Someone was kind enough to steer me to this website.
I am looking for any information about an item I recently acquired that appears to be an old radio. It is made by National Airphone Corporation in N.Y.City.
I can not find any information about it and was wondering if someone can steer me in the right direction.
A picture is available. It has connections for phones, antenna, ground, A-battery, and B-battery.
I have no idea what tube belongs in it. There was none but I got a box of tubes along with it. Several different numbers of tube will fit it. It's a 4-pin tube.
Found National Airphone listed in Vintage Radio by Morgan McMahon. They made a model GT-1 Monodyne in 1923 & 1924. Believe this may be your radio? Your radio most likely used a 201A.
Norm
:Hello Everyone,
:Someone was kind enough to steer me to this website.
:
:I am looking for any information about an item I recently acquired that appears to be an old radio. It is made by National Airphone Corporation in N.Y.City.
:I can not find any information about it and was wondering if someone can steer me in the right direction.
:A picture is available. It has connections for phones, antenna, ground, A-battery, and B-battery.
:I have no idea what tube belongs in it. There was none but I got a box of tubes along with it. Several different numbers of tube will fit it. It's a 4-pin tube.
:
:
:
:
First of all, nice picture. I didn't know you could post pictures to this forum. In the case of this radio, pictures may prompt the only help you may get since many manufacturers from this period didn't provide schematics. In fact, if you could post pictures of the top and bottom with the tube removed, especially close-ups of the engraved markings next to the terminals, they might show us where the antenna coil is connected.
Your radio is from the 1920s or late 1910s. Many of these little breadboard radios were produced back then. They were cheap, relatively easy to use, and you could switch antenna coils, allowing the user to tune the broadcast, longwave or shortwave bands.
The tube you have looks like a series '01A or '00A tube. This may not be the correct tube for this radio. Here's how you test this. You'll need an ohmmeter.
On the radio's tube socket, the pins closest to the dial are pins 1 and 4. Pin 1 is to the right of the dial, and the pin numbers increase going counter-clockwise. Using an ohmmeter, test for continuity between the pins and the A battery terminals.
Here are the tube types that will work in your radio, depending on which pins are connected to the A battery:
Pins 1 and 4: '00A, '01A, '12A, '71A, UX 199
Pins 1 and 3: WD 11
Pins 2 and 4: UV 199
The WD 11 used a 1.5 volt dry cell battery, the 199 series used batteries in the 3.3 volt range (they had different designs with different filament voltages), and the others used a 6 volt wet cell car battery. All of these tubes needed a ballast resistor in the A circuit, about 1.6 ohms for the WD 11 and about 5 ohms for the '01A, '00A, '12A and '71A. If the resistor is not built into the breadboard, then it would have been added externally.
Finally, the two metal clips probably held the C battery. (Not to be confused with the 1.5 volt C cell that is sold today.) This 4.5 volt battery provided negative bias to the tube's grid. The positive side connects to ground (and should also connect internally to the negative side of the A and B batteries). The negative side connects to the grid of the tube, either directly or indirectly through the antenna coil or an internal resistor. The grid is pin 4 on the WD 11, pin 1 on the UV 199, and pin 3 on the others.
Hope this helps.
:Hello Everyone,
:Someone was kind enough to steer me to this website.
:
:I am looking for any information about an item I recently acquired that appears to be an old radio. It is made by National Airphone Corporation in N.Y.City.
:I can not find any information about it and was wondering if someone can steer me in the right direction.
:A picture is available. It has connections for phones, antenna, ground, A-battery, and B-battery.
:I have no idea what tube belongs in it. There was none but I got a box of tubes along with it. Several different numbers of tube will fit it. It's a 4-pin tube.
:
:
:
:
Steve has some good ideas.
I doubt if your radio would have used 99 or WD11 tubes. From the photo looks like you need a tube with larger bayonet base. Both 99 & WD11 are smaller. WD11 has one large & 3 small pins.
I am going to guess the two clips held a grid leak resistor? Probably around 2 meg?
Norm
:Hi Craig.
:
:First of all, nice picture. I didn't know you could post pictures to this forum. In the case of this radio, pictures may prompt the only help you may get since many manufacturers from this period didn't provide schematics. In fact, if you could post pictures of the top and bottom with the tube removed, especially close-ups of the engraved markings next to the terminals, they might show us where the antenna coil is connected.
:
:Your radio is from the 1920s or late 1910s. Many of these little breadboard radios were produced back then. They were cheap, relatively easy to use, and you could switch antenna coils, allowing the user to tune the broadcast, longwave or shortwave bands.
:
:The tube you have looks like a series '01A or '00A tube. This may not be the correct tube for this radio. Here's how you test this. You'll need an ohmmeter.
:
:On the radio's tube socket, the pins closest to the dial are pins 1 and 4. Pin 1 is to the right of the dial, and the pin numbers increase going counter-clockwise. Using an ohmmeter, test for continuity between the pins and the A battery terminals.
:
:Here are the tube types that will work in your radio, depending on which pins are connected to the A battery:
:
:Pins 1 and 4: '00A, '01A, '12A, '71A, UX 199
:Pins 1 and 3: WD 11
:Pins 2 and 4: UV 199
:
:The WD 11 used a 1.5 volt dry cell battery, the 199 series used batteries in the 3.3 volt range (they had different designs with different filament voltages), and the others used a 6 volt wet cell car battery. All of these tubes needed a ballast resistor in the A circuit, about 1.6 ohms for the WD 11 and about 5 ohms for the '01A, '00A, '12A and '71A. If the resistor is not built into the breadboard, then it would have been added externally.
:
:Finally, the two metal clips probably held the C battery. (Not to be confused with the 1.5 volt C cell that is sold today.) This 4.5 volt battery provided negative bias to the tube's grid. The positive side connects to ground (and should also connect internally to the negative side of the A and B batteries). The negative side connects to the grid of the tube, either directly or indirectly through the antenna coil or an internal resistor. The grid is pin 4 on the WD 11, pin 1 on the UV 199, and pin 3 on the others.
:
:Hope this helps.
:
:
:
::Hello Everyone,
::Someone was kind enough to steer me to this website.
::
::I am looking for any information about an item I recently acquired that appears to be an old radio. It is made by National Airphone Corporation in N.Y.City.
::I can not find any information about it and was wondering if someone can steer me in the right direction.
::A picture is available. It has connections for phones, antenna, ground, A-battery, and B-battery.
::I have no idea what tube belongs in it. There was none but I got a box of tubes along with it. Several different numbers of tube will fit it. It's a 4-pin tube.
::
::
::
::
Thanks for the replies.
Someone else told me....
"Your set was made from 1923-1925.
It sold retail originally for $18.
The model number is GT-1.
Your photo shows that the the coil is missing on yours.
The coil fits between the two metal sections near the tube."
That is the best identification information I have received so far. If you guys and gals want more pictures I can post more. You are also welcome to write me at valiant76@yahoo.com
OH, to post the picture on this website, first I had to upload the picture to the internet, either a photo hosting service or you may have some personal webspace available with your internet account. Then I just put the HTML source code in this message box and it made the picture show up. I did not know if it would work until I tried it. Once you click "submit" here you do not have a chance to edit your mistakes later!