And now dear readers, another episode of that fascinating radio serial…
Bruce’s Bench
2009

A randomly updated view of what has crossed my workbench in the last few weeks.
Burdened with but a smattering of commentary, this is more of a visual tour.

Click on each photo to enlarge.

 

November 26, 2009 – Borden Radio Company – Armstrong RX Kit
Here was a fun little kit, easy build, and it works great!
I used to build the Radio Shack “P-Box” kits growing, up, can’t find much in the way of entry level kits today.
Have built the Elecraft K1, KX1 and K2, enjoyed very minute of it. But I really enjoyed this regen kit.
Check out Lance’s company and website, www.xtalman.com/.


 


August 20-23, 2009 – AWA Conference – Rochester, NY

 

 

 



August 16, 2009 – Paint It Black – On Refinishing Old Radio Gear

I sure wish the good old “black crackle” finish that you see on 1930-40s gear could be duplicated accurately today, but unless someone releases the formula and protocol commercially, we’ll have to settle for the light “vein” or “pebble” style of wrinkle finish used today.

I understand that the wrinkle finishes were often used to expedite the metal finishing work, one did not have to worry about a perfect metal surface if it was going to be covered with a wrinkle finish. Gloss, satin and to some degree, even flat, black serves to magnify the surface imperfections underneath the paint.

I had researched this matter extensively when I was refinishing the W1FPZ transmitter back in 2007, taking months to try and find the exact match. After all, I had spent weeks disassembling and documenting the rig, I wanted it to be 100% when done. I even posted my request on numerous internet sites and must have called nearly two dozen “coating”, as the paint folks now like to term paint, specialists about a formula matching the 1930s wrinkle. Nothing was really out there is a exact match, close, but not exact. I settled for close, used powder coating – more about that later, thinking it was better to preserve the piece rather than lost it to rust. Or worse yet, have to go back in in 20-30 years and disassemble those now 100 year old wiring harness so it could be properly refinished. If you saw the results of this project at last year’s AWA Conference, you know that it worked.

What I discovered is that their is great variation in the color, texture and design of the wrinkle finishes over the years, this is true even among the same manufacturer. When I look at my 1940s Collins 30K transmitter and compare it to the matching 75A1 receiver, bought at the same time for the same station by the original owner, you can see the 30K has more of a “pebble” finish and the 75A1 has more texture. Both pieces were built at the same time, by the same company, for the same station. Take a look at any Collins gear in the classic Saint James Gray, some is certainly black, others have a more blue hue. There is no true Collins “standard”.

I found that the same variance is true with the Gross Radio and early National gear. My 1930s Gross Eagle receiver has a large number of “veins” and even what could be described as “starburst” patterns in the paint, certainly not your typical finish. The Nationals here, from the very early SW-3 to the FB-7 and HRO all have different finish colors and textures. All are still black, but different shades of black, and different designs of texture.

Arguably, some color variation may relate to conditions of storage, sun exposure, etc. but I think to a large degree it is simply variances in paint formulation and application. Yet another issue with the wrinkle finish is the degree of gloss. On some of the pieces I’ve seen the finish almost looks “dry”, very low gloss, even after cleaning, my BC-348 comes to mind. Yet others, thinking of some of the later Collins gear, like the 75A-4s, almost glisten once cleaned.

I suspect the texture, color and gloss variances had more to due with the paint vendor than they did with the manufacturer. You still had a number of small to midsize companies back then in the paint game, rather than the few large multi-nationals we see today. Quality control was relative among many of the early manufacturers, ISO standards were decades down the pike as were the Pantone color standards. Automated manufacturing was unheard of during the early days of radio, if you’ve seen vintage photos the rows on rows of women wiring up sets you know what I mean, so I suspect that to a large degree, the finish also relied upon the skill of the fellow holding the paint gun. With so many variants of color, texture, design and gloss, it is nearly impossible to set a standard, we can only hope to come close.

So in the real world, I think the answer is to do the best you can to replicate the original equipment appearance, while making certain it will also there for future generations to learn from. We are not so much owners as we are caretakers of this wonderful gear, and we owe to future generations to be able to experience the same magic of radio that we have been privileged to witness.

W1FPZ Rig – ECO – Aerosol Finish W1FPZ Rig – ECO – Powder Coat
W1FPZ Rig – Power Supply – Aerosol Finish W1FPZ Rig – Power Supply – Powder Coat

One of the memories that I treasure most about my visits with Fred Hammond VE3HC was the ability to turn on and operate the equipment, his museum was more of a dynamic candy store for adult hams, than a static museum display. The important thing therefore, at least in this ham’s mind, is to not have static equipment displays, but rather a living, working station to enjoy. That’s my 2 cents…

-Bruce W1UJR
 



August 1, 2009 – Photos From My Radio Past
Found these old photos from my radio days in Buffalo, NY and scanned
them in. Not really the usual theme here at “Bruce’s Bench”, but at least
one is of my old service bench in Buffalo.

My old QSL Card, was KB2VKJ, then KG2IC when I upgraded to the extra class license. Collins KWS-1 station in basement – circa 1997.
First ham station, Icom 970, Icom 765, T-368 transmitter and R-390A receiver -circa 1995-1996. Close up of the T-368 and R390A in the audio processing rack, minidisk player below.
RCA BTA-500MX broadcast transmitter, K2LNU and I went all the way down to NJ and back in one day to pick up! Front panel of the RCA BTA-500MX open, showing the plate transformer and three 833 tubes aglow.
   
The original “Bruce’s Bench”, located in the basement of my home – circa 1997. The “northern hamshack”, at my office in Lockport, NY, about 1996.


July 25, 2009 – Building the Elecraft K2 CW Audio Filter
Elecraft has the best kits, what a great way to spend an evening!

 


June 27, 2009 – 1934 Gross CB-25 and W1FPZ Rig Comparison
A side by side comparison of the John Rollins W1FPZ transmitter, and
the Gross CB-25. More about the W1FPZ rig can be found on the Gross CB-25 Restoration page.

Gross CB-25 on left, W1FPZ rig on right. W1FPZ rig paired with National HRO.

The classic “46 Job”, from the 1930s series of ARRL Handbooks.
This is a circuit design very common in early homebrew transmitters.

 

Gross CB-25 Transmitter W1FPZ Transmitter
Gross metering W1FPZ metering
Gross power supply and modulation deck. W1FPZ power supply, no modulator on rig.
Gross RF deck, 47s and 46 tubes. W1FPZ RF deck, National Velvet Vernier dials.
Gross RF tubes, a pair of RCA type 46. W1FPZ RF tubes, a pair of Taylor TZ20s.
Gross CB-25. W1FPZ rig, before restoration.

May 15, 2009 – 1934 Gross CB-25 Transmitter Testing
Final testing of the Gross rig on my bench. Note the light bulb “dummy load”
in the second image in the top row. Unit tested fine on the bench, plenty
of RF, very stable when loaded properly.
 

Audio amp and power supply testing. Note dummy load light bulb.
Power supply/Audio chassis. RF chassis and metering panel.

 


May 3, 2009 – 1934 Gross CB-25 Transmitter Reassembly and Testing
The reassembly and preliminary testing of the Gross CB-25 transmitter, more to come.


 


April 24, 2009 – Macbook Pro – Case Replacement
On a recent trip out to LA, my trusty Macbook was damaged, apparently at TSA screening,
requiring replacement of the upper and lower case halves.
While these photos have little to do with vintage radio, other than the repair
project occupied the same workbench as the Gross transmitter project,
it is interesting to compare and contrast 1930s technology with the modern
laptop computer.
 


 


February 1, 2009 – Final Disassembly – Gross CB-25 Transmitter
Continuing on with last week’s project, I disassembled the RF deck for the Gross
CB-25 transmitter. That effort went flawlessly, and all the parts were
inventoried and placed into marked Ziploc bags. I found it interesting that the
General Radio air variable capacitors were mounted to the front panel with
small wooden blocks. I first thought that this might be a non-stock modification,
but on closer examination, the hardwood blocks were very precisely cut, and I
concluded that this must have been a low cost method chosen by Gross that
provided both insulation and rigid attachment to the metal chassis.

The only issue I did encounter during disassembly was the front dial bezels were
stuck into the paint. After a bit of effort I was able to carefully free all three
without any damage to either the bezel or the panel. Possibly the paint was still wet
when they were installed, or the “soft” paint I had noticed earlier had allowed the bezels
to “sink” into the finish. I used my now standard method of marking leads with paper tags,
each referenced back to a component on the digital photo.

The power supply teardown was much more complex, numerous transformer leads needed
to be carefully marked, and labels made for each removed lead. The digital camera came in
well for this part of the project, I was able to photograph lead placement and dress with
great detail, which should aid reassembly. I did discover that at least two of the transformers
and one choke, had been replaced, the replacements apparently 1940s vintage military surplus
parts. I’m not sure if this work was done during by Bill Orr or during John’s restoration. I remember
John telling me that the unit arrived in good condition, so I assume it was an earlier modification.
In either case, the workmanship was very high quality, and the chances of locating the original
units used by Gross are close to nil, I intend to the same parts during reassembly.

Given the age of the unit, I was very careful not to bend or stress the wiring harness, especially
the bus wire which had been so carefully formed on the RF deck. So after component removal, I
placed both the RF as well the power supply wiring harness onto large flat cardboard sheets.
I then used nylon wire ties to secure the harnesses to the cardboard, making a very safe mount
to move and store the harness.

The sheet metal will go out to Wayne Spring early next week stripping and powder coating.
Wayne did the wonderful job on the sheet metal for 1FPZ rig which I restored last winter.

I’d be very interested in hearing from any other Gross transmitter owner’s out there, it would be
very helpful to compare notes and operation.


January 25, 2009 – Refinishing Project – The Gross CB-25 Transmitter
With subzero temps out the night before, and not much on the agenda
for the day, it seemed like a prime time to get the 1930s vintage Gross CB-25
apart for refinishing of the sheet metal.

This is the rig which formally belonged to Bill Orr W6SAI, the well known author
and a former editor of the “West Coast Radio Handbook”. Bill had a special place
in his heart for Gross Radio gear, having grown up in NYC, he had visited Jerry
Gross’s store as a young boy. Bill later wrote about these experiences in February
1977 issue of CQ magazine. John related that Bill had given the transmitter to him
to restore (click here for video), with the understanding that John could keep the rig
after the restoration, if he would send Bill photos of the completed work for his
scrapbook. The Orr Rollins connection will be the subject for an future article in
the AWA Journal.

While the overall condition of the rig is very nice, John W1FPZ had used an
aerosol paint when he restored the transmitter some time ago, and I noted
that it seemed “soft”. Several coil forms, sitting on top of the chassis, had
“melted” into the finish, as had the front panel meters. Some of the exterior
panels showed uneven paint coverage, and rust was starting on the
bottom of the panel edges.

Given the spreading rust, I’d have to tackle this project at some time, and
with the restoration of the 1FPZ rig under my belt, I figured I’d better strike
while the iron was hot. The Maine winter is now in full force, so I have the time
to get the work done, as well as the contacts with the good folks who did so
well on the powder coating work of the 1FPZ rig.


January 24, 2009 – The “Real Radio Service” Box
While out and about today prowling the coastal Maine antique stores for goodies,
I came across this treasure. I’m not sure of the date or exact origin of the box, but
the lettering seems to tell the tale. Appears to be some sort of advertisement
for radio service. The wooden box is dovetail construction, and someone has taken
great pains to highlight and paint all of the dovetails a white color.

At first I thought it might be a repairman’s tool or part caddy, but upon closer
examination I noted that there are no handles it, so it would not be too handy to
carry to and from service jobs. I wonder if it is not part of some store or window
display. It is an old wooden box, which once held some commercial product, you can
faintly see the wood has been embossed or stamped with a product name, but it is
too faint to read. I’m not sure where “24 Beaver St.” is located or where “P-2073-R”
once called, but I found the box at an antique shop in Brunswick, Maine.


January 17, 2009 – ARBE-III Battery Eliminator – Evaluation and Repair
In the 1920s most broadcast radios were powered by batteries, rather than AC or
“mains power”. Now, the bane of most early vacuum tube battery radio sets is
the batteries. Some 80 years ago, when one needed a “A”, “B” or “C” battery,
they just strolled down to their local general store and picked one up, much like we
buy “AA” cells today. Now a days you’d be hard pressed to find a general store,
and the concept of buying a replacement battery for the early tube battery sets
is nearly impossible.

Over the years vintage radio fans have built, and in some cases cobbled together,
a number of “mains powered” battery eliminators. Most these worked, but few offer
the flexibility of the ARBE-III supply. Offering filament, “B +” and “C” bias voltages,
this supply is the way to go. The company also offers a neat series of covers to fit
over the supply, making it appear as an antique battery! You can find out more about
the ARBE-III supply on their website, entitled appropriately enough, www.arbeiii.com.

I’ve been using this supply with my Gross Eagle documentation, and during testing I
unfortunately shorted out the “C” supply, damaging the zener diode string. I emailed
the builder of the unit, it comes with a 5 year warranty, and asked if I could repair
it on my bench, rather than sending back for service. David, the owner of company, is
wonderful fellow to deal with, and he promptly sent me out replacement diodes (and some spares)
at no cost. The photos below show the ARBE-III unit during service on the workbench of W1UJR.


January 10, 2009 – Utah Jr. Transmitter Returns to Air – Restoration Done!
Finishing up a project first started in January of 2008, the Utah Jr. transmitter is done.
I had most of the rig completed last fall, waiting only to try my hand at lacing up the
new wiring harness. After some experimentation, I was able to nicely duplicate the
design of the original lacing job.

Today I finished the final assembly, testing and documentation of the rig.
Complete with the metal 6L6 Arcturus tube, the unit is now working very well on 75 meters,
and will be active on the other bands once I wind up additional output coils.

More info and photos can be found at the Utah transmitter page.



January 3, 2009 – A Gift From A Friend
On January 3, 2009 I was presented with a most wonderful homebrew creation by my good
great friend Larry NE1S. Larry has named the rig the “Pilot Quasi-Wasp” as it is based loosely
on the classic Pilot Wasp receiver from the late 1920s.

The rig uses three 201A tubes, has has plug-in cols to cover from the AM broadcast band up to
the lower bands. Built using vintage black bakelite panels, it works as wonderfully as it looks!

Instructions and a detailed write up can be found on the NE1S rig documentation page.