| Author |
Message |
    
Zardoz
| | Posted on Sunday, April 20, 2003 - 4:44 pm: | 
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If given a choice which should I get?
Yes I know they're the same inside.
What year ?
I have a large selection I'm looking at right now.
Thanks gang,
Bob |
Mrsandman
| | Posted on Sunday, April 20, 2003 - 6:22 pm: |
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get the xl its better rx
same on both tx |
Midnitexpress
| | Posted on Monday, April 21, 2003 - 2:49 pm: |
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SAME RADIO, different name |
Zardoz
| | Posted on Monday, April 21, 2003 - 3:19 pm: |
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any thoughts as to a GTL made in the '70s ? |
Sparkomatic
| | Posted on Monday, April 21, 2003 - 8:51 pm: |
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Both have the best audio circuit even though they are low swing radios. I wish someone would come out with a 148 with dual finals 40 upper channels and 40 lower channels and a variable key. Heavy audio and heavy swing........I would pay HEAVY for a radio like that. |
Cbnut
| | Posted on Thursday, April 24, 2003 - 6:08 pm: |
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IF you're looking for a guy that can work that type of Magic on a 148 GTL, I know someone, drop me an e-mail.
The guy is hinest, and excellent... not like alot of these so-called "good buddy CB techs" the guy is an actual RF engineer. He did a mod on mine that increases output power and modulation without splatter, and over-modulation. Something about compressing negative peaks. Anyways, he's good.
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Orion
| | Posted on Friday, April 25, 2003 - 3:15 pm: |
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My friend still has his Grant XL sitting in the box fully modified that he bought 6 years ago. It just sits there... brand new and never used, and old school classic. It would be perfect if it had a frequency counter. I know he has no interest in radio anymore. He bought two of them and this was the one he planned on using as a base but he was never able to get permission ot roof his Big Stick. Such a waste... |
Weakeststation
| | Posted on Saturday, April 26, 2003 - 6:41 am: |
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I would go with the grant LT, i don't think the xl is made anymore.... |
ryan
| | Posted on Saturday, April 26, 2003 - 2:49 pm: |
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you'd probably have a better time modifying the XL. i tend to stay away from modern CB radios though |
Zardoz
| | Posted on Thursday, May 01, 2003 - 10:57 pm: |
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FYI,
I ended up with a 70's vintage 148GTL (mint) in it's original box, with about a months worth of use then put away for all the years since.
Case never opened.
Bob |
frasiercrane
| | Posted on Thursday, July 17, 2003 - 5:03 pm: |
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you'd settle for only 40 upper and 40 lower channels? the mod I invented did something like 192 channels.. 26.165 to 28.085 if I recall correctly.. and yes, that with just the one crystal.. |
Tecnicoloco
| | Posted on Thursday, July 17, 2003 - 7:12 pm: |
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Hi Frasiercrane:
Will you be so kind to explain us how do you achive such range with only 1 crystal? |
frasiercrane
| | Posted on Thursday, July 17, 2003 - 10:55 pm: |
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These radios will normally do from 26.815 to 28.085, what's that 128 chans.? So the trick is to get the other 64. Unfortunately it's been years since I've done one, so I don't remember the exact wiring.. but it involves feeding the output of the PLL back into one of the inputs to trick it into locking on 64 channels lower than it should. The tripler tuning was a bit critical when doing this, and of course you have to broadband a few circuits to get this much range.
I did a few 2000GTLs with a second crystal for even more channels above 28Mhz, but these were really on the edge and the VCO had a tendency to drift over time causing it to not lock over the full range, and the receive wouldn't easily broadband to cover all those channels. |
Adshar64
| | Posted on Friday, July 18, 2003 - 5:13 am: |
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That is the floating pin 10 mod and you can find it in files at;
http://groups.yahoo.com/group/Cobra_2000/,http://groups.yahoo.com/group/Cobra_2000/
It's not real popular and involves a switched voltage divider circuit to pin 10.
The other mods in group enable a 2000 to cover 4mhz vco range plus with no drop out(shown in the photo's section). I'm doing one for technicolo soon that he's sending me, ie uhic007 vco module.Transmit can be set up to cover 2mhz at 20 watt's The pre-driver mod is a big secret to this besides so42p and an612 mods. The reciever can be made tunable or broadbanded, but will lose selectivity.Still good over 2 mhz with coil taps expanded.Same deal goes for the 148gtl.
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frasiercrane
| | Posted on Friday, July 18, 2003 - 9:14 am: |
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Hmm.. wasn't any voltage divider involved.. the mod just used a couple of toggle switches to switch the pll pins, I think it was switching pin 10 to one of the other pins. Did a vco mod with a couple of varactors, and added a little amp to the predriver to broadband tx. This was like 15 years ago, so don't know what others have come up with since, didn't see much point at the time in going any further than that with these radios.. point of diminishing returns.. no one else was doing anything like it at the time, so people were more than happy with it. |
Adshar64
| | Posted on Friday, July 18, 2003 - 5:54 pm: |
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Yes it was pin, 17 was used to feed pin 10 because it was at 1/2 vdd. However a better method of a resistance voltage divider circuit switched, was developed later. Pin 17 was only used because the voltage there put pin 10 in limbo giving a n+192.
"vco mod with a couple of varactors" ? was this a actual vco mod to the uhic007 module, ie a superdiode or whatever in series with pin 6 etc?You maybe referring to the vxo clarifier circuit?
I'm not being a smartass, just interested in other mods done etc.
cheers |
frasiercrane
| | Posted on Friday, July 18, 2003 - 11:47 pm: |
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Interesting.. now that you mention pin 17, that does sound familiar.. I always figured it was taking a signal from one pin and feeding it into the other, didn't know you could use a divider.. it worked, and that was the important thing 
The varactor vco mod was pretty simple, take 2 varactor diodes, solder the anodes to the vco coil, one on the ground side, one on the hot side of the coil. solder the cathodes together, and through a 10k resistor to a point with the vco tuning voltage. The tuning voltage now adjusts the capacitance of the diodes, gives it a pretty good range with a few cheap parts and you don't have to hack up the circuit board. You'd have to experiment with varactor values, I don't recall what they were.. wish my memory was a bit better.. |
Adshar64
| | Posted on Saturday, July 19, 2003 - 4:04 pm: |
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Thats different, never heard of that varactor mod. I dont know the range it gave you, probaly enough to cover 192ch but the real big range limit is controlled by the varactor in the uhic007 module.
This one changed to a superdiode gives 400 plus ch in lock. |
frasiercrane
| | Posted on Sunday, July 20, 2003 - 3:05 pm: |
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I came up with that one myself. it would do the 192 reliably, but at about 250 you would be pushing it..
I vaguely remember the superdiode uhic007 thing, didn't you have to cut open the module to get at the diode? Anyway, since the mod only did 192, and the receiver wasn't good for much more than that without going to a lot of trouble, this mod worked fine, if people wanted more channels they'd go for an export radio..
heheh.. just noticed the 'cheers' in the previous message... lol..
well, nice talking to y'all, thanx for making my use my memory.. |
Adshar64
| | Posted on Monday, July 21, 2003 - 12:30 am: |
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No probs. I think what you did there was like a few mods Ive seen where adding parallel caps across L19 did a similar thing. Yes you do have to attack the uhic007 module to do the mod.
You can see pic's of ones I've done here;
http://groups.yahoo.com/group/Cobra_2000/,http://groups.yahoo.com/group/Cobra_2000/
in the photo's section. join up there all free info avaliable and full service manual there.
cheers
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