Jorg,
You said the SWR meter "spikes" up to and SWR of 3. I suspect that is
simply an 'artifact' of the sampling of forward and reverse power
combined with the varying characteristics of the SSB RF envelope.
This is just a guess on my part, you will have to wait for a response
from someone who knows the firmware sampling of the power and whether or
not any averaging of SWR is done prior to displaying the value.
The forward power and reverse power cannot be both recorded at the same
instant in time - the times are close together, but due to digital
sampling of the values, they cannot occur at the same time.
If the RF voltage when the forward power was sampled was at as low
point, and then, due to speech irregularities, when the reverse power
was sampled, the RF output was higher, then the calculation of SWR would
be higher than the actual SWR. Similarly, the indicated SWR could at
other instances be less than actual.
I also believe the K3 takes several samples before deciding that the SWR
is high enough to reduce the power.
73,
Don W3FPR
On 9/22/2013 3:17 PM, Jörg Rüschenschmidt wrote:
this weekend I tested my new K3 transceiver received last week. TRX is a
factory build version with 100 watt, KAT3 tuner, KXV3A and KDVR3. I use a
Elecraft MH-2 microphone. While testing I recognized strange internal SWR
meter behavior during SSB operation. The internal SWR bar meter shows wrong
SWR if KAT3 is set to bypass. It shows spikes up to SWR 1:3 but my real SWR
is about 1:1.5. only. If I press tune button correct SWR is shown on SWR bar
meter and in digits on display. Also in CW mode correct values are shown. I
am afraid K3 will drop SSB power if SWR bar meter shows SWR of 3.
Is this a known issue ?
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