[Johnson] New member with Ranger question

[Greg Mijal]

I wouldn't worry about the plate voltage. The 2E26 will be ok.
If you want to lower the output or just move it around you may want to try 
an adjustable screen voltage scheme like a small rheostat (a standard size 
pot will not be able to handle the watts).  Take a look in the tube manual 
for the current and voltge on the screen grid and then use ohms law to see 
what resistance is necessary to move the screen voltage significantly. Then 
ohms law again for the needed watt spec for the adjustable resistor. 
Remember a 10 watt reostat is only rated to 10W when all of the resistor is 
in use.  Also, lower the grid ma's accordingly.
Have fun
73's
Greg
WA7LYO
Kinston NC
----- Original Message ----- 
From: "Bill Cromwell" <wrcromwell at gmail.com>
To: <johnson at mailman.qth.net>
Sent: Friday, April 01, 2011 4:54 PM
Subject: [Johnson] New member with Ranger question


> Hi,
>
> Thanks for having a list like this and allowing me to join. I have a
> Johnson Ranger and I would like to use it in QRP operations. I had
> though about replacing the 6146 with a 2E26 and of course tuning it up
> accordingly with lower plate current and drive, etc. The information I
> have says a 2E26 will handle the plate voltage okay.
>
> Some other hams have suggested changing the plate circuit to use the low
> B+ instead of the High B+ for qrp operation and perhaps installing a
> switch to allow changing from one to the other. I haven't looked yet but
> that seems more reasonable. Has anybody here actually done either of
> those to reduce output to QRP levels? The AM phone operation is not
> important to me during the QRP adventures - only the CW operation. What
> about any other means of doing this?
>
> My Johnson Ranger is just now coming on the bench for TLC - recapping if
> needed, dusting, cleaning, resistor and voltage checks. Maybe when It's
> ready to run again I'll discover it can back off to QRP levels (5 watts
> or less output) without bothering to modify it.
>
> 73,
>
> Bill KU8H
>
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