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Who makes decent VHF amplifiers?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by N6YFM, Jul 26, 2018.

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  1. N6YFM

    N6YFM XML Subscriber QRZ Page

    I am starting to get mildly interested in 2m weak signal and SSB, and have started
    looking into amplifiers, maybe in the 90 to 160 watt range. Of course, I am looking
    for an FM & SSB capable unit.

    Who actually makes a good one these days?

    - Mirage MFJ seems to have no electronic design skill, since EVERY Mirage amp I ever see for
    sale, going all the way back to 1990, already has a blown out preamp due to their "design" (sic)
    of the RF sensing RX/TX relays, hot RF switching that blows the JFET out repeatedly. Then, if
    you buy a recent Mirage with "MFJ" influence over the soldering and QA testing, say no more...
    Just go read reviews of the Mirage amps, not a great set of designs.

    - The nice 80W VHF amp by W6PQL uses a PA module that Toshiba no longer makes (EOL 2011).

    - There is always "RM Italy", but seriously, they are not know for "quality" design either.

    Are there ANY decent choices out there, new OR used?
    If not, I see a small market opportunity :)

    Cheers,

    Neal
     
  2. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Owned numerous Mirage amps, all during the MFJ years. Never a problem whatsoever over many years. Not a single failure of any kind.

    just a data point from personal experience

    Oh wait.... this is just another "MFJ Hate Thread". My bad.

    Carry on.

    Dave
    W7UUU
     
    K6YZF and N8VIL like this.
  3. KM3F

    KM3F Ham Member QRZ Page

    The late Mirage B 2518 G and 5018 G are very good with improved protection and Bias circuitry.
    One these bands the pre-amp is of no value.
    Does it increase the signal? Yes but the S/N ratio is not improved at all.
    If you live in an area with business repeaters operating above the 2m band, using the pre-amp is inviting severe receive IMD.
    All you see is the S meter go higher with little to no improvement in the signal.
    Bottom line is don't make the pre-amp a factor in the purchase for any amplifier.
    The proper place for a pre-amp is up at the antenna, not in the amplifier.
    I use a 2518 at 15 volts input and 35 watts drive on FM to get 190 out into stacked beams for long distance repeater access..
    Most may shutter at this but works for me without an issue.
    I do these things with out fear. If it blows it blows. As long as the SWR is low the protection circuit does not trip out at that drive level.
    Also there is an aux cooling fan mounted to the Fins.
    What makes this possible is the amplifier devices are rated to as high as 18 volts so no harm driving the amplifier a bit harder at 15 volts as long as your power supply can output the current.
    Good luck..
     
    Last edited: Jul 26, 2018
    WQ2H likes this.
  4. K6CLS

    K6CLS Ham Member QRZ Page

    I like Mirage amps. I always hard switch to TX, never use the RF detect. No trouble, ever.

    Consider adding a sequencer to your rig, to control preamp power, relays, amp TX, etc.

    Wish they still made one for 220MHz, maybe 170W or so...
     
  5. KX0Z

    KX0Z Ham Member QRZ Page

    TE Systems. Tokyo Hy-Power. KLM..
     
  6. WQ2H

    WQ2H QRZ Lifetime Member #214 Platinum Subscriber Life Member QRZ Page

    I agree with KM3F on the B 2518 G - it's been chugging along in the shack for several years now (mostly for FM). If you're transmitting into your average Diamond or M2 - SWR should be fine.

    I added two +12Vdc cooling fans blowing down on the fins - the thing does get warm at higher power with a higher duty cycle. (a bonus in New England during the winter)

    Good luck !
    73
    Jim, WQ2H
     
  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    One reason a Mirage burns out, Is because some operators do not understand the duty cycle when operating FM.

    My Mirage amp has a PTT connection to avoid burning out the pre-amp and smoking the T/R relay from hot switching.

    Do not use RF keying. That is so CB like. It works half fast.

    Have Fun everyone.
     
    Last edited: Jul 26, 2018
    K6YZF likes this.
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    TE Systems VHF amps are quite good, better workmanship than current Mirage stuff.

    Weak link in them (and almost all these SS amps) is the relays, which are PCB mounted and to replace one you have to access the underside of the board, which requires removing the entire board from the heatsink -- not a small job.

    To help make the relays last longer, never use "RF keying" at all. Use "hard, line-connected" keying (they all have such a provision) activated by your transceiver; it will be much easier on the relays and they can last 10x longer (up to several years).

    The preamps in most of these amps don't help anything and I'd encourage anyone to just keep them turned "OFF." If you find the preamp actually improves S/N of received signals, you have a problem with your receiver. Using a decent VHF receiver, the preamp in the amplifier brick shouldn't really help anything -- they do absolutely nothing for my IC-736R or IC-9100 except make the S meter read higher.:p Another problem with using the preamp is that adds more relays to the mix of relays in the circuit, and more stuff to fail.
     
    K3RW likes this.
  9. KC8VWM

    KC8VWM Ham Member QRZ Page

    I prefer toobes.

    So much better sounding than solid state. I found most 160 watt solid state VHF amps start to crap out with distortion when pushed above 110 -120 watts. The toobe amp doesn't give a crap about high SWR either. In fact, I think it actually likes it.

    I have even inadvertently tested it with no antenna attached whatsoever a few times without any problems. :D Cockpit errors can occur and solid state amps are not forgiving.

    So if you can find yourself an olde school VHF toobe amplifier, I would say go for it and leave all your solid state amplifier troubles behind.

    This one was an Ebay find and I have often seen others too.

    MVC-010F.jpg

    MVC-012F.jpg

    MVC-009F.jpg

    Other than olde school on the used market, there's very little commercial offerings available anymore.

    The majority of most serious weak signal VHF enthusiasts end up building their own high power toobe amplifiers.
     
    Last edited: Jul 27, 2018
  10. G3YRO

    G3YRO Ham Member QRZ Page

    The British company Microwave Modules used to make some really excellent and reliable Transistor 2m linear amplifiers . . .

    [​IMG]

    These days they are hard to come by . . . but you do ocassionally see them up for sale (due to lack of 2m SSB activity)

    Roger G3YRO
     
    Last edited: Jul 27, 2018
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