The need in this question is merely for a DC load, so kettles, bathroom heaters, light bulbs etc suffice here, where they would not for RF. ... On this webpage I show a method to make a resistive termination or dummy load that uses the inductance in wirewound resistors in a lossy low pass filter to extend the frequency range to cover the full HF radio spectrum. It uses a number of non-inductive resistors in parallel to achieve 50 Ohms over a wide frequency range. Testing four Arcol HS50 100 ohm 50 W wirewound resistors in series on our HP network analyser showed that the inductance affected the required impedance match at higher frequencies as expected. StevieG, Alan - Mirror Man and Swadeyboy like this post, Victor and Alan - Mirror Man like this post, Alan - Mirror Man and Tristar like this post, NUBSTER and Alan - Mirror Man like this post, NUBSTER, Victor and Alan - Mirror Man like this post. As the radio frequency power is converted to heat, interference is avoided. On this webpage I show a method to make a resistive termination or dummy load that uses the inductance in wirewound resistors in a lossy low pass filter to extend the frequency range to cover the full HF radio spectrum. The QRPGuys Dummy Load/Power Meter is a 50 Ω, 12W rated terminated load that is useful tool when setting up or diagnosing most low power transmitters. The home of ALL things Radio - CB, 11m DX, Amateur, PMR446, PLD, Network and Data. This RF-power meter combined with build-in dummy load is made to measure power levels starting from a few milliwatt up to 50 watts (or more if suitable components are used and an avalanche sinterglass diode). (If not only for me but maybe others also.). Totally agree. 2x 100ohm 100watt panel mount resistors wired in parallel. Built my own one. The answer is yes. You’ll need 30 dummy load resistors — 1.5k-ohm, metal film, 2-watt resistors soldered in parallel. var AFS_Url="DetectUrl"; The metal box helps with any heat build up. Using a DMM you should see positive DC voltages at the output of the adapter. All materials cost about £30. Useful range is from DC to 150MHz. A dummy load is an indispensible tool for the novice as well as expert ham. Use plain water with a little salt added to build your own … They can be purchased relatively cheaply new, but soon become expensive for higher wattages. So what is an RF dummy load?, a dummy load is a device used to simulate an electrical load, it is used to simulate an antenna in an RF system. How many times have you been told that you can't use wirewound resistors at RF? This device has a maximum dissipation rating of 250W and an SWR of less than 1.15:1 from LF up to more than 2GHz. Victor if you look at one of my post in the Antenna section its says " Admin please feel to post this in the Information section but give the video maker Gary (Offplanet)the credit" the reason I ask Admin to do it was when I posted the Q code list Lee put it in the info section so I thought it was up to Admin to do it ,but also I got a bit of a impression that some thought I was talking cr*p and was more interested in making ones with diodes and heatsinks which cost money ,my info cost next to nothing and was use by radio operators (not just hams)years ago in fact it's common physics and not really electrical or radio . The impedance match of the resistor low pass filter measured on a HP network analser is OK up to 30 MHz. Coming from an electrical background kind of helped. This allows RF power up to 30 MHz to flow through the resistors and be dissipated as heat. in … I made my own 50ohm dummy load using readily available parts from CPC. [size=46]Just warning beware this style and specification dummy load from a reprital cb shop or ebay seller go for about £25/£35 so when my mate and I saw them for £15 on ebay new and aUK seller thought we'll get a couple, they turned up guess what ,from China ,so my mate decided to test his one before use, well it wasn't even 50ohms like its suppose to be and was suppose to handle 30w it could only handle 5w when I checked mine it wasn't even connected inside so basically if we never check we would damaged our equipment, so if it looks a bargain beware [/size]. So if you are playing around with radio transceivers an RF load is a nice addition to your set of tools. A transceiver can be tested and configured without radiating a radio wave by using a dummy load. Optionally you can also use an oscilloscope to measure the RF voltage at the Dummy Load (not shown, also dangerous voltages are present!). AN LF TO 2GHZ 250W DUMMY LOAD. Home brew dummy loads category is a curation of 30 web resources on , Building A RF Dummy Load, QRP Power Meter and Dummy Load, RF Dummy Load. Resources listed under Dummy Load category belongs to Technical Reference main collection, and get reviewed and rated by amateur radio operators. I'm uncertain, if not perplexed by the last couple of responses to this posting, but will do my best to resolve or at least understand them. How inexpensive, depends on the dissipation you need (QRP (5-10 W) or (much) more) and how long you want to be able to apply power without frying the dummy load and setting your shack on fire. Specifications were 150 … Special flange mounting RF metal film resistors like the Florida RF 32-1037 make an ideal resistor for a dummy load. A simple RF attenuator is shown in the photo below. If an accurate 50Ω dummy load is available in the shack, we can measure RF power by measuring the RF voltage developed across the load. You’ll need a small 3/8-inch rubber grommet, to serve as a vent, as well as about two feet of #18 tinned solid wire. Using 1.5mm sq electrical cable. The circuit uses the inductance in the resistors and the capacitors as a low pass filter with a cutoff frequency around 30 MHz. My Pulse Width Modulated AM transmitter project required dummy loads to match the load impedance of the RF power stage (50 ohms) and the Pulse Width Modulator (12 to 16 ohms). Attach the transmitter through the tap to a dummy load where the output voltage can be read directly using a di- ode detector and DVM as shown in Fig- ure 6. A dummy load is a piece of equipment which allows transmitter testing and adjustment with minimal radiation of RF energy.. Salt water dummy load. I used a metal alloy box which was a bit small but a bit of ingenuity made it fit. This particular BNC attenuator is a 50 in/out with an attenuation of 3dB, but the attenuators are available in other impedances, connector types and For special designs the manufactures can produce different custom Z inputs/outputs. Contact Chris Moulding, G4HYG via Email address hidden from spambots for more details, comments or feedback. The common RF Attenuator has the same input output Z which is 50 Ohm. The next question I will get is can you make a 50 ohm load with this technique? Dummy-loads are easy and relatively inexpensive to build yourself, using one or more suitable resistors. Was it possible to use them at RF? This all came from the picture i put up and a joke after the post lol. Included is an on-board RF detector allowing accurate transmission power calculations. var AFS_Tracker="auto";