| Author |
Message |
    
Steelworker2001
Junior Member
Username: Steelworker2001
Post Number: 38
Registered: 1-2004
| | Posted on Monday, August 18, 2008 - 7:53 am: | 
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OK guys, I know what R131 does and I don't plan on removing it (did it on my Grant XL and SSB sounded terrible), but what is the purpose of TR24?
A lot of the power mods say to remove TR24 and I'm curious what it is/does.
This is a Bone Stock 1992 Cobra 148 GTL made in Philly
THANKS!!
Ken
CEF-809
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Cobra 148 GTL (1992), Grant XL (Philly), Washington 858, Texas Star DX500
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Hotwire
Senior Member
Username: Hotwire
Post Number: 2578
Registered: 1-2005
| | Posted on Monday, August 18, 2008 - 1:30 pm: |
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That is the modulation limiter.
Clipping the limiter is supposed to increase modulation. Mainly for AM mode.
This is a huge topic of debate between many cbers and techs.
Bad idea for SSB in my opinion. Causes over modulation which causes many other problems.
There are many mods you can do involving TR24 like adding resitors or switches to turn it off and on or reduce its function.
Its basically up to the owner of the radio what you prefer to do and how important premium audo clarity is to you. You can always put it back if you do not like the out come.
KEEP IT REAL!
Kenny
cef491(27.115lsb)
2sf491(27.555usb)
Indiana
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Steelworker2001
Junior Member
Username: Steelworker2001
Post Number: 39
Registered: 1-2004
| | Posted on Wednesday, August 20, 2008 - 7:52 am: |
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Thanks Hotwire.
I've seen the various power mods on the net. Some say remove R131, some say remove both R131 and TR24 and some say never remove either but put a resistor across the middle leg of TR24.
I love this radio as a SSB unit and wound not do anything to jeopardize its performance as such, but I would like to improve the AM power to drive a TS DX500V.
Thanks!
Ken
CEF-809
----
Cobra 148 GTL (1992), Grant XL (Philly), Washington 858, Texas Star DX500
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Hotwire
Senior Member
Username: Hotwire
Post Number: 2582
Registered: 1-2005
| | Posted on Wednesday, August 20, 2008 - 11:52 am: |
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Ken, You would be suprised at how well a tuned up 148 GTL can drive a DX500!
I own several 148's and when matched up to my Dx500's I have seen pretty close to max output on several meters! Of course I have 1969 final trannys installed in them but for only a single final that's not bad at all. I set the radio deadkey about 2 watts and let it swing. I good tune up and you can see around 18 to 20 watts AM. A little more on SSB.
Find a good tech in your area. Take your time and listen to the truckers who have good sounding Cobras. Word of mouth is the best way to go. I have a tech in my town who is well known by the drivers for his good honest work.
That particular 148 will not need much done to it.
KEEP IT REAL!
Kenny
cef491(27.115lsb)
2sf491(27.555usb)
Indiana
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