Are the 1kw solid state amplifier kits out of China/Russia a good option?

Discussion in 'Amateur Radio Amplifiers' started by KD7VEA, Feb 8, 2021.

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  1. KD7VEA

    KD7VEA Ham Member QRZ Page

    I am wanting to get into EME on 2 meters. I am about to purchase an Icom 9700 so the radio is taken care of, I am using a Hy-Gain VB-215DX antenna (Handles 1kw/2KW pep), so the question now is how to get some real power. 1kw seems to be the standard in 2 meter EME, so that's the direction I am looking in unless I hear otherwise. I have been looking a little at the LDMOS amplifiers on ebay, a 1kw kit would cost around $1000 by the time everything is done, so the price isn't bad, but I haven't talked to any one that has used one I would use it for 2 meter SSB/VHF contesting and of course the main reason would be for EME work running digital modes. Can anyone tell me how they hold up at that duty cycle? I assume it will be a reduced output. if all goes well, I would start looking into the HF/6 meter models. Any info would be greatly appreciated.
     
  2. US7IGN

    US7IGN Ham Member QRZ Page

    I have a Chinese HF amplifier HF 1200 http://uarl.info/forum/index.php?topic=41.0.
    Pros:
    - price
    - solid state
    Minuses:
    - lack of warranty and support
    - low quality components
    There were two faults in first year. I dealt with one (bad relay) myself. Another malfunction was intermittent (also due to a defective part). This led to the fact that for next several years I was looking for someone who can repair it.
    Its LPFs also have poor characteristics and high losses.
    On VHF everything is much more complicated than on HF.
    Think three times and don't do it ...
     
  3. N4OGW

    N4OGW Ham Member QRZ Page

    I think building a 2m single-band LDMOS amp is easier than for HF. For the multi-band HF amp you have to deal with switching the output filters. Plus on HF you will use the amp with many different antennas with different load impedance over a wide freq range, where there are more potential for instability and overdrive issues to show up.

    I'm in the process of building a 2m BLF188XR LDMOS amp using parts from W6PQL. So far it is working and I made the first qsos (SSB, FT8) with it already. W6PQL does have some comments on duty cycle on his web site. You can now get single LDMOS devices that will do 1500 W on 2m. But the problem with those for digital modes is that even if you cool the device, parts in the output circuit (coax balun, etc) still get too hot (hot enough to melt solder). But many people are using the 1 KW LDMOS amps on VHF digital modes without problems.

    Prices from China and Russia will be cheaper but it is a long wait if you need to return something or get a replacement part.

    Tor N4OGW
     

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