I've used WD-40 on plenty of rotary switches and potentiometers without any problems, but a better bet is Electrical Grade CRC 2-26. Available in the electrical department of any big-box handy guy store. Cleans as well as WD-40 does but lubricates better and lasts longer.

Avoid excessive overspray, wipe off any runs, drips or other signs of excess, and be sure to give the switch plenty of exercise while it's wet. Also won't hurt to Q-Tip off any oxidation that comes loose and is lying on the contact surfaces. The wick action in the cotton works nicely.

There are folks who will tell you to use only contact cleaner. Wrong. The switch also needs a little lubrication and CRC 2-26 is slippery enough to do the trick without turning the switch into a dust magnet. WD-40 can do the same, but it will evaporate completely within a month or two leaving you with a clean switch that doesn't move as smoothly as it should.

BTW: Check the service manual of an old Tektronix 'scope and you'll find similar advice. Don't lube a switch unless it needs it and avoid overspray as best you can. They do mention WD-40 as tested 'safe' on Tek switches.

The greater the number of turns, the greater the inductance and the lower the resonant frequency...

In other words: If you can't lower the frequency enough with the C, add a turn to the L. If you can't raise the frequency enough with the C, remove a turn from the L.

Oughta' work...

There's always the junkbox solution...

Scrounge up a nice beefy 4-pole relay and parallel the contacts. Not exactly textbook, but this is Amateur radio.

I had an Icom do exactly the same thing, but mine had the courtesy to puke & die while under warranty. Bad relay and/or driver transistor in the TX output filter and I was told Icom swapped the board. Hasn't missed a Q since.

The hardest part of the repair will likely be in getting the parts if you decide to roll your own.

Note to W7CFB:

The 6BZ6 was common as a VHF or IF amp in TV sets and, if I recall correctly, they usually had clear glass. There were tubes of similar types made with a grey band around the middle of the cylinder, but that was obviously intentional and wouldn't be described as 'blackish' or burnt looking. Since the discolored 6BZ6 is likely in the front end of the receiver section, I'd replace it...

http://hereford.ampr.org/cgi-bin/tube?tube=6BZ6

- AC5UP

As tubes age the inside of the glass will tend to take on a cloudiness. The internal haze can be any shade from white through a medium to charcoal grey depending on the tube materials and the operating conditions, as in plate voltage and current. A tube shield can influence this as shielded tubes tend to run hotter.

There are exceptions to this, as I recall RCA made plenty of 6V6's that were coated grey inside but had a circle of clear glass on top so you could see the filament. I'd replace the tube you described as a first step in troubleshooting the receiver issue. The hazy glass doesn't make the tube inherently bad, it just means the tube has seen plenty of operating hours and is probably below normal efficiency.

Now, for a little tube lore...

In a darkened room, it's not unusual to note a faint bluish corona effect around the grid(s) and inside the plate. This is particularly true of the larger output tubes that run at higher voltages. If you see a bluish corona outside the plate and up against the glass, the tube is going gassy. The exception to this are the gas-thyratron voltage regulators like the 0A2 which glow magenta-purplish when working properly.

The silver spot inside the glass is called the 'getter' and is a mercury compound intended to attract and hold oxygen atoms since no vacuum is perfect. If the getter turns a reddish-brown, it has picked up enough oxygen to become mercuric oxide. That tube is very gassy and should be replaced on sight. If the getter is white, the glass is cracked somewhere.

(every so often you'll see a piece on eBay that has a tube or two with a 'white nose'... They're cracked)

On rare occassions you'll come across a mercury-vapor rectifier and notice small beads of mercury inside the tube. When replacing, try to shake the larger beads down into the base of the tube by gentle tapping and run the tube for a good 15 minutes or better with only filament voltage applied. This heats the tube enough to 'vaporize' the mercury into a semi-conductive gas. Mercury-vapor tubes should always be pre-heated before applying voltage to the plates, usually in the range of 5-10 minutes.

Finally, tube plates are made from various metals and coatings and in some cases (like an 8080 regulator) can be made of graphite. The plate should never glow a dull red. If it does, you're pulling far too much plate current and this can be caused by a leaky capacitor across a rectifier, mis-tuned finals in a transmitter, or a short in the load. Nothing (other than rolling off the bench onto a concrete floor) ruins a tube faster than pulling too much current.

Orange filament glow = Good, Red plate glow = Bad.

- AC5UP

A lead-acid battery (and that's essentially what a gel cell is) should be charged at least twice a year while in storage. Every three months is mo'better and a monthly charging is recommended. Assuming your cells are similar to the common 7 amp-hour alarm panel batteries, charging should be limited to no more than 2 amps of current at less than 14.5 volts, max. Float charge would be 13.8 vdc around 100 mils (1/10 amp).

Anything above that will encourage 'gassing', where gas bubbles form on the plates and break the plate-to-electrolyte contact. This is not good. In service these cells start to lose charge depth at around the two year mark and by 3+ years they're ready for replacement. With the exception of a very healthy (wet) battery in its prime, a lead-acid battery that's allowed to fully discharge will rarely accept more than a very light surface charge at maybe 1% of its rated capacity.

There's a very good chance your cells pull almost no current from the charger and discharge almost instantly as the plates have sulfated so deeply that only the top surface is active... In other words, you have a pair of door stops. All gel-cells that I've seen have a date code marked on the case and anything over a year or so generally isn't worth carrying home, no matter how good the price... And I speak from experience on this.

Try running the batteries through a few charge / discharge cycles (an 1157 automotive brake light lamp makes a dandy discharger) just to see if there's any life in them, but don't be surprised if they're beyond salvaging.

- AC5UP

14.243 MHz is the default frequency for stations in the Antarctic and where they tend to run their regional traffic. It's also your best bet for a monitoring frequency. I've worked KC4AAA (South Pole) and KC4USV (McMurdo) with 100 watts into a wire, SSB, and in the case of 'USV it was almost exactly a year ago and he called me! (I was working the Oklahoma QSO Party, which starts March 22nd this year, and yes, you're all invited...)

In both cases the Q's were mid-evening local time and if my experience is typical, it has far more to do with band condx than your rig. Ain't no big station here, but it do work...

- AC5UP

Whenever I see the word 'broadband' in the context of VHF/UHF work, the first antenna that comes to mind is a Discone. Omnidirectional and vertically polarized, they look odd and are a bit complicated mechanically (which explains why you don't see them on every rooftop), but you'd be hard pressed to find anything with a broader practical bandwidth...

- AC5UP

If I recall my readings from Jerry Sevick (K2FMI) correctly, a Guanella choke balun (the second figure above, a bifilar winding with one wire designated as 'Hot' and the other 'Ground') will work as both a Balun and UnUn.

The application is essentially a line isolator / common mode 'breaker' decoupling the outer coax braid. If you're using RG-8X for the feed you can wrap 8 turns or so on a T-240, Mix 61 or 43, toroid and achieve the same goal. Otherwise, if you're running 100 watts or so, figure 8 turns of #18 insulated wire on an appropriately sized core of Mix 61 or Mix 43 material. Using enameled wire will give a winding impedance lower than optimum. If you can find some wire with a thin layer of Teflon insulation, that will get you closer to 50 ohms...

- AC5UP

You do realize that no matter how clean your station is, you will have a neighbor or two with an ultra-cheap TV, stereo, cordless phone, baby monitor... etc... And, that no amount of techno-babble will make them love you like a brother.

Avoid punching full power during normal waking hours, and remember the first 3-6dB of amplification has the most effect on the receiving side. Anything beyond that is probably just bonus income for your power company.

- AC5UP

C'mon now... No band is immune from lids, kids and space cadets, although I will agree Six tends to have a higher percentage of Newbies learning the ropes.

On the rare occassions where I'm in the presence of a blowghard, I'll take the first excuse to end the Q and move on. Life IS too short to worry about a dB one way or the other and if you can hear each other... It Works.

- AC5UP

Since we're talking Six Meters, if you want to try a full-wave loop you should also consider a bi-square...

Either should be mechanically possible on PVC pipe in a diamond configuration, and both can be made from three half waves of wire arranged with two half waves in the radiating section and the remaining wire in a ladder-line style tuned feeder... Measure a little long and prune the feeder to resonance.

20' is high enough on Six for a reasonable DX take-off angle, but it's also one wavelength above ground. With a horizontal Dipole you should be happier with the lobe pattern at three half-waves (30') above ground. Higher is usually better for local work, but do the best you can with what you have... That's what the rest of us do.

- AC5UP

A Yagi without a rotor isn't very useful, and I speak from experience on this, plus the rotor increases the cost and complexity of the setup by several orders of magnitude over an omni-directional solution. The next time I re-work the antenna garden on my chimney I have a hunch the 6 Meter Yagi is coming down in favor of an Extended Double Zepp.

Depending on your mounting options, you can homebrew one for about $5.00 plus the cost of the coax. I'm a big fan of EDZ's and have made plenty of Q's with them. Plenty of bandwidth, easy tune, zero SWR and not fussy at all about mounting height or nearby antennas. But, you're looking at a bi-directional pattern (perpendicular to the plane of the wire) which may be a consideration at your QTH.

For local SSB work a horizontal polarization is your first choice, but for DX it's not critical as the polarization will rotate. With this in mind, the Cushcraft AR-6 Ringo is a mighty fine GP vertical for casual DX work on Six. Mount it on 25' or better of TV mast and it will put out a good signal and survive plenty of storms. You could do a lot worse than a Ringo if you prefer a factory antenna...

- AC5UP

The cores from an EMI filter are likely powdered iron with a high permeability factor as they were chosen with a 60 Hz environment in mind.

This doesn't mean you can't use them, as your intended application will be like running the coax through a high-permeability RF Sponge with the goal of attenuating RF running outside the coax shield. If you can lay hands on the cores at low or no cost, go for it... Those 4" jobbies don't come cheap or easy!

I've done the same with EMI cores in the 2" range on RG-8X without a problem, just avoid coiling the coax too tight. Loose enough is good enough as you don't need to nail the last microwatt on the sheath and the recommended air coil isn't 100% effective, either...

- AC5UP