[Elecraft] Appliance Operator gets gift

[Ron D' Eau Claire]

> Today was exciting, someone gave me a heathkit DX-40 and a VF-1 vfo....
> and the manual for the DX-40.
>
> Being technically challenged I'm not sure if/how I could turn the
> DX-40 into an amplifier for the K2.
>
> So, if anyone has done it, or can point me to some real SIMPLE
> destructions, I'd be a happy camper.
>
> Thom

Wow... I'm jealous Thom!

Your DX-40 has a VFO input. Just use the K2 as a VFO. BE CAREFUL! Don't put
more than a few hundred milliwatts into that VFO jack! Turn the K2 to
minimum power and transmit BEFORE connecting it to the VFO jack. Remember,
the K2 has this nice little habit of not changing its actual output power
until AFTER you key it! (That's because the power control circuitry can't
make the change until it measures what the K2 is delivering.)

One other point is that the K2 really wants to see no worst than a 2:1 SWR.
Now, at minimum output I doubt it that is an issue but one easy way to deal
with that is to put a simple 50 ohm attenuator between the K2 and the DX-40.
If you use a 3 dB attenuator, the K2 will never see anything worse than a
2:1 swr - even if you don't hook the DX-40 to the other end. A 3 dB "Pi"
attenuator for a 50 ohm load uses two 300 ohm resistors and an 18 ohm
resistor. The 300 ohm resistors go from the center (hot) conductor to ground
at the output of the K2 and at the input to the DX-40. the 18 ohm resistor
goes from the hot side of the K2 output to the hot side of the DX 40 VFO
input.

You can make a 6 dB attenuator with two 150 ohm resistors to ground in place
of the 300 ohm resistors and a 39 ohm resistor in series in place of the 18
ohm resistor.

If you have the 160 meter module, you can hook a receiving antenna to ANT 2.
The DX-40 does NOT include an antenna switching relay, so if you want to use
the same antenna for both transmit and receive, you will need to rig up an
external switch or relay to switch the antenna between the K2 for receive
and the DX-40 for transmit.

What a fun QSO... "RIG HR HEATH DX-40 WITH ELECRAFT K-2 EXTERNAL VFO..."

Ron AC7AC
K2 # 1289