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  #31  
Old 09-26-2015, 11:38 AM
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jr_tech jr_tech is offline
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Apparently there is no external 9-10 khz switch on the radio, but did you check the circuit board for a strap (or possibly a low ohm resistor) that could be clipped or moved to the 10 khz position?

jr
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  #32  
Old 09-26-2015, 12:18 PM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by jr_tech View Post
Apparently there is no external 9-10 khz switch on the radio, but did you check the circuit board for a strap (or possibly a low ohm resistor) that could be clipped or moved to the 10 khz position?

jr
I looked at the board, next to the PLL chip, but didn't see anything marked as such.
I can't see the chip number. It looks like it was marked over with ink or paint. I wanted to see the pin-out and figure it out.
It actually looks like an almost decent performer. It has a rather good sounding speaker and the output chip, has a heat sink on it. It seems to be a better looking piece of junk.
Ordinarily, you should be able to look up the chip number on the I-net for the function and pin-out.
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  #33  
Old 09-27-2015, 01:51 PM
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davet753 davet753 is offline
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A few years ago, the radio world has it's most dramatic change since the introduction of the transistor. Silicon Labs began marketing an IC chip that consolidates about 75% of the typical radio onto a single chip, smaller than a postage stamp.

This can be good and bad. Tecsun manufactures some great portable all-band receivers. They can take one of these Silicon Labs chips (like a Si4820), add a decent RF amp to the front end, and audio amp to the back, and end up with a radio that performs great. I have a model PL606 ($40) that brings in FM and shortwave stations better than my 15 year old Icom (that cost about $800 in 2001). I just bought a $159 model PL880, and it blows anything I've ever owned out of the water, and sounds great to boot.

Sadly, there is a flip side to this. Some foreign manufacturers take these Silicon Labs chips and add very little to it, save for a cheap little audio amp chip with a plastic speaker. These sets perform like pure crap, mainly because there's not a decent front end.

These chips sell for less than $3, eliminate the need for manual alignment, and contain all the control functions needed in a radio (from band selection, volume and tone control, digital tuning, and all of it operating on only 3 volts with minimal current draw.

As to the 9 or 10 kHz question, that switching is built-in to these chips. Some manufacturers offer a way to switch this from the keypad, but if not, they have to be programmed manually.
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