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Power supplies and other questions

Discussion in 'General Technical Questions and Answers' started by K7OYZ, Aug 10, 2017.

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  1. K7OYZ

    K7OYZ Ham Member QRZ Page

    I don't know if this is the correct place to ask this but hopefully it will work. I purchased my first hf radio today, an ICOM 7100 which will be used at home and also in our travel trailer. Now I know I need a power supply, so what are your recommendations? Also, what else will I need? Tuner? What type of antenna? Anything else I must have? Thanks
  2. NS8N

    NS8N Premium Subscriber QRZ Page

    Mike, per this page, you should be able to get away with a 30amp PS.

    Lots out there as far as power supplies go.

    I would indeed recommend a tuner. Looks like that rig outputs 100w so look up '100w antenna tuner'. You can add 'automatic' if your budget allows.

    As far as antenna, that's the trickiest question here. What bands do you plan on operating on? Antenna is usually the most important part of a stations setup.
  3. AF6LJ

    AF6LJ Ham Member QRZ Page

    You are going to get many reccomendations regarding power supplies.
    I would go with an Astron 35 amp supply.

    The antenna issue is going to depend on what bands you settle on using, and that is going to depend on what you want to do on amateur radio. If you want to work DX you could start out with a simple dipole maybe one for 40 and 20 meters.
    For portable operation a tuner would be good to have since often your portable antenna is a compromise.
    If you live in some kind of managed community where you have an HOA you may have a compromised antenna at your home so the tuner would be good to have.

    You are in the power level where an automatic tuner is reasonably priced. (in the $200.00 range or less).

    I hope this helps.
    WA8FOZ and NS8N like this.
  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page


    Antennas are what make radios work. The signals don't come out of the power outlet.:)
    WA8FOZ, KC2FQ, WA7PRC and 3 others like this.
  5. AF6LJ

    AF6LJ Ham Member QRZ Page

    Steve is right you should put up the best antenna you can afford that will fit on your property.
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    A 30 ampere power supply should be more than adequate, but don't settle for less current capability, because you will invariably want to connect some accessories at some point. A "100 Wat" tuner is marginal; you want one rated at least 300 Watts to allow a safety margin.
  7. AB3TQ

    AB3TQ Subscriber QRZ Page

    You actually purchased an HF/VHF/UHF Radio. But to make full use of the HF capabilities you need a license upgrade.
  8. K7OYZ

    K7OYZ Ham Member QRZ Page

    I will be taking the general test on Monday. Hopefully I will pass! Radio won't be here until after that.
  9. WA7PRC

    WA7PRC Ham Member QRZ Page

    According the user manual, the specification is: "Power consumption (approx.) Tx Max. Power = 22A". This is the worst-case instantaneous current requirement.

    What others aren't telling you is that the AVERAGE current depends on the "duty cycle" of the mode that you're transmitting. The human voice is equivalent to about 25% D/C. In other words, the AVERAGE current is about 22 x 0.25 = 5.5 Amperes. This is why many thousands of hams are using 15-20A power supplies to run their 100W RF
    OUT rigs. I used an Astron RS-20A (20A intermittent, 16A continuous) for three decades with ZERO problems.
    K7OYZ likes this.
  10. AG6QR

    AG6QR Subscriber QRZ Page

    An Astron RS-35A linear supply is a lifetime investment that will probably outlast many radios. It's a bit of overkill, but that means it won't be strained, it will run cool, and it will last a very long time. A smaller Astron RS-20A supply would probably work, especially if you restrict yourself to SSB voice only, but if you're going to use digital or AM, or perhaps even CW, it's not wise to assume the duty cycle will always be so low. I'd recommend buying a supply of a bit more capacity than you'll actually use, to give you some room for accessories and to avoid straining the supply.

    The Astron linear supplies are big and heavy. This normally isn't a problem at home, but since you mention use in a travel trailer, you may prefer something smaller and lighter. For this I'd recommend a PowerWerx SS-30DV, which is a switching supply that is known to be very quiet as far as production of RFI on HF. I'm assuming you'll be using the radio where you have access to 120VAC. If that's not the case, the best option is probably to run the radio on a 12V deep cycle battery while camping.

    I own both a PowerWerx SS-30DV and an Astron RS-35A. I use the RS-35A at home and the PowerWerx for travel use when I have AC available. If I could only have one for both purposes, I think I'd prefer the PowerWerx. My Astron had a couple of issues that make me suspect it wouldn't hold up well to being bounced around in a travel trailer, though none of those issues would present a problem for home use. See my photos and discussion here:

    I do think the Astron linear unit is a better supply for home use, because it has a bit more capacity, uses readily available standard parts, comes with a schematic, is easy to service, has a proven long-term record, and generates absolutely no RFI.

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