[Elecraft] K3 - Eric &Co.... Please relocate the Link/UnLink button.

[Edward R Cole]

I am happy with the present "SUB" control functions.

I run diversity mode for eme (i.e. my main Rx receives vertical 
polarity 2m and the sub-Rx receives horizontal polarity 2m).  I run 
in split mode to transmit using VFO-B, while my VFO-A stays tuned to 
144.130 MHz.  144.130 is the center of a 60 KHz band that MAP65 
receives.  MAP65 runs JT65 to decode all signals inside the 60-KHz band.

I have yet to try diversity reception on HF, but have no reason for 
the radio functions to be modified for diversity mode.  Both 
receivers need to be tuned to the same frequency when in diversity 
reception so the VFO-A display is adequate. When running the sub-Rx 
in non-diversity then VFO-B shows it if unlinked.

I vote no change.  If this is to be changed then make it selectable 
as a CONFIG menu item (if that is possible).

The KRX3 makes adaptive polarity reception of eme possible.  No other 
commercial radio is this possible that I am aware of.  The IQ+ from 
HB9DRI is a dedicated dual-Rx 2m direct conversion SDR which works 
elegantly for this.  But it is a special piece of equipment for only 2m-eme.

73, Ed - KL7UW


-------------------------
Date: Tue, 05 Mar 2013 12:37:19 -0500
From: Richard Ferch <ve3iay at storm.ca>
To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] K3 - Eric &Co.... Please relocate the
	Link/UnLink button.
Message-ID: <51362D4F.6030803 at storm.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

W4TV wrote:

 > The display is VFO B *not* KRX3 receive frequency - the icon says "[B]"
 > not "[SUB]".

This is a key point. Ian's first post in this thread makes it clear that
his mental model of the two displays is that they track the two
receivers. This mental model may work with a dual-receiver K3 in
non-diversity mode, but it is not the most appropriate mental model for
a dual-receiver K3 in diversity mode. In diversity mode VFO B does not
track with VFO A; it is the subRX that tracks with VFO A.

In diversity mode, from the point of view of operating the radio there
is a single receiver controlled by VFO A. This receiver uses twice as
much hardware as a normal receiver, and it allows two simultaneous
antenna inputs instead of only one, but operationally speaking it is a
single receiver. In other words, a K3 in diversity mode is functionally
similar to a single-receiver K3 or a dual-receiver K3 with the subRX
turned off: VFO A always displays the receiver frequency, and the VFO B
display indicates where the transmitter will transmit in SPLIT mode.

Switching from a VFO A vs. VFO B display model (the current design) to a
main RX vs. subRX display model, as Ian has suggested, would waste the
capability of the VFO B display in diversity mode (what's the point of
dedicating display real estate to a second frequency display if it is
forced to be identical to the first display?). Having the VFO B display
tell you where the transmitter would be if you invoked SPLIT, exactly
the same as it does in a single-receiver K3, is a more effective use of
the display resources, particularly for someone wishing to work a split
pileup on low bands.

73,
Rich VE3KI