Richardson "5" Update

Thanks to members of the excellent Antique Radio Forums and to a Mr Richardson (No relation, I think) I have found out more about the history of this receiver. It turns out that the set had been restored in the past from fairly sad shape after being purchased at an AWA swap meet in New York.

Underneath the top desk of the radio is the text "Oct.17.1996 Billy Richardson" which confirmed that the radio had originally passed though his hands while being brought back to life.

However I'll let Mr Billy Richardson tell the story in his own words:

I'm guilty of owning the Richardson "5", guys. It was in poor condition when I bought it in an AWA swap meet in New York way back there years ago. I restored it to the best of my ability to its original condition a few years later. It was not a restoration that had anything special going for it, so it was never shown in any of the contests around the country. It was working OK when I finished it, but I can understand why it doesn't work now.

To the best of my recollection, Richardson radios were first advertised as a superheterodyne kit. Their main feature was "self evident wiring", or something like that. Naturally. they didn't get away with selling a superheterodyne kit and the next and only ad I saw after that was a small one for the Richardson "5". It used the same type of wiring.

Here again I speak from a poor memory, but the wiring for this set is one long piece of rubber coated flexible wire. Along its entire length it has lugs that simply pierce the rubber cover to make an electrical contact. Not a good thing, because only one or two strands of wire may be making contact and a wee bit of oxidation is all it would take to break the connection. This was the case with the original wire, which was also hard and brittle. I replaced it with NOS flexible wire that looked exactly the same. The finished job is an ugly sight, just like the original. All the lugs are spaced an equal distant along the wire, regardless of how far it has to go to the next connection and most of the wire is too long for those connections. In other words, it's a jumbled up mess of wire and not something to be proud of.

I recognized the photo of this set immediately as being mine because of the label under the lid. There was enough of the original left to make a good copy and I thought the reproduction turned out real well.

Billy Richardson

Alan Douglas of the Antique Radio Forums found a clipping from Radio Retailer & Jobber Oct.1925 which told of Mr Richardson's exit from the Richardson Radio Corporation. Given the very short period where any advertisements were made it seems like this corporation didn't last very long at all, perhaps only a year or two at most. In the Radio News of 1925 the January issue has quite a large advertisement while the December issue has only the smallest note possible ... perhaps a sign that things were not going particularly well.

The only additional information I could find regarding either the Richardson Radio Corporation or Mr Richardson himself come from the clipping of the Princeton Alumni Weekly, August 1936.

Unfortunately it concerns what must have been his early death and does not specify the cause which would have been appropriate at the time.

DAVID WELLES RICHARDSON '22
The Class records with deep sorrow the death of our classmate, David W. Richardson, who died at his home in Mt. Kisko on July 16.
Dave spent the first two years out of college in the radio business. He helped organize WOR and was the president of the Richardson Radio, Inc.
He then entered the employ of Joseph P. Day and for five years was head of the private sales department. About a year ago he entered the brokerage business with Harris, Upham & Co. and on July 1 entered the employ of Eastman, Dillon & Co.
Dave was married in 1932 and has a son, David Welles Richardson, Jr. To his widow, his son, and his father we extend our deepest sympathy with the assurance that we will not soon forget him.
    For the Class of 1922
    William E. Stevenson, President
    G. M. L. LaBranche
    Hunt T. Dickinson
    Robert Buechner, Secretary. 

Atwater Kent - Model 20 : Important Documents

One of the first things I do once I have acquired a new "treasure" is to gather together all the information I can find and stick it in one place.

To this end, here is what I have found online and scans of some of the paperwork I have acquired. Most will be specific to the Model 20 but some may also cover other Atwater Kent radios:

Sadly I do not have a high resolution scan of the Model 20 log card which I believe is Form F 103, can you help?

This is Form F 194 which would suit a single dial Atwater Kent radio.

The file is scanned at 600DPI and if printed at the same resolution it should be the same size as the original.

A small amount of cleanup may be required to print correctly on your printer.

Download the PNG file HERE (49MB)

At the right is the "Radio Log Cards and Important Instructions" envelope which was used to organize all the paperwork. This would typically be held in between the two clips inside the radio.

If you are wondering what those clips were used for, now you know!

The file is scanned at 600DPI and if printed at the same resolution it should be the same size as the original.

A small amount of cleanup may be required to print correctly on your printer.

Download the PNG file HERE (57MB)

This is the back of the envelope so you can see the fold patterns and get an idea of how it was put together.

I plan to clean up these images and generate a pattern which can be printed out via a large format printer at a FedEx office or similar.

The pieces I have are too fragile to use and would crumble if handled more than a few times.

The file is scanned at 600DPI and if printed at the same resolution it should be the same size as the original.

Download the PNG file HERE (56MB)

I have several of the loud speaker instruction sheets and they seem to be generic enough to suit any of the horn type loud speakers. As far as I know they all have a similar adjustment underneath and all users should heed the warning about connecting them to the receiver with the correct polarity.

As with all the images I have used full color images so you can see the original colors and then change it to black and while to increase contrast for printing.

The file is scanned at 600DPI and if printed at the same resolution it should be the same size as the original.

Download the PNG file HERE (54MB)

This is the Atwater Kent Radio Service Manual from 1928.

This manual covers from the Model 10 to the Model 52 including accessories such as the power units and loud speakers.

This manual was a pain to find so hopefully this will help some people out and ease frustration.

Download the PDF file HERE (8MB)





This is the Atwater Kent Radio Instruction Book Vol. 2 from 1925.

The instruction book covers the Model 10 through to the Model 24 and contains important photographs showing battery cables, battery boxes and other accessories.

Download the PDF HERE (14MB)








I'm looking for high resolution scans of the following two forms: F91A and F101 as shown in the picture below. If you have scans or can point me in the right direction I would appreciate it!

Philco Tropic Model 3012

Last weekend I attended the Houston Vintage Radio Association holiday dinner & picked up a Philco Tropic Model 3012 during the fundraiser auction. I had let a few other radios go without placing a bid and was beginning to think I might go home empty handed when I saw the Philco "on the block". A few seconds later I was the proud owner of this vintage receiver.

Philco Tropic 3012

Information on this model seems a little scarce, however the style of case was introduced by Philco in 1951 and used in their line of AM/FM receivers for many years after that. This particular example is a transformer-less AC/DC set with a potentially live chassis and the unusual (to me) lineup of 14Q7, 7B7, 14B6, 35A5 & 35Y4 vacuum tubes.

What prompted me to bid on this particular radio was the inclusion of two shortwave bands in addition to the typical AM broadcast band. The dials are marked off in meters which also appealed to the ham radio side of my interests.

After attaching a short length of wire as an antenna I was able to pick up signals across the two SW1 & SW2 bands so I'll be interested to see what it can receive with a long wire antenna at night.

After a gentle cleaning with dilute mild detergent to remove dirt I rubbed in some beeswax polish to restore the original gloss. Sadly the plastic dial is cracked in the middle but I can look past that given its a little more unusual than the typical All American Five receiver.

Being over fifty years old I wonder what this radio has been used to listen to and what stories it could tell. Perhaps it gave some youngster his or her first taste of ham radio, listening to shortwave stations and AM QSOs until they received the final demand to, "Switch that radio off and GO TO BED!"

Vacuum tubes could revolutionize computer chips?

No, I'm fairly sure I haven't lost my mind ... that really is the right headline.

According to a resent paper published in the American Institute of Physics, nanoscale vacuum "tubes" manufactured using conventional chip making techniques have operated at frequencies as high as .46 THz.

Dr. Meyya Meyyappan, Director at the Center for Nanotechnology at the NASA Ames Research Center, has highlighted the advantages of nanoscale vacuum devices which include resistance to hard radiation and significantly improved operating frequencies.

The increased operating frequency comes about because of the speed at which electrons travel through different materials. The speed of electron travel through silicon is comparatively slow, through graphine it is approximately 100 times faster and through a vacuum it approaches the speed of light.

While the cavity is not technically a vacuum it contains so few atoms of any other material, such as oxygen, it is functionally the same. This also gives the vacuum nanoscale device an advantage in space where hard radiation can disrupt an electron's travel through silicon leading to errors or sometimes permanent failure.

Dr Meyyappan estimates that vacuum nanoscale components will run ten times faster than the best conventional silicon chips and who knows what advances the future will hold. Faster chips will aid in signal processing and more capable software defined radios.

Do you want to monitor every CW & PSK31 transmission on the 40M band at once? With a vacuum "tube" rig you may be able to!

Hollow state decade counter.

If you have looked through my blog you'll know that I have a soft spot for tubes and tube technology. At a time when our understanding of electron mechanics and quantum theory was still in development the manufacture of advanced vacuum tubes was part science, part physics and part art.
Special purpose tubes were developed in their thousands to meet the needs of commercial, scientific and industrial applications. Their form and functions were as varied as the devices they were installed in. Sometimes tubes were developed to meet a specific need and sometimes new tubes were developed for applications not yet in existence.
The E1T tube is impressive even among special purpose tubes. It functions as a decade counter with an inbuilt display! Many years later it would take several chips and associated display circuitry to achieve the same result using solid state components.
This is a somewhat long introduction to the excellent article by Ronald Dekker on the people and the story surrounding the development of vacuum tubes technology in Holland and the E1T tube in particular.
If you have a moment take a look at The making of the E1T by Ronald Dekker and revisit a time when electronics, physics and art were brought together to create 'technology for a better tomorrow".

Another hand-made vacuum tube!

Another hand-made vacuum tube video! This time it is a French amateur radio operator by the name of Claude Paillard creating a more familiar type of triode tube with a custom four pin base.

The video runs for approximately 17 minutes and is accompanied by an instrumental version of "The Man I Love" written by George Gershwin.

Making a Type C Triode - Amazing Glasswork!

Ron Soyland is at it again and creating a Type C Triode vacuum tube. For a look at other creations click on Making a Spherical Audion Tube by Ron Soyland

A general purpose triode originally made for use by the Royal Air Force (Great Britain) in 1918 and designed by Captain H. Round of the British Marconi Co. around 1913. It is a triode that was meant for high gain high frequency use and has a 3 volt directly heated cathode.

EICO Model 625 Tube Tester

I attended the Greater Houston Hamfest and as I walked past the tables of equipment I wondered if interest in vacuum tube equipment was starting to wane. Compared to the last few years the prices of collector quality gear had held steady but parts and restorable gear seemed to be going for less.  I'd like to know your thoughts if you've noticed trends one way or the other.

I was happy to pick up a EICO Model 625 tube tester for $15. It is in good condition and appears to work well. The roll of settings for each tube is in good condition and a little searching on the internet supplied settings for older tubes like the number 78 in the picture below.

EICO Model 625 Tube Tester with a number 78 tube

The EICO 625 is not a top of the line tester but it does basic tests and will let you know if a tube is functioning and an idea of the life left in it. It was sold in kit form for $34.95 in 1958 which is roughly equivalent to $274 in 2012.

Inside the EICO 625 from diyaudioprojects.com

The EICO 625 is fairly unique in having its own 6H6 diode tube to rectify the 30V filament voltage. It provides DC for the neon short-indicator bulb. If the tube is suspected of having a short then there is a fairly comprehensive series of tests than can be administered to isolate shorted elements.

EICO Model 625 circuit diagram

Here is the Users Manual and Roll Chart for the EICO Model 625 Tube Tester

Here is the complete TUBE TEST DATA 1/1/78 for the EICO Model 625 Tube Tester

Some settings for less common and older tubes are contained in : eico_625.zip

Excellent information on servicing and calibrating your Classic emission tube tester.

ARRL President Kay Craigie, N3KN presents an insightful and inspiring talk about Amateur Radio

Lately I have been giving a lot of thought to the notion that, as a amateur radio operator, I should be engaged in this or that activity ... should volunteer for something ... should be building equipment ... should be operating more ... well, you get the picture. I enjoyed the following video because it highlighted the variety of experiences in amateur radio and how each has value to the community in its own way.

If you talk to any group of ham radio folk (or read through a ham radio publication) you'll always run the risk of feeling that somehow you're just not doing enough stuff and that you're not holding up your end of the deal. The FCC made allowances for you to operate on several bands of frequencies which are set aside for amateur radio use ... you really should be using them right?
The answer to that ... as far as I now think ... is yes, and also maybe. To be perfectly honest I do enjoy getting on the air from time to time and making contacts, usually digital as I don't seem to have an ear for picking out SSB voices from the noise. However ... there are other things like vintage vacuum tube equipment, experimenting and the history of ham radio technology that I enjoy more.
I came to realize that, much like genetic diversity, a ham radio club that has members interested in a wide range of things could potentially be more robust and offer a greater service to the community and its members. There is one critically important caveat here however and it has been the downfall of several special interest clubs in the past. In order for a club with members having diverse interests to survive and thrive there must be a significant amount of tolerance shown by each and every member. We are both united by a common interested and made unique and interesting by the variety of ways that common interest is manifest.
If you don't operate QRP then stop a moment and talk to someone who does, if you only operate CW then chat to someone who operates digital modes or phone. Different disciplines can always benefit from a little cross traffic and you may be amazed at what you learn!

Pop's Shed and the Kingsley Radio AR7

After my grandfather passed away I spent a lot of time recalling the good times I had spent scrounging around his CB shack and hanging out with Pop "down the shed". If you've spent time around old motorbikes, retired lawn mower engines, vacuum tube electronics and inches of dust you know what the shed smelt like and probably have a pretty good idea what it looked like as well.  I used to be able to send Mum into fits by embedding a combination of oil, grease, dust and grinding compound into the knees and sleeves of my good clothes after spending the day "over south" (South Geelong)

Even now I can still walk into any old auto mechanics and the smell brings back dozens of memories as clear as day ... but one memory in particular had been bugging me for a while now. On several occasions I had used a magnificent rack mounted shortwave receiver that had been hooked to a long-wire antenna between the shed and the house. It had several plug in coils housed in bright metal boxes, one for each band as well as a unique tuning dial that had windows around the circumference with numbers that updated as the dial was turned.

National HRO right? ... Nope, its an Australian clone!

For the longest time I was thinking what you are probably thinking now, I had been using a National HRO receiver right? Well, you'd be wrong ... just as I had been for years! When I eventually asked my uncle about the receiver (I waited a long time as I feared it had been thrown out & honestly didn't want to know if it had) he said, "The AR7?" ... "Yes, its here in the garage covered in dust". He went on to say that I could have the receiver if I could figure out some way to ship it ... not a slight problem given the receiver, power supply and speaker are over 120 lbs!

Knowing now that I had been using a completely different receiver I set to work and found out what I could about this National HRO clone ...

From : http://www.vk2bv.org/

The AR7 was produced during WW2 by Kingsley Radio of Melbourne for the R.A.A.F. These receivers were used in ground stations for long range communication over fixed circuits as well as for receiving signals from aircraft.

The AR7 was based largely on the National (USA) HRO model, a fact that did not go unnoticed by National. This was the subject of litigation during the war years. Over 3000 of these receivers were produced and for their time, produced excellent performance.

These sets were very popular with radio amateurs after the war and unfortunately subject to many modifications. The Wireless Institute of Australia station, VK2WI at Dural New South Wales was equipped with modifed AR7's for many years. I seem to remember that very local operators could block the receivers completely, resulting in hurried phone calls!

An unmodified AR7 is a rare beast. The Department of Civil Aviation used these sets for many years in a highly modified form, requiring a new front panel. Refinements included squelch and crystal locked coil boxes.

From : http://www.shlrc.mq.edu.au/~robinson/museum/AR7/

The AR7 is a communications receiver covering LF and HF bands. It was made in Australia during 1940 and bears an extremely close resemblance to the National HRO receiver. The receiver has a tuning range from 138 kcs to 25 mcs, with a gap of 45 kcs either side of the 455 kcs IF amplifier. The internal design is a single conversion superheterodyne receiver with 2 RF stages, 2 IF stages, a BFO and an "S" meter amplifier. The sensitivity is quoted as 1 microvolt. The front panel is stainless steel and  it is a very distinctive looking receiver.

It is a good performer, sensitive, has a nice feel, is easy to tune, but hard to find the correct frequency, by reading the frequency from the dial number and coil box graph. It really needs a crystal calibrator.  I use it for the weekly W.I.A. (Wireless Institute of Australia) broadcast, so it gets turned on once a week, and is so stable, than I don't have to retune. It is very clear for AM but a bit fiddly for SSB.

The controls are: RF gain, BFO note, AVC/BFO switch, Adjust "S" meter, Tone, Tuning, Noise limiter, Selectivity, Crystal IN/OUT switch, Crystal Phasing, Audio gain. The Audio gain control has an OFF position which removes the HT so that the coil boxes can be changed.

It has two 6U7G RF stages, a 6K8G mixer, two 6U7G  IF stages at 455 kcs,  a 6G8G detector/AVC/audio preamplifier, and a 6V6G audio output amplifier. It has a 6C8G twin triode as a BFO and "S" meter amplifier. It also has a crystal filter. The IF alignment should be done very carefully, as any misalignment will reduce the effectiveness of the filter. It is best done with a sweep generator. The 6 volt valve heaters are connected in series, for 12 volt operation.

The external power supply and speaker, are usually mounted in a short 19" rack, the AR7 at the bottom, the speaker in the middle, and the power supply at the top. The complete unit weighs about 118 pounds. The power supply was switchable between 12v and 240v.

The receiver was used as a ground monitoring receiver for aircraft. It was extremely stable. The model shown has an R.A.A.F. nameplate, and serial number 1786. The manual I have is a D.C.A. (Department of Civil Aviation) version and is a 1947 issue.

It has 5 plug in coil boxes. The coil boxes are: band A 140-405 kcs, band B 490-1430 kcs, band C 1.420-4.3 mcs, band D 4.25-12.5 mcs, band E 12.5-25 mcs. The Army version had an extra coil box covering 50-150 kcs. The large dial is a 20:1 reduction drive and has graduations from 0 to 500. It acts like a flywheel when tuning across the band, and has an effective scale length of 12 feet. The dial shaft goes into a right angle reduction gearbox and has 2 output shafts that drive 2 dual gang capacitors. The graph on the front of each coil box is used to covert the dial reading to frequency.

PACO C-25 Capacitor Tester

I recently attended the Houston Vintage Radio Association post holiday dinner and participated in the auction held after the meal. It was a great evening and if you have any interest in vintage radio I would suggest getting in touch with the HVRA and becoming a member.
Among other things I walked away with at the end of the evening was a PACO Model C-25 capacitor tester.

The PACO C-25 differs from my Healthkit IT-22b in that it tests both regular and electrolytic capacitors as well as using a 40Mc oscillator to enable a rough measure of capacitance using a bridge circuit.
Most of the time, with vintage vacuum tube equipment, capacitor values need only be "in the ballpark" to function perfectly so a high degree of accuracy is not required. For more accuracy I have a Heathkit impedance/capacitance bridge if required.
I have my doubts how accurate the tester would be when measuring capacitance "in circuit" but otherwise it looks to be a very useful bit of kit!
The users manual should be available here and the circuit diagram is shown below.

Preserving the past - Australian built broadcast transmitters

Arguably some of the best looking radio equipment was produced in the 50's and 60's when art-deco motifs, streamlining and other elements of design made their way onto consumer and even industrial electronics.
Unlike modern times, when cost is the only consideration, designers and engineers took the time to ensure that their creations looked good as well as being functional and long lasting. It was worth taking time over the placement of meters, switches & panels, even if it did mean that the final product cost a few dollars more to manufacture.
Amalgamated Wireless (Australasia) or AWA produced an extensive range of home and commercial equipment in the 60s and many vintage radio collectors have examples of AWA radio receivers in their collections. The larger equipment like broadcast transmitters takes an extra special effort to preserve as their large size, demanding power requirements and the specialized knowledge required to maintain them presents a barrier for all but the most dedicated enthusiasts.
We are fortunate then that Don Bainbridge has taken up the challenge and preserved a remarkable collection of Australian built broadcasting equipment and maintains much of this equipment in operational order. The YouTube video below and his website linked here offer a rare glimpse into the world of vintage high powered broadcast equipment before plastic took over and economical design stripped away the chrome and pinstripes.

Making a Spherical Audion Tube by Ron Soyland

Another great series of videos from Ron Soyland. In this video he recreates the classic Audion tube invented by Lee De Forest in 1906. The particular tube he creates in this video appears to be similar to the 1909 version of the Audion but substantially better made. The original Audion tubes were usually crudely constructed without the benefit of modern tooling or our current understanding of thermionic emission, they were expensive and had a short lifetime but paved the way for better tubes in the following years.

Making a Fleming Diode Tube - Ron Soyland

Its not often we get to see someone create a vacuum tube in their home workshop. Ron Soyland, a member of the Houston Vintage Radio Association, created these YouTube videos to show the process behind reproducing a Fleming diode tube. He carries out every task himself, from creating the glass envelope to final evacuation and testing.
Each video is approximately 10-15 minutes long and there are seven parts. Grab yourself a beverage and sit back to watch this fascinating process from raw glass to electronic component.

Essential information regarding 6146 tubes by K9STH

The 6146 family of tubes has been used in many home-brew commercial and transmitters over the years. The following information explains important points to look out for when replacing these tubes or home-brewing your own 6146 based transmitter. Normally I don't just copy and paste an entire article but this information should be included in every 6146 based rig's instruction manual, in bold type, at the start. KF5CZO

6146/6146A/6146B/6146W 8298/8298A/6293 

*6883/*6883A/*6883B *8032/*8032A/*8552 

Tubes Explained 

(*12 volt filament)

By K9STH 

The 6146 and the 6146A differ in the type of heater (filament) and can be "mixed" in use (i.e. one 6146 and one 6146A in a DX-100). There are no other differences. The heater in the 6146A was developed by RCA and is called a "dark heater". The type 8298 is the same tube as the 6146A.

The 6146B is the same tube as the 8298A. The 6146B is a different tube from the 6146/6146A/8298. Sometimes they will work in place of the 6146/6146A, but often they will NOT. This is due to the different bias requirements of the 6146B, different inter-electrode capacitances, among other things. Often it is impossible to either neutralize the final in a rig designed for the 6146/6146A or the neutralization does not "hold" for very long (often less than an hour).

The 6146B/8298A have a very bad habit of producing VHF and UHF parasitic oscillations which can cause all sorts of problems including TVI as well as the tube literally "burning" itself up. This is when they are used in circuits that were designed for the 6146/6146A.

Collins Radio had to modify production of the later S-Line units to allow the military to use 6146B type tubes. This required a redesign of the neutralization circuit which is in place in the later 32S3, 32S3A, KWM-2, and KWM-2A units. The earlier versions of these models must use the 6146/6146A tubes. The later version can use all three types.

There is a "pulse" tube that is a very heavy duty version of the 6146 and can be substituted without any problems. This is the 6293. A 6293 will outlast a "plain" 6146 by at least 5 times the life (over 10 times is not that unusual!). We would "kill" back in the late 1950s and early 1960s to get our hands on a pair of 6293 tubes for our DX-100s, etc.

The 12 volt equivalent of the 6146 is the 6883. The 12 volt equivalent of the 6146A is the 6883A/8032 and the 12 volt equivalent of the 6146B is the 6883B/8032A/8552. The same thing is true of these tubes, do not replace the 6883/6883A with the 6883B series of tubes.

Back in the late 1970s Motorola tried to replace all of their 6883A/8032 tube stock with 6883B/8032A/8552 type tubes. A very large number of Motrac units used the 8032 and only the very "latest" versions used the 8552 tubes. At the time I owned the Motorola reconditioned equipment center for the south-central US and we used, on average, over 100 8032 tubes a week. Just as soon as Motorola replaced the 8032 with the 8552, we started having virtually all of the Motrac units that were shipped to the customer arrive with the tube envelopes "shattered" by "normal" shipping. We had never had this happen before.

The construction of the Motrac is such that the tubes cannot be seen when the unit is assembled. What was happening is that in the 2 to 5 minutes that the radio was being tuned and final QC'd, that they were oscillating at UHF (parasitics) and the tubes were getting so hot that the glass envelope was destroyed!

We told Motorola what the problem was. However, they refused to believe us until they had well over 1000 warranty complaints from their service stations. It cost them quite a lot of money in warranty repair bills before they again started placing 8032 tubes in the boxes marked 8032!

I have quite a number of "boat anchor" rigs that use the 6146/6146A type of tubes including Collins 32S1, 32S3; Heath SB-110A, SB-401, DX-100, DX-35, Apache. I have owned rigs like the Knight T-150 and T-150A and others that were designed for the older tube. Frankly, all of them are much "happier" with the 6146/6146A instead of the 6146B.

Now, for the 6146W: Unfortunately, some of these are "ruggedized" 6146A tubes and the later ones are 6146B equivalents. The only way to tell is by the manufacture date on tubes by a particular manufacturer. Unfortunately, to my knowledge, there is no master list giving this information. Each manufacturer changed from the 6146A to 6146B construction in their 6146W at different times.

I haven't seen a notice from Heath about using the 6146B tube. However, several manufacturers, including Collins Radio, originally said that it was fine to use the newer tubes. But, after a very short period of time they found out different!

Thus, I would be very careful about using the 6146B and the 6146W tubes in place of the 6146/6146A. You might "get away" with it. However, you might also do some damage to your final amplifier section. If you decide to try the 6146W, then be sure and neutralize the final and check it after operating for an hour or two. If the neutralization remains OK for several days, then you should be "home free". But, if the neutralization changes, then you need to replace the 6146W tubes with the 6146/6146A types.

Glen, K9STH

New project - Heathkit SB-101

I've recently been presented with a Heathkit SB-101 transceiver, Heathkit SB-600 speaker and Heathkit HP-23A power supply courtesy of Philip KJ5OW of the Katy Amateur Radio Society.

The SB-101 is a hollow state rig, the only solid state components being a few diodes. It uses the well known, and fortunately fairly common, 6146 output tubes in the finals.

The manual is available here : Heathkit_SB101_Manual

Heathkit SB-101 Transceiver

There looks to be a little work required before this rig is put on the air, a few resistors have cracked for reasons unknown and the rubber belts need replacement in the load and tune controls. It is something worth taking time on as the SB-101 is a well regarded rig that is still a strong performer today. There have been some modifications made to support an external linear master oscillator (VFO) which will need to be looked at but are probably fine as they stand.

I pulled my Heathkit HD-1410 keyer out of storage and was pleased to find it was the same color and style, matching the SB-101.

Heathkit SB-101 transceiver, SB-600 speaker, HP-23A power supply and HD-1410 electronic keyer.

Specifications:

Year of Manufacture: 1967-70 (Improved SB-100[1965-7])
Bands: 80 - 10 (500kc) (2 Mhz on 28-30 mhz)
Modes: CW & SSB
Power: 180W PEP SSB & 170 input CW - 6146 Output Tubes
Frequency Control: LMO- Linear Master Oscillator (Like PTO)
Selectivity: 6 Pole filter 2.1kc @ 6db down (Accessory CW filter 400hz)
Contstruction: Aluminum Chassis & Cabinet-Printed circuit board wiring
Keying: PTT and VOX voice operation, VOX with sidetone for CW
Power Supplies: AC or DC power supplies availiable
Microphone: High Impeadance Desk or Mobile Microphones availiable.
Frequency Control: Local LMO/Xtal, Remote VFO/SB-640 w/Mod

Accessories: SB-200 Linear Amplifier, SB-500 2mtr Xvtr, SB-600 Speaker, SB-610 Monitor Scope, SB-620 Panadapter, SB-630 Station Console, SB-640 Remote VFO & SB-650 Digital Read-out.

Features: Easy to operate, TX & RX circuits track, RX RF Preamp, Easy to calibrate and read dial calibration, Two-Tone Green wrinkle paint, Switched Metering, Construction Manual very comprehensive.

Heathkit Transceiver Resources:

• Heathkit HW & SB series parts : http://www.ultrawebb.com/OHP/index.htm
• Heathkit HW & SB series modifications : http://boatanchor.com/Heath/HW101MOD.PDF
• Digital Dials for Analog Rigs : http://www.aade.com/
• Dialcord replacement for o-ring drives : http://nrwilliamson.tripod.com/dialcord.jpg
• General HW & SB repair information : http://www.qsl.net/k5bcq/102/102.html

Latest restoration project - Espey R-366/TRR-5 Radio Receiver

The Espey R-366/TRR-5 is a general purpose receiving set designed for use as an entertainment unit or auxiliary communications receiver. The receiver is a manually tuned, 16 tube superheterodyne. It has a tuning range of 540 to 30,000 kc in five tuning bands and receives either CW or voice signals.

It is similar to the Scott receiver AN/SRR-3 of the same period and produced under Contract NObsr-43229 dated 15 March 1949.

A user manual is available here : ANTRR5_INSTRUCTION_BOOK

The front panel as it originally looked.

The front panel once it had been cleaned.

First page in NAVSHIPS describing AN/TRR-5 and performance specifications.

Detailed shipping information for AN/TRR-5 receiver.

From the Antique Radio Forums :

Most of them were purged via DRMO in 1968-1973 and I only saw small numbers of them trickling through the system so I am guessing they were made in only a small quantity. None of the ones I have run across have had cabinets and all were in pretty atrocious condition. I vaguely recall the processing papers showing the equipment had come back from Vietnam, Guam, S. Korea and Japan.

Geoff Fors - WB6NVH

If you have any information regarding these receivers please leave a comment. If you have a R-366 of your own please let me know the serial number in the comments!

R-366/TRR-5 serial number registry:

1. #623 : KF5CZO - Owen Morgan
2. #050 : AE5VB - Hugh Coleman
3. #132 : W5AMI - Brian Sherrod
4. #591 : KC9KUH - Brian Love : (Compliance plate missing)
5. #290 : KC5IIE - Chris Krug (Update 01/11/2012 : Sold to W5XTL - Jeramy Ross)
6. #653 (Sold on Ebay, spotted by Brian KC9KUH)
7. #251 (Sold on Ebay, spotted by Brian KC9KUH)
8. #340 (Sold on Ebay, spotted by Brian KC9KUH)
9. #468 Jeff Wewers
10. #140 Gilbert Mendez
11. #097 James Starling

Using the formula N=m(1 + k ^{− 1}) − 1  from the german tank problem where m is the largest serial number observed and k is the count of serial numbers we see that the current estimated number of R-366/TRR-5 receivers produced is N=653(1+11 ^{− 1}) − 1 or approximately 711.

After bringing this receiver up on a variac to reform the filter capacitors I monitored the power usage and found it to be in line with the users manual @ approx 125W.

Audio is great due to the push-pull output stage and either a 6 ohm or a 600 ohm speaker can be used, both impedances are available on the rear connectors.

Readout seems accurate and the VFO is stable after just a few minutes warmup. Tuning the HAM bands is fairly touchy but this is really an AM rig by design.

Serial number 623 of how many? This seems to be a rare radio but I have heard of at least 4 other people with the R-366.

The bandchange is accomplished by rotating the circular turret. Each of the five bands has a complete set of discrete components in its sector of the drums.

Military amphenol right angled connectors. The three pin connector is 110V power in and the four pin is the 6/600 ohm speaker connector.

I was fortunate enough to be given period style military connectors for these sockets. Both neutral and active lines are fused on the power input circuit however I made sure to wire the active line to the power switch side for safety.

The receiver chassis slides out on roller slides for servicing and inspection. The full circuit diagram is also on the band change turret cover ... a thoughtful addition!

The only modification I can find is the antenna connector. Its been replaced with a SO-239 bulkhead connector for convenience. Personally not something I would have done myself but it makes life easier so I'm not complaining.

An unmodified antenna connection from another Espey R-366

Sick radio on the bench

Should have been an easy fix but I suspect, after running a few searches through Google, that it is suffering from the dreaded silver mica disease. This would require taking the IF coil cans apart and replacing the integral silver mica capacitors with external units, not a project for the feint of heart!

Another day perhaps ... there are other projects to complete first.

Zenith 6J05 chassis and IF cans, looks simple enough doesn't it?

Front view of the Zenith chassis, the dial light also requires replacement.

Tubes! ... Some will be used in a homebrew transmitter.
The EICO signal tracer (behind the box of tubes) is working fine now but the EICO RF signal generator requires work.

An old tube AF power amp, low pass filter, coils, chokes and my meter collection ... there is even an RF ammeter in there somewhere.

Hallicrafters S-85

I recently purchased a Hallicrafters S-85 radio receiver. I was lucky enough to find one in excellent condition that hadn't been modified by its previous owner. In fact, it even had its full compliment of paper labels and was only missing the owners manual which I was able to download from the net and make available here : Hallicrafters_S-85_Manual

Hallicrafters S-85 Receiver - Sold 1954 through 1959

While I'm slowly assembling the pieces of a vintage amateur radio station I have been researching what it would have been like for a ham around the period of the equipment I have accumulated. One thing I just started thinking about now was the cost of this equipment when new ...

The Hallicrafters S-85 was sold between 1954 & 1959 for USD $119.95. This relates to about USD $1014 in 2011 dollars! That is a lot of money for a young ham to come up with and perhaps explains why more modest receivers were used in novice stations. A more advanced ham would probably purchase something with crystal filters, which the S-85 lacked, like the Hallicrafters SX-99

From the little time I have had with this receiver I have been impressed by its performance. For a receiver that is over 50 years old it has withstood the march of time and performs very well. Although it is possible to listen to single side band transmissions it is really suited to AM and CW reception.

Listening to AM broadcasts is where it really shines, the generous bandwidth and tube audio make the most of shortwave broadcasts and listening becomes a pleasure rather than something you have to work at.

Hopefully one day it will be paired with a yet-to-be-acquired transmitter and I'll participate in a few AM QSOs

73

KF5CZO