ICOM 7300 not exciting my amp enough for full output

Discussion in 'General Technical Questions and Answers' started by KE0EYJ, Aug 3, 2017.

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  1. K0OKS

    K0OKS Premium Subscriber QRZ Page

    Watch YouTube on a computer and set the playback rate to 200%.
  2. KA5IPF

    KA5IPF Ham Member QRZ Page

    And the meter he's using is a peak reading meter. Ring a bell????
    WG7X likes this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    But then the Russian is so hard to understand!
  4. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    As others have stated over and over, get a real peak reading wattmeter, and you will see the difference. I was the same way. I would see about 35-40w out on a regular meter, my Swam WM3000 would show almost 100W on peaks. They really tell the real story.

    As another stated, many PEP meters are not real PEP, all they do in the PEP setting is put a cap across the meter to hold the reading. In other words, stay away from MFJ and a few others. The Palstar is a good choice.
    N8XTH and KA9JLM like this.
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    But they use a diode to charge the cap. lol :rolleyes: The meters light up too, So you can see the meter swing.
    Last edited: Aug 8, 2017
  6. KE0EYJ

    KE0EYJ Ham Member QRZ Page

    Just wanted to update this thread...

    I have since purchased an Ameritron AWM-30B peak reading wattmeter. It finally arrived yesterday.

    The Icom is peaking at around 100w output, max -- rig only. I find I only need 80w to drive the Tokyo Hy-Power amp to full power (just over 700w SSB). That's when the needle stops any and all movement. If I back off to 75w drive, the needle in peak reading mode shows a little bounce between 650 and 700w output.

    In average power reading mode, I'm peaking around 100-200w or less, at 80w drive, with the Icom.

    From this, and help from a friend who looked at my signal on his scope, along with past comments from other posters, I'm pretty confident that I'm not splattering at these levels. I now see no need to drive the amp with more than 80w. I do not have a station monitor yet, but I do keep the ALC at about half on the Icom 7300, and peak my compression at 0 to 10%, usually.

    I find that the Yaesu FT-891 only needs about 75w drive to do the same thing. Not a lot of difference, if I adjust the ALC to stay in the first 1/4 or so. The ALC on the FT-891 gets a bit wild above half, so I keep it low. Power output in average mode then equals the Icom 7300, for the most part, but with some more on peaks, occasionally.

    One more question.. is there anything wrong with me under-powering the Solid State Tokyo Hy-Power amp with lower drive. so it's only outputting, say 400 or 500w? The manual just says 75w-95w with 80w being typical drive.
    Last edited: Aug 30, 2017
    KV6O and KA9JLM like this.
  7. K0OKS

    K0OKS Premium Subscriber QRZ Page

    You are underpowering it every time you speak softly... :confused:
  8. K8JD

    K8JD Ham Member QRZ Page

    Use enough audio compression and you can overheat the amp even tho peak output is in spec :eek:Q
    K0OKS likes this.
  9. WA3QGD

    WA3QGD Ham Member QRZ Page

    One way to make new friends is too continue to run the SNOT out of it,after you make the initial contact,try reducing power so others can utilize the spectrum too,it's not just for the ARRL extras and winlink promoters
  10. K1WTF

    K1WTF Ham Member QRZ Page

    Compression on the mic side isn't necessarily a bad thing. It basically lowers the dynamic range of your voice, by making the quieter tones louder, and lowering the peaks, essentially making your voice overall sound 'louder'. Compression can be overdone, making your voice sound monotonish or distorted. This assumes you're not overdriving ALC with too much compression or mic gain. Listen to your audio via a websdr, or even another radio in your shack (xmit into a dummy load, headphones into the second radio, and just have no antenna or a short piece of coax on it). Compression can boost your power a bit, but don't over do it or it'll sound like $#!7

    As for the 7300 output power, it does 'seem' a little on the lower side compared to some radios, but I think this is due to the ALC being a little more aggressive than most radios. You can see this on your amplifier video when you compared with the amplifier off. Your yaesu was peaking higher than the icom with the settings you were using. I don't think the slightly lower average output on the 7300 is an issue at all, its probably just a less distorted signal.

    Now that you have a proper peak reading watt meter, you've seen that you actually needed to back down the power on the yaesu.

    Yup, I tried to tell people on psk they were overdriving years ago, usually they get really defensive.
    As for mnitoring on the scope, by the time you see flat topping or any visual representation of distortion, you're WAY past a little distortion. It is possible to not 'see' it there and still be splattering, but the scope can help if you actually know how to use it, and use it properly.
    KE0EYJ likes this.

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