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Maintained by Robert Meister WA1MIK

Background Information:

GLB Electronics is no longer in business; the remains were sold after the founder and chief designer Gilbert L. Boelke W2EUP passed away. Gil was a very gifted and talented RF design engineer - in addition to the Hybrid Ring Duplexer (see the Antennas Page at this web site), he designed and manufactured an excellent receiver preselector-preamplifier, and his regularly appearing advertisement in 73 magazine was the first inkling that many new hams of the 1960s had that stock VHF receiver performance could be improved and done so rather inexpensively. Gil's application document was available for an SASE, and also packed with every preselector (and Gil once commented that, from the number of SASEs that they stuffed, it seemed to his office people that about a fourth to a third of 73's total readership must have sent SASEs at one time or another).

Gil was a founder and an active member of the Buffalo Amateur Radio Repeater Association (BARRA) and they regularly held meetings at his shop. Their June 2001 newsletter "The Link" (534 kB PDF file) has a history and biography.

Gil's preamp design was way ahead of its day, and was cloned by several companies without permission. When I met him at a hamfest I overheard him telling someone else that a couple of commercial receiver designs were using his preamp as the front end RF amplifier. As far as I know he never instituted any legal action. Photos of an original unit can be found in the gallery below.

As of late 2013 the preselector / preamplifier is still being sold. See this info page (offsite link) as well as the historical information at the bottom of this page.

Gil also designed and manufactured the first practical synthesizer for amateur radio; it was marketed as a kit, or you could get it assembled for a higher price. The marketing name for the 2 meter synthesizer was the "GLB Channelizer model 400". Gil called it the "400" because that's how many channels you'd get (10 kHz steps over the 4 MHz wide 2-meter band). The "A" version was Gil's prototype. There were a few factory assembled and a bunch of kits of the "B" model sold. Their main production was the "C" model, and there were a few "D" models sold. The "D" models were designed and produced after Gil got a new car and didn't have as much under-dash space - that model was in a half-high box, had a single row of switches, and a center-off toggle for offset selection, labeled "+", "Ø" and "-" or "+", "S" and "-" (depending on the production run). There were also a large number of unauthorized "knock-offs" of the "C" model made, and for a while you could buy "GLB kits" at many amateur swap meets - two home-etched single sided PC boards, a baggie of parts, and a photocopied manual.

GLB also offered their 400B channelizers for operation on 440 MHz, 220 MHz, and 50 MHz. They now call it a "Universal Channelizer" with generic circuit boards that could be customized for any of the operating bands.

GLB also had a simplified, half-height version of the 400-series channelizer, the model 300. This had just one row of knobs but offered an automatic +/- 600 kHz repeater offset circuit. It's possible that this unit started life as the elusive model 400D.

GLB also designed and offered other products, such as the AF-10 Audio Processor.

From the flyer/catalog and other available manuals, we've come up with the following list of Channelizer model numbers. If anyone has additional information, please pass it on.

Manuals, Brochures, and PDF files:

GLB Product Flyer/Catalog, 1978   560 KB PDF donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
Model 50 Channelizer, full manual   5.1 MB PDF donated and scanned by Bob WA1MIK
This is basically a generic 400B manual with addendums and a modified schematic for 6-meter operation, circa 1977.
Model 300 Channelizer instruction manual   2.7 MB PDF donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
This manual, like the one for the Model 50, was basically a generic 400B manual with an addendum that explained what was different.
Model 400B Channelizer, full manual   3.7 MB PDF donated by Steve NUØP
Model 400B Channelizer, step-by-step assembly addendum   1.7 MB PDF donated by Dave Menges WB9TEN
Most channelizer manuals had this information spread out in some random fashion and as paragraphs of text.
Model 400B Channelizer, schematic only   570 KB PDF donated by Steve NUØP
This was their most common unit.
Lock Detector for Model 400B Channelizer   333 KB PDF donated by Paul Baxter WA1WJB, cleaned up by Bob WA1MIK
Frequency Multiplier for Model 400B Channelizer   791 KB PDF donated by Paul Baxter WA1WJB, cleaned up by Bob WA1MIK
5 kHz switch option   139 KB PDF donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
These switches and circuitry could be installed in a Channelizer or the 414 radio. There was a similar option that added 25, 50, or 75 kHz for the UHF models.
Diode matrix preset option   420 KB PDF donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
This assembly could be installed in a Channelizer or the 414 radio. It gave the owner ten preset channels including the rotary knobs.
Illumination option   130 kB PDF donated by Dave Menges WB9TEN
Yet another add-on option. Most people just counted switch detents and could operate their channelizers blindfolded.
Interfacing a Model 400B Channelizer to a Heathkit HW202 mobile radio   128 KB PDF donated by Paul Baxter WA1WJB, cleaned up by Bob WA1MIK
GLB 414 2-meter transceiver Owner's manual   1.5 MB PDF donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
Model AF-10 Audio Processor manual   84 KB PDF donated and scanned by Kevin W3KKC
This seems like it was originally integrated into their T144 transmitter module, then it was produced as a separate module to be more useful to other radios.
Model ID-1A CW Identifier   453 KB PDF donated by Fred Gephart WA2CAM
While the manual text refers to the ID-1, the circuit board picture shows the board labeled as the ID-1A. This unit was suitable for transceivers or repeaters.
Model ID-2 CW Identifier   276 KB PDF donated by Fred Gephart WA2CAM
Basically the ID-1/ID-1A with some subtle design changes and a longer ID time interval.
Model ID-2B CW Identifier   453 KB PDF donated by Fred Gephart WA2CAM
This had improvements over the ID-2 and a decent schematic.
Model ID-2C CW Identifier   725 KB PDF donated by Fred Gephart WA2CAM
The last version had an even longer time interval.
Model P50 and P500 preamplifier-preselector advertisement and order form   540 KB PDF file
Model P50 and P500 preamplifier-preselector applications sheet   696 KB PDF file
Model P50 and P500 preamplifier-preselector preliminary instruction sheets   676 KB PDF file
Model P50 and P500 preamplifier-preselector instruction manual   1.1 MB PDF file courtesy of Eric WB6FLY
GLB Modules advertisement, partial page   305 kB JPG file
GLB assembled these modules to create the GLB 414 2-meter transceiver.
Receiver modules/strips data sheet   60 KB PDF file donated by Robert Scott WB4RJE, scanned by Bob WA1MIK
Model T144 transmitter kit manual   611 KB PDF file scanned and donated by Rick Hall K5GZR
This unit was designed to be driven by a 400-series Channelizer. Rick mentioned they've been using this module in a repeater since the 1970s.
Transmitter modules/strips data sheet   64 KB PDF file donated by Robert Scott WB4RJE, scanned by Bob WA1MIK

Photo Gallery:

Toby Driscoll N5SIM provided photos of a preselector/preamp. All are 40-50 kB in size.
Front photo     Inside photo     Filter ends photo

Ron Wagner WD8SBB provided photos of the interior and exterior of his 400B Channelizer. All are 250-250 kB in size.
Front photo     Rear photo       Inside photo #1     inside photo #2     inside photo #3

Robert Scott WB4RJE provided photos of the interior and exterior of three slightly different 400B Channelizers. All are 100-150 kB in size.
Front photo #1     Front photo #2     Front photo #3     Inside photo #1     Inside photo #2     Inside photo #3
Switch Wiring photo #1     Switch Wiring photo #2     Switch Wiring photo #3     VCO photo #1     VCO photo #2

Someone sent us photos of a 400C Channelizer. This particular unit has "F" connectors for the RF outputs, but BNC and RCA connectors were common - whatever the builder needed to match his situation. If the builder had a trunk mount radio (like a Motrac, Prog-Line or MASTR Pro) he simply ran two lengths of RG-174 or RG-58 coax from the synthesizer to a pair of small matching networks next to the crystal sockets of the radio, and the cleaned up RF was passed to the crystal sockets themselves. These photos are 150-220 kB in size.
Front photo     Rear photo

Apparently they also made a 450 MHz half-height version. Steve KA6FTY supplied two photos of a model 450B channelizer. They are 130-150 kB in size.
front photo     rear photo

With all the modules they made, it wasn't long before GLB put them all together and made a 2-meter rig, the GLB 414. Inside there was a conventional 400B VHF synthesizer board mounted over a VCO assembly. Over the 400B boards was a diode matrix board for the 10 preset channels with a narrow scanner board beside it. To the rear was a GLB IF (CRT 414 IF-AF) board mounted over the Helical RF Receiver board. Along the rear panel was the transmitter audio/RF board. Behind the meter was a GLB 900 RF Hi Power amplifier board with an antenna switching relay in a shielded box, with another GLB 800A board mounted above and another smaller GLB 700 RF board to the rear of that in another shielded box. Again, thanks to Robert Scott WB4RJE we have photos of the interior and exterior of two 414 transceivers. All are 100-200 kB in size.
Front photo #1     Front photo #2     Rear photo     Bottom photo
Inside photo #1     Inside photo #2     Inside photo #3     Power Amplifier photo

Other Historical Information:

The following was received in an email to repeater-builder in February 2013:

I had worked at GLB from 1983 until 1998, and again from 2000-2001 when they had merged with Aria Wireless, and now I've been with Simrex since 2004. Simrex purchased the assets of Aria Wireless after closure. There's a very good chance that any gear bought pre-assembled from GLB between 1983 and 1993 was built by me. After 1993, I moved into the design and engineering department and had much less hands-on experience with customer products. I still build the Preselector/PreAmp when orders come in. GLB was a small company, and it was like a family. Well, in reality, it WAS family, as GLB Electronics WAS Gil Boelke, and all manufacturing and testing and such was done by my uncle's company "Sloan Distributing". Bernie Sanders was my uncle. When he passed suddenly in 1984, GLB Electronics took over the manufacturing and distribution as well, and united the entire operation.

I'm not a ham myself, and from what I thought, it always seemed like GLB was pretty big in the ham world, selling the first "channelizer" back in the 70s, and one of the first packet controllers to market. I still remember the reviews of the PK-1; I don't recall what magazine it was, maybe "73", irrelevant however, but they reviewed the PK-1, and then in print pondered why it had some different commands than the TAPR offering did, breaking "convention". Of course, the GLB model was released six months earlier than the TAPR, so it was the TAPR that broke "convention". But, it was what it was.

With the advent and the internet and nearly instant national and international communications, I've been in contact with people from all over the world, and when I find out someone's a ham, I usually ask them about GLB, and there had only been one person ever that was familiar with them/us. I just thought GLB would have been more well known.

Dan Smyntek
Simrex Corporation
Buffalo, NY

The following was received in an email to repeater-builder in October 2013:

I came across your write up on GLB Electronics. I had been GLB largest customer (SATLOC) for a couple of years and then later joined the company. I was a 1/3 partner GLB Electronics before the venture was sold to Aria Wireless and became Aria-GLB wireless systems. At the time of his passing, Gil was retired but working on projects for us in a consultant capacity. Great guy. I ended up with a lot of his lab notebooks etc. when I acquired Aria-GLB and the product lines became part of SIMREX Corporation.

As Simrex Corporation, we Still make the last SNRDS radio that Gil designed and it incorporates the famous preselector. We also build the preselector as a standalone with about half the sales being to commercial users. Interestingly a lot of them end up on the front end of well known commercial repeaters. The price has not changed since 1998. Hams get a $25 discount below the dealer price as a tribute to Gil. Any ham that buys a preselctor through me gets a bit of the Gil Boelke story with that discount. The final alignment and tuning of the Preselector is done by someone who had been doing it working with Gil.


Frank Neuperger, VE3FNZ
SIMREX Corporation

The following update was received in an email to repeater-builder in October 2014:

The GLB preselector is still made in Buffalo NY. Production has never ceased. They are currently made by the same technician that made them when Gil Boelke was heading up the company at GLB. More than half of our sales are in the commercial bands. Hams get the dealer price less an additional $25 discount as a recognition to Gil.

We donít sell a lot of them and it is entirely word of mouth.

The frequency range has been expanded slightly. We also now offer a service to provide stub filter (single notch or multi notch comb filter) to front end the preselector for specific cases that may benefit from it.

Currently only the Preselector, GLB SNRDSII radio, and the RDC4 TNC are the only surviving GLB products that are still made.

Frank Neuperger, VE3FNZ

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This page initially created 31-Jan-2010 by splitting the GLB section away from the "Other Manufacturers" page.
It was completely reorganized 29-Apr-2013.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.