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Another option is, if it doesn't get used on 80 meters, you could just pull out the offending plate. There are several options to fix the arcing issue, depending on skill, time and budget.

I modified one for use with a 6LF6 tube that required more negative bias. I took a small 24 volt transformer out of a tiny "wall wart" and used a voltage doubler. This provides over -65 volts DC to work with. Usually enough to place a stock tube into cutoff. Although, I prefer switching the...

Unfortunately there appears to be more than one issue here. Many of these designs only used a two pole relay and offer no ability to switch the bias on and off. They are tube killer's from day one as a result.

How does the larger package make it more reliable for the sideband operator, when there is no voltage drop across this part in sideband and the full 12 volts is applied to the drivers and finals? This part only affects modes with carrier, where the VCC is less than 12 volts.

One thing I don't like about the specifications, is the very misleading "low harmonic content" claim. -23dbc is more than 5 times the maximum harmonic content allowed by the FCC on an HF amplifier! It has horrible harmonic content, because no effort whatsoever was made to remove the harmonics...

Simple facts. The 60 watt transistor biased up to provide 6 volts VCC at 1 amp, will be dissipating 6 watts of heat into the heatsink. The 150 watt part biased up to provide 6 volts VCC at 1 amp, will still be dissipating the same 6 watts of heat into the heatsink. Heat disapation is a direct...

This is the solution to the problem. The problem is, where the arcing is taking place on the tune capacitor. That can start by simply having dust or debris in between the plates of the capacitor. Once the arc starts it will pit the plate and cause a prime location for the arc to continue, even...

Thinking of using one in the extended portion of the AM broadcast band? Sorry for my sense of humor.

I should mention that overcurrent protection is a very effective safety tool on the output devices used in any power amplifier. It also has the ability to detect the most commonly destructive SWR faults, that shift the load impedance below 50 ohms and force the final stage to draw more current...

While you could certainly question the level of reliability, old school original Toshiba 2SC2879s could be run on 18 volts worth of battery, charging at 21 volts. The trick to keeping it reliable, was class C operation and a matter of keeping the drive and carrier level within safe limits. Which...

I think the biggest thing to consider is the MOSFET transistors used in amateur and Commercial radio equipment, are not at all related to the garbage seen in CB equipment. Other than things like the 1500 watt LDMOSFET amplifiers, you literally can't find a single linear rated RF transistor being...

Bingo! While I have seen two of these antennas fold right over at the insulator, no amount of wind did it. One was hit with a direct lightning strike and the other, the guy hit it with about 5000 Watts. Both cases resulted in catching the fiberglass reinforced PVC insulator, on fire!

People have been known to be adamantly incorrect. Unfortunately, what he said doesn't even make sense. There is no such thing as too many amps. Only not enough. Having said that, it is nice to be able to set your current limit, just above your normal operating point. This way, if anything goes...

From not so fun experience, I can tell you that the breakdown voltage on the D&A transformer, is three secondaries. Put four secondaries in series and a humid day will find the breakdown voltage.

That is true however, the transformer in question, from the D&A amplifier was designed to be used with a full wave Bridge rectifier. Since the original transformer doesn't have a center tap, this should be a good replacement, with plate voltage that's appropriate for a sweep tubes.

Radio Shack actually sold the original Shakespeare Big Stick back in the late 1970s and early 1980s. This was long before they had Archer make their junk blue copy of the antenna, with the "100 watt fuse" in the base. I've seen bigger toroids in a 300 to 75 ohm TV antenna transformer.

The 170 volts is the maximum that the full primary can handle. The rated voltages are printed on the top. With a primary of 115 volts, that has an additional 4.3 volt winding, that could be added in series to make less than a 5% drop in the secondary voltage. I don't see how to get below 900...

I think it's a good idea to replace that original transformer with a pair of the D&A transformers. That will certainly give you headroom and I really don't see where there would be a requirement for much of any modifications. That original transformer is certainly not being run through a voltage...

With respect to lighting the filament on the 6000 tube, I just noticed that they have regulated switch mode buck voltage converters available in ranges from 50 to 100 amps today. This would be ideal to provide efficiently regulated filament voltage from 12 volts. Some of these converters are...

It's been about 25 years since I've had any experience with an AC mobile however, assuming you're not exaggerating it would appear much has changed with these alternators since then. I remember struggling to get six or seven grand out of a 165-amp shortcase Leece Neville and 10 bushels out of a...