Radio W4KAZ

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Warming Up For Sweepstakes

Time to read the rules for 2008 Sweepstakes.This is the 75th anniversary of Sweepstakes, so be sure to page all the way down to the bottom of the rules to see the ARRL special goodies.

Just in case a long sting of contesting gives you a case of “Butt-in-chair-syndrome”, there is now a solution available.

The annual update of the Sweepstakes Tips and Tweaks is also under way.

BPFF – Untangling the Web – Part 2

So, lots of interesting material to read through listed in BPFF Part 1, and much of it is available via the internet. Catch the whole series of w4kaz band pass filter musings.

This project is not really new for me but just something that was recently underscored by recent operations. Deciding which projects to tackle became a matter of choosing those that I thought are ‘possible’. For these purposes ‘possible’ is defined as

the parts or substitutes are readily available the construction appears simple enough for clumsy fingers the final tuning is simple

These criteria knocked out the W3NQN filter and the N1AL because I thought tuning the multi-filar toroidal inductors would be enough to exceed my level of patience. The W3NQN design is well recommended functionally, I just thought the tuning procedures were going to prove too difficult. As a side note, the Toroid King sells a kit of the required toroids for the W3NQN filter, and the DL2BNU article describes a method of tuning that is simpler than using a VNA (that I don’t have). The N1AL design bothers me because of the taps on the multi turn inductor and the trial and error tuning. The ARRL sidebar on the N1AL project is interesting, stating that the filters interact to give nulls on the even harmonics. Curious.

A couple of years back, I built the K4VX filters. That project is relatively simple. Tuning can be done with an MFJ antenna analyzer or using a grid dip method. My […]

Continue reading BPFF – Untangling the Web – Part 2

Yeah Baby

N4YDU passed on this link to pile-up audio from D4C. Sounds like fun. Its a pile up from 2001, back when DX was being propagated via an ionized atmosphere, all courtesy of the brightest star in the daytime sky.

Break out the contest gris-gris….Hope springs eternal.

Hard Sky – Fifty Years Later

Interesting that the “Hard Sky” of 1958 coincided with the creation of the first working integrated circuit. While “dumpster diving” in the vastness of the newly available QST archive, I ran across “After Sunpots, What” by W6NLZ (ARRL members only). There has been an additional 50 years of observations since then, but it is an interesting perspective on which to becomeacquainted.

This bottomless pit of QST history is pretty interesting too.

Band Pass Filter Fever – The Tangled Web – Part 1

Amended 3/25/2012: Again – re-Fixed broken links, added new links for VK4EMM and KG4JJH reference material

———————————— Begin original Post ————————————-

On occasion I’ve noticed I have a tendency to get wrapped up in an idea I can’t shake. Obsessed might be a close description despite the negative connotations. It’s not quite an obsessive mania, nor is it complete fixation. Perhaps fascination is closer to the truth. A “passionate fascination” sure sounds better than “obsession”. Not much difference semantically, but there it is.

Oddly enough, the most recent subject of interest is band pass filters for HF. (Reeks of geek, no?) Conjured by both this year’s(2008) Field Day and the IOTA operations, it is something I became interested in out of need. Commercial filters are available. It also seems that it is still possible to home brew decent band pass filters for relatively low costs. There are several designs widely available. Using coaxial stubs is also an option.

Homebrew is more fun, and in this case, possibly even less expensive. The difficult part of the problem for me is a simple method for tuning the filters. I don’t have access to a lot of test equipment. Also, some of the designs are easier to build than others. Selecting appropriate parts is also a bit of a problem in some cases.

Ideally, a good band pass filter will have a low insertion loss over the pass band, and a high level of rejection outside the pass band. I’m no […]

Continue reading Band Pass Filter Fever – The Tangled Web – Part 1

50 Years of IC

This collection of ones and zeros brought to you courtesy of IC’s, 50 years young. Not to mention all of the other wiz-bang gadgets….. like modern radios!

Shelby 2008

Well, the new site for the Shelby hamfest has possibilities, but it seems many of the normal indoor vendorsabandonedthe fest this year. I don’t know if it was due to limited indoor area, or just a convenient time for them to hit the exits, but that’s how it appeared to me.

The outdoor flea market was still well attended, and that was after a several day period of heavy rains. The rain must have given some folks pause, because the flea was spread out over a lot of area, mostly grassy fields. But I was happy to see so many had come out anyway. Hopefully the larger vendors will come back too – even in a reduced form after a forced relocation, it is still one of the better ham fests locally. It will be nice if it can build back up to its previous level. Perhaps they will better luck with the weather next year.