"What are recommended dummy loads to consider for use when running the K3 TX
Calibration?"
Thanks to all who've replied both on and especially off list.
The general consensus is that BIRD makes the best dummy loads. Avoiding units
that incorporate BeO is a consideration.
Others
I have a db Products 50 watt dummy load which was sold on ebay as
surplus cellular test equipment. That should mean it's good to a GHz I
guess. Even though it's only 50 watts I have used it briefly at 100.
There used to be lots of these on ebay but now all I see are 25 or 30
watt versions.
Some of the best dummy loads are built from Caddox Thick Film Resistors.
The 50 ohm resistors are non-reactive and flat up through 500 MHz.
They MUST be mounted on a heatsink to achieve their power rating.
Using careful wiring practices (close to zero length leads), you can
wire 4 of the 25
Try to find carbon resistors as newer film resistors may be reactive.
Older carbon resistors have a tendency to migrate upwards in value. Be
sure to check them with a meter.
73
Bob, K4TAX
On 8/26/2018 7:50 AM, Bill Frantz wrote:
For my KX3, I built a dummy load from three 150 ohm 2 watt
For my KX3, I built a dummy load from three 150 ohm 2 watt
resistors and a BNC connector. The resistors are in parallel
with a lead going to the center conductor of the connector. The
other leads are folded back over the resistors and attached to
the ground-side of the connector. The whole
While one can measure a dummy load with an ohm meter, this is only the
DC resistance of the resistive element. It does not assure that it is
non-reactive as reactance is an AC component related to frequency.
Dummy loads should appear as 50 ohms at all frequencies within the range
where
Sorry, that is twenty resistors, not fifty.
wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)
> On Aug 25, 2018, at 5:35 PM, Walter Underwood wrote:
>
> I built the Oak Hills Research RFL-100 dummy load kit. It is supposed to be
> good to
> 144 MHz, so it should
The QRPGuys QRP tuner kit I built is very nice, but don't go over its 12W
limit, or you'll blow the diode.
Thankfully, I have a pile of them on hand just in case. ;)
Gwen NG3P
On Sat, Aug 25, 2018 at 8:36 PM Walter Underwood
wrote:
> I built the Oak Hills Research RFL-100 dummy load kit. It
I built the Oak Hills Research RFL-100 dummy load kit. It is supposed to be
good to
144 MHz, so it should be fine at 50. If you’ve never built a kit, this is a
good one to
start with. The kit is $50. I got the $5 BNC option, since my shack is 100% BNC.
http://www.ohr.com/rfl100.htm
Here are
Any decent commercial nominally 50 ohm 100W+ DL ought to work fine, as long as
it isn’t a piece of junk that falls apart at 50 MHz. It doesn’t need to be
NIST traceable :-)
Grant NQ5T
K3 #2091 KX3 #8342
> On Aug 25, 2018, at 7:09 PM, Steve Lawrence via Elecraft
> wrote:
>
> What are
A good one that you know is 50 ohms over the range of frequencies and power
you want to use it at. Unfortunately, any particular model may be good or
bad, depending on how it has been used or abused. Is there any way you can
get access to an analyzer to determine if the dummy load is good? I have
What are recommended dummy loads to consider for use when running the K3 TX
Calibration?
Thanks - Steve WB6RSE
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