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Wolverine
| | Posted on Wednesday, June 25, 2003 - 3:35 am: | 
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Is it true that dual final export radios will drive an amp better than a single final radio? Example: lets say I have a 2x sc2879 amp that will key on high at 150 rms, and swing to 350 peak. If I used a 10 meter dual final export radio, will this drive my amp to key 200+ rms, and swing to a higher peak from what it did previously?? Also what other benefits do export radios (dual finals) offer over regular radios?? |
Kc0gxz
| | Posted on Thursday, June 26, 2003 - 1:42 am: |
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Wolverine-
For years, CBers have been (and still are) trying to get every ounce of power from their single final radios. But the smart CBers soon discovered a problem. The not-so-smart-ones are still in the dark about it.
"The Problem"....
The more wattage you try to squeeeeze from a single final radio, the less modulation you will have. Well, how come for why gee whizz you may ask? It's because that single final with all of the squeeeezed wattage that is being sent over the air doesn't have much room left to carry too much audio along with it.
Question....
Have you ever heard someone's radio that showed you a good receive signal but the audio sounded like it was coming from a telephone? I'm sure everyone has at one time or another. It's kind of like ordering a drink at your favorite tavern. You end up with a lot of ice (power) and not much room left over for the (audio) beverage.
Answer....
A OVER DRIVEN FINAL and YOU'RE OVER PAYING FOR THE DRINK. From a single final radio, you aren't going to get a "dead-key", (notice I said dead-key) of 10-12 watts and still see a upwards power swing with 100 or 100+ percent modulation.
Or put another way, fill a glass up with water. Now put your ice in it. What's that you say? No room for the ice? (Boy am I going to get some flack about that paragraph)
Enter the "dual final" radio.
A radio with dual finals is a whole different animal. One of the "advantages" is, if set up correctly, it WILL allow you to have a 10-12 watt dead-key and still achieve (May God Forbid) massive 100+ percent audio.
I'm guessing that you may have a Texas Star 350. You never did say what kind of radio or amp you have so I'm only guessing.
According to Texas Star, their 350 is a class AB1 amplifier. It will do around 180 watts with a 4 watt input and around 350 watts with a 20 watt input at a draw of 30 Amps. If you could manage to put a continuous 20 watt input to it, yes, you may possibly see around 350 watts output but the amplifier would have a very short life span.
If your amplifier already "swings" to around 350 watts, that's about the best it's going to do for an amplifier that is using a pair of 2879s. I wouldn't try to squeeeez any more out of it. If you feel way down deep in your heart that you NEED MORE POWER, get a bigger amp. When it comes to amplifiers, one size does not fit all.
I am curious to know what kind of radio you are using and what kind of power you are using to drive your amp. And what mods (if any) were done to your radio.
And to answer your question, no, you DO NOT need a dual final radio to get a amplifier with a pair of 2879s to go to full or near full power providing the radio is set up correctly for the amp. It also depends on the radio itself. Some single final radios will do it and some won't.
73s my friend.
Jeff, kc0gxz. |
Wolverine
| | Posted on Thursday, June 26, 2003 - 2:24 am: |
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uuhh, someone, anyone. I'm just looking for answers. |
Tech808
| | Posted on Thursday, June 26, 2003 - 9:53 am: |
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Wolverine,
Your Amp cannot tell the difference if your radio has a Single or Dual final radio driving it.
If it takes 4 watts to drive it you can use any radio that gives it the 4 watts.
A dual final radio will give you more power out of it than a single final radio will without having to use an Amp.
A Dual Final radio will generally give you more power out, But if you overdrive the AMP you Will Blow It Up.
No matter if it is being driven by a Single or Dual Final Radio.
If your Amp calls for a 4 watt drive use 3 watts or less and make it last a lot longer.
#1 Reason for Amplifier Problem's / Failure is being OVERDRIVEN!
Most if not all of the newer AMPs will work Great with between 1 1/2 to 2 1/2 watts. Unless they are a High Drive Amp.
Hope this help's answer your question.
Lon
Tech808  |
Wolverine
| | Posted on Thursday, June 26, 2003 - 9:11 am: |
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Thanks KcOgxz, just turned on my computer again, and I see that you answered my question as I was posting another one at 2:24 am. Both posts just now popped up. Anyway I have a 4 pill sd1446 palomar, and a 2 pill red devil (2x2879). My uniden 78ltw has 4 watts drive and is better suited to "Excite" the palomar sd1446 quad (70 watt pills). But to gain the maximum potential from my 2 pill red devil with 2xsc2879 pills (120 watts apiece), I thought or maybe hoped,that a dual final radio with a variable could produce a greater RMS drive to max out the 2 pill amp, as oppossed to my wimpy 4 watt driven uniden78 ltw. Just an experiment to try, but thanks for the answer, you saved me wad of cash. |
Wolverine
| | Posted on Friday, June 27, 2003 - 5:16 am: |
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Thanks also Tech 808 for the info. I guess there is a lag time between California and Kentucky as far as myself receiving answers to my posts. My Uniden 78ltw is bone stock, never has been super-tuned, and it has no mods. My radio keys 4 watts and probably swings to 12 watts. But even without the wild peak swings of a dual final radio, I've been told that my audio is top notch, loud,loud,loud! I don't want to "Blow up" my amps, so I'll just leave well enough alone, until I get a bigger amp. Thanks again. |
Highlander
| | Posted on Friday, June 27, 2003 - 7:49 am: |
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You still might need to lower the carrier on your 78ltw to 2 watts to get the best performance from your amp--not necessarily the most power, but best performance - audio, signal purity, no excessive heat, amp longevity. But it does depend on the amp. |
Tech808
| | Posted on Friday, June 27, 2003 - 8:15 am: |
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Wolverine,
The Lag Time is really determined by when we can get the time to check the Forum for NEW post's.
The Tech's and Moderator's for the Forum here all live in different states. We all Work Full time jobs, and some have Two jobs as well as Donating our time to Help on the Forum.
I am lucky as we have our own business and that allows me to check in more often and approve the Post's that are submitted.
But, if one of the other Tech's or the Forummaster approves a post it might take me a day to try and catch up and read most of the post's that are posted.
With all of us Tech's and Moderator's living in different States and Time Zones, it's hard for us to try and be online at the same time.
This Forum is really growing FAST and it takes awhile to read everything that is posted each day.
BUT, I love to see it Continue to Grow.
KEEP ON POSTING!
Lon
Tech808 |
Kc0gxz
| | Posted on Friday, June 27, 2003 - 1:44 pm: |
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Wolverine-
Highlander has a very good point there. Personally I prefer a 1.5 watt dead-key into an amplifier. That's just my preference.
Good thinking Highlander. I forgot all about mentioning that in my previous post to Wolverine.
73s
Jeff, kc0gxz. |
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