TV day at Dulwich - 10th Sept

[ppppenguin]

Thanks for giving details of how to do the job properly, I cannot fault your reasoning or methods. However I feel it's not really necessary if the set is still unmodified. Merely connecting a 75R co-ax feed to the balanced input will give ample signal on any system we're now likely to use. The mismatch will also be unimportant. To give you an idea, the Vintage WIreless Museum's distribution system is designed to give +6dBmV at each outlet which is equal to 2mV. With a tolerance range of 1mV to 3mV. Most of us will be using an Aurora as a source of 405 signals. Even when split 8 ways the signal will still be of the same order. When the signal is that strong I don't think we need to worry about losing some through bad matching.

Any reflections due to bad matching are unlikely to give trouble. They will tend to absorbed at the sending end so the "3rd time aound" reflection will be negligible. If there genuinely is a reflection problem and some more signal can be sacrificed the old trick of an attenuator in the feed is a good one. A 6dB pad will reduce the wanted signal by 6dB while the 3rd time around reflection will have passed through the attenuator 3 times and hence be 18dB down, or 12dB lower than the wanted signal.