100-300 Watt Amp?

Discussion in 'Amateur Radio Amplifiers' started by K7MGM, Feb 5, 2011.

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  1. K7MGM

    K7MGM Ham Member QRZ Page

    Hi All
    I have a Yaesu FT-950 (100 watts transmit) and an antenna that is restricted to 300 watts of power. Due to my homeowners association I can't increase the antenna size or profile. I would like to add about 100 to 175 watts of power. Can anyone suggest a good solution? Many thanks in advance.
  2. K0BG

    K0BG Ham Member QRZ Page

    An amplifier will help others to hear you, but won't do much for you hearing them. What kind of antenna are you using?
  3. WG7X

    WG7X Premium Subscriber QRZ Page


    The difference between 100 watts and 300 is so small that no one could tell the difference... Really,

    That is only one of the reasons why you don't see many low power ham radio amps. There is simply no reason for one, unless you are running a QRP rig that sometimes needs a boost. There is a significant difference between a 5 watt signal and a 100 watt one; but very little difference between a 100 and 300 watt signals.

    In my experience, going from 100 watts to 500 seems to be the most significant change.

    As Alan asked, what kind of antenna do you have? It seems strange that an antenna would be limited to 300 watts or less. I've made antennas here from hardware store stuff that will handle anything I can throw at it, up to legal limit and still have not spent more than twenty dollars.... No, change that I decided to buy ladder line at .36 cents a foot... That brought the price up a bit.

    The antenna itself is very cheap and takes power well...

    It is a simple dipole fed with ladder line. Many CC&R limited hams run these in the attic with good results. I suspect that instead of using more power, you need to study the antenna angle bit more.

    73 Gary
    KX4CC likes this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    There aren't any "100w in, 300w out" amplifiers on the market.

    The ALS600 and similar amps (100w in, 500-600w out) are about where they "start."

    You can use one of these and simply reduce the drive to it by turning down the power on your transceiver, to limit the output to 300w if you wish.

    Most antennas will handle a kilowatt or more easily. Those that can't usually have small coils or lower voltage capacitors, or undersized matching devices that limit their power rating. It's easy to change antennas to something that can handle more power: A wire dipole made of almost any sized wire can handle a kilowatt.
    KX4CC likes this.
  5. W9GB

    W9GB Ham Member QRZ Page

    Gene -

    Best advice,
    IF you desire more RF output is to sell yout FT-950 and buy one of the newer Yaesu 200 watt RF output transceivers (FT-2000 version ?)

    You will not find a plug-n-play or commercial HF amplifier to go from 100 watts to 300 watts. WHY? Pure Economics.

    By the time a manufacturer (or DIY builder) purchases the necessary parts for that amplifier --
    you have spent same $$ as the Ameritron/MFJ ALS-600 HF amplifier at 600 to 700 watts !!!

    KX4CC likes this.
  6. K0RGR

    K0RGR Premium Subscriber QRZ Page

    I'm afraid going to 300 watts isn't going to buy you much. 100 to 400 would be 6 dB, or about one S unit, the way some manufacturers defined it years ago.

    Improving the antenna usually gets you much more than increasing the power for the same price. Another way to get more bang for your watts is to use CW or one of the digital modes. They truly outperform SSB.
  7. KI6ZIF

    KI6ZIF Ham Member QRZ Page

    I don't seem to recall very many antennas limited to 300watts of power. Now I do recall quite a few tuners that are though.

    What antenna are you using. What is the layout you are limited to, and importantly - what bands are you looking to operate on. Otherwise we are left to assume you are limited by either a home owners association, etc.. Or running a poor antenna on a band that you do much better on with an antenna that could be built better.
  8. K7MGM

    K7MGM Ham Member QRZ Page

    THank you so much for your help.
    Gene KF7NKL
  9. AD7N

    AD7N Ham Member QRZ Page

    Gene -

    What kind of antenna do you have?

    If you're on your way to buying an amplifier, I would recommend upgrading your antenna first to something with more gain.

    However once you've gotten your antenna upgraded, and you still want an amplifier...
    I would *highly* recommend going all the way - a 1 KW or 1500 W amplifier. Anything less is simply not going to make the investment worth it in my opinion.

    A 1KW amp vs 100 watts is pretty significant, but 1000 vs 1500 watts isn't nearly as big a difference.

    1000/100 is a 10:1 difference
    1500/1000 is only a 1.5:1 difference!

    If you can find a good deal on a 1KW amplifier I'd take it!

    Best luck!
    Last edited: Feb 6, 2011
    KX4CC likes this.
  10. KC7QNM

    KC7QNM Guest

    You might be using a mobile ant that is low profile...300 watt class...Hustler or simular loading coil antenna. If so High power "resonator's are available to 1 Kw for replacing the 300 watt coil and does not increase visual profile..You then can go to a 500 or 1 Kw amplifer with a punch...A 108" stainless steel whip and tuner can load 1 Kw on 40-10 meters...and be a way to go that can quicky set-up a fixed station , or pick up and move with you if needed. Do not omit the public library and a local ham club for help..as the restricted antenna subject is one you can find help with..as is "hidden antennas" for the ham radio operator. best regards...
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