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Input and output impedances are pretty much consistent with the drive levels... IE, the input impedance of a GROUNDED GRID amplifier won't be the same at 50 watts in as it will with 150 watts in. That's the reason you can't use the MFJ technique on a cold tube.. It needs to be warm, and at...

Yup. The 800 is a 1200 with smaller transistors. Think it was ORIGINALLY designed around the MRF454... I STILL have a pair of boards with the 454s in them from a 16 pill amp :) The 1200 is the M2000, cut in half and using the basic board assy from the 4v, rather than the boards from the...

I do the same, but use a Field Strength meter from Radio Shack lol.... They pretty much accomplish the same thing, and once you KNOW what your near field is, it's pretty easy to pull it out of the center console and take a reading. "Great Minds".... A wattmeter only introduces loss via...

I almost hate to recommend them, but MFJ has a 3Kw mobile meter with a meter assembly that rivals the Dosy and Blackcat meters.... I like either NO meter in my mobile, or something big enough that I can see whats going on via my peripheral. No meter is typically how I run mine, though. Volt...

If you want to run SSB, not very many. I had a local purchase one, and he had 2 amps... A 4 pill battlebox and my sweet sixteen. The VHP was WAY too much radio for BOTH amps. After it blew up 3 times, I spoke with Monika and their tech at Galaxy at length. The basic premise was, that...

Oil2gas, it's a 2 driving 4 (high) or straight 4, class AB2. 300 watts SSB PEP output, about 50 watts AM. Good amplifiers, run within spec...... But, as I stated earlier, you can REALLY abuse the 6K*6 tubes.... --Toll_Free

The current 'batch' of amplifiers coming onto the scene (for the last 15 or so years, mass produced) can pretty much be counted on to be INPUT power. The 300 you're talking about takes 300 watts INPUT from your power supply to create the 150-200 watts output. Peak. Marketing ploy, sure...

If you're using a dual final radio, you don't need the JB12, 443... It only serves to overheat the grids of the tubes in your finals :) --Toll_Free

If it's the stud mount devices, tell your friend to buy another amplifier... Seriously, those things are SPENSIVE when ya can find them. If it's standard flange mount, then call RF Parts. RF Parts Company™ Amateur Radio Catalog They can tell you which devices from their SRF line will cross...

After looking at Shockwaves posted model, finding the thread, reading through the last 10 pages, etc. I've come to a couple conclusions. I was one of, if not the first person to model the antenna, and have been running through my models for the last couple weeks, as I had an I10K come down, and...

Shame on that 25+ year old linear's pot going out!

Best advice yet! And to the gentleman wanting to parallel two supplies.....: MAKE SURE THEY ARE RATED FOR SUCH USE, OR THEY CAN BLOW!!!! Some of the Astrons have a stud on the back for doing JUST this.... I've never tried doing it with mine... When I need more power supply, I have a...

Kinda like tryin to modify a 4V for HF use. Open mouth, insert something...... Also, a proper sized power supply WAS recommended. When that was rebuked, duty cycle, battery and load over time was brought into the equation. I've used lead / acid storage batteries for > 15 years in...

I don't quite agree with the statement that a battery doesn't add peak power.... That's pretty much ALL a battery is, unless you run a marine type.... And even those have a huge peak discharge capability. Don't believe me, fully charge one. Then gently place a 1" x 1.175 box end wrench...

For those interested in the 'math(s)' (the Europeans and some Canadians pluralize it????), it kinda goes along like this. (for biased amplifiers) TOTAL CURRENT DRAW (power out X 1.4 = power in ) / voltage at COLLECTORS!!!!! That goes for a STRAIGHT amplifier, not one with driver(s)...

I shut down a 70 amp supply with my 667 turbo mod. FYI, 20 amps a 'pill' for 2879s is a good ballpark. 16-18 for 2290s, 15-18 for the SD1446 type devices. --Toll_Free

Brass makes a great parasitic choke... Just make sure you look at a 'skin depth gauge' and ensure you're using brass that's thick enough.... I PREFER to make hairpins for my inductors.... I've had better luck with them, you can assemble the resistors to be IN the airflow, AND that helps...

Yeah, it was the Cali AMI net. I guess I should have qualified my 100 watts.... That's 100 percent flat out PEP.. lol. AM power is a measly 20 watts of carrier :( Like the transmitter. I'm REALLY envious of K1JJ's new rig, a pair of 4-1000s modulating a single 4-1000. Me WANTS! I...

You need RF rated capacitors. 160 meters is a KILLER!!! RF Parts Company™ Amateur Radio Catalog can fix you right up. Just because it's a doorknob DOES NOT mean it's an RF rated cap, either... Keep that in mind.... TV type doorknobs are known to let go when used in higher powered...

Agreed. Best part is, call Rich up, tell him your tubes, and plate voltages, you'll have a set of suppressors delivered. BUT, if you are a "ten" meter operator, beware! The Nichrome suppressors at 10 meters will turn a slight orange when you're keyed up.... The nichrome DOES dissipate some...