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My New "Boonton" Model 59 GDO

Here is my big acquisition from the Nutmeg Hamfest this weekend. It is the classic Measurements Corp. Model 59 Megacycle Meter. Some of us would know it as the "Boonton Grid Dip Oscillator." From what I've been reading, a variant of this unit was first produced in World War II. The manual, available here and here on the Internet, bears a 1947 date. The company was sold to Edison in 1953, so this unit was probably produced in the early 1950's. (The meter/power supply unit is serial #750, the oscillator head is #695, the coil set is #734.)

The developer was the well-known engineer Jerry Minter. (See his IEEE.tv interview that prominently shows the Model 59.) His was one of a number of instrumentation companies active in Boonton, N.J. after the War. There was no connection to Hewlett Packard. (An impression I had at one time.)

I used a Model 59 extensively in the 1960's and 70's, but I did not know that it was a classic even then. Now, it's very satisfying to have my own! It is far superior to the Heath GDO and tunnel diode dipper that I have also used. I see one advertised at $75 on E-Bay, but I got mine for about half that.

The grid dip oscillator is a very handy item for generating signals, checking for resonance, and making rough frequency measurements. This one covers the range 2.2 to 420 MHz in 6 bands.

[Click photos for more detailed versions.]

It is necessary to inspect all new equipment here at AA6E. (The unit was in remarkably good condition. It worked the first time and only needed a little cleaning.) This device had wonderful "build quality" -- as we say these days. The important part is the tunable oscillator assembly, which is meant to be hand held. The inner works are all gold plated (!) and very sturdy. A single 955 "Acorn" triode tube is the active element. Lead inductances are kept very low to allow UHF operation.



Dial calibration is meant to be quite good. Each unit's coil set is supposed to be calibrated to work with a specific oscillator head, although my coil set's serial number doesn't match my oscillator. The tuning "feel" is very smooth.



The power supply uses a 5Y3 GT rectifier and an OD3/VR150 voltage regulator tube. The red filaments and the purple regulator discharge, along with the incandescent (!) pilot light, are a treat by themselves. Not shown is the neat wiring harness beneath the power supply chassis.

Now I need to build another RF gadget!

Kindle Hack Prescience

Yesterday's post foresaw the wonderful things that could happen if someone did some "special research" on the Kindle. Well, today's news (Ars Technica) tells of a hacker who has indeed gained access to the K2's Linux essence via the USB port. The original Kindle was hacked way back in 2007.

I don't expect to do this myself any time soon, but it is fun to watch another digital barrier fall.

Kindlemania

This is my 2 cent review of the latest gadget here, the Kindle 2 from Amazon. If you haven't heard about it, it's a hand-size tablet with a 7" ePaper screen, for very high quality black & white display of text (mainly). It is sold as an electronic book reader with a direct sales link to Amazon.

It's really a lot more than that. It is a free wireless web browsing terminal. The browser identifies itself as "Mozilla/4.0 (compatible; Linux 2.6.10) NetFront/3.4 Kindle/1.0 (screen 600x800)". The "3G" wireless link is actually free with no monthly or setup charges, after you buy the Kindle. The browser is labeled "experimental", and it has a lot of the feel of a cell-phone or PDA browser, but the screen resolution is quite acceptable for sites that are reasonably formatted for its size. I can log in and use my gmail account, but I wouldn't say the Kindle is going to replace my PC for general email.

It is a Linux box. You can see that from the Browser ID above, and you can also see it by reading the 70 (!) pages of legal information that are thoughtfully provided in Kindle's memory. There are interesting possibilities: I suppose it won't be long before we have hackers providing a Linux console session. You could use the Kindle as a (free!) wireless adapter via USB for your laptop. And so on. (Of course, Amazon may not smile on such activity.)

So we have a Linux box with ~2 GB of internal memory, a wireless link (Sprint, I think), USB, audio output, a nice screen, and a semi-useable keyboard. It will hold "1500 books", they say. You can convert and/or install your own pdf, doc, text files, etc., but not if they're too large. The only advertised conversion option for non-txt files, is to send email to Amazon where they pass it through the "cloud" (I suppose) and send the result over RF (for $0.10 a shot) or by email (free). But the file size is limited by the email process, ruling out many Google Books image-type PDFs, for example.

What the Kindle is not:

• Email or IM machine. The keyboard is even worse (in some ways) than my Palm Treo's. There is no email client, but the platform would obviously support it.
• Color, and the ePaper is too slow to support any animation or video.
• Open. You have to use Amazon's applications programs, and there aren't many of them (yet). Our friendly hackers may overcome this in time, but expect Amazon to defend their platform even more than Apple and its iPhone, particularly because of the bundled RF link (which could be abused) and because of the "secure" commercial authentication that links you, your Kindle, and your Amazon account. (Where they hope you'll spend a lot of $$.)
• Secure. There is no password or other protection on the Kindle, which means that anyone who gets the physical unit can cause mayhem in your Amazon account. This is a pretty serious shortcoming IMO.
• Media Machine. The Kindle will play mp3's and show pictures, one at a time. The file browser function is rather weak (no folders), so you'd get lost pretty soon if you loaded up a lot of small files.
• Telephone. It would not be a big technical step to incorporate a cell phone (VOIP) into the Kindle concept, but there is no audio input, and the network model might not support phone usage. Still, I don't know how many separate high-function digital devices I want to carry with me. The market will sort this out some day.
  

All in all an interesting device. I will use it for reading books, newspapers, and a few blogs, while waiting for the hacks to appear.

Debian Purity, iMacs & the usbserial problem

I'm moving my ham-oriented computing (digimodes, logging, etc.) to a 333 MHz purple Apple iMac. A beautiful older machine with plenty of zip for these uses. Since it is PowerPC based with only 384 MB RAM, my Linux choices are restricted. Happily (I thought), Debian would do the trick. One of Debian's virtues is that they provide Linux for many less common machine architectures.

All is well and good. I've got my USB-attached sound system working. (A story for another time.) I set up the build environment for Hamlib rig control and managed to compile the latest stuff from Sourceforge CVS. Fldigi and Xlog compile, too. So what remains?

I need to connect the iMac to my TenTec Orion's serial port. No problem, just move the 4-port Keyspan USB-serial box from my main x86 computer (running Ubuntu) to the Debian iMac. Surprise - the Keyspan's LEDs don't light. The Keyspan driver module doesn't load. Wait, the Keyspan driver module (part of Linux kernel) does not exist!

Cut to the chase: The Keyspan usbserial driver for my device has been deemed "impure" by the Debian group. This driver passes all the legal and policy hurdles for Fedora and Ubuntu, but Debian seems to have a "one drop" rule. Any hint of restriction on a software module means it's not going to be in a Debian release. Apparently, the Keyspan driver uses code that carries a phrase like "only for use on Keyspan products".

(It is possible to get the driver source and recompile the kernel to include it, but this would take time that I don't want to spend.)

My solution? Use a different USB-serial device. I happen to have one based on the FTDI chip and driver, which is supported on Debian (plug and play). This one-port gadget has no manufacturer's name on it, but I recall buying it at Staples, possibly under the Belkin name.

One problem with USB devices and Linux is that you can't easily tell if a particular device is supported, because the Linux drivers support particular chipsets, and the vendor's packaging rarely tells you what chipset is being used. At least one on-line vendor, USBgear, does tell you. I have no experience with them, but they do offer a number of 4 port units in the $70-90 range.

Debian's "purity" philosophy (similar to GNU's?) is very strict. They have a point, but flexibility is good, too. This idea of "freedom" is going to cost me $80 and several hours of head-scratching. For me, that will be the price of PPC support.

A "perfect" gadget

This is an Encore ENRXWI-G "Wireless LAN Extender". I needed to extend my home Ethernet into the basement, for a project I'll describe later. For about $30 (newegg.com), this box saves me an hour or two struggling in my crawlspace for CAT 5 installation. That's a fair trade, I'd say! I bought two of them, with one as a spare.

In addition, it turns out this is a Linux box. (If you're up to it, you can reverse engineer the system and flash it with your own OS. But I will let that exciting project go for now...) And it can actually be used as a full-blown WiFi access point and in a couple of other modes. The only limitation is its single 10/100 baseT Ethernet connection.

I did try the "Repeater" mode with the second unit. Maybe this would help me get a better signal to the basement ENRXWI-G? My main WiFi access point happens to throw a shadow into the basement area that I am using, probably because of an intervening brick chimney. Moving my AP a foot or two seems to cure the problem, but could the repeater function do the same? I set it up according to instructions, and it seemed to help on the basement-to-AP route, but if anything hurt the performance (lost packets, etc) AP-to-basement. (puzzling) In any case, no joy.

A WiFi repeater is probably more appropriate when your client and AP are truly separated by long distances, and the signal strength directly from client to AP is really weak. The AP-to-basement path here is relatively short. My transmission errors may be due more to multipath reflections than to weak signals.

The only downside of this box, shared with most WiFi devices, is that there is a lot of setup required. The supplied documentation is about average, but many people will scratch their heads at some point when setting things up.

In summary, score one for cheap Internet appliances.

Z100 -> P100!

After a little discussion with Jack Smith about the inner workings of his Z100 Tuning Aid (last post), one thing led to another.

The result is another little Python utility that does much of what the Z100 does, but in software under Linux.

The scoop and download are available here.

A Z100 Arrives

This is the Z100 "Tuning Aid" from Clifton Laboratories, as described by Jack Smith K8ZOA in the January/February, 2008 issue of QEX. I bought the kit and put it together as sort of a post-Christmas present to myself.

The Z100 is a pseudo-spectrum analyzer, using a simple zero-crossing detection and averaging algorithm as I understand it. It is intended to help "zero beat" a received CW or RTTY signal so that you can respond on the same frequency within a few 10s of Hz. (It's not zero beating really. With current rigs, you want to tune to a certain offset "spot" audio frequency that corresponds to your transmitter's output.)

A few notes on the Z100 so far

• Assembly was straightforward until it came to making the LED bar-graph indicator, which you must construct out of individual LEDs and spacers. Getting a neat result is tricky. I judge I managed it fairly well on the first try, but you need to read the instructions carefully. A number of hams have contributed handy alternative techniques that Jack includes in his write-up.
• Assembly of the board into the case, along with a clear lens and an optical filter film is the next tricky part. All in all the mechanical work with the LEDs and the case seemed overly difficult. It would have been very helpful if the filter film could be dispensed with -- e.g., if a neutral density Lucite lens could have been used.
• Operation (for an hour so far!): The Z100 is easy to connect and use. It does require reasonably strong CW signal (i.e. fair SNR) to make the CW note show up clearly out of the noise. I seem to work weak stations quite a lot, and the tuning aid may be difficult to use for them. A more intelligent algorithm would be able to pick a coherent signal out of the noise much better, but that would be beyond the capability of the simple PIC processor, I reckon. It would boost this kit well out of the $60 price category.
• Jack is to be commended for producing a very "open source" project. The PIC code is available for study and modification, and the QEX article and product documentation gives full design details. (A perfectionist might say that a true open source project should also distribute Gerber-type files for the PCB design, but that would be a quibble!)
  

This kind of tuning aid should be very helpful to any CW or RTTY operator. (I suppose it would make a reasonable guitar tuner, too...) In an age of DSP radios, this capability should have been incorporated into the transceiver itself, but alas this is not yet true of my radio.