Posts Tagged ‘money eater’

New Radio Thoughts

November 19th, 2012

As I mentioned in a previous post about my trip to the Aleutians, I am the owner of a new radio.  The reasons for the purchase were manifold, but driven by a fundamental shift in the way I view my operating (and living) philosophy.  I had long (at least 10 years) been collecting gear for a two- (or three-) tower contest station.  In this philosophy, the emphasis was on collecting antennas and towers as they became available on attractive terms.  It also meant keeping the inexpensive but well-performing pair of TS-930S HF transceivers for my SO2R setup and the FT-840 for my portable operations.  You can imagine from those past few sentences of description alone that this consumed a non-trivial amount of space and time.

Sarah began subtly hinting that “wouldn’t it be nice if we could clean up that pile of tower on the patio so we could have people over?”  My parents have been slowly migrating my junkbox from their place to ours.  It became increasingly clear to me that as long as we lived in this area it would be unlikely that I would put up the towers.  I started contemplating how to remedy this situation.  I identified a large collection of gear (including the Rohn 45 on the patio) that 1) could be replaced by a new radio, 2) I was not using, or 3) for which I simply did not have a plan.  So, I set out with the following theme to find a new rig:

Excellence in portable operation and competence at home.

I considered four radios:  Ten-Tec Eagle, Kenwood TS-590S, Elecraft K2/100, Elecraft K3/100.

I was strongly considering the K2/100 initially.  Its size and price seemed attractive.  However, when I did the math on what configuration I wanted, it basically ended up a draw with the Kenwood and the Ten-Tec with only a small bump more to the K3/100.  Plus, I’ve built enough kits to know that many of life’s most rewarding tasks tend to look better in the past than they do in the future.  Personal preference, of course!

The Kenwood TS-590S is acclaimed by a number of contesters as “the poor man’s K3.”  It has very similar features and performance numbers at a very attractive price.  I have always enjoyed Kenwoods as well.  But, the one thing that ultimately killed the TS-590S and the Ten-Tec Eagle was their lack of BCD band-data outputs.  The K3 also offered the 2-meter option, IF output (for panadapters), and very easy transverter interfacing.  It was really a no-brainer for me at that point since I had sold off enough gear to cover the cost entirely.

I bought the K3 kit and assembled it.  Anomalies notwithstanding, it amuses me greatly when people announce to the Elecraft e-mail list that “K3 #7777 is on the air”…it’s hard to keep from responding, “Congratulations on assembling your first LEGO kit.”  Unlike the K2, these “modular-kit” radios are very easy to assemble if you have a few hand tools and can follow basic directions.

My friend Oli, DJ9AO, informally asked me to compare the K3 to the TS-930S.  I’ve tested (subjectively) the K3 in a couple of demanding environments and I’m pleased to say that the K3 performed well, even with essentially “factory default” settings.

The K3 wins hands-down the strong-signal handling contest, even with the Inrad roofing filter in the TS-930S.  40 meters in ARRL Sweepstakes CW is a good test for this.  The FT-840 used to have severe mixing products (“beeps and bloops”).  These are not common with the TS-930S, but severe AGC pumping from nearby signals often covered up weaker signals.  Neither of these are problems with the K3.  In fact, the K3 is so good that you can tell just exactly who has key clicks because it’s possible to find two signals of otherwise identical strength on the S-meter and one will be inaudible within a few hundred Hz and the other will continue to bleed through and pump the AGC.  Well-done, Elecraft.

One thing that surprised me about the K3 was its apparently poor performance on the pileups from NA-039.  With the BW cranked down to 400 Hz, the filters rang like a bell in a pileup.  I have the 400-Hz 8-pole and 2.7-kHz 5-pole filters.  Widening the DSP bandwidth out to 700 Hz or so (which switches to the 2.7-kHz roofing filter) alleviated the problem with occasional AGC pumping from louder signals in the pileup.  In a post to the PVRC e-mail list recently, Frank, W3LPL, also confirmed that he prefers the 1-kHz 8-pole filter for CW operation.  Because I had the opportunity, I recently sprung for the special-order 700-Hz roofing filter.  It should arrive in March 2013.  I suspect there is considerable tailoring that could be done to the AGC system but I’m not there yet.  Once I realized that the bandwidth of 700 Hz was a sweet spot, the radio worked great in the pileups.  I have a feeling that I’ll also end up with the 1-kHz filter eventually.  But, I rarely open up beyond 700 Hz on CW so it will be interesting to see what is best.

A few other bright spots:

  1. CW-to-Digital:  This is just plain cool.  Send with the built-in keyer and the radio modulates PSK31 or RTTY for you.  Decode it right on the screen.
  2. Multifunction knobs:  The entire industrial design of the K3 is really unmatched in my opinion.  It has just the right number of knobs and menus.
  3. Options:  They are plentiful and easy to install.  Keeps the initial cost low(er).

I’m extremely delighted with the K3 so far and my shack is getting more compact.  It’s also nice to have a radio with a built-in keyer for once…

W3NQN filter wrap-up

October 9th, 2011

After about six years of sporadic effort, I finally finished the W3NQN filter set by building the 10- and 15-meter filters over the past two weekends.  Now I can operate SO2R with impunity on all bands.  Several band combinations are still problematic, but those are problems that filters can’t solve.

Because the geometry of our home does not permit me to have a walk-behind station desk, I had to attach the filters to the mounting board by laying on my back with a right-angle drill.  That sort of thing is always a bit exciting!

The Rupture 2011

May 22nd, 2011

Thanks to some quick thinking on Sarah’s part, I was able to attend the Hamvention (Saturday only—the day that the sewer backed-up and “ruptured”…spewing nasty water down through the fleamarket) for the first time in a few years.  This is a recap from my perspective.

  1. Attendance was down.  The fleamarket was shrinking.
  2. There were a lot of lookers but few buyers in the fleamarket.  Predict that the fleamarket will shrink further next year.
  3. There were still good deals to be found in the fleamarket—I picked up some LMR-600, a WA2AAU 2304-MHz amp (unmodified 1900-MHz PCS amp), a Rohn 45G rotator plate, some 20-GHz rated SMA relays, and some miscellaneous parts.  And, I passed on a few good deals as well.
  4. I saw a lot more young people than I remember from past years.  Or maybe I’m just getting older and the population of hams younger than me is growing on account of that.
  5. Hamabouts (and their drivers) were not so obnoxious as prior years.
  6. Hara Arena may be a dump (K1LT told me the story—don’t know if it’s true—that during the Rolling Stones first U.S. tour, they had been booked at Hara, but refused to play when they saw the facility); but, it’s perfect for the riff-raff who show up for the Hamvention.
  7. In the end, the Hamvention (like ham radio itself) is about the people you know and meet.  I had fabulous eyeball QSOs  with guys from almost all phases of my ham career (except the early years from 1993-2000).  The VHF/UHF weak signal crowd is a pretty amazing bunch of hams.  I had a great time getting to know some of them in the fleamarket.

The Joy of Homebrew

May 18th, 2011

This is about building electronics, not making beer, at home; although, I am sure there are parallels.  Three things brought me to writing this:  1. an eHam forum thread I responded to a few weeks ago;  2. the June 2011 issue of IEEE Microwave magazine (has articles by K2UYH, N2UO, and KK7B, perhaps others? thanks to W3KL via the PVRC reflector for bringing it to my attention since I let my IEEE/MTT membership lapse); and 3. a few minutes spent last night resuming a partially-completed Softrock kit gifted to me by a friend who decided to buy a FLEX-3000 instead.

Every once in a while, a thread appears on an amateur radio forum that goes a little bit like this, “Hi, I’m a new ham and I don’t have a lot of money to spend so I want to build an HF SSB station from scratch” or something similar. Somehow, somewhere, somebody has given the impression that it is less expensive to build your own amateur radio equipment than to buy it.  That’s true in some circumstances, but certainly rarely for anything that is mature, mass-produced, and readily-available on the second-hand market.  After all, there is nothing novel about a 100-watt superheterodyne HF SSB transceiver these days. The principal uncounted cost is the “engineering cost” associated with getting your first few projects working and keeping them working.

One of the first construction projects I undertook as a new ham was to build a Ramsey Electronics HR-20 (NE602-based) 20-meter receiver—$20 at a hamfest.  It did actually work eventually—but this was a simple kit with maybe two dozen parts.  Next, I built a ONER transmitter kit from now defunct 624 Kits.  I think that was another $20.  I never made any QSOs with that combination because I was always afraid of blowing out the receiver with the transmitter.  The first thing that I built that I actually managed to make a QSO with was a Small Wonder Labs SW-40, which I still have.  That set me back $55 and it did not work immediately.  Suddenly, that’s over $100 by the time you include the money I spent on a soldering iron and solder.  That’s one-third to half-way to a “real” used HF transceiver and I had two bands at 1 watt on CW only.  Furthermore—these are all kits—they leverage economies of scale in purchasing parts from various vendors and they have instructions to help you along.  And, I’d like to think that I was a relatively representative example of a recently-minted ham who had more ambition than money or skills…

As I soldered down 1206-size (easy ones) SMT capacitors last night, I was thinking of times that I rushed through a homebrew or kit project just to get it on the air.  In those instances the process was often, as I have belabored above, about saving money, not about the act of creating something.  Last night was about creating, not saving, and that is the joy of homebrew.

QRL for Sprint and September VHF

September 16th, 2010

As I mentioned previously, I was planning to make the NCJ North American Sprint and the ARRL September VHF contests my kick-off to the Fall/Winter contest season.  When a work trip was scheduled for that weekend, I assembled my portable station.  But, Sarah convinced me not to take it since carrying the ham gear always complicates travel a little bit.  Since the work trip was radio-related, I thought I’d share a couple of pictures and stories.

One of the projects in which I participate is the middle-latitude expansion of SuperDARN (Super Dual Auroral Radar Network).  SuperDARN is a global HF radar network that is used to monitor plasma processes in the polar ionosphere/magnetosphere.  It was recently highlighted on  Last year, we built a pair of radars near Hays, KS.  This year, two radars are under construction in central Oregon.  I went out to assist with the initial phases of the build.

The radars are installed on an old HF over-the-horizon-backscatter (OTH-B) radar transmitting site in Christmas Valley, OR.

Two of these radars were constructed for the U.S. Air Force as an early-warning system for aircraft, one in Maine and one in Oregon/California.  The western portion of the radar was only turned on briefly for testing before being relegated to “warm storage” and then decommissioning.  Typical.  None of the antennas or transmitters are still on site and a lot of the copper wiring has been looted.  Everything left inside the building, including the backup generator, was in essentially mint condition.  As an aside, the transmitters from the Maine site were recently installed at Arecibo Observatory.  I have no idea what happened to the transmitters from this site.  Despite the fact that the antennas and transmitters were missing, there were a number of interesting things to see.

This OTH-B radar was a megawatt class (output, not ERP) system split into three segments/sectors, facing NW, W, and SW, each fed by four transmitters.  Each sector had a separate, dedicated 3-phase power line that came from a substation some 50 miles away—I found it on the way home.  You could follow the poles straight to it if you knew what you were looking for.   Each of the transmitting arrays was surrounded by a fence, for obvious reasons.  The fence was made entirely of wood.  Furthermore, almost all of the washers were a fiber material, not galvanized steel like the bolts.

At first, I thought that the washers might have been an electromagnetic consideration, like the wooden fence, which might have distorted the antenna pattern in the best of cases or simply melted in the worst.  But, I suspect now that it was a mechanical consideration to deal with dramatic changes in temperature and humidity in central Orgeon’s Great Sandy Desert.

The actual construction of the SuperDARN radar is not that exciting at this point, but here are some of the 72 aluminum poles we dressed with cables for the two radars.  Each radar has a 16-element phased-array of folded dipoles mounted in a corner reflector.  I installed a lot of N connectors on LMR-600 and a lot of Preformed end-grips on Phillystran, in addition to some more cerebral tasks.

The site has good optical conditions, too.  So, I’m looking forward to trying some of my optical instruments out there.  Here’s a quick star-trail exposure I took with the camera propped up on a picnic table in the motel parking lot.

So, that’s what I was doing instead of Sprinting and grid hunting!  I should be QRV in the NS Ladder tonight.

TS-930S PA/PS Postscript

August 11th, 2010

Long-time followers of the blog know that one of my TS-930S transceivers has been a money and time sink for about the past five years, fully 60% of the time I’ve owned it.  So, if you haven’t been following the story over the past couple of months, I pretty much replaced (almost—get to this in a second) all of the electrolytic capacitors in the power supply and power amplifier, plus replaced the driver and final amplifier transistors.  As I increased the drive past the point where I got 50 watts output, I started to get a lot of AC hum on the signal.

At first, I thought the hum might be associated with a low-frequency instability in the power amplifier.  I read all the Helge Granberg articles I could find on the topic and tried all of the prescriptions he suggested.  Last night, I even went so far as to tweak the feedback resistances in the PA stage to increase low-frequency stability.  Still there.  Finally, I measured the frequency of the AC hum—exactly 120 Hz—full-wave bridge rectifier leakage.  Tonight, I pulled the power supply board out of the radio, which is a herculean task, by the way.  There were still three small, insignificant-looking electrolytic capacitors that I hadn’t changed.  I found two of them in my junk box and crossed my fingers on the third one (a 25 uF, 100-volt unit), leaving it in place.  While I had it out, I also found and shunted a pair of dying PCB traces with pieces of wire.

After putting the board back into the radio, I disconnected the PA 28-volt line and powered it up.  I checked the 28B voltage…right on 28.5 volts.  So, I reconnected everything and it fired right up at 100 watts without the hum.  Perseverance seems to have paid off.  For now.  I keep telling myself that the next time it breaks, I’m going to get a K3/100.  But, I just can’t bear to buy a radio that’s worth more than my car.

TS-930S PA mod — first try

May 25th, 2010

As I wrote recently, I have been tackling the low-frequency instability problem in the TS-930S PA unit.  My first attempt was to add several bypass capacitors to from the supply side of L7 to ground (through a lug on the Q7 mounting screw a short distance away).  This should tame the drivers, although the problem is not there.

The hum came back when I pushed the power beyond about 50 watts.  The push-pull MRF-422 final amplifier circuit in the TS-930 comes from Motorola EB27, with a few small modifications.  However, it is not clear to my untrained eye where additional precautions could be taken.  I have a hunch that my next target will be this portion followed by the 2SC2075 pre-driver stage if I come up empty on the finals.

Bedrooms or Beverages and the 20-meter Money Eater

September 11th, 2008

Two of my favorite QST articles are “Bedrooms or Beverages” by K1TN (Oct 1994) and “The 20-meter Money-Eater” by W7KCN (Apr 1991).  Now that QST is online, you should go look them up. 

The April 1991 issue is the first issue of QST I ever read.  We picked it up at a used book sale before I was licensed in 1993.  It has a lot of hilarious articles in it.  The DXDC (DXCC deleted countries) list is quite funny, too.  “The 20-meter Money Eater” pretty well describes any homebrew project I’ve ever worked on.

The first year Dad and I were ARRL members was 1994.  Those QSTs got dogeared in a real hurry.  Either QST was better then, or I’m jaded now, or both.  Anyhow, I didn’t even know what a Beverage was when I read “Bedrooms or Beverages.”  In fact, I didn’t know what half the article was about.  But, it was good reading.  I read it again recently when I was at Mom and Dad’s place.  It’s even funnier now that I’ve thought about doing some of the things K1TN tells about.  I actually had an e-mail exchange with him a few years ago about joining a Sprint team in which I told him it was my all-time favorite QST article.  He said that all of his years of writing/editing for QST were worth it when people told him things like that.  I always enjoy his writing.

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