Six 1940 Philco tv's giveaway

[decojoe67]

Common knowledge has always been that Philco's first line of production TV's was in 1948. I've seen a slew of photographs of earlier Philco prototype sets, but they were just that. I can only guess that these winners received limited pre-production sets. Maybe it was a promotion by Philco to give these sets away and get feedback to decide when to go into production. Sales of TV's were very poor in the pre-war days and there was a lot of problems both with the sets and the availability of programming. Most companies like Philco opted to wait until things got worked out, which was about 1948.

[tubesrule]

Originally Posted by decojoe67

Sales of TV's were very poor in the pre-war days and there was a lot of problems both with the sets and the availability of programming.

I'm not aware of any specific problems related to pre-war receiver design and operation. These sets performed fine for their times, and are on par with many early post-war sets.

This contest is certainly very interesting. As Dave A pointed out, why would they have a nationwide TV contest where only a few people could actually use the sets?.

[dtvmcdonald]

Originally Posted by tubesrule

I'm not aware of any specific problems related to pre-war receiver design and operation.

Indeed! Except for the bad paper caps, none of the parts in my two prewar TVs, a TRK12 and a TT-5, seem problematic. Of course, they don't
have flybacks. The HV oil caps are sealed and are at least OK.

Now about that TRK-12 radio ... the Rube Goldberg radio motor driven
system looks like it was designed become sparky, flaky, noisy, and
a general pain. The direct-drive pushbutton setup in the U-10
radio-phono that provides the TT-5's sound is much simpler and in fact
more reliable, not to mention cheaper.

[decojoe67]

Originally Posted by tubesrule

I'm not aware of any specific problems related to pre-war receiver design and operation. These sets performed fine for their times, and are on par with many early post-war sets...

It was not so much about the operation of the sets being a problem, but their reception. I've definitely read of annoying interference problems that pioneer TV watchers dealt with in the day that were eliminated in the post-war years. The general performance of pre-war sets was adequate, but with huge leaps made in electronics due to the war-effort, many bugs were worked out and advances made for post-war TV's. It is definitely noted that the 1946 RCA 630TS is a superior set compared to the 1939 TRK-12. Between the circuity improvements and the timing being right for the public to accept the new technology, TV in the USA was basically re-introduced in the post-war years.

[tubesrule]

Originally Posted by decojoe67

It was not so much about the operation of the sets being a problem, but their reception. I've definitely read of annoying interference problems that pioneer TV watchers dealt with in the day that were eliminated in the post-war years. The general performance of pre-war sets was adequate, but with huge leaps made in electronics due to the war-effort, many bugs were worked out and advances made for post-war TV's. It is definitely noted that the 1946 RCA 630TS is a superior set compared to the 1939 TRK-12. Between the circuity improvements and the timing being right for the public to accept the new technology, TV in the USA was basically re-introduced in the post-war years.

The only interference problems due to the design of the reciever I am aware of is from an anecdotal tale of the local oscillators in nearby sets interfering with each other. Other external interference sources would have been the same before and after the war. (ICE ignitions, diathermy, brushed motors, etc.) This in no way inferrers a lack of understanding on the part of the pre-war engineers or a limitation of the technology available to them. Most pre-war receivers lack an RF amp in front of the tuner, just like many post-war sets, as this was deemed unnecessary given most sets would be sold and used in a major metropolitan area.

There were really no technologies developed during the war that advanced the basic operation or performance of the receivers immediately post-war. The advances came in the form of miniaturization and cost reductions. While a 630TS is probably the pinnacle of immediate post-war design, it contains no technology that was not known, or could have been built pre-war for the right amount of money. Mass production and building to a certain price/performance target is what drove the technology. For instance, having a flyback power supply while technologically advanced and known before the war, provides no tangible operational advantage to the user over a mains derived supply. It does provide a cost and size advantage.

All this is to say a pre-war receiver like the TRK12, while not as technically advanced as a 630TS, will perform as good or better than many immediate post-war sets from the users point of view. Take for instance the ubiquitous VT71. These represent probably the most common design of post-war sets and their performance pales to many pre-war sets.

[Electronic M]

Originally Posted by tubesrule

The only interference problems due to the design of the reciever I am aware of is from an anecdotal tale of the local oscillators in nearby sets interfering with each other. Other external interference sources would have been the same before and after the war. (ICE ignitions, diathermy, brushed motors, etc.) This in no way inferrers a lack of understanding on the part of the pre-war engineers or a limitation of the technology available to them. Most pre-war receivers lack an RF amp in front of the tuner, just like many post-war sets, as this was deemed unnecessary given most sets would be sold and used in a major metropolitan area.

There were really no technologies developed during the war that advanced the basic operation or performance of the receivers immediately post-war. The advances came in the form of miniaturization and cost reductions. While a 630TS is probably the pinnacle of immediate post-war design, it contains no technology that was not known, or could have been built pre-war for the right amount of money. Mass production and building to a certain price/performance target is what drove the technology. For instance, having a flyback power supply while technologically advanced and known before the war, provides no tangible operational advantage to the user over a mains derived supply. It does provide a cost and size advantage.

All this is to say a pre-war receiver like the TRK12, while not as technically advanced as a 630TS, will perform as good or better than many immediate post-war sets from the users point of view. Take for instance the ubiquitous VT71. These represent probably the most common design of post-war sets and their performance pales to many pre-war sets.

I disagree with your point. One example I can give is intercarrier audio IF. It was a WWII invention that reduced the tube count greatly, and stabilized relative fine tuning of sound and picture...So they would drift together and in the same direction as the set warmed up.

[decojoe67]

Originally Posted by Electronic M

I disagree with your point. One example I can give is intercarrier audio IF. It was a WWII invention that reduced the tube count greatly, and stabilized relative fine tuning of sound and picture...So they would drift together and in the same direction as the set warmed up.

I would like to add further from an article by Jack Davis in A.R.C. Here is an excerpt:
".....the 630TS was the first set to use a 13 channel turret tuner. The video IF's were stagger tuned to give a video bandwith of 4 MC and the horizontal sync was automatic frequency controlled allowing the set to lock-in on a signal as weak as 50 microvolts, thus expanding reception to so-called "fringe" areas. The 10BP4 picture tube, designed for the 630TS, operated with an anode voltage of 9,000 volts, developed through the now familiar fly-back method, doing away with the lethal 60 cycle power supplies that were used in the pre-war sets. The high definition picture that was produced was about sixty foot lamberts, almost ten times brighter than the TRK's. In addition, the area contrast of a maximum of 90 to 1 was the best ever. The set was simple to operate because of the drift-free circuitry...."
Also from Ray Bintliff, from an article about the 630TS in A.R.C.:
"....it is apparent that the 630TS was vastly superior to the TRK-12. It's picture size was slightly smaller, by about roughly one inch in width and height, but it produced better quality pictures and sound...."
I may also add of the addition of the ion-trap on the 630TS to prevent ion burn that plagued the pre-war CRT.
Joe

[tubesrule]

Originally Posted by decojoe67

I would like to add further from an article by Jack Davis in A.R.C. Here is an excerpt:
".....the 630TS was the first set to use a 13 channel turret tuner. The video IF's were stagger tuned to give a video bandwith of 4 MC and the horizontal sync was automatic frequency controlled allowing the set to lock-in on a signal as weak as 50 microvolts, thus expanding reception to so-called "fringe" areas. The 10BP4 picture tube, designed for the 630TS, operated with an anode voltage of 9,000 volts, developed through the now familiar fly-back method, doing away with the lethal 60 cycle power supplies that were used in the pre-war sets. The high definition picture that was produced was about sixty foot lamberts, almost ten times brighter than the TRK's. In addition, the area contrast of a maximum of 90 to 1 was the best ever. The set was simple to operate because of the drift-free circuitry...."
Also from Ray Bintliff, from an article about the 630TS in A.R.C.:
"....it is apparent that the 630TS was vastly superior to the TRK-12. It's picture size was slightly smaller, by about roughly one inch in width and height, but it produced better quality pictures and sound...."
I may also add of the addition of the ion-trap on the 630TS to prevent ion burn that plagued the pre-war CRT.
Joe

Joe,
The 630TS was a well designed chassis. I have not argued that point. My original post was in response to your assertion that pre-war receivers suffered from interference and poor designs that were improved by technological advances during the war. I have yet to see anything to support this assertion. Flybacks, ion traps, staggered IF's... had nothing to do with technologies developed during the war and were all known before the war. The RR359 used staggered IF's, the pre-war Philco's used ion traps, the Telefunken E1 used a flyback... The 630TS is simply the culmination of value engineering to create a smaller, well performing receiver. While many innovations certainly were in the works and came over the following years, my point was the technology advances of the war did not result in immediate advances to the underlying design of receivers.

While I never had the pleasure to meet Mr Davis, I believe the excerpt you posted is simply his opinion and not in any way a technical evaluation of the two sets. My 630TS has sat next to my TRK12 for 15 years, and in my subjective opinion, they both produce images of excellent quality (being fed directly from a modulator), are equally easy to operate, and neither one requires any readjustments do to drift. The TRK12 has a strong, original crt and is nearly as bright as the 630TS. There is simply no technical reason the 10BP4 at 9KV would be 10 times brighter than the 12AP4 at 7KV.
In my engineering opinion, while there are certainly parts of the design that make the 630TS superior to the TRK12, the TRK12 is not inferior due to a lack of knowledge by the pre-war engineers, or by the "advances" made during the war.

Intercarrier sound was developed post-war and is one of those technological advances that is double edged as David pointed out. From an engineering standpoint, it's great as it simplifies the design (cost) and offers better drift performance (tangible benefit to the user), but can cause problems of it's own.

The original topic I was replying to was technologic advances created directly or indirectly by advances during the war, yet no instances of such advances have been presented.

Darryl

[tubesrule]

Originally Posted by Electronic M

I disagree with your point. One example I can give is intercarrier audio IF. It was a WWII invention that reduced the tube count greatly, and stabilized relative fine tuning of sound and picture...So they would drift together and in the same direction as the set warmed up.

Tom,
You got me curious about the development of intercarrier sound. I haven't been able to find a definitive source of the early history of it's developments, but did come across this well researched thread:
http://www.forum.radios-tv.co.uk/vie...php?f=5&t=3824

From this source it would appear to be a post-war development. I also found several patents dating from 1950. Does anyone else have a source for the history of intercarrier sound?

Darryl

[Electronic M]

Originally Posted by tubesrule

Tom,
You got me curious about the development of intercarrier sound. I haven't been able to find a definitive source of the early history of it's developments, but did come across this well researched thread:
http://www.forum.radios-tv.co.uk/vie...php?f=5&t=3824

From this source it would appear to be a post-war development. I also found several patents dating from 1950. Does anyone else have a source for the history of intercarrier sound?

Darryl

I'm by no means an expert, but I seem to recall reading probably on the ETF website or in a 50's publication that the experimental TV guided bombs of WWII were the first use of intercarrier sound...I'm fairly attached to the notion that it was a WWII military development.

[dieseljeep]

Originally Posted by tubesrule

Tom,
You got me curious about the development of intercarrier sound. I haven't been able to find a definitive source of the early history of it's developments, but did come across this well researched thread:
http://www.forum.radios-tv.co.uk/vie...php?f=5&t=3824

From this source it would appear to be a post-war development. I also found several patents dating from 1950. Does anyone else have a source for the history of intercarrier sound?

Darryl

Motorola designed the intercarrier sound circuit, as their first 10" TV didn't have it. They designed it as a cost savings approach for their 7" line.
Every other manufacturer seemed to adopt it, except RCA and a few others.
It did state, on the licensing label, on the later RCA sets, that it did use inventions of Motorola Inc and several other concerns.