Subject: RE: [AMPS] QSK5 Unit
As George states below, there are now PIN diodes that install
with wrenches. (like tubes with handles?)
I highly recommend the Ameritron QSK-5. It is a close variation
of the old Heath unit developed for the SB-1000 years ago.
I prefer the "stand-alone" box, as I use it with several amps, from
a solid-state Henry SS-750 to a Henry 4-K Ultra. I have had no failures
for several years, since new. I also live in a lightning prone area, and
never leave the QSK-5 in line when not in use. I sprung for the fan
kit for contest use, but I added a switch to turn it on and off, as required.
(((73)))
Phil, K5PC
>
>>>? Correct. The max allowable inverse for a PIN diode is c. 1000v.
>>>RJ-1A and HC-1 vacuum relays are typically 5000 piv - and they can
>>>recover from a static discharge - unlike PIN diodes. The switching
>>>speed of these two vacuum relays is under 2mS if a speedup circuit is
>>>used. See my Web site for details.
>
>Since the statement above seems to posit that there is only one kind of
>PIN diode in the world, I feel compelled to respond as someone who has
>designed with and uses PIN diodes in amateur radio and professional
>applications.
>
>There are available from MACOM PIN diodes with a PIV of 3kv. Several MRI
>machine manufacturers use them in their machines. These diodes are very
>expensive, though some are starting to show up in salvage. Since I typically
>ground everything in the shack via mechanical coax switches, when I am not
>operating, I have had no problem with lightning. I live in a very
>electrically
>active area, in the mountains above Boulder, CO, and so far have not lost
>any
>PIN equipment. The circuits to work with PIN diodes are much more
>complicated
>than with relays, but if you need the speed...
>
Indeed. For super speed cw, PIN diodes are the only game in town.
cheers, George
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