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More “Cheap Yagi” construction notes: push nuts

March 6th, 2011

As I have mentioned in previous posts, I am a fan of the WA5VJB “Cheap Yagis” as described by W0FMS.  One of the construction techniques W0FMS describes is the use of a “push nut” to secure elements to the boom.  I bought some push nuts from McMaster last week.  Since Mom and Dad were in town over the weekend, I took the opportunity brainstorm with Dad about methods and mechanisms for installing the push nuts.  McMaster would have happily sold me a tool for $60, but as usual, I was feeling thrifty.

And, this is what a push nut is.  They come in various sizes.  These are for 1/8-inch shafts (McMaster part number 94807A024).

Here is a jig with an oversized (3/16-inch hole) for installing push nuts:

With a push nut fitted:

Dad demonstrates operation of the jig (why yes, those are tower sections in the background):

Demonstrating how to do the other side, notice that the installed (top) push nut works as a positive stop:

And, a (nearly) finished 10-element Yagi for 903 MHz:

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Triple Play / LoTW status

March 3rd, 2011

Happily, Sarah returned from Texas last night.  You don’t always know how much you miss your spouse until they’re not around.  But, she (and the baby—we’re expecting in July—very excited) is (are) home again!

She also brought the Trusted QSL-containing MacBook home safely and I uploaded my RTTY log to LoTW.  Got a whole bunch of matches!  So, the Triple Play award from the Maryland QTH is indeed coming along nicely:  CW 50/50 – PH 34/50 – DG 29/50.  Lots of easy ones still needed.  Also have 31/50 states on 160 (lacking easy confs like VA, for instance?!).  It’s also amusing to have more states on 2 meters than 15 meters.  I guess I should spend some time on the high bands. 🙂

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RYRYRY O RLY?

February 27th, 2011

A few readers of this blog may have been surprised to contact me on a new mode last night…RTTY.  I’ve tried radioteletype once before in the past (also in the NAQP contest) but rather unsuccessfully the first time.  The second outing was a bit better.  I suppose with practice it becomes fun, but the primary motivation here is ARRL’s Triple Play award for contacting all 50 states each three times, using CW, SSB, and digital.  CW was, of course, easy.  And, I’m making good progress on the SSB totals.  So, I figured I would stop putting RTTY off and give it a shot.

As you are probably well familiar, I normally contest with two TS-930s.  Their prior owners (who were CW contest/DX types like myself) made various “improvements” to them, most of which I appreciate, but I have no idea how they affect FSK. One radio simply does not work on FSK (need to look into this) and the other has the passband shifted about 50-100 Hz off-center of the normal RTTY frequencies. So, when I was running AFC in MMTTY, it would “walk” to the point that having a lock on the other station would put me at the edge of their passband. I had a terrible time making QSOs for the first hour until K0TI told me I was off-frequency (thanks, Dan!!!) and then I started paying attention to all of the numbers in MMTTY and turned off the AFC, which had some deleterious effects that I overcame thanks to the occasional repeat. Typical analog op becomes digital lid op.

I sent the MacBook (our “home” computer) with Sarah to a conference yesterday.  Since that’s the only place I have LoTW’s Trusted QSL installed and I failed to export a .p12 file, I’ll have to hold tight for a couple of days until they return.  (This is not entirely true, I have an old .p12 file, but I haven’t backed it up again since I renewed the certificate a few weeks ago.  Bad backup practices…although I just got a new external drive so the old drive can be used to do a Time Machine back up…finally.  Another day, another project.)

This post mostly mirrors my 3830 post, but here are the numbers for the curious.  My grepping missed one QSO on 80 meters when I did the totals (N1MM rounded the frequency up to 3600 kHz) for 3830.  So, these numbers are right, aside from log-checking discounts:

Call: K8GU
Operator(s): K8GU
Station: K8GU

Class: Single Op LP
QTH: MD
Operating Time (hrs): ~3

Summary:
 Band  QSOs  Mults
-------------------
   80:   37    21
   40:   58    27
   20:   35    18
   15:
   10:
-------------------
Total:  130    66  Total Score = 8,580

Club: Potomac Valley Radio Club

Team: PVRC #1

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Wallops Island SuperDARN

February 21st, 2011

A few photographs from work on the Wallops Island SuperDARN radar last week…

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NA Sprints, ARRL DX, and other notes

February 21st, 2011

February, like November, is a busy month for contesting:  the CW edition of the NA Sprint leads off the month (along with the Minnesota QSO Party), followed by the phone edition of the NA Sprint the second weekend, and of course, the ARRL DX CW contest on the third weekend.

In short…

NA Sprint CW SO-LP:  claimed 162 x 38 = 6156, preliminary 158 x 38 = 6004.  Four busted QSOs is actually better than I felt at the end.  So, that is good.  Still not happy with the numbers, though.

NA Sprint Phone SO-LP:  claimed 28 x 16 = 448 in 1 hour operating time.  As KE3X told me, his NS score was higher that week!  The phone Sprint is more fun from a bigger station, but really suffers from lack of participation.

ARRL DX SOAB-LP:  claimed 544 x 243 = 396,576 in 14 hours.  This should have been a bit better, but I got sucked into trying to make myself heard in EU on 160 before their sunrise.  Killed almost 60 minutes on 15 QSOs there.  Also only operated about 1-2 hours during prime EU time on each of Sat/Sun morning.  Efforts at getting a run started were a complete failure.  Need. More. Firepower. I was very pleased to work ZM1A on 10 meters, though.

Other notes…

After 17ish years of amateur radio, I finally installed my first 30-meter antenna—a dipole at 35ish feet.  First QSO was ST2AR, so I guess it’s working alright.

A box full of goodies arrived from Down East Microwave this week and I started working on buttoning up the 1296-MHz W1GHZ transverter.  Massive thanks to Ben, N3UM, who lives nearby for sharing his construction notes with me.  Not too far along other than punching and tapping a few holes in a diecast box.  The DEMI box also included a couple of LNA boards that I hope to tune up for 432.

High winds (90 km/h gusts, according the forecast) from Friday night through Saturday night did not manage to topple my FO12 and A50-3S from their perch on the chimney.  I haven’t checked the rotator to see if they still turn, though.  This antenna situation needs to change eventually.

Finally, I also managed to score about 250 feet of RG-213 and 10 feet of LMR-600 from a dumpster-diving excursion.  The LMR will make nice jumpers from the 903 and 1296 transverters to their respective antennas and I can use the RG-213 to replace the RG-8X on some of my HF antennas.

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CQ 160 CW

January 31st, 2011

We got a dose of Mid-Atlantic winter weather last week—that once or twice a year event that is too much for the utilities and drivers to handle.  Snow, sleet, freezing rain, and rain arrived on Wednesday.  Power was out from 2030 LT to 0200 LT on Wednesday night/Thursday morning and then again from 1600 LT on Thursday to around 1100 LT on Friday.  So, I didn’t get to operate NS this week on account of no power!  I did think of going out to the car, but I was too wiped out and cold from the furnace blower being off.  I just wanted to crawl under a big pile of blankets and sleep until the electricity came back on.  As I have mentioned before, I grew up in an area with many Amish.  A coworker many years ago was teasing me about finding an Amish girlfriend.  I responded by asking him how an electrical engineer would fare in a society dedicated to not using electricity.  He had to agree, although the Amish have rather ingenious mechanisms for harnessing electricity to do their work.  But, as usual, I digress—we’re slightly dependent on electricity in ways we probably should not be!

I like contesting on 160 meters (1.8 MHz).  When you call CQ, you are usually rewarded with blistering rate from loud stateside stations.  When you’re tuning up and down the band, weak DX stations pop out from between said loud stateside stations.  Now that I have something resembling a 160-meter antenna, I gave the CQ 160 CW contest a shot after some friends left on Saturday night.  Another nice thing was that the station is working well enough (with the exception of the K9AY relays and possibly directivity) that I could just walk into the shack and operate.

So, that’s what I did…  Only worked a handful of Europeans, but that’s not too surprising.  They were loud here, even with 10 dB of attenuation in line to reduce IMD from really loud local stations.  There were numerous other European stations that I could hear (on the TX antenna) but was unable to raise.  But, in about four hours (three in the CQ 160 and one in the NAQP) of operating on Topband, I have only the hard states left for WAS from this QTH:  ID, SD, ND, WY, AK, HI.  I’m waiting for the LoTW confirmations to start showing up!

                    CQ 160-Meter Contest, CW

Call: K8GU
Operator(s): K8GU
Station: K8GU

Class: Single Op LP
QTH: MD
Operating Time (hrs): 3

Summary:
Total:  QSOs = 182  State/Prov = 48  Countries = 8  Total Score = 25,984

Club: Potomac Valley Radio Club

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ARRL January VHF Sweepstakes

January 31st, 2011

Last weekend (two weekends ago now), Sarah was out of town with friends from college, so I was free to meander in and out of the shack at will.  Between making QSOs on 2 meters, I got a “modern” computer set up for SDR.  More on this in the future.  Was pleased to make some QSOs into New England with the “$200 VHF station” that consists of the TS-700S, Mirage B3016G amplifier, and homebrew FO12 antenna.  Nevermind that the Pro-Set, Bencher, and Keyer cost at least that much again.

Still working on getting the other bands going.  50 MHz is very close, although with the recent sale of some extra gear, a K3 is almost within striking distance if I sold one the of the TS-930s.  One of the locals has offered to lend me his FT-736R to get on 222 and 432 for now.  So, I think I’ll try to finish up the 50-MHz transverter and pick up the ‘736 while working on the antenna situation for those bands.  I’m going to have to change the rotor/mast situation to do that.  Not sure how that will go…I may just duplicate a “rover mast” and accept whatever sacrifice is introduced by stacking the beams too close together.

                    ARRL January VHF Sweepstakes

Call: K8GU
Operator(s): K8GU
Station: K8GU

Class: Single Op LP
QTH: FM19la
Operating Time (hrs): 

Summary:
 Band  QSOs  Mults
-------------------
    6:
    2:  44     15
  222:
  432:
  903:
  1.2:
  2.3:
  3.4:
  5.7:
  10G:
  24G:
-------------------
Total:  44     15  Total Score = 660

Club: Potomac Valley Radio Club

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Ice Snake

January 27th, 2011

More ice formation on the car—this time on the helical windings of my 40-meter mobile antenna.  That ought to tell us something about the structure of ice.

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W7IUV preamplifier

January 20th, 2011

An evening project:  W7IUV low-band receive preamplifier.  Total cost:  < $10.  Total time:  1 hour.

It worked pretty well on 80 and 160 with the crossed K9AYs.  The 48-volt relays in the box at the antennas are sticking (thanks to using a 40-volt PSU).  I need to rebuild this with lower-voltage relays or a higher-voltage power supply.

W7IUV claims that he just leaves his connected to his RX port all the time.  But, he probably has more spacing between his TX and RX antennas than I do.  It will be interesting to see if I get enough RF coupled from my TX antennas to destroy the transistor.

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SoftRocks

January 15th, 2011

Finally got all of the SoftRock downconverters here enclosed and repaired.  Turns out I managed to cross two of the wires on the input transformer of my 20-meter v6.2 Lite (“upgraded” variant).  Once I found that, it sprung to life.  The other project was getting the 144-MHz Ensemble II VHF into an enclosure.  This has been a long-standing struggle since the nearest size diecast box is just a hair too small.  So, I put it into an extruded aluminum enclosure I found at Dayton a few years ago.  Unfortunately, I had to make my own front and rear panels.  But, I had an old minibox that was perfect for the donor material.

I should have polished the edges of the front and rear panels, but it’s not too bad.  KK7B opined in a QST article many years ago that after homebrewing “about 50 enclosures, they start to look respectable.”

Holes were punched with a hand punch from Harbor Freight.  Given the cost of the Roper-Whitney equivalent and for as much as I will use it, this is perfectly acceptable.  There’s nothing like having the right tool for the job!  However, mine came with two 5/16-inch punches (no 1/4-inch), but one each 1/4-inch and 5/16-inch die.  Ooops.  VFBBYQC.  So, I had to drill the 1/4-inch LED hole.  A nibbling tool made quick work of the USB cut-out.  I cut the panels with hand shears.  So, I guess it should be clear what’s next on my sheetmetal shopping list…

Now, I need to actually play with some “real” SDR instead of just diddling around with Rocky (which is very capable).  I’m running it under Windows XP on a 1.3 GHz Pentium IV with 1 GB of RAM.  The sound card is a Creative Labs Audigy 2 ZS.  There is a little latency when running a large waterfall and resizing windows, but it’s adequate for tinkering.  Eventually, I’d like to try some of the GNU/Linux SDR engines.  But, I’m just going to wait until a new (to me) computer falls into my lap before that happens.

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