Entries from February 2009 ↓

DVD Labeling

We have quite a collection of CDs and DVDs. Every since they became affordable we have been using them in place of floppy disks for storing data, audio, and video. They work for backing up small hard drives too.

When you have more than one disk you need to identify it. Label it.

There are several methods of labeling that provide professional results. Perhaps the most professional is the Lightscribe system. This takes a specially equipped CD/DVD writer and uses its laser to ‘write’ to the flip side of the CD/DVD leaving a visible etching identifying the disk. This takes a special drive and (I believe) special disks. Costs money. Not sure how much but if you do as many disks as we do, even a dime would have a significant effect.

A second way to identify is to use stick-on labels. First you print the label on an inkjet (most economical) or laser printer then you apply the label to the disk using a fixture to align the disk with the label. Works fine but has some limitations. CDs are not effected by paper labels, but DVDs can be damaged by paper labels. Evidently the higher density of data on a DVD combined with the higher temperatures inside DVD drives tends to play havoc with adhesives and paper that has a different coefficient of expansion with heat than the disk. In other words, you have to use special vinyl labels on DVD disks. Special meaning expensive.

After you put all that together, buy all the supplies (about 20 bucks for 50 labels, 50 bucks for inkjet cartridges), design the labels, then finally print and apply them to the disk, you are looking at a significant amount of investment in time and money.

You ask yourself, ‘is this trip really necessary?’ The answer is NO.
Save your money and time. Invest in a two dollar laundry marker, a sharpie works well, and learn penmanship.

Fancy labels are marketing tools. As long as you are not trying to sell your disks, you don’t need fancy labels, just legible identification.

Cheap Computers

I just found a 10 bay computer case with 480 watt power supply for around $30. Last week I bought a pentium 4 MB with IDE and SATA and USB for $40. PC-3200 memory for the MB is going cost around $30 for a 1gig stick. Probably want a DVD drive that reads AND writes. That is another $20. Keyboard at $10 and mouse at $5. Oh, and a harddrive at about $50.

MB has on board video, sound, nic, usb, sata, and ide. So that is it, a basic computer for….lets see…30+40+30+20+10+5+50..= $185 total.

Or you can buy a basic X-Box for close to the same price.

Oops, I forgot the CPU. Wonder what a 1.8gig pentium 4 sells for?

Ah-ha, Intel Pentium 4 at 2 gig, refurbished, sells for $11.50 bringing our total to $196.50.

That is less than I paid for two 8k memory boards for my S-100 CPM system in 1980!!

Of course before we put our money down we might want to see what ‘refurbished’ means. We might also want to consider the cost of a monitor. Hard to tell what is going on without a display. If we are willing to settle for a CRT based monitor we might get one for free. Anyone for dumpster diving?

Rats, I forgot the operating system. Well, Debian Etch would do a bang-up job for free. I hear they just release Debian 5.0 too.
Or we can go with XP but that is going to add another $200 plus to our $196.50. No, you don’t want Vista. Not enough hardware of the right kind (expensive) in this deal. Actually, you don’t need Vista but I can see where most users would be more comfortable using XP. So our final cost is going to be around $400. Buy this stuff on the internet from the Geeks and you can avoid paying tax in the purchase. Shipping is going to be around $20 or so.

Drake Case and Cover Screws

Now that I am completely done with the upgrades, mods and repair on both the R4C and T4XC, I figured it was time to install the screws connecting the bottom cover and top covers to the main chassis of each piece of equipment.

Takes #6-32 pan head, black oxide, plain slot, machine screws that are 1/4 to 3/8 inch long. Need 24 of them, 12 per radio.

I found lots of screws on the internet (pun intended). One outfit had the exact type of machine screw needed and was willing to sell in box lot quantities. Trouble was their ‘boxes’ held 10,000 screws and cost over $100. Not a prudent solution.

After a search of the ‘junk box’ I did find several dozen nickle plated, phillips head, 6-32 machine screws of sufficient length to do the job. They are now doing the job.

Not original but they actually look better. At least now you can tell if the screw is installed because they show up very clearly with their bright silver finish.

All I need to do now is find spares for the tubes used in these two radios and I will be set for quite some time to come.

T4XC AM Mod

I saw this modification on the web somewhere but don’t remember exactly where. Google on T4XC AM Mod and see what you get.

The mod is a simple matter of replacing the 220 ohm cathode resistor on the 6AU6 am modulator with a 1K pot. Then the 1K pot is adjusted to give 20 to 30 watts carrier output with the transmitter in AM mode and keyed on the air via the microphone.

Why do I need this? My thought exactly. I had always known that the T4XC had an AM function but why bother with it when it has such a good SSB feature?

I probably still will not bother with the AM function but this mod makes the AM function much more functional. You see the transmitter goes to ‘controlled carrier’ mode when doing AM. Carrier output is only about 10 watts or so when unmodulated in AM mode (dead mike). Power out increases when you talk up the mike but for those periods of silence between sentences the signal appears to disappear as the power level goes to QRP.

So, by increasing the bias resistor value from 220 ohms we can get more carrier output with a dead mike and the signal does not disappear as much. Carrier output increases to 25 to 30 watts. You could probably get more but it makes it hard on the finals.

The mod has you installing a 1K pot in one of the extra phono jack holes on the rear apron of the transmitter. After I figured out my pot would not fit such a small hole, I used a small PCB mount trim pot soldered to heavy wire extensions from pins 2 and 7 of the 6AU6 socket.

While working on the socket trying to remove the wires and one resistor lead off pin 2, I ended up breaking off the solder lug part of the tube socket pin. While it is not impossible to replace the socket, it is a major undertaking that I was not interested in undertaking. I ended up removing a pin from a surplus 9 pin socket and inserting it in place of the broken pin. I pushed the new pin down into the socket with the 6AU6. It worked and the wires and resistor were far easier to remove off the broken pin now that it was out of the radio.

Once the pot is installed, you tune up the transmitter for max power out in the tune position, switch it to AM making sure the SSB switch is in the XLSB position, and monitor your power out while adjusting the new pot. I set mine to output about 30 watts. Have not tried it on the air yet but it sounds okay on the receiver. Then it sounded okay before the mod too.

One last thing about the mod. You don’t need to leave the pot installed. Measure the resistance of the pot after the adjustment and replace the pot with a fixed resistor of that value. Note that the original 220 ohm cathode resistor is left with one end remaining soldered to pin 7 just in case someone wants to remove the mod and return the transmitter to stock condition. I figure if it is a mod worth doing, it is a mod worth keeping. Still, my T4XC now has an extra unused 220 ohm resistor hanging off pin 7 of the 6AU6 socket.

Drake T4XC

Yup, that is my main transmitting rig. Older than sin but still works and looks good. It is also not stock, or maybe some would say ‘mint’. It has been modified in several ways but the main mod is a conversion to use 6146Ws in the final cage. A minor mod is the addition of a fan to cool the finals but that has been disconnected because I got tired of listening to the fan noise. Not that it was all that noisy but I could tell it was on because the shack is otherwise quiet as a tomb. I finally realized that the finals would not be on but for a few minutes and even then would not be running flat out so the additional cooling was not really necessary and I would appreciate the quiet much more.

This transmitter gets used at least once a week on 75 meter SSB.

Recently I found an additional mod for the Drake T4X series of radios. An audio modification claiming to make the audio easier to listen to. Make it more natural sounding and of HI-FI quality. Well, I never have taken much stock in striving for HI-FI on the ham bands but I took an interest because the mod included a simple addition of capacitors in the mic amplifier circuit.

Those not familiar with Drake equipment may not realize the construction and difficulty in executing any mods of this nature. All the T4 series of Drake radios uses small PCB boards that are mounted on-edge to the chassis. This makes it difficult to even see what is on the boards much less change anything.

It took the better part of a day just to find the manual. Then the entire afternoon to find the parts in question. The idea was to add capacitance to existing capacitors to improve the frequency response of the mic amp at the lower end of the audio frequency scale.

Turns out that my transmitter did not need the extra capacitors. It already had sufficient capacitors installed. Guess maybe it was a later model. What this excercise did disclose was that the 6AU6 AM modulator was disconnected from its PCB and a 100k resistor had been broken on another PCB. Obviously these deficiencies did not effect the operation on SSB lower sideband in the 75 meter band. Still, these deficiencies needed to be corrected and they were.

So now I can use the transmitter on AM if I want. That probably will not happen but it puts the spotlight on what might be problematic in the future. Every indication was that the lead that had been disconnected was due to fatigue of the wire in the soldered termination on the PCB.

Drake used solid conductor hook up wire on all their equipment. This works well but introduces the problem experienced. On installation should the solid wire be nicked even slightly before it is terminated to a connection chances are good that it will break sometime in the future if it is subject to stress. In other words, if you wait long enough, all the hook up wire in the radio will fall off when you remove the covers. Hopefully this may not happen for 500 years but I know of at least one wire connection that did not make it past 30 years.

So, although the repair was really not necessary, I am glad it was made and the rig is back to its normal self.

openSUSE

Well, on the recommendation of an acquaintance I tried openSUSE 11.1.

Slick install as far as the graphics went. Sort of like Microsoft stuff but without the congrats and promise of fun ahead.

The first thing openSUSE asked for was permission to activate some swap space. Okay no problem, I let it activate some swap space. Then when it came time to copy software to the hard disk it tells me there is no space on the hard drive. HuH?

So I check the hard drive, it is only a 10gig drive, and it turns out the dummy assigned all 10gig to swap space. Things went from bad to worse from there and I finally stored the installation DVD in a very safe place.

Could be I am the dummy. Could be the hard disk was not large enough or I did not have enough memory or the hardware was too out of date or any one of a number of additional problems that are usually solved before installation by reading the minimum system requirements listed on the cover of every operating system box I have ever used. Every one except the openSUSE system. It did not come in a box. It was downloaded off the internet and the minimum system requirements could not be found.

Now I hope the installation DVD will also never be found again either.

Life is too short to waste time on buggy or user unfriendly software.

I have been doing computers for 30 years now and this is the fifth time I have run into problems with system installations. In all but two of the five cases the software was a new ‘enterprise’ release by some big-shoot firm of Linux software that had been working just fine before it was ‘enterprised’ Had problems with RedHat, Mandriva, and now openSUSE.

Sure glad God made Debian.

Lost Mind

When someone accuses you of having lost your mind, just tell them:

Its not lost. I know exactly where it is. I just don’t bother to use as much as I used to. Gives me a headache.

Then see what happens. You might be elected to office.

Heaviest Element

The Heaviest Element Known to Science:

Lawrence Livermore Laboratories has made a startling discovery in finding the heaviest element yet known to science.

The new element, Governmentium (Gv) has one neutron, 25 assistant neutrons, 88 deputy neutrons, and 198 assistant deputy neutrons, giving it an atomic mass of 312.

These 312 particles are held together by forces called morons, which are surrounded by vast quantities of lepton-like particles called peons.

Since Governmentium has no electrons, it is inert; however, it can be detected, because it impedes every reaction with which it comes into contact. A tiny amount of Governmentium can cause a reaction that would normally take less than a second, to take from 4 days to 4 years to complete.

Governmentium has a normal half-life of 2-6 years. It does not decay, but instead undergoes a reorganization in which a portion of the assistant neutrons and deputy neutrons exchange places.

In fact, Governmentium’s mass will actually increase over time, since each reorganization will cause more morons to become neutrons, forming isodopes.

This characteristic of morons promotion leads some scientists to believe that Governmentium is formed whenever morons reach a critical concentration. This hypothetical quantity is referred to as critical morass deposits. The location of Governmentium deposits is found in every state Capital. with a mother lode in Washington, D.C.

When catalyzed with money, Governmentium becomes Administratium, an element that radiates just as much energy as Governmentium since it has half as many peons, but twice as many morons.

Tornadoes

I guess spring is here already. Last night we were forecast to get rain. Then we were forecast to get thunderstorms too. I did not dwell on the forecast weather too much. After all the last time we got any significant rain, it came from a thunderstorm.

About 9pm we heard the sirens. Then came the rain followed by the wind followed by more sirens. Some folk in our area suffered damage from the tornadoes. Typical tornado in the trailer park scenario. I am convinced that trailer parks cause tornadoes.

We did not get any tornado damage. Guess maybe the sirens scared them off.

It is going to be an interesting spring.

Tube Amp

This tube amp is something suitable for use as a small computer speaker amp. Inspired by the recent discovery of the Morgan amp.

The Morgan amp is a simple three tube single channel amp using old AC/DC 5 tube radio parts.

A 50L6 output, 35Z5 rectifier, and 12SQ7 pre-amp all cobbled together to give at least an honest 1 watt of audio to a pair of simple speakers.

Cheep, cheap, inexpensive. The Morgan amp runs directly off the 120vac line. Not a safe application, but it can be made safe by using an isolation transformer, fuse, and on/off switch.

The low cost is a direct result of the simple design.

I did not have but one 35Z5 but I did discover a few 12AV6s, 50C5s, and 35W4′s. These are the miniature equivalents to the tubes used in the Morgan amp. So I decided to use them in an updated Morgan design. The only change was to replace the tubes with the ones I had on hand.

Folk who do not have a box of parts to pick from can still build this amp. The most economical approach is to find two AC/DC radios at a thrift shop or garage sale. Working or not, these radios can provide all the parts necessary to build a two channel Morgan amp. Three of the tubes in these old 5-tube AC/DC radios are used in this amp. One of the remaining tubes is an IF amplifier and the other is a mixer.

It could be argued that this amp driven by a crystal radio can provide far better fidelity reception of AM signals than the original radio. Instead of a superheterodyne style radio we revert back to a simple detector and audio amplifier. We might loose a little in selectivity and sensitivity but I doubt anyone listening to powerful local stations would notice anything but the lack of interference, noise, and squeals with the mixer gone. (Wonder why these things are called SUPERheterodynes? Most things I see with the ‘super’ label, are anything but super.)

In my design I used the goofy printed circuit mounted tube sockets found in the AC/DC radio I had. I simply cut them out of the old printed circuit board and mounted them with screws to a scrap of unused printed circuit board I had been saving. Somewhat more work than it should have been but very effective.

The housing for the amp was made from scrap pieces of redwood that had been salvaged from a demolished redwood deck. The complete enclosure is redwood and plexiglass. The plexiglass is also of the salvaged variety.

The end result is lots of noise for little cost. Actually no cost except for the time to build the thing.

You might well wonder ‘why do this’. Okay, you can buy new amplified computer speakers for under
ten dollars but then they are ten dollar amplified computer speakers. They don’t have the characteristic sound of a tube amp.

What characteristic sound? The sound of rock and roll.

All this started when tubes were cheap and amps were popular. Folk were not too concerned about how linear the sound was. Or how well a full spectrum of sound frequencies were replicated. All they wanted was something to make noise. Meanwhile, tube amp designers were not all that concerned about building expensive stuff with super good specifications. Why bother when it cost much less to build something that just made a lot of noise. Besides this is what was selling. No future in building stuff no one would buy. It was much easier to sell a cheap tube amp than a more expensive carefully engineered amp. The rock and roll crowd picked up on the cheap amps and used them. Their cheap and distorted audio gave the music a distinct flavor and rock and roll was born.

Now days real rockers can appreciate the sounds of that distinctive distortion that you can only find in music coming from a poorly designed tube amp.

So here you have it, a poorly designed tube amp for the rock and rollers.

You don’t have to dream about it. You can actually re-live the past. At least listen to the music of the past on real tube equipment.

When you can do it for no cost, why not?