Radio W4KAZ

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Revised W7IUV Preamp

Sometimes procrastination pays off. On W7IUV’s web site, he has a link to his “W7IUV preamp”. The document was revised a few months ago, and it includes schematics and parts lists for both versions, as well as a general discussion on the preamp. It appears that no suitable surface mount parts were found to replace the transistor.

Not like I want to play with surface mount components anyway.

Small Parts List

Some suitable and inexpensive parts for future projects. A continuing aggregated list of Stuff I Use To Play Radio.

Small signal DPDT relay: (For K9AY et al, & 12v control switching) Axicom V23105A5003A201 ??AZ822-2C-12DSE?? Data Sheet C934/MT2 Relay Series(200mw coil, DPDT, 12v) TYCO MT2 Series #3-1462000-7 (12v, 1.5A DPDT) Omron SPST…..omron-g6e-134p data sheet. Panasonic TQ2-12v (also a latching version, tq2-l-12v) TX Antenna switch relays: P&B RTB14012F(SPDT, 12A), RTD14012F(SPDT, 16A) P&B RT424012F(DPDT), P&B RTE24012F(DPDT) AZ755-1C-12DE(SPDT)American Zettler power relay for KK1L & KOxxx projects – AZ755 Data Sheet note: The Zettler and P&B DPDT relays are interchangeable(pin layout compatible) if the power ratings are sufficient for your application and both poles of the P&B are tied together and used as an SPDT[i.e., for the KK1L 6×2 switch project] Fujitsu, VSB12STB SPDT, 12V, 16A(data sheet marked “to be discontinued” (??replacement??) ?? SRUDH-SH-112D1,000 ?? ??OMI-SH-112L,394?? cd4028: Logic chip for band decoder to drive 2n2222 or 4401 lm3914( Obsolete?): DL6RAI BevBox – Logic chip for resistance driven switch, drives pnp(part#?) Panasonic capacitors(data sheet on 1/1/2010) from NVARC project. Many RF uses. (Digikey part) Capacitors: ????CDE DPPM16D1K-F ???? ????TDK CK45-R3AD102K-NR???? ???? Murata DEBB33F102KA3B???? Toroid King – Iron powder and ferrite toroids, W3NQN toroid kit Kelvin – Loads of cool hobby stuff Toroid core, type 75 material, Digikey #240-2524-ND (Steward) TDK clamp-on ferrite(11mm fits RG-8/RG-11), TDK data sheet, Mouser#810-ZCAT2132-1130BK Velleman 8 channel relay card kit, with rs-232 programmed PIC McMaster-Carr, coil form edge trim, pn 85085K8 (also bare copper wire, pn 8873K51) Dry Box, MCM Dri-box […]

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Recycled Radials

Finally figured out what to do with burnt out strands of Christmas lights. Scavenged about 100 ft of wire in 20-25 foot long hunks and used it to augment the radial system on the K9AY.

The K9AY RX antenna itself is in need of replacement. It is constructed of 18ga wire, and has had several breaks in the past couple of years. Right now it has five or six splices where repairs were made. Probably time to replace it with 14ga THHN, now that copper prices are down again. A 500ft spool of 14ga stranded THHN housing wire was $35.00USD yesterday at the local BigBox retailer.

Time to stockpile before hyperinflation kicks in?

Flotsam and Jetsam

These items washed ashore on the most recent web surf. Not really related to anything I generallylog regarding the KazShack activities, but some of it caught my interest enough to save the links here rather than get lost in the BookMarkMultiverse.

A useful chart of the evolution of storage. It unfortunately omits Hollerith punch cards,cassette storage, the 8 inch floppy, tape drives, or the old mainframe removable spindle drives. Gotta draw the line somewhere.

This is just plain cool, and its available as a kit. The LED Bulbdial Shadow Clock from EvilMadScience. Way cool.

These would just be fun to slap on a jewel case of any program. Originally issued for Vista I suppose, but fun to slap on the kid’s PC games – just to see if they react. Be great back on the floor of tech weenie cubicals too.

DAMN! Somebody stole another one of my ideas. Well, OK, I suppose they arrived at the same mental junction independently, but if I still had access to a welder, I’d have made some already.

Empirical Evidence On Longevity Of Bare AL Radials

Finishing up on the yearly mess of litter generated by the biological antenna supports was much more painful this year[literally]. The wet weather makes dragging large quantities of sopping wet leaves a real chore. Messy too. Using a leaf blower here is equivalet to bailing the Titanic with a teaspoon. Futile. The massive quantity ofvegetative miscreants combined with a gentle uphill slope renders the leaf blower useful only for clearing small areas. Maybe a chainsaw…..

During the process, two of the radials on the K9AY were “discovered” to be broken. [Ooops!] The radials were simple 17 ga. AL electric fence wire, purchased for a pittance in 1/4 mile quantities from the local farm supply. These radials were in direct contact with the soil. Soil testing a few years back showed the PH to be about 5, slightly acidic. No real idea of the chemical/mineral content, which I expectis probably a bigger factor than the acidity.

These radials have been in place for about four years. I broke both of them while raking leaves. A closer examination showed that the portions of the wire in direct contact had become quite brittle. It took little pressure to break them this year, although they withstood similar abuse over the past three seasons. A closer look showed the aluminum to be getting flaky in spots, and it had zero ductility. Even an easy bend was enough to break the wire in those areas of heavy oxidation.

Not too shocking a discovery, but worth documenting. […]

Continue reading Empirical Evidence On Longevity Of Bare AL Radials

Seeing Spots – Cycle 24

This is a few days old, but a link from G3XBM blog sent me over to the current sunspot and 10.7cm flux projections for the next five years.

It looks like high end projection nowtops out at about 100. Based oncomparisons with the last cycle toreported contest scores, we can expect better 10m activity with sunspot numbers over about 60. That’s not to say there will be zilch before then, or that a flux associated with the 60 spot count will guarantee band openings. We won’t cross the 50 number in the projections before the end of next year. [Hopefully.]

It also looks like 15m propagation should show improvements with only a moderately slight improvement in the solar activity. YipppEEEEE! That could mean Field Day 2010 would be more interesting if 15m activity can be increased.

O’course, projections arereally just guesses – cuz no one really knows enough yet to make a high confidence level prediction. Maybe in a couple more centuries of observation and computer modeling, but not today.

I’ve always favored the lower sunspot numberprojection, but was hoping I was wrong. But like the great big ball-o-fire itself, nothing is set in stone.

Additional ‘stuff’.

VE3EN’s solarcycle24 website. NW7US’s radio propagation website.

Web Cheat Sheets

A nice compilation of links to handy cheat sheets.

Amazing Scale Models

A local friend copied me on this in an email. Its not radio, but since I have always had a fascination with WWII vintage aircraft, and it is hard not to be impressed at the level of craftsmanship required to produce these scale models by Mr. Young Park. It is beautiful detail work, and I’m glad the photos and story are available.

2009 ARRL 160m

Got a chance to work on the matching network for the inverted-L, adding in series capacitance, a choke, and balun. This gave me a good match at about 1840, and the SWR was decent from 1815 up to about 1860. The results seemed to be an improvement in the chances of being heard by most stations. That’s with just 100w. Decent results, given the low power and inefficient antenna.

Got in three really nice runs. The first was disrupted by another station sliding in. That was annoying, because the 10 minute rate was up over 100. After I moved, I settled into a nice 40 minute run that finally pooped out of its own.

There was only a limited amount of time available, so the periods from 2300 local “until” were chosen from both evenings. There seemed a whole lot less activity on Saturday evening. Logged about 3 hours and 130 Q’s Friday night but only 2 hours and 70 Q’s Saturday.

Found KH6ZM working a big pile-up on Friday night. Listened to that for a while, but I only heard him work a couple of east coast stations. The west coast and mid-west were pretty thick, so I didn’t waste time. Tuning up the band I found HI3 calling with no pile-up. Also worked a G3 and a few Caribbean stations.

The K9AY made the difference on several Q’s. The noise wasn’t bad, but There were a couple of relatively weak stations that really peaked on the K9AY but […]

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Seeing Spots – Cycle 24 On The Brink

Well, I knew it had been pretty dull, but I didn’t realize 2009 was getting ready to equal 2008 as “crappiest year for 10M ever”. But it looks like 2009 is on track for earning that dubious distinction. Only five more spotless days required.

O’course, that article is two days old, so I suspect we are down to three……and counting.