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Galaxy 979 am power upgrade??

Discussion in 'CB Radio Modifications' started by Pirate71, Mar 9, 2016.

  1. Pirate71

    Pirate71
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    Hi folks, i have a galaxy dx979 and want to have more power in AM....the max i can have is 7 watts but i want to have at least 10 watts...any tricks for having it?? Thks!!


     

  2. sonoma

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    guess you are talking about a dead key of 10 watts. that radio is a single final and you do not want it to key that much.the final will pop with any more dead key.
    if you are talking about swing the radio will swing more than that with a good tune up. you need to explain just what you are wanting it to do.
     
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  3. Pirate71

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    Yep, that i want is a 10-12 w dead key....i read on a research on this forum that this radio can do that but they don't explain how to reach it.....
     
  4. Justme

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    7 to 10 watts is less as 1.5 dB extra, not even noticed on the other side.
    just raising the carrier power will make the modulation weaker...
    Best way to up that power is to use a good amplifier, and leave the Galaxy for the factory settings.

    I see a lot of peope tinker to get the last milliwatt out of the standard transceiver not realising they stress the parts above the factory specifications and with the already inadequate heatsinks risk overheating the parts till they go bust.

    To make a difference doubling the output power is barely noticed, 4x the poer is 1 S point and can be heard quite well.
     
  5. Pirate71

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    The goal of this is to run my linear...recommended power is 10-12 watts...:)
     
  6. sonoma

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    what amp are you trying to run that it takes that much to key it.
     
  7. Pirate71

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    RM kl-505....i know what i'm doing :).... Just want info about my question....thks!!!
     
  8. sonoma

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    you are not going to get 10 to 12 watts out of a single final radio. it will swing that much but not dead key. you need a dual final radio to get close but most of them say to dead key on high at about 7 watts. then let the rest swing.
     
  9. Robb

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  10. Justme

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    Run it with the standard power, then your output will be relative clean from the unfiltered amp...
    You get te same results as i stated above, running the amp with 7 watts might give a relative clean output of 200 watts, 12 watt input will drive it i uncharted waters with lots of harmonics and maybe real 250 - 270 watts out before the fuses pop.
    That is the same difference of less as 1.5 dB but at high power your neighbours might not be happy with you.
    as stated RM Italy is quite liberal in specifications, to say it understatingly.....don't believe what is written on their box, i repaired enough of their crap to know that.
    Starting with a "tuned up" radio that already produces more crap in harmonics feeding an overdriven amp is asking for trouble.

    As ham i use the Heathkit SB 1000 at 800 watts with clean output, the new tube and refurbished innards let me drive it at 1000 watts, but for what? less as 1dB difference and stressing the components? and run the risk of a not so clean output?
    I drive the amp in class A from the Ft 2000 - D with 60 watts to get 800 out with the nw RF parts 3-500ZG.

    Its your amp and radio, but you got some good advise here from the guy's above.
     
  11. Pirate71

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    Well, thks for all information guys...appreciate your help...wil stay with my 7 watts...more safe for all!!!
     
  12. 9C1Driver

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    Here are the specs on the KL505 amplifier.

    • Frequency: 3-30 MHz
    • Power Supply: 12-14VDC
    • Input energy/power: 10-34 A
    • Input power: 1-15 W AM/FM
    • Input power: 2-30 W SSB/CW
    • Output power : 200 W Max AM/FM
    • Output power:400 W Max SSB/CW
    • Mode - AM-FM-SSB-CW
    • Fuse - 3x12 A
    • Output power level - 6
    • Size - 170x295x62 mm
    • Antenna preamplifier - 26 dB
    • Electronic Switch
    • Inversion polarity protection
    This does not mean you must hit that amp with a 15 watt dead key. The Galaxy 979 has variable power so you should be able to adjust you dead key from the front of the radio. If your radio was properly peaked and tuned by the shop that you bought it from you should be able to vary your dead key from 1-6 watts with plenty of foreward swing on AM. On SSB 18-24 watts PEP should be no problem.

    With the RM Italy amplifiers less is always better, they are very much low drive amplifiers that rarely actually do the "advertised" wattage. First make sure your radio has been tuned. Next I would get reliable watt meter and give that amplifier an input dead key of what ever it takes to key the amp at 40-50 watts. This might actually only be 2,3, or 4 watts. You will have to check it out and see.

    Hitting that amp with a 15 watt dead key will not give you any more "talk power" so to speak. With such a high input dead key the amp might key right at 200 watts and maybe only swing 220 or it could even swing backwards. This is a sure signe you are overdriving it and it will run very hot. By giving that amp say a 3 watt dead key input, the output could be say 45 watts dead key swinging 200 watts. This would sound great.
     
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  13. Justme

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    Normally the carrier in AM is 1/4 of the output with maximum modulation.
    My Yaesu FT 2000 - D in Am has 50 watt carrier and 220 watt output maximal modulated in Am which is just fine.
    Setting your carrier ( dead key) higher might show a higher output unmodulated but your modulation will "swing' less now compared to the carrier and sound weaker.

    So, setting your carrier too high will overheat the amplifier that in between the voicepeaks still drives the carrier, and makes you sound weaker, but the output meter stays higher... i rather sound stronger...

    The stated input power and output power of the RM italy amps are way too high, and will certainly overdrive the amp, and since it is a broadbanded amplifier without any output filtering as in our ham radio's cause severe problems with harmonics.

    The difference anyone jusst barely notices is a doubling of your power i.e. going from 100 to 200 watts, going from 200 to 270 or even 300 watts will not be noticed on the other side.
    Keeping your signal clean is more important and keeping your people next door happy as well.
    As does producing strong harmonics over a wide frequency cause probllems with hams and official services, and a visit of the FCC if things run out of hand too bad.
     

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