Early radios and TV input

[Kirk]

I recently acquired a Silvertone console set that I believe is a 1939
model. I was surprised when I checked the back of the chassis and
found a large phono jack labeled "TELEVISION - PHONO" input. On the
schematic, it looks like this jack bypasses the oscillator and IF
stages, and connects into the detector stage.

I suspect that the "television" was more of a marketing thing in 1939,
but it got me wondering how early TV support started appearing in
radio sets.

Anyone have other experiences with TV and radios?

Kirk

[John Goller, k9uwa]

In article <1185558034.4...@z28g2000prd.googlegroups.com>,
kirkva...@hotmail.com says...

>
>
>
>Anyone have other experiences with TV and radios?
>
>Kirk
>

The TV input thing was a big deal on the 1939 and 40 models.. and
later... seems that at first there were some TV sets built that didn't
have audio systems in them... and yes its useful as a Phono or other
low level audio device input...
John k9uwa

[Phil Nelson]

There were a handful of prewar TVs that lacked audio -- you plugged into a
radio or other amplifier for the sound. Radios with "TV" audio inputs were
made for a few years after the war, but that scheme didn't last long, since
TV buyers quickly decided they would prefer a set that produced its own
sound.

Phil

[steve...@gmail.com]

The bottom of the line 1939/40 TV sets from RCA and GE had no audio
output tube or speaker, and needed to be connected to an amplifier for
audio:

http://www.earlytelevision.org/ge_hm171.html

http://www.earlytelevision.org/rca_tt5.html

[Jim Mueller]

My guess is that it was a gimmick to sell radios. Who would want to buy a
new radio if television would make it obsolete next year? By making the
radio an essential part of the television receiver, manufacturers could sell
both.

--
Jim Mueller wron...@nospam.com

To get my real email address, replace wrongname with eportiz. Then replace
nospam with sacbeemail.

<steve...@gmail.com> wrote in message
news:1185584930....@m37g2000prh.googlegroups.com...

[Jeffrey D Angus]

> I suspect that the "television" was more of a marketing thing in 1939,
> but it got me wondering how early TV support started appearing in
> radio sets.

As someone else pointed out, the first TV sets didn't have an
audio output per sey (Stand alone) and the manufacturers assumed
most buyers would have a radio with an external audio input.

By the same token the radio manufacutrers were more than happy to
re-tool and add the "TV input jack on their radios if it meant that
people would continue to buy radios.

Yes, there was some concern at the time that suddenly radios would
become obsolete.

Side note: One of the funnier eBay auctions that was refferenced
here was a big console with the TV jack on the back. However, the
buyer said that the radio could be converted to TV operation by
replacing the tuner assembly (behind the big glass dial cover) with
a small TV set. "Factory Accessory!"

Jeff

--
RESTRICTED AREA. Anyone intruding shall immediately become subject to
the jurisdiction of military law. Intruders will be subject to lethal
force, without warning, and on sight. USE OF DEADLY FORCE IS AUTHORIZED
under the Internal Security Act of 1950.

[William Sommerwerck]

> My guess is that it was a gimmick to sell radios. Who would
> want to buy a new radio if television would make it obsolete
> next year? By making the radio an essential part of the television
> receiver, manufacturers could sell both.

But... DUH!... Many radios had an RCA jack for a record player. The TV's
audio output would go there. The customer would not be buying another radio
to go with their TV.

[Steven]

On Jul 28, 5:24 am, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

Nobody told them that...you are at the end of the Great Depression,
William, and Philco has as much at stake as RCA Victor. There were
still a lot of radio companies but many died over the previous 10
years.

Willie Loman would've been in television not plastics if it had been
about 27-8 years earlier. The war took an industry that wanted to
explode and strangled it for nearly fifteen years. If the war had not
happened, how would frequencies have been allocated? UHF was nowhere
near ready and the lack of bandwidth would have stunted TV more than
the war and subsequent freeze ever could have done. Investment in new
broadcasting plants would've been made moot and existing stations
would've gone ridiclously high in resale value. The TV industry
could've shot itself.

The Freeze may have been the best help TV ever had.

[ken scharf]

TV remained "around the corner" for many years. WWII only helped to
extend this as by 1939 there were many experimental tv stations on the
air and the FCC was ready to allocate frequencies for both FM and TV
broadcasting. In the beginning it was thought that video could be just
added to radio. In fact the early mechanical tv systems had limited
bandwidth and COULD be sent over radio channels. So the radio could
have feed an audio signal to the video adapter to convert to a picture
(like ham SSTV). Later on the thought was that a radio station might
send the sound and a separate station would send the picture.
Finally, as others pointed out, the cost of early tv sets was held down
by having an external audio amplifier and speaker, which could have been
a radio with an audio input jack.

[Michael Black]

I was going to post something about the early outputs, until I realized
the jack in question here was for an input.

But given there were those output jacks for the early attempts at tv,
that likely set the "standard" for "tv jacks". Since it had already
happened, that likely made it easy for companies to decide to continue
with the practice, but with a bigger stretch since it would only
use the radio as an audio amplifier.

Michael

[Gary Tayman]

"Jeffrey D Angus" <jan...@socal.rr.com> wrote in message
news:46aad685$0$4861$4c36...@roadrunner.com...

>
>
> By the same token the radio manufacutrers were more than happy to
> re-tool and add the "TV input jack on their radios if it meant that
> people would continue to buy radios.
>

Did they even bother to re-tool? Possibly their labelmakers. During the
1930's a lot of radios had "phono" inputs for, well, just that -- an
external phono. As television became the new technology that people were
following, the same darn input was rebadged "Television," making the radio
"television-compatible." Notice this was before Madman Muntz abbreviated
the word to "TV."

So anyone shopping for a new radio in 1940 might go after the one with the
television input, so they'll be ready for the day they come back to buy a
television. It's a little like the TV antenna that's "color approved."
What's the difference? However with terminology like that, you'll certainly
want to buy a new "color" antenna when you upgrade to a color TV.

I find it interesting that many radios have phono inputs with an RCA jack.
However I've got a Zenith which has two pins for the input -- and an RCA
jack that somebody added later on.

--
Gary E. Tayman/Tayman Electrical
Sound Solutions For Classic Cars
http://www.taymanelectrical.com

[Lou D]

Jim Mueller wrote:
> My guess is that it was a gimmick to sell radios. Who would want to buy a
> new radio if television would make it obsolete next year? By making the
> radio an essential part of the television receiver, manufacturers could sell
> both.
>

Yes, that was the main reason since the radio sales could be put off if
TV was coming soon. It was no big deal to add 2 more tubes to the first
TV sets which were already a high end item and were only sold to people
who had money to burn. Of course the war broke out and the whole idea
was scraped. It was just a sales promo like HD ready would be today.

[radio...@gmail.com]

On Jul 28, 2:00 pm, ken scharf <wa2mzeNOSPAMB...@bellsouth.net> wrote:
> Kirk wrote:

> In fact the early mechanical tv systems had limited
> bandwidth and COULD be sent over radio channels. So the radio could
> have feed an audio signal to the video adapter to convert to a picture
> (like ham SSTV). Later on the thought was that a radio station might
> send the sound and a separate station would send the picture.

I recall a prewar Philco console, model unknown, that had "Television"
marked on the dial in the 20-25 Mcs area as well as a few other spots
across the SW spectrum. It also had a "tv" connector on the rear.
Does this ring a bell to anybody? I'd like to take a look at the
schematic to see if they were actually intending to use this as an
output as opposed to an input.

-Bill

[steve...@gmail.com]

Many British prewar sets, such as the Marconi and HMV lines and the
Cossor 137T, used the shortwave radio in the TV set to tune the audio
IF frequency (usually around 4 mHz). No American company used this
approach as far as I know.

http://www.earlytelevision.org/prewar.html

[Steven]

I'd be willing to bet that it was for the audio to Philco broadcasts
or else 30-60 line transmissions. Low bandwidth television lasted
longer than some might think. The BBC may have begun modern television
service by 1936 but there were still a few experimental things dying
out or changing over.

[Scott W. Harvey]

[steve...@gmail.com]

> I'd be willing to bet that it was for the audio to Philco broadcasts
> or else 30-60 line transmissions. Low bandwidth television lasted
> longer than some might think. The BBC may have begun modern television
> service by 1936 but there were still a few experimental things dying
> out or changing over.

Possible, but Philco's TV broacasts were above 50 mHz. I doubt if any
Philco radios of that era had shortwave that tuned that high.

Mechanical broadcasting was over by 1933 in the U.S. with the
exception of a couple of stations run by universities in the midwest.

[Kirk]

It's interesting. I think either there was lots of confusion about how
television would actually work, or the radio marketing folks were
trying to make the most of it. After looking more closely at my radio,
I found the dial marked "Tel. Sound" in the Foreign band between
8-9MC.

Also, on the back of the chassis above the RCA jack, there is a paper
label that says:

"NOTE -- This Jack for Connection of Television Converter or Record
Player"

Ah, the early days of new technology!

Great discussion!

[William Sommerwerck]

> "NOTE -- This Jack for Connection of Television Converter
> or Record Player"

If the jack sat at the output of the detector, right ahead of the volume
control, it could be used as either an input or output. I believe.

[steve...@gmail.com]

On Jul 29, 12:24 pm, Kirk <kirkvansl...@hotmail.com> wrote:
> It's interesting. I think either there was lots of confusion about how
> television would actually work, or the radio marketing folks were
> trying to make the most of it. After looking more closely at my radio,
> I found the dial marked "Tel. Sound" in the Foreign band between
> 8-9MC.
>

Almost all of the prewar American sets used 8.25 mHz as the audio IF.
Philco made a televsion set without sound, but none of them survive.
It is possible that it had an audio IF output at 8.25 mHz:

http://www.earlytelevision.org/philco_prewar.html#converter

Kirk, does your Phico console look anything like the set on this page?

[steve...@gmail.com]

I re-read the text on our website about the 1940 Philco "Television
Converter". It says that the converter broadcasts the sound wirelessly
to any 1940 Philco radio. So, that is what the TV sound marking on the
Philco set between 8 and 9 mHz is for.

[Kirk]

On Jul 29, 12:21 pm, stevemc...@gmail.com wrote:
> Almost all of the prewar American sets used 8.25 mHz as the audio IF.
> Philco made a televsion set without sound, but none of them survive.
> It is possible that it had an audio IF output at 8.25 mHz:
>
> http://www.earlytelevision.org/philco_prewar.html#converter
>
> Kirk, does your Phico console look anything like the set on this page?

No, actually mine is a Silvertone 6490 from Sears.

[steve...@gmail.com]

> No, actually mine is a Silvertone 6490 from Sears.

Very interesting. Sears/Silvertone did have a prewar vision-only TV
set, but is was made by RCA and had an audio output. I'll do some more
research and see if Philco attempted to convince other manufacturers
to put 8.25 mHz on their dials.

If anyone else has a radio with TV sound in the SW band, please let me
know.

[Moth]

I have a Silvertone model 6436 and it has the Tel Sound on the C band
right after 8 mc. It also has a button labeled Phono/Tel'v'n. cheers

[steve...@gmail.com]

I've been reminded that one Philco 7 inch vision-only TV receiver does
still exist.