I don't believe it was due to the bandpass limits in the radios in question (my
recollection is that as the audio frequency went down the drive level required
for a given RF output level went up and this effect was fairly constant thru
the audio pass band as opposed to only happening at high or low frequencies.)
It is possible there may have been an issue with the audio interface(s) used to
connect the computers to the radios but I recall the effect being more or less
the same with both a commercially made unit and a home brew test scheme. I
also recall using two different connections (on the radio) to feed audio into
one of the radios in question and the results were largely the same.
Not a huge issue but thought I would mention it. To recap it was quite easy to
detect this using the meters / indicators in the radios and I like to think
amateur radio licence holders should typically be able to deal with this type
of issue but I can see some one who perhaps paying a lot of attention or had a
built in meter set to say SWR (as opposed to power out or ALC) getting tripped
up by this.
I don't have these types of issue with my IC7300.
73
Mark Spencer
VE7AFZ
netsyn...@gmail.com
> On Aug 1, 2018, at 3:22 PM, Black Michael via wsjt-devel
> <wsjt-devel@lists.sourceforge.net> wrote:
>
> If you're needing different levels at 500 or 2500 then you are probably
> hitting the bandpass limits you have set on your rig.
> Levels SHOULD be constant across your entire transmit bandpass.
> I can imagine 2500 might be a push for an older rig but 500 shouldn't be.
>
> de Mike W9MDB
>
>
>
>
> On Wednesday, August 1, 2018, 5:19:36 PM CDT, Mark Spencer
> <netsyn...@gmail.com> wrote:
>
>
> Just to add to this:
>
> In my experience it is also helpful to carry out this type of test procedure
> at various audio frequencies within the audio pass band of the equipment in
> question. This is probably another good reason to run "CAT" control along
> with "Split" so that the audio frequencies that are fed to the transmitter
> are kept within a narrower range.
>
> I have at least two older radios that require significantly different audio
> drive levels at different audio frequencies. While I don't routinely use
> these radios with WSJT any more there may be other hams who have equipment
> with a similar issue who may not realize that settings at an Audio frequency
> of say 1500 Hz which give a good result may or may not be appropriate at say
> 500 or 2500 Hz ? I will add that looking at the appropriate meters /
> displays on the radios in question does indicate to me that there is an issue
> that needs to be addressed and in my view it is quite simple to adjust the
> power slider to correct this. Still it wouldn't surprise me if at least some
> of the sub optimal signals on the air were due to this type of issue.
>
> I've never gotten a bad audio report while using the radios in question for
> SSB voice and when I used to run them on RTTY I used FSK so I never noticed
> this issue until I started using these radios with WSJT.
>
> As usual the opinions and experiences of others may differ from mine.
>
> 73
>
> Mark Spencer
> VE7AFZ
> netsyn...@gmail.com
>
>
>
>> On Aug 1, 2018, at 11:41 AM, Black Michael via wsjt-devel
>> <wsjt-devel@lists.sourceforge.net> wrote:
>>
>> Good instructions for the analog world.
>>
>> There's one more way that works on most any computer these days....
>> Even people with direct USB connections to their rigs are having problems.
>>
>> I would add this...and it should work on most any rig setup....
>>
>> #1 Set WSJT-X to minimum power
>> #2 Set audio devices (record/playback) to 0dB
>> #3 Rig to 50% of rated power for CW (some rigs can do full power on CW, some
>> can't)
>> #4 Rig gain to zero (MIC gain if you're input is the MIC, or USB gain if
>> USB, or Data gain if one of the DIN connectors)
>> #5 Click Tune on WSJT-X
>> #6 Bring up WSJT-X power SLOWLY to max...you should still see no power or
>> very low output on your rig (assuming rig gain is at zero).
>> #6 Bring rig gain up SLOWLY until you get 5W or so of power. If you don't
>> see power coming up then you have the wrong gain control. Then look at your
>> ALC meter. Whatever your ALC meter shows at this stage is where it should
>> stay as you bring up the rig gain. Some rigs show 1 bar of ALC (e.g.
>> IC-7100), some show 30-50% (eg IC-7300/7410), some show no ALC at all.
>> #7 Bring rig gain up and eventually you will see the ALC start
>> rising....back it down to the level you had at 5W. What ever transmit power
>> % you have at that point is all you will be able to transmit without ALC
>> kicking in. It will probably be 80-90% of your rated CW power.
>> #8 Bring up rig power to full CW power level and the ALC should stay
>> constant. You can now adjust your transmit power either from WSJT-X or the
>> rig.
>>
>> de Mike W9MDB
>>
>>
>>
>> On Wednesday, August 1, 2018, 12:51:38 PM CDT, Jim Brown
>> <k...@audiosystemsgroup.com> wrote:
>>
>>
>> On 8/1/2018 9:50 AM, Black Michael via wsjt-devel wrote:
>> > IMHO better if ops learn how to set up their rigs properly though.
>>
>> Exactly right. The last page of this link has detailed instructions for
>> setting audio levels that avoids distortion.
>>
>> http://k9yc.com/USB_Interfaces.pdf
>>
>> 73, Jim K9YC
>>
>>
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