Posted by
EUGENE GABRY on
Jul 27, 2017; 12:38pm
URL: http://elecraft.85.s1.nabble.com/TX-Test-Mode-garbage-tp7632695p7632749.html
Hi Dan,
I see exactly the same thing, although, on my analog watt meter, even running dits continuously, I don't see any movement of the needle. Must be micro watts leaking in extremely fast/short duration. I guess I would have thought precautions for clamping down in the TX chain, prior to antenna coupling, would have been implemented, so no RF leaking could occur.
I'm even more curious now to find out what all is engaging during key down in test mode to be drawing an additional 1.5 amps. I'm assuming it should only be circuitry to engage cw keyer and side tone in test mode, but obviously a path in the TX chain is activating that maybe should not, allowing leak through.
Guess I'll pop this thing open for the first time an do some tracing :)
I've added our thread back to the reflector, as I don't think this should be a normal operating function. If the intent of a test mode is to test without actually emitting a signal, then this oddity of RF leaking is not acceptable.
73 Gene, N9TF
> On July 27, 2017 at 6:49 AM Dan Atchison <
[hidden email]> wrote:
>
> I think that is normal, Gene, as all the oscillators in the TX chain are working. What I and others are seeing is short spikes of power when doing CW in TX mode.
>
> Try this: Hook up your K3s to a dummy load through a digital wattmeter and send a long string of dots. You will eventually see power out - enough power to show SWR. The resultant signal is heard as key clicks and can be heard as key clicks (with no CW "tone") miles away. It's a very short duration signal (only microseconds of an entire dit) and is only heard as clicks. Note, you can only "see" the issue with a good instantaneous reading digital wattmeter because of the short duration. I measure several watts of this intermittent click.
>
> 73
> Dan
>
>
>
>
>
> On 7/26/2017 11:00 PM, EUGENE GABRY wrote:
>
> > >
> > Out of curiosity I just checked this with my K3S and found the same oddity. During CW key down into a dummy load in TX Test mode the K3S draws 2.5 amps from the 1 amp in RX, and the hash signal heard in another receiver into a different dummy load appears to be 2.7Khz wide. Starts out as full scale signal in the receiver and drops quickly to S5 but never goes away during key down. Cant detect any power indication on the dummy load power meter during key down. Maybe a pre driver stage getting bias in TEST MODE?
> > Interesting...
> >
> > Gene
> > N9TF
> >
> >
> > > > >
> > > On July 26, 2017 at 9:03 AM Dan Atchison via Elecraft <
[hidden email]> mailto:
[hidden email] wrote:
> > >
> > > > >
> >
> >
> > > > >
> > > Yes, the K3s does put out power during this clicking and it has been
> > > observed by operators who live close by. Power and SWR are noted on a
> > > digital power meter.
> > >
> > > 73,
> > > Dan
> > >
> > >
> > > > >
> > >
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