RF Power los

[Dean Hunter]

I recently spoke to an expert (50years experience) while having my DX7S repaired.

He tested the power output of my Tx he described it as useable but borderline!! I do the range test as per the manual - in his words not a true test of the power output as the test drops the power output as part of the 30m range test. If the power output while flying is low then the range test is obviously not a true reflection of power output!!

His reasoning for this reduction in power output is poor quality components over time, with a corresponding early failure and decreasing efficiency A trend that is on the increase.

Does this explain the odd 'glitch' in the air?

I am no expert - so any thoughts appreciated.

[Peter Christy]

What did he measure the power output as and how did he measure it? Did he measure the actual power at the terminals, or did he measure the Effective Radiated Power by measuring the field strength?

If he measured ERP using a field strength meter or similar, then the fault could be with the aerial and/or connectors as much as the actual RF board. If he measured at the terminals, what did he use to measure the power?

Power measurements at these frequencies can be tricky and need specialised equipment - although relatively inexpensive power meters are now available. Also remember that to meet EU regulations, the transmitter does not transmit continuously, but in short bursts. This means that measuring average power, rather than peak power, will give a false impression.

He may well be right, but without a lot more information about how he measured the power, and using what instrument, it is impossible to give an accurate diagnosis.

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Pete