Do super radios differ from old radios?

[jras20]

I found some old AM radios that I got a while back from yard-sales. This one I have right now, is a Solid state RCA radio, it seems to realy pick up good, is there a big diffrents between that and a super radio? I thought older radios most of the time picked up better then the newer ones?
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jras20</P>

 

[clichemoth]

> I found some old AM radios that I got a while back from
> yard-sales. This one I have right now, is a Solid state RCA
> radio, it seems to realy pick up good, is there a big
> diffrents between that and a super radio? I thought older
> radios most of the time picked up better then the newer
> ones?
>
I use 60s-70s vintage receivers exclusively and they generally do pick up better AM (and for that matter, TV) than anything new. . . Don't know how they stand vs. the SR3 or CC, although I'd suspect they're roughly equal.

Only problem with using good old stuff is that there's no X-band. . .

 

[westlife]

> Only problem with using good old stuff is that there's no
> X-band. . .

If you go back to the '30s and '40s, many radios tuned the Expanded Band and beyond, to let people listen to police radio calls which were transmitted just above 1700 kHz. In fact I had a Philco table radio, circa 1941, whose shortwave band, covering about 1500 - 2500 kHz, was called the "Police" band. This became less common in the '50s, though, as more and more police departments converted to 2-way low-band VHF FM radio (usually supplied by Motorola).

Nonetheless, just about any analog-tuning radio can be slightly "tweaked" to extend its AM tuning range up to 1710 kHz. All it takes is a careful readjustment of the IF coils. The only consequence is that the dial markings will no longer be 100% accurate.
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"This is the New York Emergency Broadcast System satellite channel. They took the crosstown bus."</P>

 

[rbrucecarter]

There are three elements that make a good radio:

(1) Antenna
(2) Front end gangs - one or more tuned RF stages
(3) IF stages

The GE Superadio 3 has a large ferrite bar, wrapped most of the length, to capture all the flux it can. As far as I know, it is among the largest ferrite bar antennas put in a portable, regardless of vintage. Still - tube radios of early vintage had large open air loops, and the larger box they were in allowed the loops to be large enough to be really efficient - although tracking with the antenna portion of the tuning capacitor on the low end was bound to be an issue.

As far as the front end, the GE has a tuned RF stage. A good general rule is that any radio with a tuned amplified RF stage - separate from the antenna stage (3 gang) - is going to outperform radios that don't have a tuned RF stage (2 gang). Hallicrafters and some other manufacturers do a good job without a tuned RF stage in their front ends, but all make higher end models with tuned RF stages. Hammarlund's SP-600 is the only one I know of with two tuned RF stages (4 gang) and it is the standard by which AM performance is measured.

With IF stages, the more the better. The GE has four, the most of any AM radio I have seen. I had an old Radio Shack with 4 IF stages, but selectivity was not as good as the GE. AM radios, particularly those with shortwave bands, can have double or triple conversion designs - which improves the IF but adds the potential for noise.

As far as the radio in question - I had a GE at one time that had a tuned RF and three IF's, with a decent sized ferrite bar. It was kind of a wierd looking unit, with half the frequencies on one side and half on the other. As I recall, it had some serious stability issues - tending to have heterodynes (I suspect with shortwave stations).

When I go to garage sales - if the radio doesn't have tuned RF stage (three gang), I pass it up unless I am going to scrap it for a large ferrite bar or the tuning capacitor.