Copper Talk » Modifications » Radios » Variable Power Mod for Grant XL. Anyone?? « Previous Next »

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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 318
Registered: 4-2006


Posted on Thursday, April 12, 2007 - 10:07 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

OK. I'd like to put variable power in this thing. Just tell em what to do. I already added the channels, now it's time for the Variable power. Show me the way. I am looking to dead key 1.5 and swing to 4 or 5 when using my 667,,,and swing higher with it off. Right now I am dead keying 4 and swinging 5 (too much for the 667). Show me how. Thanks.
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 3609
Registered: 7-2004


Posted on Friday, April 13, 2007 - 5:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

eaiest way to add variable, remove wires from rf gain or squelch, tie 'em together 'wide open'. remove AM power vr pot, & put onto whichever front mount pot you disabled. OR, you can wire them to the dim or hi/lo switch 1st, then to the pot, so you have use of rf gain or squelch.
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1476
Registered: 6-2004
Posted on Friday, April 13, 2007 - 8:49 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Disable squelch? I guess that's cool because I don't use it anyway, but RF gain? NO WAY! I'm constantly adjusting RF gain to take advantage of the gain curve to peak the signal/noise ratio. I don't know how I'd get along without it.

I'd sooner get rid of mic gain which I rarely use anyway and is redundant if you're using a powered microphone as most people seem to do anyway.
Aack! - Bill the cat
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 3610
Registered: 7-2004


Posted on Saturday, April 14, 2007 - 4:24 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

that's why i suggested disabling one of the switches. had an XL here last week to wire a mic for, & it was done like that. was trying to test it & couldn't figure out what was controlling what. once i realized someone disabled brt/dim & wired rf gain & variable into it, i thought WOW, that's a great idea. i'd thought of it before, but never implemented it.
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1482
Registered: 6-2004
Posted on Saturday, April 14, 2007 - 8:22 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

That is a pretty cool idea, but I'd rather have both controls available at the same time. I think if I'm going to bother opening the radio to do something like that, I'd just get a dual pot and knobs from a junk radio and replace one of the single pot controls.

Some company should make a replacement chassis/cover/faceplate that's twice the normal height, with lots of places to insert pots and switches for nuts like us to customize our radios. A couple of spots for meters would be cool too. I always wanted a mobile with more than one meter. A slot for a frequency counter wouldn't hurt either.
Aack! - Bill the cat
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2488
Registered: 9-2004


Posted on Saturday, April 14, 2007 - 11:17 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

james, get yourself a suitable 5K ohm linear taper potentiometer.
if you dont mind putting a hole in the radio, just mount it where you want it.
if you do mind, remove one of the controls on the front that you dont use and mount it there.

solder three wires to the pot. (a 2 conductor + shield cable would be better)
unsolder VR10 from the board and solder the three wires from your new pot to their respective holes.
(VR10 is in the rear right corner of your radio)

while you are in there, replace TR41 with a 2N6487 or an NTE152.
makes for nicer AM audio peaks.

if you cant turn the power down far enough, remove R196 and replace with a jumper.
best of luck,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Dale
Advanced Member
Username: Dale

Post Number: 760
Registered: 12-2002
Posted on Sunday, April 15, 2007 - 9:05 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

u could do that but instead of drilling a hole in radio put the knob on the back of rafdio by coax jack exisiting holes already there and it keeps a nice clean look to your radio
dale/a.k.a.hotrod
cef426
cvc#64
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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 328
Registered: 4-2006


Posted on Sunday, April 15, 2007 - 6:49 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thanks all for the help.
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Dale
Advanced Member
Username: Dale

Post Number: 770
Registered: 12-2002
Posted on Sunday, April 15, 2007 - 9:21 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

welcome leave us know what ya do
dale/a.k.a.hotrod
cef426
cvc#64
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Monk
Junior Member
Username: Monk

Post Number: 29
Registered: 2-2002
Posted on Tuesday, May 01, 2007 - 5:22 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I install the variable power on the SWR adjust pot.
Unsolder the wires from the SWR adjust pot.
Take the two wires that aren't to ground and solder a 2.2k ohm resistor between them.
Unsolder the rf power trim pot from the board and run wires to your SWR pot.
You gain the variable power and don't lose the SWR function.

Monkradio
In the NW corner
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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 375
Registered: 4-2006


Posted on Wednesday, May 09, 2007 - 9:33 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Kid writes:

"while you are in there, replace TR41 with a 2N6487 or an NTE152. makes for nicer AM audio peaks."

Where is TR41 (Q41)? I can't find it. Also, If I decide to upgrade the final, are there any other parts that need to be chanegd or any ohter tune ups that need to be done? Or is it as simple as simply installing a new part? Thanks.

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