT8.
I always set my TX tone to 1500 ( + or - 100 )
I select "Hold TX Freq"
I allow CAT to select the correct band frequency.
The TS-2000 frequency never changes unless I change bands.
I seem to be able to make contacts with this configuration.
but am I doing something wrong ? Am I missing something
that would increase my contacts count ?
What is the advantage of NOT selecting "Hold TX Freq"
and allowing CAT to do ( what ? ).

I can unplug the CAT connection and make the same contacts.
So what advantage does using a CAT connection do for a single band
operation like six meters ?

I appreciate your knowledge on these subjects and hope this can be a
"Teaching Moment".

Don W4DNR


Ken White
 

I've never used CAT control and admit I know nothing about it. But I'm willing to look into it. Now - Where do I start?


Ken White
 

Martin. With everything maxed out (radio at 100 watts, computer USB audio maxed = 0dB, and TX pot maxed) I transmit 78 watts and tehe ALC reads about 1/4 scale. 


Don Roden
 

Quoting Ken White <khw210@...>:

I've never used CAT control and admit I know nothing about it. But I'm willing to look into it. Now - Where do I start?
Ken,

I've used CAT on my TS-2000 using HRD, but like you, I would like
to know if I could gain any advantage by using CAT with FT8 other
than clicking on a WSJT-X band and having the TS-2000 switch to that
frequency without touching the rig that is within an arms reach away.

Don W4DNR


Reino Talarmo
 

Hi,

The main advantage of CAT control is freedom to select a 'free' transmit frequency, of course provided that either Fake it or Rig is selected for split. With that setting WSJT-X keeps during transmission audio frequency between 1500 Hz and 2000 Hz and compensates audio frequency shift by changing either VFO or using VFO B. Refer to User Guide 4.2. Radio.

In short you may select any transmit frequency and your signal will be clean and TX power stays at what you selected.

73, Reino OH3mA

-----Original Message-----
From: main@WSJTX.groups.io [mailto:main@WSJTX.groups.io] On Behalf Of Don Roden
Sent: 28. elokuuta 2020 20:33
To: main@wsjtx.groups.io
Subject: Re: [WSJTX] Power Transmitted vs Power Out #ft8 #FT4 #power #IC-718 #Icom #WSJTX_config #wsjt-x


Quoting Ken White <khw210@...>:

I've never used CAT control and admit I know nothing about it. But I'm
willing to look into it. Now - Where do I start?
Ken,

I've used CAT on my TS-2000 using HRD, but like you, I would like to know if I could gain any advantage by using CAT with FT8 other than clicking on a WSJT-X band and having the TS-2000 switch to that frequency without touching the rig that is within an arms reach away.

Don W4DNR


Martin G0HDB
 

On Fri, Aug 28, 2020 at 06:16 PM, Ken White wrote:
Martin. With everything maxed out (radio at 100 watts, computer USB audio maxed = 0dB, and TX pot maxed) I transmit 78 watts and tehe ALC reads about 1/4 scale. 
I assume you're measuring the 78 Watts on your Diamond SX200 power/VSWR meter; it's highly likely that its calibration is not very accurate so the indicated 78 Watts might or might not be anywhere near the true RF output level! 

If you put the 718 into CW mode with the power set at 100 Watts and then key the transmitter, what output power does the SX200 read?  If it's again in the region of 78 Watts then that might indicate that the DC power supply you're using to power the 718 might not be capable of maintaining an output voltage of 13.8V when the rig is drawing maximum current.  It might also indicate that the fuses in the DC power leads between the PSU and the 718 might be causing an excessive voltage drop when the rig is drawing maximum current, which results in less than 13.8V actually reaching the rig.  It might be worth taking the fuses out and cleaning them, and/or perhaps replacing them with new ones (of the same rating!).

With regard to your 1/4-scale ALC reading at the maximum RF output power level, that doesn't sound too dramatic but it might be worth getting someone nearby to check that your signal doesn't sound distorted and that it doesn't appear to have any undesirable artefacts when viewed on a WSJT-X or other waterfall.

In another posting you ask about CAT - this is well worth while implementing because it'll help ensure that, as explained by Bill G4WJS, your transmitted signal never has any nasty audio harmonics associated with it when you're operating using any of the WSJT-X modes (FT8 etc).  To implement CAT you'll need to use an interface between your MacBook and the 718's CI-V 'Remote' port; again as explained by Bill you'll need to find a USB-to-CI-V interface for which there are MacOS drivers.

I've just checked the details of G4ZLP's 'Icom CT17 CAT Interface' on his website at https://www.g4zlp.co.uk/unified/IcomCAT.shtml and the device is claimed to be compatible with various MacOS versions including OS X, so it might be worth trying one of those interfaces - it only costs $19.99.  FWIW I use two of the G4ZLP CT17 CAT interface devices in my system and they work perfectly in conjunction with a Windows PC.

--
Martin G0HDB


Jim Shorney
 

Being able to do this is not restricted to CAT control. If you know how your radio works, have clean low distortion audio stages, and don't overdrive said audio stages then CAT is not needed for this capability.

73

-Jim
NU0C

On Fri, 28 Aug 2020 20:50:42 +0300
"Reino Talarmo" <reino.talarmo@...> wrote:

The main advantage of CAT control is freedom to select a 'free' transmit frequency, of course provided that either Fake it or Rig is selected for split.