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Delerius
| | Posted on Sunday, September 01, 2002 - 9:23 pm: | 
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I had the lucky opportunity to stop by Copper's location to pickup a TX 400v and I want to first say thanks for the friendly service. I just got the TX 400v hooked up and the Dosy meter is showing a dead key of 150 watts and I get a max swing of 225 watts with the variable power switch off. I am using 4 gauge power wire and the radio that is driving it, is a Connex 4800 with the npc mod done, dead key of 1 watt and swings about 22 watts. Is this about all I can get this amp to do or does the amp have a problem? With the variable power switch on and to the max, I get a dead key of 10 watts and a max swing of 200 watts. any solutions? |
2600
| | Posted on Monday, September 02, 2002 - 1:32 am: |
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Uhh, for starters, what kind of wattmeter are you using? The Connex 4800 should have all the drive power this amp needs. Is the motor running when you make your readings? With the motor off, you will be running from the battery alone. This will reduce you wattmeter readings by as much as 1/3. If your wattmeter is a typical "loose" meter that has no battery or power cord that runs the "peak" side, it will never show you true PEP on modulation. Some "Peak-Reading" meters that have no powered PEP circuit will show as much as 85% to 90% (like a Bulldog meter) of true PEP. Others will show you about 2/3 of true PEP. If you start the motor, and gently raise the idle speed until the wattmeter reading stops rising, that is a much more realistic test. Texas Star amplifiers are rated for a power supply of 13.8 volts. Any less DC power than that will cause a legitimately lower reading. You can come closer to this reading by turning the mike gain full up on SSB, giving it a loud whistle and THEN keying the mike. It won't 'chatter' the relay doing it like that. A wattmeter that reads higher this way than it does on AM modulation is a "sorta" peak meter, not a true PEP reading.
BTW, I recommend leaving the variable on the amplifier off, or turning the knob full clockwise, and setting your dead key with the radio on this model. I don't think they used a large enough part for the variable control. Running the knob full to the right protects the control from overheating. And there is no room to mount a larger control in the thing. That is my only criticism of an otherwise solid amplifier design.
One other little detail: Does the radio have its own power lead to the battery or fuse panel, or is it tapped off the #4 wires that feed the amplifier? Running the radio from the amplifier wires will reduce the voltage getting to the radio. That will reduce the power that it can deliver when the amp is keyed. Even the small voltage drop you'll have on those fat wires will cause a significant drop in the radio output when the amp is keyed and drawing current. A separate pair of wires to run the radio will avoid this pitfall. Just be sure that ANY hot wire that taps directly from the battery has a separate fuse or breaker UNDER THE HOOD at the tap-off point. This fuse is to protect the WIRE, not the radio or amp. They have their own fuses for that. If a fender-bender pinches that #4 wire, and it has no fuse under the hood, you'll get a fire. No fun.
73 |
Delerius
| | Posted on Monday, September 02, 2002 - 10:11 am: |
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Thanks 2600 for the response. This setup is installed in a big truck and the meter readings I have gave are when the truck is running. I also have the radio on a separate power line. The Dosy meter is the TR-1000 meter which gives peak wattage readings. The readings that I am getting, are they typical readings I should get with this setup? Also, the dead key at the amp at max power, is that ok or should I lower it? As of right now, I am at 1 watt dead key at the radio, will the Texas Star be ok with a 1/4 or 1/2 watt input? |
Delerius
| | Posted on Monday, September 02, 2002 - 10:41 am: |
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Well, I was just looking at Texas Star's web site and on the specifications for the 400v they have the output power as 200 watts. If I am correct the 2SC2290 is rated at 70 watts each X 4 = 280 watts. So in the end I guess what I am getting in readings is correct. Just another quick question, would it be possible to drive a TX 1200 or 1600 with the 400v? |
Sixkiller505
| | Posted on Monday, September 02, 2002 - 4:03 pm: |
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HEY DELERIUS!!! if you look at the section you got those SPEC. from,the top of the section SAY"S UTPUT WITH 4WATTS input!! if you go to the next section beside it, it say"s APPROX.POWER WITH 20 WATTS INPUT:400WATTS AT 40AMPS DRAW.you say your radio swings 22watts,radio seems fine.you drive a big truck ,your alternator is at least 120 or 130 amps and you should already have 6 or more batteries installed from the factory(mine did)and alternator doing 14 to 14.5 volts at 1500 to 2000rpms(without volting up)you should be getting 350 to 400 watts min. |
Taz
| | Posted on Monday, September 02, 2002 - 4:56 pm: |
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no!
Dont do that!!!!!!
100 watts drive or a texas star v-mod will drive it perfect! |
Delerius
| | Posted on Monday, September 02, 2002 - 5:50 pm: |
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Thanks Sixkiller505... I noticed that also that Texas Star says about a 4 watt input. Will I be saving components from early failure by only driving it with a 1 watt dead key, or is it still safe to bump it up to four watts? I notice some where on the forum that someone said that at max power, dead key shouldn't be more than 125 watts dead key metered at amp output. Any reason for this? Also another thing I don't understand is when I have the variable power off, I get a dead key of a 150 watts metered at amp output, but when I do have the variable button pushed in and the pot turned to max, I get a dead key of only 10 watts at amp output. what gives with that? One last thing, with TX's specs they say with a 20 watt input I should get 400 watts but how? Is that 400 watts PEP? |
Tech671
| | Posted on Monday, September 02, 2002 - 6:25 pm: |
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20w peak input = 400w peak output @ 14.5v. Your Dosy TR1000 tends to read on the "tight" side of peak, or more average than peak. Maintain your 125w carrier, that is plenty carrier out for that amp. Your variable pot may have a problem with it, like 2600 said run with the variable inactive. |
dale
| | Posted on Thursday, September 05, 2002 - 3:34 pm: |
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first of all does it say h.d. on the front of it. tha stands for high drive these types will handle alot of dead key from your radio. i suggest running your radio dead key on high or fully clock-wise.i drive mine with a 2990 set at a 30 watt dead-key.your radio will drive fair if you set it at high power but they work alot better with 20-30 watts of drive i hope this helps you out |
Snapperhead
| | Posted on Thursday, September 05, 2002 - 7:46 pm: |
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Delerious, I finally got my Texas Star DX400 from Copper in mail. Went ahead and hooked her up to my Chevy pickup...I'm running a Tweaked up Cobra 148 wich I installed a Variable deadkey AM power pot on back of rig. With my Dosy TFC-4001 at 1w deadkey it was around 40w with kicker on. It was swinging up to just over 400w on the meters. And that was with variable knob on Texas Star cranked. SSB was around 480w. That's what was showing on my meter. I don't want to open a can of worms with a Watt War on forum.....LOL but that's what I was showing...Barefoot Cobra 148 was swingin' to about 18 to 20w on AM and SSB was swingin' to about 22w........In my book, for the price of Texas Star amps it's a A+++ in my book........73's |
Tech671
| | Posted on Thursday, September 05, 2002 - 10:58 pm: |
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set your radio power so the amp keys about 100w on high. |
Hoosier Cardinal
| | Posted on Friday, September 06, 2002 - 4:15 pm: |
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Snapperhead.
Dont fret the wattage deal. Hey if someone make a coment like "um no that linear will not do that and this" just blow them off! Not everyone has or wants a damn birdie meter or cares what a birdie meter shows in compariosn to say a dosy. If you are happy with what you get out of your amp hey thats what matters!!!! |
Snapperhead
| | Posted on Friday, September 06, 2002 - 8:17 pm: |
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LOL.......Hey Hoosier Cardinal, Well I just wanted to say what my meters were showing....Sometimes you make a comment on what your radio is doing and then there it goes....The WATT WAR. I'm just a blue coller carpenter who likes to talk on CB's.....73's my friend..... |
Brer Rabbit
| | Posted on Friday, September 06, 2002 - 11:38 pm: |
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Nobody in this forum has mentioned that if the antenna is out of tune or can not handle the power being dumped into it, your reading will be useless. When doing your tests, be sure to check on a dummy load rated for at least 500 watts. Once you have tuned your equipment on a load, then check again on your antenna. Note that when you modulate your SWR will increase some but it should not be too out of hand. If your SWR reading is too high when modulating then replace the antenna with one that can handle the power your putting out or if you have a good antenna then check your ground plane situation. |
2600
| | Posted on Sunday, September 08, 2002 - 1:03 am: |
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Hey, Brer Rabbit, you're definitely on to something there.
If there is any way to drag a dummy load out to the truck, substitute it for the anteanna, and compare the power readings. The bigger the difference between THIS power reading and one taken with the antenna in line, the more you are seeing the antenna warp the meter reading. It's always a good idea to at least take a power reading into a dummy, even if only for comparison's sake. If the accuracy of the meter (checked on a dummy load) is not good, it'll read whatever it reads. The only ways to trust a wattmeter are 1) corroborate it with one that is KNOWN to be right, or 2) Be VERY lucky, all the time. |
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