The OHR RFL-100
100W RF Load Kit
The Oak Hills Research RFL-100 was designed specifically for the QRP operator and builder, who needs an accurate and stable 50 Ohm load. Most single-resistor commercial loads are low by four or five ohms, and that can be important when every milliwatt counts. Tolerance errors in the RFL-100's 20 resistors tend to balance each other out, and the completed kit will come up within a couple decimal points of 50 Ohms.
Note that the RFL-100 will support a continuous 100W load. Most so-called 100W dummy loads will only handle a 100W load for a few seconds, with a cooling off period of a minute or so before 100W can be applied to it again. You can put a brick on the key and go have supper-- the RFL-100 will be perfectly fine when you come back, still with a 1.1:1 SWR. But that's pretty much a "don't try this at home" scenario, because your transceiver is not meant to put out full power for more than the length of a dash, and the test described above presents a serious risk to your finals.
And yes, the derating curve works both ways-- you can safely put 200 or 300W into the RFL-100 for a few seconds. We don't publish an official de-rating curve because there are other factors (chiefly air-flow and ambient temperature) that will affect it and a statement based on some arbitrary "standard" is meaningless in the radio shack So whether you are running QRO or QRPp you will have an RF Load that will more than handle it.
In most commercial radios tuning is done at low power, and choosing a continuous duty mode (100% duty cycle) like AM, RTTY, and FM will automatically set lower power output.
The RFL-100 is also our easiest kit to build, with big fat resistors and solder traces, simple hardware, and no "alignment" necessary. The assembled RFL-100 measures 4-1/4" wide by 6" front to back by 2" high, and weighs 12 Oz.
Features:If you would prefer a BNC connector, you'll find a conversion kit on our Parts Page.
- 50 Ohm Resistive Load to 144MHz
- 100W Continuous Power Dissipation (higher loads are possible for short periods)
- Air Convection Cooled through vented enclosure
- 20 Metal-oxide Resistors for shared power and heat dissipation
- Non-inductive load within 2% of nominal 50 Ohms
- SO-239 connector
- High temperature printed circuit board with two-ounce copper traces
The Oak Hills Research RFL-100 kit contains all necessary parts for assembly and installation, including a ventilated, painted and silk-screened cabinet, schematic diagram, and complete parts list.
Want OHR to build it for you? Click here for details.
OHR RFL-100 RF Dummy Load Kit, $49.95 Build, Align, Test OHR RFL-100, $25.00
S0239 to BNC Conversion Kit
Push on PL259 Connectors
Tools and Solder
See also the OHR/CQC 10-W RF Dummy Load Kit