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Galaxy 225 questions..

Discussion in 'CB and Export Equipment and Accessories' started by CB590, Jun 23, 2019.

  1. CB590

    CB590 W9WDX Member

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    Grabbed a decent one today for $115 shipped.

    What can I expect with SSB as far as output with say 4-8w of voice level swing with this? My Ranger 296 peaks at say 14-16w on SSB with a whistle.. but obviously I don't talk as loud as my whistle..



    I'm hoping for 150-170w with that level.. my RM203 is good but my MFJ non peak meter shows like 120w (aka x8 or x9 of input or so) or so with a whistle and only 30-40w with my voice..

    Obviously not my old TS350 either..

    Was looking at the new 250FET by RocketBox but $115 is cheaper than $169.. and not sure on how well fets hold vs pills.
     
    #1 CB590, Jun 23, 2019
    Last edited: Jun 24, 2019

  2. CB590

    CB590 W9WDX Member

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    We'll the unit will be here in 2-3 days. I will run a non tech type test and post some pics and results of what I find with it being driven by my radio.

    I have a handheld tone generator on my phone that can do a 1khz and 2.4-2.6khz tone. And though not dual tone it will at least get me consistent numbers instead of trying to hold a whistle while I snap a pic..

    If anyone has input as well. Feel free. I know it's not going to be as 'clean' as my TS350 was 'supposedly'.

    Bought it from Roosters CB in TN.

    Screenshot_20190623-153444~2.png
     
    Shadetree Mechanic likes this.
  3. CB590

    CB590 W9WDX Member

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    Rooster sent me an internal pic. Couple of MRF455's..

    Based on reading the spec sheet at 13.8vdc and say 4w should yield 75w or so. 2.5w gets you like 60+.

    So I'm guessing I should see about 140+ on SSB with my normal 4-7w voice modulation.

    Stay tuned.. lol
     
  4. Robb

    Robb Yup

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    First off, you cannot tell how much power your radio puts out unless you have it connected to a 50 ohm dummy load (NOT an antenna) and a reliable watt meter. But let me save you the trouble. That radio - if peaked - will have an out put of approx 20w/SSB.

    Problem is, is that that amp is only spec'd for a max watts of 10. Just 10w. Any more than 10w, and you are running that amp into distortion. Splatter Box City.
     
  5. CB590

    CB590 W9WDX Member

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    I get that. Hence the 4-6w with my voice peaks should be fine I would think. Not trying to push it..

    I think the RM203 is technically probably cleaner. But it's showing on my meter as a measly 40-50w on the SSB swing with my voice.

    Like I said the radio peaks according to DTB he got 16w out of it clean. And that's what I wanted for my then TS350. But that got sold do to a $584 truck repair.
     
  6. Robb

    Robb Yup

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    A TS350 uses 2879 transistors and are spec'd for 20w/max input.
    That 225 doesn't have 2879 transistors and can only handle 1/2 as much power.
    Just saying.
     
  7. CB590

    CB590 W9WDX Member

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    I appreciate it. Some other may not read the spec sheet and assume it's a HD and its not by along shot.

    Be interesting to see what my voice gets is the reason for the 2 pill upgrade from the single in the 203..
     
  8. nomadradio

    nomadradio Analog Retentive

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    Sweet spot for the carrier output on that amplifier is 30 to 40 Watts. Set the radio's carrier for that target. Never mind whether that turns out to be 1 Watt, 2 and a quarter, or 1.89775 Watts. The radio's carrier power is only important after it is set to make the amplifier happy.

    The actual carrier power you'll need from the radio will vary a lot from one amplifier to the next, so there's no point it setting it by watching what comes out of the radio. It's what comes out of the amplifier that's important.

    73
     
  9. CB590

    CB590 W9WDX Member

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    Copy that. Appreciate it.
     
  10. CB590

    CB590 W9WDX Member

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    Using channel 20 which shows a 1:1-1 on my A99 I get the following with my Ranger 296 on my MFJ822 meter..

    AM is 1.5w dk that pushs to exactly 3w with a 2200hz tone thru mic.
    SSB is 11w with same 2200hz tone

    With current RM203
    On AM is 30w dk with amp on and needle goes to 40w with same 2200hz tone thru mic
    on SSB I get a solid 140w with same tone when in SSB mode

    So that's our baseline
     
  11. nomadradio

    nomadradio Analog Retentive

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    That's a strictly average-reading wattmeter. Sounds like you have in the zone.

    73
     
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  12. CB590

    CB590 W9WDX Member

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    Is there a reason then why on SSB it reads 140w if it's an avg meter? I'm guessing I can't be getting more than that from a 203.. unless your saying I'm clocking like 200w out of it at full tilt and it's not reading it..

    I get the AM part because it's not going to show pep/peak..

    Just asking not trying to be 'smart'.
     
  13. nomadradio

    nomadradio Analog Retentive

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    A whistle or steady tone into the mike of a sideband radio gets you a straight RF carrier out of the final stage.

    Good chance that if you see more than half this much on that meter from voice modulation that the radio is overdriving the amplifier on SSB.

    The hams call this "flat topping". The peaks of your voice waveform get clipped off and flattened when the amplifier reaches its saturation level and can't amplify any more. Flattening the peaks of your voice and leaving the "valley" parts of the waveform the same will boost the average-power reading.

    But does so at the expense of voice quality.

    This is the reason that the "SSB" switch on a Texas Star amplifier also cuts the radio's drive power to the amp roughly in half.

    You can drive a solid-state amplifier harder on AM before the audio quality suffers. To sound good on sideband always requires a lower drive level to the amp.

    73
     
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  14. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    I always use another radio to monitor my signal. The 148 in the front of the desk surface has headphones and no antenna connected. Makes dialing in the mic gain easy
    . IMG_20190530_201748348.jpg
     
  15. CB590

    CB590 W9WDX Member

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    Oh. So me seeing 20-45w with my normal voice with RM203 would be ok on SSB without it banging the high-end and killing the audio quality..

    Also I did notice that on my TS350, I didn't know what it was though. So besides the relay the SSB circuit has a limiter on it..
     

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