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Author Topic: Heath SB-200 linear vs Yaesu FL-2100B or FL-2100Z  (Read 3211 times)
VE7ALQ
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Posts: 349




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« on: January 01, 2005, 05:09:49 PM »

Hi. I used to own a HeathKit SB-200 linear amplifier, now I have a Yaesu FL-2100B in the shack, and have a Yaesu FL-2100Z on order (mucho $).  All these linears use a pair of 572B transmitting tubes, plate dissipation 150 watts each.  They will run one kilowatt DC Input on CW, which is the legal limit for CW in Canada, so I am not looking for something more powerful like my Clipperton-L with four 572B tubes and 2700 volts on the plates(!)  I am not impressed with the Heath SB-200 or the CLipperton-L having a single meter.  I recall that the Canadian Radio Act required simultaneous metering of Plate Voltage and Plate Current, so the instananeous DC input could be easily derived.  The Yaesu Linears comply with this regulation as does my Heath SB-220 which I sold. I also sold my Heath SB-200.  All these amps can be jumpered to run on 117 VAC or 234 VAC.  In my apartment I only have access to 117 VAC, but the Yaesu FL-2100B handllec it without blowing the 15 amp breaker for the lighting circuit.

I intend to sell my Yaesu FL-2100B and Clipperton-L amplifiers because I like the 160 meter and WARC bands covered by the Yaesu FL-2100Z, which is why I paid premium dollar for my FL-2100Z. I also don't need three (3) Linears in the Shack at once?!
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N0TONE
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Posts: 173




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« Reply #1 on: February 08, 2005, 06:07:06 PM »

Are you asking a question?  I don't see one.  But I would point out a misconception.  The meters on these amps are not instantaneous peak-hold meters.  Therefore, you can not read instantaneous input power.  If the Canadian regs really require an instantaneous power measurement, then they are requiring you to adapt metering that the manufacturers do not supply.  And, in fact, to the best of my awareness, isn't available from anybody.

Sad to say, but the metering in amps is way off the mark anyway.  You're lucky to have meters within 10% of correct, due to poor component selection and drift with age.

1kW DC input?  That's quite strange.  In the days when the FCC allowed US hams to calculate power based on input, we had to calculate the TOTAL input to the tube, including plate and grids, PLUS add a reasonable estimate of the RF drive power supplied by the previous stage - we were allowed to measure its DC input and multiply by 50% for that estimate.

The reason the FCC switched to the 1.5kW OUTPUT spec is that, fundamentally, RF output power is nowadays easier to measure than DC input power.

AM
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