[Elecraft] (no subject)

Tue Aug 5 18:12:00 2003

Don and all,

That does look a good candidate for some dummy loads.  Ohmite does not state
the RF resistance, nor what can be expected at high frequencies.  I guess
that will be for hams such as us to experiment with.

The Ohmite number is TCH35P100RJ for the 100 ohm TO220 package and
TCH35P51R0J for the 51 ohm.
Mouser's numbers are 588-TCH35P-100 (100 ohm) and 588-TCH35P-51 (51 ohm)

I did notice on the ohmite website, that the power rating is valid if the
case temperature is kept at 25 deg C. or less.
At higher temperatures, the wattage rating must be reduced. - but then, that
is what the heat sink is for!!!  Just a note to size it adequately for the
power you are expecting to put into it.

73,
Don W3FPR

----- Original Message -----
From: "Don Brown" <[email protected]>
To: "Elecraft" <[email protected]>
Sent: Tuesday, August 05, 2003 5:29 PM
Subject: [Elecraft] (no subject)

Hi

Ohmite makes a 50 ohm non-inductive resistor in a two pin TO-220 type
transistor package. This resistor can handle 35 watts in air when attached
to a proper heat sink. I would bet if bolted to a proper heat sink and then
placed in a can of oil it would handle much more maybe even 100 watts. You
could use two 100 ohm versions of the resistors in parallel for even more
power. TenTec uses one of these resistors as a dummy load in their 2 meter
transverter so they should be good up into the VHF range with a good SWR.
Maybe someone with some time should try building a dummy load from one.

You can order the resistors from Mouser for around $5 or $6 each

Don Brown
KD5NDB

SNIP

>
> 2) Is the purpose of the extensions to get the terminator into the
> middle of the jar so it will be surrounded by oil, or is there another
> reason?

Yes. like the Heath Cantenna

SNIP

73's Fernando NF6Q/NNN0JYM
San Jose,CA. 95123
Elecraft K2 #2330;KBT2
CCA #01187 FISTS #8649 FP#-622
<http://pages.sbcglobal.net/nf6q>

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