1947 bendix 847-b
 

I was wondering if any of you could help me with information on this radio,
and possibly a schematic? I got one recently (the one in the picures is not the one I have.) The model is 847-b made by Bendix in 1946-48.

Did you check Nostalgia Air, for Riders coverage, or maybe Sams. :scratch2:

Nostalgia Air, has perfect coverage on that model. Rider's scans. :banana:

Thank you

Interesting that the FM dial scale goes up to 109Mc.

I know, I was just noticing that myself, I didn't realize that the modern FM went up to 109 Mhz... although an old Silvertone radio I had (I ended up scrapping it out and keeping the cabinet for a TV stand because it was too far gone for me to try and salvage it) supposedly went up to 109 Mhz according to the Sams photofact I had for it and that Silvertone was from around 1948... :scratch2:

my guess is that the 109 Mhz portion of the original modern FM Band was reallocated by the FCC to either the police or the Military (just like everything else was that the FCC didn't think we needed anymore including the old Analog TV broadcast spectrum, I'm kind of seeing a pattern here... :scratch2: :sigh:

The entire FM broadcast band is between TV channels 6&7, plus the aircraft band. The old FM band, 42-50mhz is around the low band TV channels.
I'd have to read up again to be real exact. :sigh:

Yeah, I'm not sure either all I know is that the reason why FM was created in the first place was because the FCC got rid of Channel 1 with Analog TV shortly before we entered WWII so then because of that then the 42-50 Mhz FM Broadcast Spectrum came into being, but then the FCC thought that the military could make better use of the 42-50 Mhz spectrum better which was when they decided to open the modern 88-108 Mhz FM band just shortly after WWII (but I wasn't aware of it being originally 88-109 and from when to when that was I don't know.)

A little history of the FM bands:

http://www.damninteresting.com/the-t...h-of-fm-radio/

I don't find any reason to believe that it *ever* extended to 109 mhz in the US.

jr

Then why would there be several American made radios from the 1940s (including my example I mentioned earlier) that would have 109 Mhz listed on their FM Dials if it never went that high at some point in time? You can't just randomly manufacture an AM/FM Radio that includes a part of the FM Broadcast spectrum that never existed and expect the radio to sell (which obviously in the case of this old Bendix it must of sold a few or else this one never would of existed) so obviously the modern FM Band must of went up to 109 Mhz at some point in time in order for manufacturers to even have a reason to put it on their radio dials when they made them, otherwise it would of been false advertising.

And yes I know all about the history of FM broadcasting I've read the wikipedia entry about it several times now, and just like your article you listed it didn't make any mention about any sort of history of different frequency changes or additions or subtractions to the FM Band in its long 70+ year history dating back to 1938, they make mention about the major changes to the FM Band like talking about its initial bandspread when it was initially conceived of in 1938 of 42-50 Mhz and then they make mention about the change from the 42-50 Mhz bandspread to the 88-108 Bandspread and then the conception of FM Stereo and FM Quadraphonic, and that's about it, but they don't make any mention about any time in history when the FM Band may or may not of included 109 Mhz in it, which it would of had of had included it at some point in time in order for manufacturers to put it on their radio dials otherwise like I said you run into fraud issues.

No fraud issues there. So the set includes a bit 'extra' coverage...So what? It was not all that uncommon in the AM only days to include extra bandwidth in places it is not useful....Often it was because the cheapest tuning capacitor/coil combo they could get had a bit more range than needed. As long as it had the 'in use' part of the band I highly doubt anyone cared that it had anything extra....
If your car came with a sealed bottom and a propeller such that it could safely cross lakes, but other wise was a normal car, and they did not advertise that feature or sell you on it, would you not think that was cool or at least not a problem even if you never bothered to use it?

Its a bit like a volume control that goes to 11.. I think the band always ended at 108. Not unusual to see an AM set with a little extra coverage past the end of the band.

Yes, I'm aware of the "extra bandwidth" you speak of from the AM broadcast days, because the original AM Broadcast spectrum used to be the same as it is now (530-1710 kHz) prior to the 1940s then in the 1940s they dropped the AM Band spectrum from 530-1710 to 550-1620 kHz because they decided to reallocate 1630-1710 kHz to the Police and the 530-540 kHz to military use it wasn't until the 1980s that the AM Band was set back to 530-1710 kHz again by the FCC because of the advent of UHF and VHF Police radios. So actually no it has nothing to do with having access to parts that were too big and having to compensate for it by adding to the tuner dial, because if you think about it its kind of stupid and a waste of money to add an extra number to the radio dial that doesn't even exist to the radio you are making just because you got too big of a tuning capacitor, it only makes sense to put those "extra numbers" on the dial if they actually did exist at some point in time, again with the "cost saving" explanation, doesn't make sense. If anything it would cost more to use up extra ink to put on extra numbers onto a tuner dial being manufactured for a radio that was being manufactured with a tuning capacitor that was slightly larger than they needed, all they would of had to of done was just painted a couple of extra lines and that's it they wouldn't of needed to paint on the non-existing 109 MHz to save money. So like I said previously I'm sure at some point in time in Modern FM's history there was a 109 Mhz but it was probably very short lived (like Quadraphonic Stereo FM Broadcasts were).

Some AM radios of the 1930s tuned 540 to 1700 kHz by design, with the 1600-1700 spot on the tuning dial marked "police". This was when police departments had one-way radios in their squad cars, which were in reality AM car radios that tuned to 1700 kHz. The officer on duty would hear the call over the radio, then would stop at the nearest police "call box" to contact the police station for the details.

This was replaced by 2-way VHF police radio in, IIRC, the 1950s. The extended coverage (1600-1700) can now be used to listen to standard AM radio stations operating in the "expanded" AM broadcast band, 1600-1700 kHz. These stations generally operate with far less than 50kW; most of them are 10kW or less, with a few even operating daytime only.

BTW, I've seen only one other AM/FM table radio (aside from the picture of a Bendix radio that tuned 88-109 which Radiotron attached to his post) that tuned 88-109 MHz on FM. It was a late-1940s-early 1950s Sylvania table set my great-aunt had in her kitchen. The photo of the Bendix set reminded me of it. :yes:

Surprisingly had this one. It's in Sams 27.