# UK Amateur Radio ## Foundation Licence 2002
### Feeders & Antennas Part C
## DUMMY LOADS
Above (left) is shown a commercial Dummy load capable of use with a 100 watt transmitter. | Above (right) is a kit built Dummy load which can only manage to absorb a small RF output but must be used in a suitable tin can with suitable oil.
This is another example of a dummy load. The one pound coin gives you some idea as to its size. This dummy load would be used for transmitters up to a max power output of 15 watts thus would be ideal for use by Foundation Licence operators who are only permitted low power operation. The connector at the end would link direct to your transmitter's output connector, or the aerial side of a SWR meter.
### Use of a dummy load This is used in the place of an antenna (aerial) when you want to use the transmitter but do not want to radiate any signal. The dummy load is a large resistor (or number of resistors) used in place of the real aerial. The dummy load must be large enough to be able to absorb all the power that the transmitter is trying to radiate. The dummy load must be completely resistive and non-inductive.
You can carry out a simple check on your SWR meter so that you know that it is working properly. Connect a dummy load to the aerial side of the SWR meter and the transmitter to the other. Set the transmitter into transmit (but only leave it like this for a few seconds enough to make a reading) and if it is FM the SWR meter will show forward power but should show show zero reverse power. If you are using SSB then you will need to talk into the microphone and again you will see the same results but this time the needle will be swinging about in time to your voice. However this is not good practice and frowned upon by many radio amateurs. It is better to use CW or FM mode for a SWR test. Now you have the confidence to try it with your aerials, but remember "Use the lowest amount of power possible to make a reading and for the shortest time".
An HF aerial system is in the centre with VHF and UHF aerials each side | A VHF aerial used mainly for receiving thus it is much lower than the transmitting aerials.
Here you can see a substantial car mounted aerial base. There is a cover on the top to stop water getting in when the aerial is removed. | The mount with the aerial installed.

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