[Elecraft] Suggestions for 160 meter homemade dummy load - tuning up 160 meter module for K2

[Charles Greene]

Fran and All,

You can buy 5 watt and 2 watt 100 and 200 ohm non-inductive metal film 
resistors from Mouser.  I built up a 10 watt dummy load using two 100 ohm 5 
watt resistors in parallel.  I bought some heat sinks that fit around them 
to help dissipate the heat.  You also can build a dummy on a short length 
of RG-58 with a BNC plug.  Use two copper disks the size of a dime to hold 
the resistors.  Drill one hole the dia. of the inside coax insulator in the 
center of the first disk, and 4 small holes for the resistor leads around 
the periphery on both disks and one in the center for the coax center wire 
in the second disk.  Then use four 200 ohm 2 watt non-inductive resistors 
with the copper disks up against the resistors to help dissipate the heat 
and the center conductor and insulator of the shield going through the 
first disk and the center conductor soldered to the second disk.  The coax 
shield is soldered to the outside of the first disk.  It will take 15 watts 
for a several minutes.  It is good up into the VHF frequency range.  The 
resistors are 5% tolerance, and they have a slight negative temperature 
coefficient.


On: Mon, 17 Feb 2003 05:31:17 -0500
"Francis Belliveau" <flb@attbi.com>
On: Monday, February 17, 2003 2:25 AM
"James M Wiedle" <jwiedle@acsalaska.net>
wrote:
 > ...
 > Any ideas on a homebrew 160m dummy load?
 > ...
James,
There is nothing special about 160m compared to other HF bands. If
anything, it is more forgiving. The easiest homebrew dummy load is just a
resistor soldered to a connector. You can parallel up a bunch to get enough
power dissipation. The more you use the more likely that there will be some
reactive components but they are usually insignificant at HF frequencies. I
used 20 1K 1/2 watt resistors in parallel to give me a 10 watt load.
There was an old email that had a URL to a picture where somebody used
pennies for each end of the resistor set. Maybe the designer will pipe back
in with an update.
If you are talking QRO then any HF or higher load should work. You could
buy & build an RFL-100 kit.
See: http://www.ohr.com/ for details.
Good Luck,
Fran, KA4FRH



73, Chas, W1CG
K2 #462