• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

My new Toy, Readers Digest RDA127

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#1
Im not sure where I would put this but I did here because I mainly use this thing for SWL and AM

Well this is part review, and part bragging..LOL sorry guys I couldnt help it
I went to the Pawnshop Monday, was my day off and came across this jewel.
How Much you ask? 15 dollars, the guy working there thought it was a plain ol' boom box. Well I took it home and started to fiddle around with it, I figured if it didnt work I could at least have if for an onament or sell it to someone who might need it, low and behold it worked, not great, it made a static'ishy noise on every Knob I turned, The lamp for the dial didnt work and it was dirty.

I took it apart to see what might be wrong on the inside and the only thing was the antenna wires broke where they attach to the whip antenna, not a big deal.

I ran to Radio Shack to get a 12v Light Bulb, some extra solder(as if I dont have enough) and Electrical Contact Cleaner. I started doing my thing fixing it up when I realized for the lamp to stay on you have to hold the button on the front, well I didnt want that, so I happend to have an switch laying around, I by-passed the button and went to my switch(as you can see on the first picture, the white deal by the max vol)

Got it all cleaned up and no more noise making from the Knobs, Now its time to test it out, it has AM, FM, CB, SW 3.5-12.5mhz, TV CH2-13, AIR, Weather, and PoliceBand which also includes 2meter Ham which I thought was the "cats meow" Its like a Wide-Band RX. I works real well on everything except TV and AIR didnt hear a thing!
Has an Ext Antenna Jack with the 1/8 plug

But thats not all it has it has a Line Input, WOW Talk about loud for a little thing like this, Now I dont have to listen to my dinky Laptop sound when Im away from home.
On the Headphone Jack also works as an EXt. Speaker:twisted: .............
FM Band+Ext Speaker=...BASS Im talking enough bass to wake your wife up LOL
I just couldnt belive this thing.

And thats not all, it has 3 power Inputs, AC, 12volts DC, and 6 D Batteries, WHICH CAN BE RECHARGED from either AC or DC. Does it ever end?

One Question it has a switch labeled AFC, what does that mean?

Its made in HongKong, and has a Time chart on the back which can be handy a times
Ive googled this radio but came up with very little.






 

fredg

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#2
Neat radio!! I had old radios with the AFC switch, never knew what it did... Googled it and found this on AFC:

"If you have a portable, or a radio with manual (non-digital) tuning, you may find it harder to tune stations precisely. The radio's AFC function, usually switchable, may help, but it may also lock on a stronger nearby station, usually the one you are trying to get rid of!"

http://www.mindspring.com/~brucec/select.htm
 
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#4
The Purpose of AFC

I know I'm revealing my "vintage" - but - the mechanics of using AFC (automatic frequency control), which was also alternately know as AFT (automatic fine tuning), was:
1. turn the AFC control off
2. tune the desired station as closely as possible using an analog (non-digital) dial
3. turn the AFC on
The intended result was to "capture" the desired frequency exactly, as is done with true digital tuning. Obviously, AFC/AFT mostly disappeared as digital tuning became the norm.
 

Zaratsu

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#5
MFD4305 said:
I know I'm revealing my "vintage" - but - the mechanics of using AFC (automatic frequency control), which was also alternately know as AFT (automatic fine tuning), was:
1. turn the AFC control off
2. tune the desired station as closely as possible using an analog (non-digital) dial
3. turn the AFC on
The intended result was to "capture" the desired frequency exactly, as is done with true digital tuning. Obviously, AFC/AFT mostly disappeared as digital tuning became the norm.

huh, so like a sync detector, but without the active sideband being generated? I might be wrong, but I think i'm thinking along the right lines, but I get my electrons and protons confused often.

I have an AFC button on the Lafayette 1970s portable I got from the hamfest two weeks ago. Couldnt figure out what it did, but I figured it had something to do with how it was described above.
 

kb2vxa

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#6
No guys, you have the AFC thing just a teensy bit wrong. It only works on FM broadcast and it only existed because analog tuning tends to drift a bit. Never tune with it on because it can drag a station halfway across the dial and makes fine tuning highly inaccurate. Like the man said, tune with it off, then turn it on to lock the station in. It can jump to a stronger station nearby or "pull" so if that happens logically you leave it off, better radios didn't drift and never really needed it.

Nope, a synchronous AM detector is a horse of a different color and you have that one completely wrong. It's called synchronous because it generates a "carrier" that synchronizes itself with the stations carrier so you don't hear a heterodyne should it be slightly off frequency. This locally generated carrier replaces that of the station when propagation shifts cause selective fading, that phenomenon where a station fades and sounds garbled. That's because the carrier and one sideband are lost and all you hear is single sideband. Since all you need is one sideband and a carrier to hear it clearly just replace the lost carrier as you would for SSB reception. That's a technique used in the absence of a sync detector, just receive in SSB mode and tune for zero beat.

BTW, I like that "boom box", it even has CB on it for those who like listening to trash talkers with fuzzy audio, beeps, whistles, echo and other silly noises. (;->)
 
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Messages
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#7
I listened to the local ham net on 2 meters and it sounded better on this thing than my scanner, I figured out the AFC is for FM only by playing around on it.
 
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#9
I can tell you that the radio dates from the late 70's. I badgered my mom to get one and it was exactly like the one in your photo.
 
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#11
im so lucky!

i went to a garage sale once and i found one of theese in working order and got ti for free!
 
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Jan 18, 2005
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#12
Replacement antennas?

I found one of these sets recently, but both antennas had broken off. Does anyone know where I can find replacements that will fit this unit?
 
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