Yesterday Radio, From Yesterday Back to Spark Gap and Crystal Sets

Bruce I love your new threads (sounds like I'm complimenting you for a new suit).

I came to the site tonight wanting to talk about portable radios and look how perfect this is, you just started the three threads!

I had to write the three topics down and think for a minute so I get the right story on the right thread, and Grundig FR-200 is A RADIO OF YESTERDAY, so it goes here.

Tonight at sunset I had the Grundig FR-200 out back and set it on a table.

Turns out the radio got set in the null of KDX AM 1550 and brought in a 50kW station from Cincinnati. But WCKY is on 1530, so what was actually happening?

Well, as you know Bruce, the FR-200 drifts! It needs constant retuning!

Still, the Grundig FR-200 is the neatest radio I know of for carrying about with its leather handle. It's like Tinky Winky's purse from the Tele Tubbys.

So I went on Universal Radio's website where I recall seeing a similar style radio under the Eton name...

But I learned that the FR-200, FR-300 and FR-400, under the Grundig/Eton name, have ALL been discontinued and waving money around cannot bring them back.

Fewer and fewer analog radios are listed, and they have dainty wrist-ropes so they can dangle from your hand like a girlie accessory. No thank you.

I'm depressed now.

wrist strap. 

So yes.  This 2 meter HT radio was a brick and the optional

huge battery pack with almost as long as the

radio.  So together they were a big long rectangle. 

The little dainty wrist strip didn't work out. 

I like my FR-200 a lot.  Mine doesn't drift on the

AM BCB.  Shortwave is another matter. 

For a local power outage, it's probably good enough. 

If you have a 50kW all service radio station not

too far away.  My FR-200 is yellow, which makes it

stand out in the inside of a pile of stuff.  I love the

way it looks, and the power crank really works. 

I wonder what you heard on 1550.  Maybe it's a

1550 that is licensed somewhere around the

Cincinatti area but is not actually there?  Then

again, maybe not.  By the way that 1530 slams

in to Hartford at night like a ton of bricks.

Bruce

I wish the light on the front was an LED and not

a light bulb. 

Here is a 5-part professionally produced PBS documentary titled "Radio Collector" from 1985 that will certainly bring back memories for the old timers. Enjpy.

http://www.californiahistoricalradio.com/radio-collector-video-series/

By the way - - have you even seen

" Empire of the Air" ?  I think PBS

did that one, too.  But I don't know

how to get it. 

I will probably look at your link tomorrow.

Thanks a lot

Bruce

You really like listening to the AM BCB

band during critical hours.  You have

mentioned this many times.  I like it too.

Bruce

My radio "career" started when I was about 7 years old. Our family had a combo phono and radio console and the radio included the shortwave bands. I spent more time behind the thing listening and viewing the tubes than in front where normal people (my brother) placed themselves.

I recall hearing RTTY signals which are sort of a warbling sound. My father told me that some stations are set up in the jungle and have a microphone so we could listen to the birds. I think I was much older when I discovered the truth about this hoax.

The Russian jamming stations were all over the bands and once again my father had a explanation. They were doing construction at the stations and that was the sound of the saws. Despite this I really did love my Dad.

When the radio broke we couldn't afford to have it repaired so I begged to be able to take it apart which I did. It was a great learning experience but I now regret that the radio no longer exists.

Sometime before age 11 I scored a 1936 model Crosley tombstone table model radio and this was my primary radio until late high school when I obtained a Buick car radio from a junk yard and modified it for 120 VAC operation. This radio, due to its superior sensitivity and audio power replaced the Crosley since it sounded much better playing rock and roll.

Both radios are still here in my abode and the Crosley still works. The Buick doesn't and I haven't spent the time to fix it. It is a jumble of wires inside and the insulation is brittle but it would still be nice to hear it again.

My broadcasting started in around 1957 when a neighbor gave me an old phonograph with a built in one tube oscillator. This was later replaced with the KnightKit broadcaster which provided for some serious Part 15 fun.

Neil

P.S. My Icom IC2-AT still works and I still use it.

"I spent more time behind the thing listening and viewing the tubes than in front where normal people (my brother) placed themselves."

I had a Kennedy floor model with Type 80 tubes and the rest. I made a nearly fatal mistake of connecting 2000 ohm headphones to the wrong pair on the speaker. I did not know that the time that the magnet on the speaker was the filter choke for the power supply. So when I heard this LOUD buzz, I ripped off the headphone only to get the shock of my life from the connecting wires to the headphone elements. I think I was 13 or 14 at the time.

Great stuff.  I have to come back later when things

are less crazy.

In the meantime:  Yeah, in my radio hobbiest life -

I didn't know for years that some old radios used

the speaker magnet for the filter choke.  Oh MAN!

Bruce

This is for my next post here. 

My available computer time is

variable and unpredicable. 

You guys have great stories. 

Bruce

Actually, there was no permanent magnet in the speaker.  Rather, the choke coil formed an electromagnet.  When the power is applied the choke (electromagnet) produced the magnetic field for the speaker.

If the speaker failed and you replaced it with a permanent magnet speaker you'd have to either replace the speaker field coil with a suitable choke or leave the old speaker field coil (choke) in the circuit.

Virually all of the radios made from the mid 20's, when AC powered (rather than battery powered) radios were introduced, up until WWII had the speaker field coils. There were actually two technical reasons. The old wet electrolytic capacitor technology limited the typical values of the power supply filter capacitors to the 4 to 16 uF range. The low value of the filter capacitors mandated a fairly large choke to eliminate hum. Also, the permanent magnet technology of that period precluded making speakers with permanent magnets. So, the ideal compromise was the speaker field coil. It acted as a choke to provide the necessarily large inductance for the power supply choke and provided a high magnetic field for the speaker.

It's common when restoring a radio to replace the speaker with a modern permanent magnet version. This requires substituting an appropriate resistor equal to the field coil DC resistance, and replacing the low value filter capacitors with much higher value modern electrolytics to compensate for the removal of the filter choke.

The speaker field coil is a common point of failure. They had a very large number of turns of small wire. The wire tends to break somewhere in the coil over time. If you are lucky, it breaks at the terminals and you can fix that. But, it also would break randomly somewhere inside the coil. Rewinding the coil is possible in some speakers that can be dismantled to remove the coil. Many speakers basically had the coil support framework welded onto the speaker, so it can't be removed for rewinding. Finding a working, used equivalent speaker is practically impossible, but sometimes you can get lucky.

I got some of my first shocks while examining old time radios, and I realized half of the reason for highly electrified speakers - I knew they were electro magnets and could be re-purposed to pick up scrap metal in a junk yard.

"Chokes" were a mysterious component that I only knew in their transformer-like versions, but I didn't know what they did nor why they later disappeared from newer circuits.

Now, at last, it has become "known knowledge."

Thank you, gentlemen.

The original radios were built like grand musical instruments, their cabinets sufficient to produce room filling tone with low bass response.

When dance orchestras came over the network from a big city hotel I'd stand by the coal burning stove at night listening to the thump thump thump of the plucked upright-bass-fiddle. Oh it was good.

What do we have now? Deaf people playing artificial instruments at maximum volume with screamers pretending to sing, pushed on over-amplified radio stations ignored by the public on their perpetual cell-phone calls defiant against the growing brain tumors.

Good thing I'm not bitter.

A short time ago I picked a Philco Model 18 from someone's trash.

After a good clean up of the cabinet three filter caps were replaced.  The radio came to life with a grand sound.

The only thing left to do is replace the rubber grommets which support the tuner caps.

It uses the field coil type speaker.