No, the real question is why doesn't Elecraft make a KPA1500!
I agree about the Alpha PIN diodes. I had an Alpha 86 for a few years, and never had any trouble with the PIN diodes -- and I made plenty of 'antenna mistakes'. I sold it because I was tired of waiting the 90 seconds for it to warm up, and I believed that Elecraft was about to release the KPA800 and 1500.
I suspect some of the PIN diode failures were due to static discharges. I had ICE antenna protectors that provided a good DC path to ground and a good lightning ground system. Or else I was lucky.
73, Vic, 4X6GP Rehovot, Israel Formerly K2VCO http://www.qsl.net/k2vco/ On 1 Mar 2017 01:14, [email protected] wrote:
The Elecraft KPA500 silent QSK is achieved without expensive PIN diodes but rather with relatively inexpensive switching diodes. I’ll guess that the 1500 watt Elecraft prototype amp of some years ago used a similar inexpensive, silent design. Avoiding QSK should be because of operator preference not because of fear of relay failure. In the case of operating non-QSK, it’s vital for the operator to keep calls short and not be caught in a cycle of doubling with the DX that’s heard all too often. My Alpha 87A of 17 years or so has never had a PIN diode failure. When the 87A was first introduced there were indeed PIN diode failures. This was attributed to a bad batch (or batches?) of PIN diodes. Subsequent runs of 87A's ceased to exhibit PIN diode failures. Yet the urban legend persists that 87A’s should be avoided because of the PIN diodes - which are expensive to replace. The real question is why amplifier manufacturers continue to use vacuum relays when inexpensive switching diodes can do the job. Thank you Elecraft. 73 - Steve WB6RSE
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