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Cobra 148gtl Hi fi Tx/Rx mod?


TX mods:
Change C46 to a .2 monolithic cap.
Change R114 to a 10K.
Replace the big electrolytic cap on the board from a 1000mf to a 2200mf or a 3300mf (its near the large transformer) - IIRC.

See if that info checks out - to be sure first.

Sure that others may have more tips too.

Think that ExitThirteen, The DB, Unit248, unit_399, slprydk, and a few others may have some answers for the TX side of this radio.

Receive mods are in this pdf:
 

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You must be a different Curly that I was talking to on another radio forum who said that he did the hifi mod on his radios?
 
Goldfinger 148Mod

Tx side

C46 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C101 Change to 1.5uf tantalum 16 to 50 volt
C102 Change to a 910pf ceramic disc
C104 Change to 2.2uf tantalum 16 to 50 volt
C108 Change to 1uf to 2.2 uf tantalum 16 to 50 volt
I found that if you have a very deep voice start with 1uf on C108
and work up if need be.

If you need more highs on tx Change C 105 to .001 to .0001uf mylar/polyester film The smaller you go the more highs you get.

RX

C71 Change to 1uf mylar/polyester film or non-polarized electrolytic

C75 Change to .001 to .0001uf this will give you more highs on rx
optional
C76 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

C182 Change to .001 to .0001 for more highs on rx and tx
optional
C183 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

C187 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

With C75 and C182 you can start with no Change to them, then if you feel you want more highs then change them out
 
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Hi Fi is really a bad name for the mod....the mod is supposed to make the radio wider banded....wide band mod would be more correct I suppose.....weather it truly makes the radio wider banded is debatable.....but I have heard radios that have had it done and they do sound like they are wider banded allowing more lows and highs to pass? :)
 
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If you do decide on doing this to your Cobra you will have to run it with some rack gear as well. Then you will have to make sure you have the EQ all dialed in just right. After that your 300 dollar heil mic will need to be dialed in with the system and your voice.

When I hear these guys on 11m running all this stuff maybe 2 out of 10 sound good. The rest have a mono tone drone or nasal sound. I suppose those running a Kenwood or Yaesu radio can hear the difference better.

Hmm. here is an idea. Since we are on 11m and your Cobra was made to talk there why not give it a correct tune and alignment. Add a nice desk mic, maybe a small AB amplifier, and the best and tallest base antenna you can and be done with it.
 
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Reactions: Rick Hicks
tx mod

Goldfinger 148Mod

Tx side

C46 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C101 Change to 1.5uf tantalum 16 to 50 volt
C102 Change to a 910pf ceramic disc
C104 Change to 2.2uf tantalum 16 to 50 volt
C108 Change to 1uf to 2.2 uf tantalum 16 to 50 volt
I found that if you have a very deep voice start with 1uf on C108
and work up if need be.

If you need more highs on tx Change C 105 to .001 to .0001uf mylar/polyester film The smaller you go the more highs you get.

RX

C71 Change to 1uf mylar/polyester film or non-polarized electrolytic

C75 Change to .001 to .0001uf this will give you more highs on rx
optional
C76 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

C182 Change to .001 to .0001 for more highs on rx and tx
optional
C183 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

C187 Change to 2.2uf mylar/polyester film or non-polarized electrolytic

With C75 and C182 you can start with no Change to them, then if you feel you want more highs then change them out
I need more lows on tx Thanks Len
 

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