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. RANCH55

    RANCH55 QRZ Member

    My Icom 7300 will peak at 135 watts on SSB using a Heil Pro 40 microphone set at 60% mic gain, with compression set at 1. I generally run my power level at 40% and mic gain at 55% to obtain 1500 watts PEP output on my AL-1500 amp. At 40% drive power, rig only output is around 55~60 watts PEP. I use an Array Solutions POWERMASTER II Swr/Power meter on my setup.
     
  2. K6BRN

    K6BRN XML Subscriber QRZ Page

    Ranch:

    That must be a pretty special IC-7300. The one I've been playing with only puts out about 100W peak into a Bird attenuator and dummy load - a little more on some bands and a little less on others. As measured by an HP437B power meter and a Telepost LP-700 (within 3%).

    Did you get the IC-7300HP version?

    Brian - K6BRN
     
  3. KE0EYJ

    KE0EYJ Ham Member QRZ Page

    My 7300 puts out about 103w PEP. The FT-891 puts out about 90w PEP, basically new from the box. Have seen from engineer posts that this is due to a too long/too thin power cable included with the rig. I'm not sure. The average power on the Yaesu is generally similar, or a bit higher than the 7300, when driven properly (as mentioned, probably because it's far less clean).

    I have people telling me I'm loud and clean with both, so I don't care anymore. Actually, I back it down quite a bit, when the power is not needed.
     
  4. N9IGD

    N9IGD Ham Member QRZ Page

    I'm going to jump in here with my 2 cents on this because it's something that's been concerning me for weeks now. I sent my first 7300 back to the dealer for absolutely poor power-output on SSB. I'm now on my second radio and while it's a tad (holding fingers really close!!) better.....it's still poor from any other radio I've had and I've had a 745, 746, 756, 706 and a Yaesu 757. Every one of those other radios would peak the watt meter at about 75-90 watts when talking normally into a mic. This thing (the IC-7300), BARELY puts out 25 watts on peaks. On CW and FM it's a solid 100-108 watts out. I'm tuning it into a dummy load too. My normal (ocf dipole) antenna tunes absolutely flat when using the external tuner. One more disappointment....the internal tuner....but I figured that before buying it.

    On that same note, some of the contacts I've made when the bands were exceptionally good (and I suppose I was pretty much QRP!) complimented me on my audio. I use a rebuilt D-104 and the stock mic.

    My concerns were exactly what was discussed here. My plans are to buy an amp soon, and will this pitiful 25-watts output drive that amp to it's potential or even at all?
     
  5. K0OKS

    K0OKS Premium Subscriber QRZ Page

    What type of meter were you using?
     
  6. KA5IPF

    KA5IPF Ham Member QRZ Page

    From HP literature: "HP-437B is a low-cost, high performance, single-channel, programmable, AVERAGE Power Meter" Hmmmmm.
     
  7. WA7ARK

    WA7ARK Ham Member QRZ Page

    If my IC-7300 would not deliver power into the input of my kW amp, I would first connect the IC-7300 to my 50 Ohm dummy load, and see what it's power output is. If it makes full rated power into the dummy load, but does not when connected to the amp, I would be looking at the tuned input circuit of the amp...

    If something is wrong with the amp's tuned input, then the swr protection circuit inside the IC-7300 will fold-back and reduce the power. That would be shown on the metering SWR and POWER bar graphs if you put it in that mode...
     
  8. KE0EYJ

    KE0EYJ Ham Member QRZ Page

    Nothing wrong with the amp. It works perfectly.
     
    Last edited: Dec 15, 2017
  9. KE0EYJ

    KE0EYJ Ham Member QRZ Page


    Here's what I've learned, through much use...

    With the 7300, less is more. First, turn compression off, and set the mic gain so the ALC peaks about 1/4 to never more than 1/3 up the scale, max, as you talk... then turn on the compression to anywhere between 1 and 6. This will up that average power reading to more normal levels. I find that about 10 to 15 percent compression is on the meter (about setting 4 to 5 on compression, once ALC is set up as mentioned above) is needed to drive it to better levels for DX. Never go above 15% compression. With local rag chew, a compression of 1 to 3 is ok (0 to 10% on the scale). I also find this drives my amp better.

    If you set the mic level so that it's driving the ALC above half, it begins overcompensating, and you end up with weaker average power output. Your peak reading watt meter will read 100 (mine reads about 103, actually), but your average power will be a weak 25 watts or less.
     
    Last edited: Dec 15, 2017
  10. KA9JLM

    KA9JLM Ham Member QRZ Page

    Get one with a 8877 and you will be fine. :)
     

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