Sub RX - Diversity vs. Linked

[Ken Widelitz]

Is the difference between the Sub RX being Linked and being in Diversity
merely that you can still change the Sub RX frequency using the VFO B knob?
If you can tune the Sub RX independently using the VFO B knob while linked,
what is the purpose of being linked as opposed to just being in Diversity
unlinked? Am I missing something?

Another related issue - because I use Writelog with the W5XD Multi-Keyer for
SO2R, I need to have the headphone audio output from each radio in mono,
that is, the Sub RX and the main RX mixed together, so I can listen to both
left and right radios at the same time. Does mixing the Sub RX and main RX
together in Diversity mode negate any of the Diversity benefits, or will I
get the same benefit, just in mono so I won't know which antenna is doing
the better job at any particular time without playing with the RF gain
control for each?


73, Ken, K6LA / VY2TT










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[Mike K2MK]

Hi Ken:

In LINKED you can set different filter parameters for the sub. In DIVERSITY
the sub filters are the same as the MAIN filters. The modes can be different
in LINKED as well (not sure who might find that useful).

73,
Mike K2MK

Ken Widelitz
Sat, 14 Mar 2009 14:47:51 -0700

Is the difference between the Sub RX being Linked and being in Diversity
merely that you can still change the Sub RX frequency using the VFO B knob?
If you can tune the Sub RX independently using the VFO B knob while linked,
what is the purpose of being linked as opposed to just being in Diversity
unlinked? Am I missing something?

Another related issue - because I use Writelog with the W5XD Multi-Keyer for
SO2R, I need to have the headphone audio output from each radio in mono,
that is, the Sub RX and the main RX mixed together, so I can listen to both
left and right radios at the same time. Does mixing the Sub RX and main RX
together in Diversity mode negate any of the Diversity benefits, or will I
get the same benefit, just in mono so I won't know which antenna is doing
the better job at any particular time without playing with the RF gain
control for each?
 

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[Jim Brown-10]

On Sat, 14 Mar 2009 14:47:01 -0700, Ken Widelitz wrote:

>Does mixing the Sub RX and main RX
>together in Diversity mode negate any of the Diversity benefits

There's something different about how the two receivers handle audio
that I don't yet have a handle on. I suspect it is a difference in
latency, but there may also be a difference in the audio response.
For example, even in diversity mode, summing them to mono will make
a RTTY signal almost impossible to decode, while the output of
either receiver works great. One of these days I'll set up the
instrumentation and study it.

73,

Jim K9YC


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[Bill W4ZV]

Ken Widelitz wrote

Is the difference between the Sub RX being Linked and being in Diversity
merely that you can still change the Sub RX frequency using the VFO B knob?
If you can tune the Sub RX independently using the VFO B knob while linked,
what is the purpose of being linked as opposed to just being in Diversity
unlinked? Am I missing something?

##See page 37 of the current manual.  When LINKed, VFO A tunes both Main and Sub at whatever offset the VFO offsets were when LINKed.  You can then change VFO B, but then VFO A will tune BOTH at whatever the new offset is.  I don't know what purpose an offset serves but possibly repeater splits, transverters or some other feature I never use.  I always LINK my VFOs on the same QRG.

In Diversity, both VFOs are LINKed to what was set on VFO A and VFO B is now independent (and can be used to set a SPLIT TX freq for example).  See below for a note I sent to Frank W3LPL about how I use Diversity.

>Another related issue - because I use Writelog with the W5XD Multi-Keyer for
SO2R, I need to have the headphone audio output from each radio in mono,
that is, the Sub RX and the main RX mixed together, so I can listen to both
left and right radios at the same time. Does mixing the Sub RX and main RX
together in Diversity mode negate any of the Diversity benefits, or will I
get the same benefit, just in mono so I won't know which antenna is doing
the better job at any particular time without playing with the RF gain
control for each?

##I haven't actually tried that myself so I can't say for sure.  If the two audio channels are summed, it seems like you should get some of the benefits (e.g. QSB reduction, hearing a signal present on one antenna and not the other, etc).  Having used true Diversity for ~8 months, I dislike using the K3 without it on the low bands.

73,  Bill

P.S.  My note to Frank W3LPL:

Hi Frank,
 
The simple way to set Diversity is to first set up the Main RX exactly how you want it.  Then double-tap A>B which copies all settings to VFO B (single-tap just copies freq).  I like to equalize RF gains so I have my TX array on VFO A and Beverage on VFO B with ATT set for VFO A and PRE for VFO B (you can do this by going into BSET and separately setting PRE instead of ATT which was copied in the A>B above).  Then the two RF Gain settings should be reasonably close.  I also use the CONFIG: SUB AF Balance feature so my AF Gain tracks Main and Sub using the inner AF knob only.
 
Once you have Main and Sub set up the way you want, HOLD SUB a LONG time...initially it LINKs the VFOs together and then it goes into Diversity (a flashing decimal point in the Main VFO readout indicates Diversity mode).  Then both RXs will track together with VFO A.  Then set SPLIT and now you can TX on VFO B with both RXs tracking in Diversity on VFO A.  This sounds complicated but I basically leave my rig set up in Diversity mode all the time.  Read below for how to easily go in and out of Diversity using the two antennas on Main and Sub:
 
http://n2.nabble.com/-K3--KRX3-Antenna-Flexibility-td1499595.html#a1500426
 
I'm surprised you don't find Diversity with the K3 to be much better than the MP on CW.  As I said above, I basically leave Diversity on continuously when on the low bands in CW.  I actually haven't operated the K3 much on SSB yet (...waiting for 10m to come back!)

(Note:  My last comment was in response to my misunderstanding what Frank actually said.  He said his K3 + Diversity was "vastly superior" to his MP on SSB, but he had not actually used Diversity on CW yet, since he just got his KRX3 going after the ARRL DX CW).