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Old 05-07-2015, 04:59 PM
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wa2ise wa2ise is offline
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Thumbs down Bad modern cheap radios with really bad performance

You've seen them, my brother had one someone gave him, a combo AM/FM/LED flashlight. Has very little selectivity, as if they didn't bother with a filter in the IF stage. Uses one of those AM/FM radio chips, so sensitivity is cheap, but you still need to spend a little more for a decent IF filter...
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Old 05-07-2015, 05:25 PM
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A LOT of 'em have "Crosley" written on 'em... Poor Powel must be flippin' in his grave...
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Old 05-07-2015, 08:45 PM
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The Chinese must produce hundreds of them hourly - I see cheapo giveaway radios all the time. Mostly with big insurance company logos....

On a port visit to the UAE, we visited Dubai, and on an excursion away from the gold souk, some friends and I visited one of their versions of a 5 and dime store. Everything in the place was less than 15 Dirhams (~ $4.50). Among the dozens of radios they had for sale were multiband "Sonny" and "Grundid" radios for 6, 8 and 10 dirhams, and these little clip-on FM radios with autoscan and earphones for 5 dirhams. No volume control, no on-off switch, just a scan switch that moves you up the FM band (not marked, but scans locally just fine). You plug in the earphones and it comes on. I bought three to play with - the scan up the FM band was quick and the reception was remarkably good, but mono. I tore one open to see the chipset, thinking it might be a TDA7000 knockoff, but no markings on the chip at all, nor any of the two or three surface mount transistors. I still have one of them - the battery is dead, but it probably still works. Really thin plastic case - fragile as can be.

I left the place after spending about 11 dollars (42 Dirhams) and got 6 multimeters (like those that Harbor freight gives away, with batteries and nice leads!), three radios, a half dozen white LED-based tap-lights, and a multipack of some really nice mint gum.

A buddy bought one of the little multiband radios for 8 Dirhams, and picked up just one station - on about 3 or 4 points on the dial. One IF can , one chip, and two diodes in the whole radio - for 6 bands? Pure crap.

The one Radio Shack I found in the mall there had a whole wall of power transformers - and they were ALL 120V primary! This in a part of the world where 220/240 is the line voltage. I thought that to be quite odd, if not stupid.
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Old 05-08-2015, 09:23 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by wa2ise View Post
You've seen them, my brother had one someone gave him, a combo AM/FM/LED flashlight. Has very little selectivity, as if they didn't bother with a filter in the IF stage. Uses one of those AM/FM radio chips, so sensitivity is cheap, but you still need to spend a little more for a decent IF filter...
I buy them at garage sales and thrift shops for a buck or less, just the disect them. It's really interesting to see, what went into them.
Going back a few years, the GE Superadio, that we all know and love, uses the same Toshiba main chip, as even their lower end, small clock and portable radios. The main difference is the front end board and some of the components in the output stage, plus higher battery voltage.
The output stage is in that chip! The chip doesn't even have a heat sink on it!
Even though, the output stage seems to put out more than a watt.
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Old 05-08-2015, 10:48 AM
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Nothing was worse than those radios GPX put out in the 80's/early 90's.
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Old 05-08-2015, 11:07 AM
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What irritates me a lot more than a cheap radio performing badly, is how bad AM sounds on some more expensive modern units. For example, in a lot of modern cars, or in stereo receivers, it seems like it's nothing but a poorly implemented after thought.
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Old 05-08-2015, 12:46 PM
dieseljeep dieseljeep is offline
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Nothing was worse than those radios GPX put out in the 80's/early 90's.
How about Lenoxx sound?
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Old 05-08-2015, 12:59 PM
dieseljeep dieseljeep is offline
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What irritates me a lot more than a cheap radio performing badly, is how bad AM sounds on some more expensive modern units. For example, in a lot of modern cars, or in stereo receivers, it seems like it's nothing but a poorly implemented after thought.
I was discussing that topic at the last radio meet.
A fellow collector remarked that the sound is somewhat compressed at the station, for better results when using solid state transmitters????
I know someone could chime-in with a better understanding of this theory.
The AM on my Toyota Prius, doesn't sound that good.
I bought an older Japanese built HH Scott receiver, that was designed for better AM reception, as it has a three gang AM tuning condenser and tuned RF stage.
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Old 05-08-2015, 01:01 PM
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I think the problem has to do with frequency response. AM can have decent frequency response up to 10,000 Hz, but modern receivers roll it off at 5,000 and even lower. I think they basically expect that it will only be used for talk radio, and no buying decisions will be affected by a bad AM tuner, making quality a non issue.
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Old 05-08-2015, 01:07 PM
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Since AM radio in the US and Canada is now mostly talk, today's radio manufacturers probably don't see the sense in designing the AM section of AM/FM radios for high fidelity; the FM in most of these is probably not much better. I have a "Windsor" branded AM-FM clock radio that works well enough in my area (a small town about 40 miles from most Cleveland radio stations), but the AM isn't much better than a glorified crystal set. When I lived in the suburbs, I once had a Zenith integrated stereo system with an AM tuner that was so bad I was actually getting short wave around 1000 kHz at night; that system's tuner must have been as cheaply designed as the one in my clock radio, although the latter at least doesn't turn itself into a shortwave receiver after dark. Maybe living in a small town well outside greater Cleveland, with its much weaker radio signals, has something to do with it.
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Old 05-08-2015, 01:59 PM
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Originally Posted by maxhifi View Post
I think the problem has to do with frequency response. AM can have decent frequency response up to 10,000 Hz, but modern receivers roll it off at 5,000 and even lower.
I've modified receivers and radios to have wider IF filters and thus better frequency response, to capture the 10KHz audio.
See http://pw2.netcom.com/~wa2ise/radios...tml#solidstate
where I change out the narrow ceramic IF filters with LC circuits or a wider ceramic filter (usually found in narrowband FM transcievers).
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Old 05-08-2015, 02:31 PM
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The problem with any cheap radio made in the past 2 plus decades sucks.
Selectivity,Sensitivity is in the toilet.Stereo separation is in the toilet if the radio is stereo FM.

I rather have a radio with 8 to 10 transistors then a radio with 100 plus in a chip.

My 1970's Kmart or Barkers 6 transistor specials or my 1970's Realistic AM/FM handheld will do better then any crap from today.

Speaking of cheap all in the one radios.I have a Totes crank up radio.It sucks big time on picking up stations even with batteries.I got it at Big Lots for $5 bucks.
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Old 05-08-2015, 04:13 PM
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The NICEST car radio I ever remember is the std AM radio that is in my '69 Lincoln. Wondered why, in '69, it didn't have an FM unit, too, but it didn't. It apparently was designed w/some thought as to how it would actually SOUND, which isn't that much of a concern nowadays.
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Old 05-08-2015, 11:40 PM
centralradio centralradio is offline
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Those 1980's Delco car radios were great for sensitivity on AM and FM.
I made up a Frankenstein type boombox with my old Delco pulled out of my old 1987 Chevy Caprice wagon and mound it into a wooden box with speakers and a cig lighter plug.I modify the radio with line outputs so I can do on the road radio airchecking and DXing with my digital recorder in my summer travels.

I upgrade it to a 1980's Delco AM Stereo FM stereo about 6 years ago when I found the AM Stereo unit at the local fleamarket for about $10 bucks.

The local AM station here is in Stereo 24/7 with oldies music.It sounds great.

Those car Pioneer Super tuners were good in their day too.
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Old 05-09-2015, 12:52 PM
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Quote:
Originally Posted by dieseljeep View Post
I was discussing that topic at the last radio meet.
A fellow collector remarked that the sound is somewhat compressed at the station, for better results when using solid state transmitters????
I know someone could chime-in with a better understanding of this theory.
The AM on my Toyota Prius, doesn't sound that good.
I bought an older Japanese built HH Scott receiver, that was designed for better AM reception, as it has a three gang AM tuning condenser and tuned RF stage.
For maximum range at a given power consumption most modern transmitter rigs use DSP to compress the audio such that they can maintain 100% modulation (or as near to it as possible) almost constantly. IIRC PWM and other less than linear tricks are employed to reduce power consumption as well. It sucks for music, but in terms of keeping operating costs down (and thus pleasing corporate bean counters) it is a very effective system.
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