Six 1940 Philco tv's giveaway

[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.

[vts1134]

Going back to the original topic. I've posted photos of the contest as it was advertised before the giveaway. I've always thought the model Philco they were giving away was one of the absolute best looking deco television ever made. I would love to find one in the wild! I would hunt down the surviving family members if I weren't so damn tired and sleep deprived .

[decojoe67]

John, I've seen that Philco prototype TV before in photos, but never an existing model. It would certainly be exceedingly rare today!
Also, Darryl, being just an amateur historian of early TV for many years and not a technical person, I can only relay information that I have read. Also, I have heard from long-time TV collectors that they are not at all impressed with the performance of pre-war sets as compared to post-war. Your experience and knowledge of these early pre-war sets is very interesting and sheds new light on the subject.
Joe

[David Roper]

Originally Posted by Electronic M

The average split sound set had 4 video IF tubes and ~4 audio IF tubes for a total of 8.

Average? I've never seen one. Show me.

Motorola's VK 106 is an intercarrier set with four video IF amps and three audios IF amps. Andrea's prewar 1-F-5 is a split sound set with two video IF amps and one audio IF amp. Substantially different designs, but each one's tube count appears to be wholly unaffected by the scheme of the audio stage.

Perhaps David was in need of coffee, or feeling contrarian when he posted...

Unsupported declarations bring out the contrarian in me.

[ChrisW6ATV]

Originally Posted by Eric H

One of the San Fransisco winners was Gilson Willets, probably this guy:

http://www.joshuablubuhs.com/blog/gi...s-as-a-fortean

And some more info here, apparently the winners who weren't in range of a TV station could take a Philco Radio instead.

http://onetuberadio.com/2015/01/27/t...uite-so-lucky/

Thank you for posting those links, Eric.

[teevee]

Originally Posted by Electronic M

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.

Can't think of any reason a camera guided bomb would need audio...
(lots of wind noise and then a very brief boom.) just my 2¢

[old_coot88]

..To carry audio tones for reed relays maybe? Just a SWAG.

[earlyfilm]

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. . . .

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. . . .

Originally Posted by dtvmcdonald

. . . . When the band changes happened, they had to rewind the coils, and it wasn't pretty. . . . .

For an interesting article on converting a pre-war Televiser to 1941 NTSC with post-war frequency changes, go to:

http://www.americanradiohistory.com/...Page_Guide.htm

and download the Radio-Craft September 1946 issue.

(It will be much easier to read directly from the PDF than to try to read it on line.)

Go to page 832 for Rebuilding a Televiser. It is interesting how they describe removing a single loop on the tuner channel coils to make it reach the newer higher channels.

By the way, the set they used to illustrate the conversion was not a Du Mont, but an Andrea KTE5 kit.

http://www.earlytelevision.org/andrea_kt-e-5.html

Also there is an interesting editorial, Is Television Really Here? on page 821. Hugo Gernsback quotes Commander E. F. MacDonald, Jr. President of Zenith Radio Corporation, whose prediction turned out to be completely wrong.

James