[Elecraft] K2/100: Three ways to switch from QRO to QRP

[Charles Greene]

At 05:52 PM 2/25/2002 -0800, Wayne Burdick wrote:

Wayne,

Sounds great, but immediately some questions come to mind.  When using the 
QRO amp and mains but with a gel cel connected to the QRP amp power 
connector, will the gel cel be on a float charge?  Will it be on float 
charge when the K2 power switch is OFF but the ""QRO power supply is on 
like the internal battery?

When can I order one?

>I wanted to do a brief summary following all of the questions regarding
>how the K2/100 can be switched between QRO and QRP modes.
>
>Since it was important to us that the K2/100 remain true to its QRP
>roots, we've made it very easy to drop into an efficient QRP mode. There
>are three ways to do this:
>
>1. Turn the POWER knob to 10 watts or lower. The 100-w final is put into
>"thru" mode at this threshold (you'll hear the RF bypass relays click on
>the KPA100). In this "auto-QRP" mode you can set power from 0-10 watts
>in 0.5 watt steps. (Above 10 watts, you'll have 1-watt steps to slightly
>above 100 watts.)
>
>2. In the menu, set PA to OFF. This puts the final into thru mode and
>restores the K2's normal 0-15 watt POWER control range (0.1 or 0.2 watt 
>steps).
>
>3. Turn off just the high-current power supply, leaving the K2's normal
>low-current supply connected. This again drops the rig into the 0-15
>watt range.
>
>We included this dual-supply operating feature specifically to handle
>field and emergency power situations, which the K2/100 will be ideally
>suited for. The low-current supply could be a small 12V gel-cell or
>motorcycle battery connected to a solar panel, for example. This supply
>is completely diode isolated from the high-current supply, and it will
>switch in automatically if the power mains go down. (When you turn the
>high power supply off, you'll see a confirmation on the K2's LCD: "No PA
>PS". When you turn the supply back on, you'll see "PA PS On".)
>
>Perhaps the K2/100 is the world's first Uninterruptible Desktop
>Transceiver  ;)
>
>In all cases, QRP or QRO, the total current drain of the K2/100 in
>receive mode remains well below that of other 100-watt-class transceivers.
>
>73,
>Wayne
>N6KR

73, Chas, W1CG