Archive for January 2007

Another All Band Vertical

January 31, 2007

Some time ago I realized that I could make a multiband vertical by simply taking half of my 80/40 meter trap dipole and turning it on end.

There is another way to do this by using a tapped, switched, loading coil at the base.

I recently saw a design that covered four bands with a 27 foot vertical radiator. A quarter wavelength on 40 meters is 33 feet. That 27 feet is a mite short for a quarter wavelength on 40 but add a little inductance and you have a quarter wave resonant radiator for 40 meters

With considerably more inductance you can force the thing to be an electrical quarter wavelength on 80 meters.

Other bands can be covered by forcing them to be resonant as 3/4 wavelength and 1/2 wavelength radiators on the bands of interest.

The main difference in utility between the trap vertical and this is the need to change taps on the coil for this design. A trap vertical will cover multiple bands without need for tap changes.

There is also a large functional difference between the two designs. In a trap vertical, each trap acts as an automatic switch disconnecting sections of the antenna that are not needed at the higher frequencies. For instance, a trap vertical will disconnect all but about an 8 foot section to obtain resonance on 10 meters. When you consider that the live section remaining might only be a few feet above ground, you may well fear some problems getting the smaller antenna to radiate effectively.

By using 3/4 wavelength and 1/2 wavelength sections you use more of the the full length of the vertical. It has always been assumed if not written that an effective antenna presents as much metal as high as possible into the sky.

The disadvantage of having to change taps can be solved by providing a remote switch to do the job.

One additional factor to consider is bandwidth.  The higher frequency bands usually have plenty of bandwidth, but the lower frequency bands ten to suffer with bandwidths as low as 100khz on 40 and 50khz on 80.

This situation can be improved by not trying to cover all bands with traps.  A dual band, 80/40 meter antenna using a pair of traps will have a bandwidth more than twice what was quoted above.  Better but still not capable of covering the entire band on 80 meters.

Depending on your operating habits, there may not be any need to improve bandwidth.  Just center what bandwidth you have on the frequency that interests you.

Potato Chips

January 25, 2007

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Want to make some potato chips? I guess the million dollar question is why? So much easier to buy them. True, but if you don’t want or can’t go to the store right now, here is a way to get your chips without leaving the house.

Of course you will need to already have at least one potato and some cooking oil. Might help to have a deep fat fryer too.

I first hit upon this idea while peeling some potatoes. The potato peeler I use is a popular one. It cuts very thin slices. Thin slices prefect for making crispy potato chips.

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Pictured here is one potato reduced to chips with the potato peeler.

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Cook them a few at a time. I put enough in to just cover the bottom of the basket.

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Bubbling away as they cook. Don’t leave them unattended. Takes about 3 mins or so to get them crispy. Stir them with a fork or spoon while they are frying to keep them from sticking together .

I used one potato. Took three batches to cook the entire potato.

Doneness was judged by color. Black is crispy too but golden brown tastes better. They stay white for a long time before turning brown, but when they turn, they do so very quickly and need to be removed from the oil immediately.

I don’t use a thermometer. I don’t have one. I just heat the oil on high heat to the point where the food fries with vigerous bubbles as it cooks.

It turned out pretty well. They stayed crispy until supper. They probably would have stayed crispy longer but we ate them all at supper time.

All Band Antenna Solution

January 23, 2007

After kicking this subject around for decades, I have finally decided on the best solution for my purposes.

I already have a multiband beam which covers 20, 15, and 10 meters. All I really need now is a multiband dipole (inverted-vee) for 80, 75, 40, and 30 meters.

Since I already have the 40 meter traps, all I need to build is the 30 meter traps to cover that additional band.

It is going to be a cloud burner on 80 and 75 because the apex is only going to be about 50 feet high, but on 40 it might do better and it will be close to a flattop dipole on 30 at a decent height.

My only concern is that the bandwidth will suffer because of the traps. Then that is no big deal. I don’t do much frequency hopping now and don’t intend to change my operating habits.

Although I am not considering the remaining two WARC bands at all for now, it will be possible to include them in a two band beam mounted on the second mast which now holds a vertical antenna.

Or, I might just modify the 40 meter vertical to cover those two bands.

FireWalls

January 22, 2007

If you are sufficiently computer literate to get on the internet, you probably already know what firewalls are supposed to do and why they are called firewalls. However you may not understand how they are best installed and used.

I often hear the computer novice claim that his router has a firewall that is fully operational and protects his computer. It is not until he answers a few questions about how it got installed that he discovers he is not as well protected as he thought.

When you consider firewall installation and setup, the novice nearly always is daunted by the need for a list of all the IP addresses and services that should be blocked. This is a backwards approach. You don’t block unwanted IPs and unneeded services. You block everything. Then you enable IPs and services on an ‘as-needed’ basis. How can you tell something is needed? Well, one way is to launch your program that needs external access. If it works, all is well (maybe). If it does not work, then it may require an address or port be allowed to pass through the firewall.

Even that is a rather tough way to set up your firewall. It is better than researching for all the addresses and services that need to be blocked, but it requires a good knowledge of your application software and its requirements to create access through the firewall for a specific purpose.

It would be nice to have a program that identifies application software seeking external access. I use Tiny Personal Firewall to do that.

Tiny Personal Firewall is a program that runs in the background under windows and identifies and alerts when application programs attempt to gain external access. There are other programs like Tiny Personal Firewall that provide a similar function but I am only familiar with Tiny.

As with all good firewall installations, the Tiny installation blocks everything initially. Then, as applications make themselves known, the firewall allows you to grant access either one time or permanent and allows you to customize the access as well.

I consider programs like Tiny Personal Firewall to be an important part of a complete firewall. They take care of programs that try to call home.

I would also recommend the use of Ad-Aware to clean out software that is adware.

More good information on firewalls and firewall testing can be found here

Aging

January 19, 2007

Well, it is official now. I never thought I would see this day. For some reason a 20 year period in the 60’s seems to be much longer than the same period in todays time. I am not sure why the long, dim, past appears expanded while the more recent past seems compressed, but I do know where that old people smell is coming from now. It is coming from me.

Funny, seems only yesterday it was coming from the old folks we used to visit. You don’t suppose it was something we caught from them??!!

The Rest of the Story

January 19, 2007

I have finally become convinced that what you hear, read, see on any media source could very well be misleading, in error, or complete nonsense.  This is especially true if the tale is full of emotion eliciting details and/or lacking those details.

Some of these attempts at deception indict themselves.  For instance, any story that begins with ‘what would Jesus do’ immediately tells us it has been crafted by an unholy blasphemer on a slide to hell who is searching for company on the way down.

Others may not be so easily recognized.

This morning I listened to a story regarding a man flying the american flag on a newly installed flagpole.  He was being fined 1200 dollars a day for not complying with the local statutes regarding flag flying.

His claim was that he was being persecuted for being a patriot flying a flag.

The rest of the story is that he is actually a moronic lawbreaker flying a flag from an 80 foot flagpole when the safety ordinance only allows flagpoles of 40 foot maximum height.

There appear to be lots of reports of this type throughout the media.  Half truths were only one aspect of the story is revealed.  In otherwords, propaganda.

So, beware.  Just because you hear something outrageous on your favorite talk show does not mean the outrage is warranted. Could be the only thing outrageous is the talk show host himself.

PSK31

January 17, 2007

Phase Shift Keying, thirty-one style, came out some time ago. Shortly after it appeared, I began using it.  The requirements were PCs running DOS or Windows and using sound cards as a poor mans dsp. One application I had used a real dsp. A TI 50dsp thing that used a DOS driver to develop the signals.

PSK31 is different from other phase shift keying systems in that it is a very narrow shift. That allows it to fit into a very small spectrum giving it a very good signal to noise factor, making it a very reliable means of communication. You do not need much power, much antenna, or much patience to work lots and lots of good DX when using PSK.

Perhaps that is why I became bored with it very quickly. No challenge.

A few days ago I decided to see if my PSK setup was still usable. It was. Had a 30 minute chat with a ham in Tucson around noon.

My standard setup is an ICOM-737, homemade sound card interface, athlon +1800 computer running windowsXP and Digipan 2.0. With that setup the QSO worked flawlessly for about 25 minutes before XP locked up with that stupid screen asking if I wanted to send a note to its maker so it could report how screwed up XP was. Honestly, if I had known what a nuisance XP was going to be I would never have tried it.

I never had any Linux distribution lock up like that. So I decided to try Linux.

Having already had considerable success with Debian-Etch, KDE 3.5, and a few multimedia applications I decided to use that same setup and see if I could get KPSK working. It took the better part of an afternoon to get it to work right but it does work once the alsa mixer is setup correctly and all the right setup and configuration files are complete.

KPSK looks very much like the old version of Digipan. Same sort of display as old Digipan but KPSK can copy four QSOs at the same time. Now, new Digipan 2.0 can copy 26 plus QSO’s at the same time but it has a tendancy to lock up on my computer. I figured that four QSO’s and no lockup was better than all the QSO’s on the band if the thing locked up.

So now I am running Linux and KPSK on one machine.