Jerry,
Your K2 #1 DOES have AGC - it is built into ALL K2s.
There are 2 possibilities - 1) the AGC has been turned off - that is a 2
button function of PRE/ATT button and the AGC button pressed at the same
time. Normally just using the AGC button changes between FAST and SLOW.
2) The AGC threshold is not correct. If the serial number is 3000 or
above, there is a pot (R1 on the Control Board) to adjust the threshold
- see the K2 manual for where to measure while setting it.
There are 2 VFOs in the K2 although only one is displayed at a time. A
simple tap of the A=B button will sync the 2 VFOs
It sounds like you might benefit from downloading the K2 Quick
Reference from my webpage www.w3fpr.com. Look near the bottom of the
homepage. There is a lot more function to the K2 than meets the eye.
You will have to get the answer to your QSK on the K4 from someone else,
but I expect it to be superb - I know both the K2 with the K2 Keying
Waveshape Mod (SN 4660 and above) and the K3/K3S have excellent QSK
keying, and I expect the same with the K4.
Unfortunately, the K2 Keying Waveshape Mod is not available from
Elecraft, but Dave Van Wallaghen W8FGU was talking about providing a kit
for it. If your K2 does not have it, I would recommend contacting Dave.
To check your K2 for the presence of that mod, remove the bottom panel
and look at D36 - if it is a clear PIN diode or a PIN diode mounted on
and SMD carrier board, the mod is installed. That mod is important for
preventing keyclicks which are not noticeable for the QRP K2, but become
obvious with the KPA100 (or other amplifier).
73,
Don W3FPR
On 10/24/2021 3:52 PM, jerry wrote:
So: Somehow I wound up with two K2s. I bought the first one because
it was small - multiband - and QSK. I have
become enamored of transparent, conversational QSK - the kind where
your transmitted signal just sounds like all the other signals. The
K2 alas is not that, although it is PIN diode switched. I don't think
any commercial transceiver is.
Got K2 #2 to get the KPA100. Moved the KPA100 to #1, because #1 has
all the good mods - the PLL mod, the volume control mod, the upgraded
crystals, etc.
The closest I have been to really good QSK is a QRP-labs QCX+ kit.
But it's only one band, and the receiver is probably not as good as a
K2 with a crystal filter - and K2 #1 even has the DSP audio filter.
AND it lacks AGC. I was operating field day, a local came on and
nearly blew me out of my chair :).
So here's my idea for perfect QSK: I use the two K2's as a
transmitter receiver pair. One on transmit, the other on receive.
Connect them to the antenna with a custom PIN diode switch. W6JL has
a lot of info on that in his QRZ page.
Arrange something like 130dB attenuation or whatever 100W ( or
500w if I use a linear ) down to a microvolt or two.
HOWEVER... I really don't want to be synchronizing VFOs all the
time. So I find some sort of open source transceiver
control program. And modify it so it tunes TWO radios at the same time.
How good is QSK on the K4? Smooth/transparent? Or
clicky-choppy-AGC-pumpy?
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