200W 30M amp

Discussion in 'Amateur Radio Amplifiers' started by N3DT, Jan 14, 2020.

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  1. N3DT

    N3DT Ham Member QRZ Page

    I'm looking for 30M amp that will be driven by my ts2000. I know it's only 3dB, but I'm willing to spend maybe $200 for an amp that will work. I saw the TC-300, but was not duly impressed, plus it looks like it works best above 20MHz, not sure how it works at 30M, specs are hard to come by. I'd even be willing to go for someone's home brew if it works. But I don't want to start a new project, I want pretty much plug and play. SS would be preferred. I see the Communication Concepts board, but it looks like it needs a lot of work to get it running right and it's $160 off the bat. Not like it's a complete kit. I'd even go for a kit if the price is right.
     
  2. K6CLS

    K6CLS Ham Member QRZ Page

    30m is allowed max 200W dBd; 100w in to a dipole with 2.7dBi achieves that. No need for an amp.

    Might do better with a 2 element beam. Cushcraft has one, sorry I forget the model number.
     
  3. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Part 97 defines power limits, including those for the 30m band in terms of PEP out of the station, not in ERP or EIRP terms. There are no 'dBd' or 'dBi' based power restrictions for the 30m band.

    Here's the relevant portion of Part 97.

    The FCC does not take antenna gain into consideration when setting 30m power limits.
     
    W7UUU and K3XR like this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    That's why the guys with big signals on 30m, assuming they're actually legal, are running phased verticals and beams.:)

    2L 30m beam can be built for $200.
    [​IMG]

    Source for that: http://n6jv.com/30meterbeam.html

    Commercially built versions cost a lot more, but are available.

    IMO the "problem" with a 200W amplifier for 30m (or any band) when using a 100W transceiver is there isn't any kind of amp that has only 3 dB gain, so the exciter level will need to be turned way down and one accident ("oops") can blow up the amplifier.:p It's more realistic and likely safer to start out with a QRP rig like a K2 or KX2/KX3 or something to avoid letting the smoke out of the amp.
     
    K7TRF likes this.
  5. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Either that or start with a commonly available amp in say the 600 watt range that can handle 100 watts of drive power and just reduce the rig's drive power as necessary to limit total power out of the amp to 200 watts. An oops in that situation may place you momentarily over the legal transmit power limit but you won't smoke your amp and amplifiers in this power range are readily available on the new and used markets.

    It's also easy to add a swamping resistor or a T or PI section attenuator to an amp's input so that the rig can be run closer to normal 100 watt output power while limiting input drive to the active device(s) in the amplifier as needed. Well, easy enough though it would take some fairly large resistors from a power handling standpoint to build something like a 10dB pad with comfortable margin when driven with 100 watts.
     
  6. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    CLS:

    It is the 60-meter band, not the 30-meter band, that has the effective radiated power restrictions.

    Glen, K9STH
     
  7. K6CLS

    K6CLS Ham Member QRZ Page

    And

    Yep!! Thanks gents.
     
  8. N3DT

    N3DT Ham Member QRZ Page

    Beam/tower is not an option. The TS2000 easily turns down to anything between 5 and 100W out. The 30M dipole I have is at 70' so it's not bad, I just want a bit more oomph. It seems I hear a lot more than I can touch. Like this morning, I was hearing a lot of EU to RU in the -15dB s/n but the bulk of them couldn't hear me even with 100W. I do have the option of the AL80B, but if I can get there easier.....

    I have entertained a switchable tuned input for 30/20M on the 80B. There is no good 'balance' between 30 and 20M with the current input circuit. And I've tried the tuner from the 2000, no deal.

    Or I could just forget 20M for a while and retune the 80B, it's not my favorite band anyhow. I usually try to avoid it. It was my favorite back in the late 58-60's when I had a wide spaced 3L Hy-Gain beam on my dad's house with the Armstrong rotor. I could work into EU anytime with the DX40. Times change.
     
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I've found there's a balance with my AL-80B for 20/30m that works fine. Input VSWR on 20m about 1.5:1 and on 30m about 3:1. That's more than good enough for the very few times I've loaded it up to 200W on 30m. However, at only 200W output, the LOAD control must be set to "0" (max capacitance) because the amp is very under-driven. But it still works fine and produces 200W output with ~30W drive on 30m.
     
  10. N3DT

    N3DT Ham Member QRZ Page

    Thanks for that info WIK. I actually haven't even tried to mess with the 20/30M input circuit. I do remember reading quite a while ago about some people adding some reactance in the relay circuit to tune out the reactance, especially at 6M. I notice I loose about 20W or more from 100 running it through the amp at 6M. What I may do is play with seeing if I can stub tune the input of the amp at 30M. Just a thought, then maybe I could have a coaxial stub tuner external to the amp when I wanted to use 30M? It may be worth a try, need to put the AA600 on the 80B input and see what it says.
     

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