Archive for June 2007

Impedance Matching

June 30, 2007

Also known as antenna tuning, impedance matching has taken on new importance in my shack. For years I was using a ricebox that contained an automatic antenna tuner. I got spoiled. I could load nearly anything and, most importantly, I could drive all my RF amps to full output without having to twiddle any input knobs.

Recently I began testing and then using some older rice boxes that did not have built in antenna tuners. It took a while to figure out why the TS-120 was only driving the amp to an output of 200 watts.

Took a look at the SWR present between the TS-120 and the amplifier. It was 2:1. Not bad at all but after reading the manual on the TS-120 I discovered that into a 2:1 SWR the TS-120 would output less than 50 watts. My amp needs 100 watts or so to drive it to full output.

The old Z-match to the rescue. At first I was contemplating on throwing together a pi-network. Then decided on a Z-match. I took a look at offerings regarding a Z-match on the internet. Nothing earth shaking. Someone had figured out that the two coils used in the Z-match could be made as one coil and the common tap between them made into a conventional coil tap. They also discovered that a toroid core could be used. I am not sure why I would want to go to the expense of a toroid core and wind on more turns that I need for the air core coils. Take a look at the original Z-match design on this web site. You need to call up http:\\www.k5dkz.com/blog/home. Then find the listing for the Z-match project.

So, I decided to use the last two air variable capacitors in the junk box to build a 100watt plus Z-match of diminutive proportions. These were broadcast style variables. Plate spacing probably good to 300volts or so. One with three sections, two of them at 365pf for the dual section part of the tuner. The other cap was the typical 5 tube AC/DC wonder, both sections were paralled and used as the input capacitor.

The single coil is wound on a surplus ceramic form approximately one inch in diameter. Roughly 40 turns of #12 center tapped. Only one output link was used. Five turns of #20 hookup wire with teflon insulation wound on one side of the center-tapped coil. One side of the link to ground. The other side of the link to coax output connector. No need for balanced output in this application but I do intend to provide for that once I get the new Z-match in a proper box with proper connectors.

Breadboard style construction with copper clad board for ground plane where needed.

After careful adjustment this brought the SWR to the amp down to 1.3:1 and improved the output power from the amp to 450 watts. That is pretty close to optimum for a pair of 572Bs. If I really push them, I can get 550 to 600 watts but you can’t tell any difference in the signal at the receive end from 450 watts, so why bother. Now, you CAN tell a difference at the receive end between 200 watts and 450 watts.

Anyone who has used a Z-match (or even an antenna tuner) knows that you can’t just crank one adjustment and then crank the other to get a match. Matching is a two handed operation where you crank both controls as quickly as possible at as low a power as possible until you see a drop in SWR. These adjustments are easier to make if the capacitors are tied to a reduction drive. In my case for this project all I had was some large knobs. No reduction drive. So I was pretty much at the mercy of the standard 180 degree rotation of the caps. Not good.

Trouble is I do not have suitable reduction drives available and no money to buy some. So, we will just have to homebrew them too. I figure I can use some salvaged potentiometer bushings to work with some short 1/4 inch shafts that can be made to drive a large disk ( like maybe a defunct CD ). A rim driven disk run from a 1/4 inch shaft should get me a 10 to 1 drive reduction easily.

Once I get this thing built and de-bugged, I will probably add it as a low power Z-match project.

Yeah, it works great for matching the TS-120 to the amp input but it probably should not be in the circuit on receive. With it in there on receive, I probably loose a whole S-unit in signal strength. Now I have to figure out a way around that one too.

Made in China

June 28, 2007

Are the Chinese even capable of manufacturing products suitable for consumption by the west. Seems each week or so we find something that came from China that is tainted, poisoned, counterfeited, or otherwise unsuitable for use. It is not just by accident that quality seems missing in Chinese products. Fact is, the problems go far beyond any quality issues. Take a look at the list below.

Poisoned pet food ingredient.
Unsafe tires
Plush toys stuffed with hazardous waste
Cough syrup made from poisonous antifreeze
Tooth paste made form poisonous antifreeze
Counterfeited drugs
Seafood tainted with cancer causing chemicals
Lead paint on children’s toys

The items on that list did not become unsuitable by accident. They were produced to be unsuitable by design. The Chinese communists seem to be waging an undeclared war on us and are sending us tainted merchandise to poison us. They are attacking us using a low grade of chemical warfare. We just sit here and wonder why while they make all the motions of showing they care.

The latest news flash is that they guarantee that their products are safe. Take another look at the list above. Is there something lost in translation or are we being played for fools?

Any more when I find something interesting, at a decent price, I check to see where is was made. If it was made in China, I put it back because there is a better than average chance that if I purchase the item, it might kill me.

What about the importers? Are they Chinese too? Why is it this junk is well on its way to the consumer before we find out it is hazardous? Why doesn’t our government take some sort of action on our behalf. Are all our politicians sitting on their collective fat asses again stressing about earmarks and re-election? If they can’t find this stuff before distribution, what chance do they have of finding a suitcase nuke?

I can see it now. A Chinese suitcase nuke disguised as five kilos of mariuna smuggled across our southern border by one of those ‘guest’ workers and placed on the whitehouse lawn. Now there is another job Americans would not do.

ATM FEES

June 25, 2007

Some not such a long time ago a certain bank ran some loud and boisterous radio commercials claiming immunity from ATM fees. Their bank customers could avoid being charged ATM fees if they submitted the receipts for credit, kept a 1000 dollar minimum balance in their accounts and met some other requirements that were lost in jibberish spouted by their fast talking lawyer at the end of the commercial.

I always view with suspicion those boisterous commercials proclaiming grand advantages for consumers. They almost always end up being some sort of scam.

Recently I began banking at Century bank. Century bank does not charge your account with ATM fees regardless of sex, gender, or account balance. You don’t need to submit receipts because they know when other banks try to stick you with an ATM fee. It shows up as an extra charge to your account when the ATM transaction clears.

Century merely takes care of that charge by NOT allowing it to be charged to your account. I am not sure how they square that with the bank that made the charges and I really don’t care. What is important is that I don’t have to pay any more ATM fees regardless of where the ATM is or who it belongs to. In addition, I do not need to do anything special to enjoy freedom from ATM fees. I just need to be a Century bank customer.

Requests for Advertizing Space

June 24, 2007

I use Akismet to take care of any spam that might be directed my way and onto the blog. Akismet is pretty efficient and about 99.9 percent effective. However, I still get one or two bits of spam a week disguised as comments to posts.

Comments to posts are welcome but must be reviewed and approved before they are posted to the blog. If I did not do that, I would have all sorts of morons competing to spam my posts. Unfortunately some people are denser than others and still try to advertize through the comment feature.

I view these as requests for advertizing space. Even if you disguise your name and falsify your email address to gain access to the commenting feature, I still get your IP address. A simple click on that IP address discloses who you are and where you originate. So you cannot really hide by submitting false information. Your IP gives you away everytime.

Having your IP address allows me to chose several options. If I wish, I can contact your ISP and request that he deal with your misuse of bandwidth. Not all ISPs are responsible enough to discourage spamers, so I can always block your IP or even the entire range of IPs assigned to your ISP.

A very creative but labor intensive remedy is to send the offender a registered letter informing him that further spam events will be considered default acceptance of an offer to provide bandwidth and storage space for that spam at a rate of $100 per occurance. Future occurances are then billed. After a number of billings go unpaid and unchallenged they are taken to small claims court where the judgement is usually against the spamer.

Or, I can offer you advertizing space on my blog.

Rates are $30 per month per ad payable through paypal. Your ad will appear in a radio button similar to the one used for paypal. Interested prospects can click on that button and it will take them to your website where you can provide more information.

We reserve the right to refuse ads for certain products and services.

Fish Dish

June 23, 2007

If you like fish, you might like this dish. It is a very economical talapia and vegetable dish. Fish, potato, and carrots all garnished with dill and garlic. Lots of garlic.

I used to think that talapia fillets were super thin. I guess the ones I bought were. Recently we bought some talapia loins at sam’s. These were about half an inch thick. More like the whitefish I like at a talapia price.

The prices were good on carrots and potatoes too. Dill is an herb and you are going to be out two or more bucks for a bit of dill. We splurged and got on the those large containers of dill.

The vegetables are baked. Line a pan with aluminum foil. Drizzle in some oil to cover the bottom of the foil. Cannola is fine. Olive is better. Slice up some garlic cloves. I know everyone says to crush them. I find slicing them thin works too. Peel one large russet potato and cut in half lengthwise. Cut one half in half lengthwise again and cut quarter inch thick slices from it. Save the other half of the potato for some other time.

Peel some carrots. Four medium sized carrots will do. Cut them into sections about two inches long. If the carrots are bigger than an inch in diameter cut them in half lengthwise.

Now put all the vegetables in the pan. You should have as many carrots as potatoes. Cover the vegetables with the thinly sliced garlic. Sprinkle everything with dill and bake in the oven at 350 degrees F for half an hour. Cover the pan with aluminum foil.

Pour a small quantity of oil into a large skillet and heat it on low. Add some thinly sliced garlic to the oil and let it heat until the garlic starts to fry. Now add the fish. Give it about five minutes per side and cook it with a lid on the skillet. Season the fish lightly with salt and pepper. Both sides. When the fish is turned over in the skillet sprinkle it with dill. One side only.

The fish could have been baked along with the vegetables. The only problem is that the vegetables need thirty minutes and the fish only takes ten minutes. I don’t care for over cooked food.

Fish and vegetables are quick and easy to fix. Everything tastes better with dill on it. This recipe serves two. Cost is about three dollars a serving and the food is every bit as good as what you would expect at a fancy thirty dollar a plate dinner.

Picture Headers for Kubrick

June 22, 2007

I like variety. The header pictures on this site rotate randomly among pictures of ham gear, vacations, and some of the QTH.

The rotator is PHP code that I found on the internet. The pictures are formed using Paint Shop Pro.

The header has a 720 by 200 format (give or take a pixel or two). You will want to preserve that aspect ratio to minimize distorting the picture.

You need to save a copy of the normal Kubrick header. Plain blue background is fine. I found my header among the files of the Kubrick theme. I was also able to get a header template by trying to use kubrickr. Kubrickr is a web based header creation utility. It requires you to upload pictures to flickr, set the tags and license data properly, then select the picture, crop the section of interest, and save the result which should be a kubrick header. This would not work for me reliably. I kept getting a blank (black) header image. It works fine for a template to be used by Paint Shop. The Paint Shop solution is faster and everything is done locally on your computer.

Call up Paint Shop and browse to the directory containing your pictures. Select a picture and crop it to the 720 by 200 aspect ratio. Save the cropped portion by going to EDIT and selecting COPY.

Now open the file containing the copy of the Kubrick header you saved earlier. Select the magic wand from the menu at the left of the screen. Move the cursor to the area inside the header and click the mouse. A dashed line should appear around the active area of the header.

With the dashed line flashing, go to the EDIT function and select PASTE, further select PASTE INTO SELECTION. Wait until the picture appears in the header. It might take a couple of seconds.

Now save the new header to a file using SAVE AS. Give it a unique name.

That is it. New header picture is ready for upload to the server.

There are probably other ways of doing this. Maybe even better ways of doing this. The method described here works for me and is easy.

Leadership

June 21, 2007

We often hear candidates for political office claim that leadership is important and they can provide all the leadership anyone could want.

Look out Nelly! Any time a politician uses the leadership card you can bet that he is up to no good.

Leadership is a commodity that gets in the way of good representation. Not only that, but most leaders are convinced that they alone have the answers. Their answers are not open to debate. They are compelled to carry out their agenda and the activities that follow may be hazardous to ordinary normal people. It is not at all unusual for such persons to belong to organizations that also think they are the answer to all of humanities woes. The one true belief. The only path to salvation. The biggest lie ever swallowed.

History is full of leaders. David Coresh was a leader. Jim Jones was a leader. There were leaders demonstrating how to deal with heretics during the Spanish inquisition. Stalin was a leader. Hitler was a leader. All of these people were leaders by the simple fact that they had a following.

No, not all leaders are evil, but why take a chance? In a representative democracy we need representatives, not leaders. Since our political representatives do not have to be leaders why take a chance at attracting someone that has a personal agenda of evil.

Facts, just the facts. Find out what the candidate claims to do if elected. Research to see if he kept his promises in the past. See if he has changed his positions on issues near and dear to your own. Has he engaged in negative ads? Is he claiming to be a leader?

If a candidate cannot be trusted, is wishy washy on the issues, attacks his opponents instead of the issues, makes unsubstantiated claims of leadership, such a person is not fit for political office.

Of course we are all aware of those factors. Some of us may not be aware of how senseless claims of leadership really are. Strong leadership qualities benefit despots and dictators. Leadership qualities are not desired or useful in a democratic environment because they have potential to endanger the freedoms we hold dear.

Look at the most recent history. The history after WWII. Nearly all of the politicians who claimed to be leaders, lead us into adversity and harm. These so called leaders have grown government beyond all reason. It has become a nanny to the people. An nagging spiteful entity that is more interested in dictating every detail of our lives than helping us live in the freedom we desire. Expecting us to serve it instead of the other way round. As old offices of this dysfunctional governing body fail, they linger on and on, sucking up tax dollars while new offices are created to take care of the failures of the old. Yet only seem to promise even greater failures in the future.

We do not need leaders. We need representatives who can be trusted.

So when you hear some politician claiming to be a leader, show him how much you understand and appreciate his foolishness by voting for someone else.

Unfortunately it is becoming more and more clear that there may not be anyone else. At least no one who qualifies to past standards that seem to have disappeared overnight.