1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

Rm Italy KL-503 watts vs amps

Discussion in 'General CB Services Discussion' started by CbRadiosPRONTO, Jul 19, 2014.

  1. Slowmover

    Slowmover Elmer

    Joined:
    Feb 17, 2015
    Messages:
    5,178
    Likes Received:
    8,031
    I’ve changed from a KL203P velcroed to a Uniden 880 or 885 installed in my Petebilts provided overhead location, to a KL7505v installed in a radio carrier that sits on the passenger seat.

    203 was 70W (with 1-reflected) on MFJ 945 mobile Tuner in a co-phase setup (FL Cascadia), to bench test notes showing 180w (and up depending on 3-position power) with the 7505 with variable power on a 99v2 Galaxy set at 2.25w

    12A fused to 30A fused (change).



    Accessing power and running coax today’s job on this 579 Pete during a 34-hour HOS “re-set” while on the road (Cullman, in Alabammy)

    .
     
    Shadetree Mechanic likes this.

  2. Batteryman

    Batteryman Member

    Joined:
    Sep 27, 2015
    Messages:
    3
    Likes Received:
    3

    My RM Italy KL503HD ( high drive version) puts out 450 watts max PEP on SSB and draws only 30 amps ( checked with a certified Fluke meter).
     
  3. kopcicle

    kopcicle Sr. Member

    Joined:
    Feb 17, 2016
    Messages:
    1,973
    Likes Received:
    3,054
    So, let's review
    30A x 13.8 Volts = 414
    414÷2 = 450 watts max PEP on SSB
    o_O
     
  4. Cutlass327

    Cutlass327 Well-Known Member

    Joined:
    May 1, 2016
    Messages:
    309
    Likes Received:
    208
    Might I recommend a dummy load? Disconnect antenna, connect to dummy load. May take a while to figure out why no receive, but is will save on $$$ parts burning out.
     
    barefootindian and Slowmover like this.
  5. loosecannon

    loosecannon Sr. Member

    Joined:
    Mar 9, 2006
    Messages:
    3,966
    Likes Received:
    3,162
    and that's not even taking amplifier class efficiency into account!
    LC
     
  6. KD2GOE

    KD2GOE W9WDX Amateur Radio Club Member

    Joined:
    May 30, 2013
    Messages:
    946
    Likes Received:
    206
    like a Class D audio AMP ROFL
     
  7. El Kabong

    El Kabong Say what?

    Joined:
    Apr 11, 2018
    Messages:
    104
    Likes Received:
    54
    Anyone know what the "new version" of the 503 has new about it? This is not the high drive version.

    Thanks!
     
  8. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    354
    Likes Received:
    77
    There’s a high drive version???
     
    El Kabong likes this.
  9. El Kabong

    El Kabong Say what?

    Joined:
    Apr 11, 2018
    Messages:
    104
    Likes Received:
    54
    Yes. There is.
     
  10. davev8

    davev8 Gold Star/Marvin Award Member

    Joined:
    Apr 26, 2011
    Messages:
    146
    Likes Received:
    28
    then you have to divide by 2 again as rf amps are only about 50% efficient ...1/2 of the power is heat hence the big heat sink ...so about 225w
     
    Judas likes this.
  11. Big Kahuna

    Big Kahuna Sr. Member

    Joined:
    Jul 31, 2008
    Messages:
    1,062
    Likes Received:
    1,860
    I'm testing a KL 7505 right now 4 x 455 (60 watt) and output is around 200-220 driven with 1 watt deadkey 12 watt swing.

    On high setting - 1 watt in 60 watt deadkey / 10 watt swing around 200 watts.

    I did test 2 watts in and it keyed 100 watts so no way I'd run more than a 1 watt deadkey into a KL7505.
     
    Slowmover and CB590 like this.
  12. Slowmover

    Slowmover Elmer

    Joined:
    Feb 17, 2015
    Messages:
    5,178
    Likes Received:
    8,031

    Had these on the bench at Clays 01/19:

    Radio (Galaxy 99v2)
    Low setting on a Galaxy 99v2
    2.25w, swing 15w
    (High: 15w, to 30w; not used)

    Amp (RM ITALY KL-7505)
    Low: 40w, to 180w
    Med: 80W, to 225w
    High: 125W, to 250w

    Used it this way while mobile for several months. Double that of a KL203. I wanted over 100w with a margin.

    Set the radio to lowest.
    Set the amp to lowest.
    Just fine.

    The install was the pain. Potential amp draw + voltage loss led to use of 4-AWG cable. Must have weighed 30# due to near 30’ length. Coax another near 30’. Past $200 DIY.

    Will go into my pickup where the install is pretty much permanent (versus big truck I don’t own).
    .
     
    #72 Slowmover, May 24, 2020
    Last edited: May 24, 2020
    CB590 likes this.
  13. 9C1Driver

    9C1Driver Sr. Member

    Joined:
    Aug 13, 2008
    Messages:
    3,533
    Likes Received:
    1,389
    And all that for maybe 1/2 of an S unit increase over the kl203.
     
    AudioShockwav likes this.
  14. Big Kahuna

    Big Kahuna Sr. Member

    Joined:
    Jul 31, 2008
    Messages:
    1,062
    Likes Received:
    1,860
    125w carrier swinging 250 is not what I’d recommend for running that amp. I’m surprised clays set it up like that.
     
    AudioShockwav and Slowmover like this.
  15. Slowmover

    Slowmover Elmer

    Joined:
    Feb 17, 2015
    Messages:
    5,178
    Likes Received:
    8,031
    A bench check. Didn’t actually “set” anything.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!