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Im4jc
Junior Member
Username: Im4jc

Post Number: 19
Registered: 11-2005
Posted on Saturday, December 24, 2005 - 12:12 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

If I get a Uniden Grant LT with the intention of running a linear with it, should I have the LT peaked or should I leave it stock?

I'm under the impression that you can get about 18 - 20 watts PEP out of a Grant. This would be nice because it would give me a little bump when running barefoot, but there's something I don't understand. The amplifiers usually call for a 1-4 watt input. Some of them call this deadkey, and some of them call it input. If I have the Grant set up for a 2 watt dead key and 18 - 20 watt PEP, does this conform to the 1 - 4 watt input requirements for a non high drive amp, or is this really an 18 watt input?

Arrrgh, I'm so confused.

Also, if the Grant will do 18 - 20 watts AM once it is peaked, what will it do on SSB? And will this be too much input for the SSB delay input for a linear?

I'm either thinking about a Texas Star 350 HDV or a KL 400. I want something with variable power so that I can run it around 50 watts PEP for normal use, with the ability to crank it up when needed.
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Hollowpoint445
Advanced Member
Username: Hollowpoint445

Post Number: 966
Registered: 6-2004
Posted on Saturday, December 24, 2005 - 3:39 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Peaking out a radio is a bad idea for many reasons:

Peaking makes the radio more sensitive to VSWR mismatches.

The components will run hotter which will make their service life shorter.

The extra output doesn't show up when your signal is received. It would take 4 times the stock power to show only one S-unit increase in signal, and you're only doubling it at best. That's 1/2 S-unit or less.

Depending on how it's installed there may be voltage drops when more current is used, and that can make your signal sound poor on AM, and it DEFINITELY will make it sound bad on SSB.

Your reasoning about using it with an amplifier is correct. Overdriving an amplifier is the fastest way to break it and you'll sound bad too. Underdriving it will keep your signal linear and sounding like you aren't even using an amplifier - which I wish you'd reconsider. Amplifiers are bad - m'kay?


Radios are are engineered with the extra power in reserve for reliability. I'd leave it stock as far as output power is concerned. Get a good alignment after using it for a while, and be done with it.
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Im4jc
Junior Member
Username: Im4jc

Post Number: 21
Registered: 11-2005
Posted on Saturday, December 24, 2005 - 4:58 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hollowpoint445: Hmmm. Maybe I'm using the wrong terminology or something. Maybe I should be saying "supertune"? By "peaking" it out, I mean replacing the existing final transistor with a bigger one, not pushing the existing one to the max. Or maybe I'm all wet...could be.
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 2114
Registered: 7-2004


Posted on Sunday, December 25, 2005 - 11:01 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Im4jc...it should not take much work at all to get that LT to do 15-18 PEP or 10+ watts RMS swing, both AM & SSB. a variable dead key for AM use would be nice, then you could further adjust the output of whatever amp you decide on. if you don't go 'variable', leaving the dead key at 'just under 3 watts' would be fine. you would get pretty much maximum safe dead key out of amp, & with 15+ PEP, you'd also be seeing the true max PEP of amp-or close to it. i never found swapping out the finals-or adding bigger finals-to be anywhere worth the effort & aggravation. you never get what you expect & tuning is always a hassle. if you're gonna run an amp-just run it. lo, high, off whatever. it'll be there when you need it.

my preference is texas star over kl series, really never saw any problems with kl, just hear of excessively high PEP readings with them, which is usually a sign of excess garbage going out.

with output of LT as i suggested, the HDV model texas stars are not neccessary. the 350 should key around 60-80 watts & swing to 250, the dx400 80-90 key/320 swing, dx500 120 key/450 swing, dx667 125-150 key/ 450-500 swing. that's on the 'high' setting. they can be switched lower, & variable on radio could fine tune even more.
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Im4jc
Junior Member
Username: Im4jc

Post Number: 23
Registered: 11-2005
Posted on Monday, December 26, 2005 - 11:40 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Ok, well I think I am understanding it a bit now. When the amps call for a 1-4 watt DK, they are not talking about the peak envelope power from the radio, but just the carrier. I wish that when a website advertises an amp, that they would publish not only the max DK, but also the max PEP (from the radio) input that it can take as well. This would make it alot easier to choose an amp.

And to Hollowpoint: I understand what you are saying about not running an amp and not peaking out radios, but in a truckers world, that's kind of like taking a knife to a gunfight. I need my radio to be heard in a world of bleedover/cut AMC's, etc. My radio is one of the primary tools for doing my job. Most truckers are running 30+ watt radios that sound terrible and have had multiple CB hack shops do the golden screwdriver thing, and I need to get out over the din, so it's not realistic for me to pull a 4 watt radio out of a box and be done with it. And when I'm not using it as a tool, I'm DX'ing on SSB when the skip rolls in, and I don't have the luxury of attatching a 40 foot pole to my truck with an Antron 99 on top when I'm rolling down the road at 75 mph. Sure, if I had that, maybe 4 watts would be enough to get some QSO's, but in a mobile environment, the extra power really helps. No disrespect is meant here, that's just how I see it.
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 2121
Registered: 7-2004


Posted on Monday, December 26, 2005 - 1:51 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

many advertisements for amplifiers are JUST PLAIN, for lack of a better, more courteous word, OVERGENEROUS & INCOMPLETE.

if you WERE to take that STOCK 4 watt CB & hook it up to a 'bargain-type' amp, it would probably work just fine. when you are using high dollar radios & amps, looking for optimum performance, you 'should' do it right. the BEST way to set up an amp, say an S9 with DX500 TS would be(after, of course, antenna/swr issues dealt with):

radio mic gain turned to ZERO

radio external rf power knob turned to ZERO

with watt meter AFTER amp, turn radio rf power knob UP til amp shows 25% of the total wattage of transistors(dx 500, with 4 x 2879 @ 120 watts each, would equal 120 watts carrier from amp). exactly where radio wattage ends up is not important. make sure airflow to amp is good, add fans if needed.

turn up mic gain until PEP swing is 4 times the carrier, or around 450-500 watts.

FORGET what amp advertisement said about OUTPUT of amp. they are 120 watt transistors, that's what you're gonna get out of 'em. setting up amp this way is for durability & longevity-and best sound. while PEP is pretty much 'it', you MAY increase radio rf power til amp carrier reaches 150 watts & still see GREAT results. added fans MAY allow as much as 250 watts carrier, though no increase in PEP swing, but HEAT = DEATH to the amp, & at that point, you ARE pushing it!

this way to setup works with ALL amps-if you know what transistors are in it. go to www.rfparts.com & see what input they will handle, add together & if your radio exceeds that, you'll either have to turn it down, or use another radio. (remember, you can turn down radio PEP/swing somewhat by turning mic gain DOWN. S9 has PEP of 40+ watts, & you can turn mic gain down til PEP goes to less then 20 watts & see little or no effect on 'loudness')
then, by adding up 'output' of transistors, you can see what the 'high power' of any amp SHOULD be.

so, when you see an ad for an amp with 4-mrf455 transistors that does 500+ watts-LAUGH! at 60 watts each, you'll know 250 watts is more realistic, & if you DID see 500-it's hash, trash, harmonics & bleedover! nothing else!
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Hollowpoint445
Advanced Member
Username: Hollowpoint445

Post Number: 971
Registered: 6-2004
Posted on Tuesday, December 27, 2005 - 12:35 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Im4jc- The myth that you need an amplifier to be heard is rediculous. The extra power only gets you a couple extra S-units over a stock radio. If your radio sounds good people will chat with you. Conversely, I won't chat with people who run radios that are hacked to sound like garbage. A proper alignment will bring modulation up to 100% on peaks and you'll sound clean and clear rather than the average crappy sounding hacked up trucker radio.

I ran a CB mobile 8+ hours a day, 6 days a week for more than 5 years. I NEVER had a problem being heard or getting a response on 19, although I readily admit I didn't spend much time there. Usually I was letting drivers know their doors were open, trailer lights were out, or helping with local directions when they were blocking the normal flow of traffic.

I mostly chatted with local radio friends who were as far as 40 miles away. Stock radio. SSB rocks!
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Sparkomatic
Intermediate Member
Username: Sparkomatic

Post Number: 389
Registered: 10-2002
Posted on Saturday, January 28, 2006 - 6:47 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

If you run an export or stock CB radio get it peaked up by someone who isn't a hack.
A $100 radio with the modulation opened up will sound better than a $350 radio that has not had the modulation opened up.
Why spend money on a nice radio just to have it sound like a $25 peanut whistle......get the modulation opened up.
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Rldrake
Member
Username: Rldrake

Post Number: 73
Registered: 1-2006
Posted on Wednesday, February 15, 2006 - 8:29 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

That's not true. "Opening up modulation" only causes splatter and distortion. For some reason alot of CB-types confuse being just plain LOUD with having a good clean signal. The way to put out the "best" signal is to put your money in the best antenna and location that one can afford...not with overdriving the rig.
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Sparkomatic
Intermediate Member
Username: Sparkomatic

Post Number: 393
Registered: 10-2002
Posted on Friday, February 24, 2006 - 12:20 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Rldrake....I guess maybe I have doing everything wrong for the last 29 years I have been into CB. I suppose I would have to disagree with you 1000%. I would rather have killer loud audio with less signal than a meek sounding radio with more carrier.
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1200ri
New member
Username: 1200ri

Post Number: 1
Registered: 1-2004
Posted on Saturday, February 25, 2006 - 9:31 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I hear you sparkomatic.The Grant sounds great when you clip r131 and put a variable on the rf gain you can control the audio from the mike gain.Its one of the best sounding radios in this form and the best rx in cb.

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