P3 SVGA - Spurious Spike

[Edward A. Dauer]

Just installed the SVGA option in the P3 and have an odd spike appearing
on the screen.  Any help would be appreciated.  Here are the symptoms:

The spike appears at 11.8 KHz above the VFO A frequency, and stays at that
distance as VFO A is tuned - that is, it moves as VFO A moves.  It appears
on 10, 15, 20, and 40 meters (haven¹t tried others).  The apparent
amplitude is over S9.

But there is no signal there - tuning across the spike¹s frequency with
the SubRX produces nothing audible in the K3.

The spike disappears when SVGA EN is set to OFF.

The spook appears although there is no SVGA monitor connected, and no
computer connected to anything, so it¹s not from some other box.  Seems to
be residing in the P3.  Did not occur before the SVGA option was installed.

Firmware in both the K3 and the P3 and its SVGA are current as of
yesterday - but the anomaly appeared both before and after the updates,
and before and after the synths were changed.

Any ideas or suggestions?  Thanks!

Ted, KN1CBR

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[Mike K2MK]

Hi Ted,

Do an archive search for the string:

SVGA ribbon cable

Review the posts and see if they bear any similarity to what you are now experiencing. I think the gist of the thread was that placement of the ribbon cable could be the cause of spurious spikes.

73,
Mike K2MK

Dauer, Edward wrote

Just installed the SVGA option in the P3 and have an odd spike appearing
on the screen.  Any help would be appreciated.  Here are the symptoms:

The spike appears at 11.8 KHz above the VFO A frequency, and stays at that
distance as VFO A is tuned - that is, it moves as VFO A moves.  It appears
on 10, 15, 20, and 40 meters (haven¹t tried others).  The apparent
amplitude is over S9.

But there is no signal there - tuning across the spike¹s frequency with
the SubRX produces nothing audible in the K3.

The spike disappears when SVGA EN is set to OFF.

The spook appears although there is no SVGA monitor connected, and no
computer connected to anything, so it¹s not from some other box.  Seems to
be residing in the P3.  Did not occur before the SVGA option was installed.

Firmware in both the K3 and the P3 and its SVGA are current as of
yesterday - but the anomaly appeared both before and after the updates,
and before and after the synths were changed.

Any ideas or suggestions?  Thanks!

Ted, KN1CBR

[Bill-3]

There was also a problem with the BNC cable feeding the P3. I
experienced that and merely changed to a mil spec cable. That cured the
problem. No idea what caused the problem, but that cured it.

Bill W2BLC K-Line
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