[ARC5] BC sets and others.

[Fuqua, Bill L]

  Probably two reasons for the RF amplifier in the car radios.
It is maybe a chicken vs egg sort of thing. 
  1. The short vertical antennas need a lot of RF gain.
  2. The use of lower frequency IF allowed narrower bandwidth but required extra RF selectivity.
  Unlike the table model radios, they could not use loop antennas with cars due to directional properties
and the metal car body could detune them as well. The vertical rod antenna was just what was needed.
73
Bill wa4lav

________________________________________
From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on behalf of Mike Everette [radiocompass at yahoo.com]
Sent: Tuesday, January 21, 2014 9:08 PM
To: kgordon2006 at frontier.com; Geoff
Cc: ARC-5 Maillist
Subject: Re: [ARC5] BC sets and others.

The way I heard it, and this may be right, who knows... 262 KHz is capable of greater selectivity, and still-decent tracking, than 455; and with an RF stage, which is typical of most car radios, the image problem is gone.  Though I have amongst my voluminous junque pile a Motorola radio from a 1947 Chrysler, so I was told, that does exhibit images near the top of the dial, hmmm.  This radio uses loctal tubes and with a pair of 7C5s in the output, feeding a 12 inch ex TV speaker, makes some "damgud" audio.  I used it to listen to a couple of stations near the top of the AM band (1520 and 1530 kc I think) that both played "early rock-n-roll" until they both chucked the format about 2004 or 2005.  I still occasionally use it to listen to "Radio Progreso" in Havana on 640 kc, which offers some really good Latin-Caribbean music at night.  Other than that, there is little worth listening to on AM any more.

As for car radios and SW... there were such beasts.  I once ran across a description in one of the Riders manuals of a Buick radio from around 1940 that had something like NINE bands on it.  I bet this was interesting, given the ignition-rich emissions of cars back then.  I'd love to find one of those radios today.

73

Mike
WA4DLF





On Tuesday, January 21, 2014 8:22 PM, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:

On 21 Jan 2014 at 15:49, Geoff wrote:

> If you want a good compact BC set get a post WW2 to about 56 auto
> radio with PP audio; 6 or 12V.
>
> Sensitive with an RF stage, selective enough with the 262kc IF, full
> range tone control.

Yes. When I still lived in Missoula, Montana, at least 35 years ago, I would
go to my favorite junk yard, buy nice-looking auto radios, and build them into
nice cabinets with an AC supply, and sometimes one of those spider-wound
flat loop antennas, then sell them.

The owner of that junk yard, Doug, who was about my age, just loved them.
He said, and I had to agree, that they were the very best BC radios one
could buy.

They sure beat the crap out those stupid AA-5s.

I sold a bunch of them. I don't know how many are still around. Probably not
many/any.

> I have a 49 Plymouth Deluxe model out in the equipment trailer and fed
> by an old 70's regulated 5V 18A mini computer PS bumped to 6.5V by
> changing the reference zener.
>
> A 50 Buick version sits in the garage and a 51 Buick on the auto radio
> repair bench in the basement of the 1830's part of the house.

Yes. Those are excellent.

Since my wife just loves to listen to talk radio on AM, I just may build her one.

Or I may just use the NC-109 I have here instead...

She likes to listen to SW too.

Ken W7EKB
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