Suitable preamp for a HT

    I have a brand-new General license and while studying for it I got interested in satellite radio communication. I’ve been reading https://www.amsat.org/introduc…rking-amateur-satellites/ and it seems like the right level of challenge for where I am.


    I have been involved in Summits on the Air and wanted to buy an antenna for “chasing” from my home station on 2 meters. In order to also pursue my new interest, I got the M2 Antennas Satellite Antenna Packages SATPACK1. Reviews for that antenna (and the third and fourth articles linked in the above-mentioned URL) mention a preamp. The specification sheet for the MHP-145 illustrated in https://www.amsat.org/wordpres…Getting%20Started%204.pdf says that it is a “preamplifier for high power, up into the kilowatt range.”


    I wouldn’t mind buying something that would also work when I buy a higher powered transceiver as described by https://www.amsat.org/articles/houston-net/amps.html. For instance, I found the Advanced Receiver Research preamps with 160 watt through power capability (which I’m guessing is different than “power handling capacity” or “operating voltage” times “power consumption”). However, for now what I need is something that would work with my Yaesu FT-60R/E. I’m guessing that what I need is a SSB LNA 200, but I’d like someone with satellite experience to confirm that.


    Any suggestions about a suitable mast mounted preamp would be greatly appreciated. And, just to satisfy my curiosity, is there a difference between receive preamps and transmit preamps? It took me a while to realize that my Google searches were yielding preamps used for transmitting.

    Hi Marcia!


    For 2 meter mast mounted preamp look at:

    https://www.ssb.de/download/EN-1049_SP-2000.pdf

    The preamp works with HF-VOX, then the max power is 100 watt on ssb.

    With ptt for example with DCW-15B the max power is 750 watt on ssb.

    http://www.radiomanual.info/sc…_SP-2000_SP-7000_user.pdf


    And by the way - this preamp gives you a better receiving signal to your radio, especially, if your feedline is long and the Sat signals are low.. it has nothing to do with transmitting amplification..


    73, Guntram oe9dgv.

    Thank you so much, Guntram, for your quick and knowledgeable response. The documentation is very helpful.


    Just as a note for anyone else with preamp questions, SSB Electronics has changed its naming conventions for this preamp. You can see a picture of the “Super-Amp 2000” at the top of https://www.ssb.de/en/amplifiers/preamplifier/vox/100w but the brands offered for sale are, for instance, “SP 200.”


    I have a few follow-up questions that I hope are of interest. The antenna I have bought has a boom with two antennas attached. I am planning to use a duplexer (such as a Comet Antennas CF-416W) so I only have one coax run. Does this preamp send power down the coax? I’m not seeing this question answered in the documentation provided so I would assume the answer is no. However, if power is sent down the coax, will the duplexer interfere with sending DC over coax? Can I have preamps next to each antenna be fed by just one power supply? I understand from my reading of the “Getting Started” pages that I should choose low-loss coax, but is there a practical limit to that advice? Or should I just get the most expensive coax I can afford?


    Many, many thanks,

    Marcia KJ7NOY

    Hy Marcia!


    For duo-band antennas look here: https://www.hamradio.com/detail.cfm?pid=H0-016812

    On Leo satellites you have to here your own signal back and so I´m not shure, that a duband antenna is a good choice.

    To the coax cable: It depends on the footage of your feedline. I think, the attenuation in db/100m on 432 MHz should not be over 9. But the longer the lesser attenuation is claimed.


    Hope this helps..


    73 Guntram oe9dgv

    Hi



    Both is possible. You can feed the Preamp with external Power or a bias T via the Koax line. Please note that a duplexer has a DC pass only at VHF. For UHF you have to feed the power direct to the amp. Buy the way, I'm using a Duplexer as well.
    I don't want to practice some advertisement, but these company produce extremely good LNA as well.
    https://www.tgn-technology-onl…Masthead-Preamplifier-23/
    Maybe you can check this as well.


    vy 73 Alex

    Hi,

    you said "for now". Unless the cable you are using is very long and/or thin and thus lossy, I think you will not need a preamp for the FM-satellites at all, given your transmit power is about 5W from your hanheld? So for now go without a preamp. Or buy a preamp AND an amp. Being able to hear even the weakest signals makes no sense if you don't have enough power to be heard. And vice versa.

    But in the first place, you will need a transceiver capable of transmit on one band and receive on another, simultaneously. The FT60 can't do that, can it? Or you need a second transceiver for the other band.


    73, Martin