Copper Talk » Ask The Tech » Radio's Mobile » I want my radio to have variable DK, but same peaks « Previous Next »

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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 339
Registered: 4-2006


Posted on Monday, April 23, 2007 - 12:42 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I've been searchig and searching, but I can't seem to find a mod that allows me to vary my dead key, BUT always keep the same peak/swing. For instance, I want my radio to dk 1 and swing 4.5. But then let's say I want to increase my DK to 3 BUT STILL SWING to 4.5. I know there is variable power mods , but it seems as if the Swing also increases as you turn it up. Any ideas?

O yeah, it is a Uniden Grant XL Phillipines. And as a side note, no matter what I do, I can't get this thing to dead key any further than about 4.5 watts. Is there something internally that prevents all this? Thanks.
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 3631
Registered: 7-2004


Posted on Monday, April 23, 2007 - 4:15 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

4-5 dead key from a stock xl is a good #, mine won't do any more then 5, & usually stays around 2. why would you want it to do more then 5?

4.5 swing? why so low? a diode mod or an npc-rc mod will allow you to lower dead key & keep same high swing-that is the 'normal' way of doing things.

if you really need less swing, you can reduce swing by lowering the mic gain. the xl (& most exports) will allow the mic gain to be lowered quite a bit, before audio starts to drop off.
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2506
Registered: 9-2004


Posted on Monday, April 23, 2007 - 7:27 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i would think that if the radio were basically stock, and had the variable power control brought to the front panel; that the deadkey to swing ratio would remain about the same no matter where the control was set.
like, 4 watts swinging to 6 watts avg.
would be 1 watt swinging 1.5
2 watts swinging to 3 watts, etc...
its only with the swing mods etc. that the radio will still swing high from a low deadkey.

BTW, james, check the internet auction site's for an "end fired phased array" set of plans.

i bought it just for kicks, and the plans are actually pretty good.
shows how to use two 102" whips on a van roof for a forward gain of about 4-5db.

looks pretty easy to do too.
just thought you might like it.
later,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 340
Registered: 4-2006


Posted on Monday, April 23, 2007 - 9:51 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Kid_Vicious writes:

"its only with the swing mods etc. that the radio will still swing high from a low deadkey. "

Ok, sounds good. Can you please tell me how to do the swing mod? Or at the very least, link me to the right direction. Thanks.

I will look into that end fired phased array. Thanks.
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2508
Registered: 9-2004


Posted on Wednesday, April 25, 2007 - 11:18 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

simplest mod is to remove R228 and replace it with a 1N4001 diode.
banded end towards the back of the radio.
and remove R131.

thats it.
then you set your deadkey where you want it with VR10, and swing up from there.
if you want variable deadkey on the front panel, you can wire one of the front panel pots to the VR10 location as was mentioned in one of these threads.

if it were my radio, and i was looking for what i think you are looking for, these are the mods i would do:
replace R228 with 1N4001 diode.
remove R131.
replace TR41 with a 2N6487 or an NTE152.
replace C172 with a 2200uF 35+ volt capacitor.
replace C18 with a 1000uF 16+ volt capacitor.
replace R114 with the 10K resistor that used to be R131.

then i would set the deadkey at 3 watts and go to town!
you may choose to go the variable power route, which is cool too.

these mods will give you smokin' audio, and give the radio the ability to deliver it consistently.

have fun!
post pics of your antenna fun!
later,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Jameslarson
Intermediate Member
Username: Jameslarson

Post Number: 354
Registered: 4-2006


Posted on Tuesday, May 01, 2007 - 11:16 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hey Kid, thanks for the information. real quick, you say this: "replace R228 with 1N4001 diode."

OK, but which way does the banded side of the diode go? A resistor can be installed either way, but the diode can;t. Thanks.
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2520
Registered: 9-2004


Posted on Friday, May 04, 2007 - 12:31 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

banded end of diode goes toward the rear of the chassis.
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!

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