Have you ever noticed that Six Meters tends to be 'dead' before and after Field Day but miraculously opens up for an hour or more during Field Day?

Same Deal.

Over the past few months there have been plenty of times when 27.185 was wall-to-wall with skip shootin' gear jammers but 10 was 'dead'.

Sure... Even better if it's properly connected to a ground rod and kept as short as possible.

I'm using a (mostly) triangular terminated loop for general RX aligned horizontally using available supports about 10' above the ground on average. It's not textbook by any stretch of the imagination and has about 80' of wire broken approximately midpoint with a 270 ohm carbon resistor. The feedpoint has a dual-core 4:1 Guanella style Balun, then RG-59 back to the radio. None of this is critical. Adjusting the value of the resistor can change the characteristics somewhat.

Works very well on the SWL bands, extremely well on the AM BCB and lower Ham bands. Good noise resistance and it's more than adequate to tell when 10 and 6 are open. Could be better if I worked at it, but for what it is and what it cost I have nothing to complain about.

If I used a traditional single core voltage Balun (trifilar winding) it would improve the lower bands at the expense of the higher bands, but considering that I can copy WWVB on 60 kHz from Tulsa I'd say the LF response is adequate.

Use a 1:1 Balun or at least wind a coaxial choke as mentioned previously. If you have the space for an 85' wire you can build an Extended Double Zepp. Better gain and bandwidth than a Dipole, but it will be more directional than a Dipole.

If the wire of an EDZ runs North-South the lobes will be East-West... Same as a Dipole but with a sharper pattern.

Dr. Jerry Sevick, W2FMI, published a book about Baluns and UnUns which is discontinued but can still be found at Hamfests and swaps. There is a chapter on building step down UnUns for ground mounted verticals which do exactly what you're looking for as well as step down Baluns for Lo-Z feed point Yagi's and such. Amazon lists it here:

http://www.amazon.com/Understanding-Building-Using-Baluns-Ununs/dp/094301624X

If you're not much on rolling your own, check these links:

http://www.cwsbytemark.com/prices/baluns.php

http://www.cwsbytemark.com/prices/ununs.php

Chances are there's a thrift shop like Goodwill, Salvation Army, local agency, etc near enough to be worth an occasional visit. It's not unusual for a donated compact all-in-one stereo system to arrive toes-up electrically, but the detachable speakers are still good. Some stores will sell the orphaned speakers for a dollar or two each. Others will sell the whole mess for five bucks and marked "sold as is for parts or repair".

Either way, look for speakers of decent heritage in reasonably good shape. Heavier is better. I've scored some nice SONY items with 5" drivers intended as the rear speakers in a 5.1 setup that play well. Small enough to fit the desk, big enough to sound good. Boston Acoustics made computer speaker systems with a sub woofer and two wing speakers that come through from time to time. The wing speakers are noticeably heavy for their size, very small, and sound good. Wire up a mini-plug and you're golden.

Sometimes you'll find a foam surround with a crack or two that can be repaired with a small piece of a paper towel and a dab of wood glue. Use a thin coat so it can flex a bit.

Also... Ask the clerk if they have a box of orphaned wall warts and remote controls. Most thrift shops do, and for the sake of 50 cents or a buck apiece they do come in handy.

Here's a 'no math' response just for grins:

Consider that a CW signal is either ON or OFF. The TX is at full power whenever the key is down. Same with RTTY. In my experience these are the two modes most likely to tolerate weak signal condx.

With SSB the modulation varies the output level and gives 'nuance' (for lack of a better word) in both frequency and amplitude. Throw in the usual background noise, QSB, QRM, QRN, wider filter(s), etc and the signal to noise ratio degrades more rapidly under marginal conditions. And, speaking of nuance, one could argue that S/N is the deciding factor of copy / no copy more often than the received signal strength alone. The typical semi-modern receiver has a noise floor well below the 'cosmic' band noise... Even at a quiet location... So, how can we improve the S/N ratio at the receive site?

Increase the signal strength or limit the bandwidth in the receiver. CW and RTTY do both, compared to SSB and AM. You can look at it in terms of power vs bandwidth or the probable S/N ratio across the link. Either path pretty much takes you to the same place.

In the 60's tubes were relatively cheap, in the 70's even cheaper as they transitioned toward obsolescence. Adding a delayed start to the B+ line wasn't worth the cost and in the case of consumer electronics, where the same folks selling you a TV also sold replacement tubes, there was a bit of Gillette / Kodak marketing at play. I.E. Sell the razor or camera cheap, ring the register for blades & film for years to come.

Many Tektronix 5xx series 'scopes featured a 45 second delay relay in the B+ line to extend the tube life as there were scads of the little glass devils inside. In the case of mercury vapor rectifier tubes the warmup sequence was 5 minutes or longer... The tube filament had to build enough heat to vaporize the drop of mercury inside before it would conduct full rated current.
 
Considering the cost of tubes today, a separate switch for B+ is well worth the effort. A delay circuit is even better as it removes the temptation to speed up the process.

Set the 'scope for AC coupling and hang the probe across the output... Assuming we're not talking about a high voltage supply. Scope probes and the AC coupling cap in the scope are good for something like 400 volts DC. Avoid measuring any circuit where there is a good chance of spikes in the hundreds of volts or greater, like a TV sweep circuit. Average is low, spikes are muy grande.

BTW: You can do the same with a DMM. Set it for AC volts and see how much non-DC shows up. That's my quick & dirty test of PS filter caps. Anything above a fraction of a volt of AC across the cap usually means it is eligible for retirement.

Squirt a Q-Tip with some CRC 2-26 and see what it can do for you. WD-40 would be a good second choice but the CRC is rated for electrical use and tends to last longer.

Float the worst of the oxidation off the surface and don't worry about making the coils sparkle... It's continuity you're after. No grit, the plating will be a bit slower to re-oxidize, and the hint of lubrication is enough for smooth operation without turning it into a dust magnet.

You can find manuals for SB-6xx 'scopes here: http://bama.edebris.com/manuals/heath/

From the Cebik article @ http://www.cebik.com/trans/spcoax.html
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"...all transmission lines consist of two or more conductors so arranged that they do not radiate RF energy. Whatever the exact arrangement of conductors, 2-wire lines have equal current magnitude and opposite current phase at every point along the line, thus resulting in the confinement of RF fields to the region of the line. Since the lines do not radiate (when installed correctly), the energy applied at one end of the line is available for controlled use at the other end of the line."

--- edit ---

"In this application, we use the center conductors of two coaxial cables that run side-by side--to ensure that they are of the same length. We can separate the lines, since the currents and voltages on each leg of the line are functions of the center conductor and the outer cylinder. By connecting the outer cylinders (or braids) together at the top and bottom, each line will have comparable current magnitudes in opposite phases at each measurement point along the cable length. Many applications permit only a ground connection for the braid at the lower end of the cable. However, if a grounding point is available at the upper end of the line, it is useful for sustaining the balance between the currents on the two center conductors."
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I realize that words like 'all' in the first quoted paragraph should be approached with caution, but as the second quoted paragraph mentions, current flowing along the coax shields will be of comparable and opposite magnitudes at any point. Much like the case of an open wire feeder. Assuming the two cables are kept in close proximity to each other (which can be achieved by twisting the pair one turn every foot or so) the feedline should be resistant to an imbalance caused by proximity to other conductors. You'll also note that Cebik considers a ground at both ends 'useful' in maintaining line balance, not mandatory.

While I appreciate your attention to detail, consider that few methods of transitioning from one type of feedline to another will be perfect --- either electrically or practically --- and the vast majority of antenna installations require some compromise between the two.

BTW: What solution would you recommend to K8JDC?
 

The shields can be grounded or left to float... If it's practical I'd ground the outdoor end of the shields as a static drain and/or an alternate path for a lightning strike.

The advantage is that the coax pair acts like a shielded balanced line which can tolerate being run near metal objects. I have air ducts, Romex, phone lines etc. in my attic and a 4" PVC pipe that drops down into the shack as an 'RF Raceway'. I can work around some of this, but the PVC pipe carries several runs of coax from the VHF / UHF antennas and would not be a good path for an open wire line. I'm also concerned that an open wire feeder might tickle the phone lines in the attic a bit too much.

Visit this link http://www.cebik.com/trans/spcoax.html for more.

I like the concept of open wire feeders but I know I can't do a quality install between the shack and antenna. Too many metal things to work around. So... My next antenna experiment will likely feature an open wire feed to an eave under the roofline, then transition through a 4:1 dual-core Guanella type balun (which in this case will be acting as a balbal) to a Siamese pair of RG-59 cables.

Check your handbook for details. The basic concept is that two 75 ohm coaxial cables can be used as a balanced (and shielded) 150 ohm feed line. The shields are connected at each end of the run, center conductors are used as the balanced line. Slightly more loss than an open wire line, but delightfully tolerant of installation compromises. If you're a purist, use two runs of RG-8X to your 450 ohm feeder. 450 / 4 = 112.5 which is close enough, especially since you'll be using a tuner.

Since part of the original question was about applications... Here's a starting point:

For the KDE desktop --- http://www.kde-apps.org/
For Gnome / GTK+ --- http://www.gnomefiles.org/

The vast majority of this is freeware. K / X / Ubuntu, OpenSUSE, Mandriva, etc have an installer utility to add repositories and manage your software configuration. The package manager can also check for new versions of * everything * loaded on the machine at boot... Not just OS patches, any available upgrade for any installed app.

Very handy.

Last I saw, there were 22,000+ software titles available for Linux.