| Author |
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Straycat
| | Posted on Tuesday, May 13, 2003 - 7:40 pm: | 
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When changing out the stock final and driver in a 29 LTD is the swap out just that ? A simple swap with no other mods required ? Saw this done once and when the radio was turned back onthe radio smoked and burnt . Can you do the same with a 25 LTD ? |
Wyatt_Earp
| | Posted on Monday, May 19, 2003 - 11:28 pm: |
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don't you have to change out possibly a cap and a resistor? I can't remember and am too lazy to do a search. |
Gunship
| | Posted on Thursday, August 14, 2003 - 11:29 am: |
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A 2SC1969 final will give you all you need in a 29 and it's a straight swap. Will work in a 25 too. It's a standard part of the supertunes I do in 25/66's and 29/76's. Lots-o-swing. |
Tech808
| | Posted on Thursday, August 14, 2003 - 6:57 pm: |
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Gunship,
First off I am not trying to cause a rift here.
I have heard of these SUPER TUNES for years now and never really knew exactly what they consist of or what is Actually done to a radio.
Would you be so kind as to explain what goes into a SUPER TUNE.
Or what do You do when you perform a SUPER TUNE and what parts do you re-place or modify.
Also could you please tell me what a Galaxy Final is?
I have had people coming in for years asking for Galaxy Finals but I have never seen one.
Actually, I never even knew Galaxy made finals.
I am always willing to learn new thing's, and these Supertunes and Galaxy Final's have had me stumped for years.
Lon
Tech808 |
307
| | Posted on Thursday, August 14, 2003 - 9:20 pm: |
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A "Galaxy Final" is the term that applies to the standard RF Final transistor that some wizz bang desided to call it to make boo-coo piles of money on. To enhance the definition of Standard RF Transistor to something everyone would want to buy , some garage tech said it was a "Galaxy Transistor". This guy took the $1.99 transistor and made a whooping $25.00 on it. I have people ALL THE TIME asking about them. Tell them the truth , Galaxy does NOT make any parts (semiconductors). Toshiba , Hitachi , Sanyo and many other MASSIVE companies build ALL CB Semiconductors. Galaxy is just a small group of people. |
Bigbob
| | Posted on Thursday, August 14, 2003 - 9:52 pm: |
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A 2sc1969 may have more swing,but a 2sc2312c is more easily stabilised and a bit hardier,I have found from experience that the higher gain 1969 is more easily poofed from a too high swr. |
Tech671
| | Posted on Friday, August 15, 2003 - 5:22 am: |
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The addition of a 1969 transistor to your Cobra 25 or 29 adds all of 2-3w more peak power (if that). If you're doing it as experimentation, fine. If you're believing some shop that your Cobra will do 40+ watts, save your hard earned money. |
Gunship
| | Posted on Friday, August 15, 2003 - 7:40 am: |
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Guys, as I understand it, what they mean by a Galaxy final is a 2SC2312. Now, as for the 2SC1969, I have a GRant XL which I've done my version of the 'DREADED SUPERTUNE' to. It's also been mod.kitted. On the Hi-power side it deadkeys 10 watts and swings to 25. On SSB it'll do almost 35watts. This is all on a Military-calibrated Bird Tru-line Peak-reading meter. Now, there's no way anybody will get 40 watts out of a 25/66 or a 29/76 but, 25 watts or so of AM swing is possible.
Tech808, I was taught to do this type of tuning by Weather-vein and a tech called Rusty-Bucket. I have all the info at home(I'm at work, my home computer has a dead power supply right now). IF...you are willing to wait until Monday Morning I will bring in the data on tuning a Grant/148GTL and publish it for you guys to try. Is that equitable? |
307
| | Posted on Friday, August 15, 2003 - 12:41 pm: |
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Gunship , A 2SC2312 is NOT made by Galaxy , It is made by Mitsubishi.
307 |
Kc0gxz
| | Posted on Friday, August 15, 2003 - 3:41 pm: |
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Tech808
And let's not forget the world famous "Connex Board". I hear about them all the time but none of my vendors have any.
Jeff, kc0gxz. |
Adshar64
| | Posted on Saturday, August 16, 2003 - 2:39 pm: |
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The 2SC1969 is more limited by its heat dissapating heatsink factor than its actually ability to amplify.Especially as the tag is common emitter.
With mica insulation and fan forced cooling it can sustain up to 35w pep ssb output, but getting it there is not that easy and impedance matching must be just right in the drive-final and output networks (670pf output coupling with a 3.5 turn tunable coil seems to be the right balance) and we are looking at getting ~2w drive from the preceeding section.Up to 28w is sustainable in a light to medium ssb duty cycle with good heatsink coupling and no forced air. Thats why the npc mod with the reduced carrier helped this final sustain a higher am swing without the carrier load factor.Its safe to say under a normal situation 20~22w is probaly your best setup for long life of the final Thats why the collector dissapation is rated at 18w to keep it safe due to heat, but doesnt mean its the max rf pep out this final will do. You will see variance in these finals on their ability depending on the batch. |
Gunship
| | Posted on Monday, August 18, 2003 - 6:35 am: |
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307, I realize who makes the transister. That doesn't stop the unwashed masses from calling it whatever they want.
Adshar64, you're right but, you don't need a tuned tank to get there in reality. I usually keep them to a saner level myself( Around 25watts PEP), except on a base station like a Washington where I can rebuild the power supply to about 10-12 amps constant and supply 14.5 volts to the transister. I usually mount a commercial TO220 heatsink to the back of the final with a mica insulator and plenty of white heat-sink paste. |
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