LiFePO4 batteries for base station? HF antennas?

Discussion in 'General Technical Questions and Answers' started by KD2QQM, Sep 17, 2019.

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  1. KD2QQM

    KD2QQM Ham Member QRZ Page

    Hey everyone,
    So I'm another new guy getting my gear together and in need of advice. I ordered a used ft-857d with plans to use it as a base station and to sometimes throw it in a backpack to make some quick, semi-QRP CQ's while hiking and camping. I might use it mobile eventually, I'm not sure yet. I want this thing to be my only radio other than my little dual band Icom HT. I'm willing to sacrifice some amount of performance--other than the wattage--for convenience, versatility, and portability.

    My thinking is to save some money and simplify things by skipping a power supply and just running it on a 12V, 12Ah Bioenno LiFePO4 battery all the time. Is this as practical as I think it will be? Can I just slap some power pole connectors on the power cord and run straight to the battery?

    Also, HF antennas. I'm a newbie but I managed to pass the general exam off the bat so I'm looking at operating voice on primarily 40m and 20m. Running with the shack-in-a-box theme of the 857, I'm looking at antennas like the MFJ-1899t. I like its form factor and price but I'm not blown away by reviews. Is the Buddistick worth the money? I actually prefer the idea of building my own antennas but my interest is in something compact and easy to deploy. I don't mind the idea of multiple antennas. End-fed wires or inverted vees, etc? The radio came with an LDG meter which I think measures SWR, among other things. Is that enough to do the necessary testing? Is there a cost-effective kit to start with? Anyone ever homebrew a good pedestrian rig, even for VHF?

    Anyway, this is becoming an essay so thanks if you've read it all, haha. And thanks for any advice, very much appreciated.

    Alan KD2QQM
  2. KF9BD

    KF9BD Ham Member QRZ Page

    I have actually done something similar. I have several Bioenno LiFePO4 batteries and use a 30 Ah one for my base station. It works very well. The only issue I see with your idea is that the 857D draws a little over 21 amps when running 100 watts, so, the 12 Ah battery is going to be at its max draw. That isn't much of a problem in SSB, but, if you intend to run much digital at full power it could stress the battery and perhaps shorten its life.

    As for the Buddistick, I don't have the buddistick, but, I do have the buddipole delux. The buddipole product is very well made and works very well. I have used it several times portable and have enjoyed the versatility. For me, it has been worth the expense. I have had several MFJ products and they usually work ok. They are less expensive and are usually of lesser quality materials and manufacture.

    Equipment for testing is an easy recommendation for me. Pickup an antenna analyzer, MFJ, Iportable, Comet, etc. I finally bit the bullet and picked one up about a year ago, after thinking about it for years. I didn't want to spend the money and figured and SWR meter was plenty. Man was I wrong. A good antenna analyzer really helps when building and tuning an antenna.

    I hope my comments are helpful. Welcome to the hobby.

    Danny - KF9BD
  3. KM4DYX

    KM4DYX XML Subscriber QRZ Page

    Setting up a battery powered base station sounds like a fun project. Remember that batteries don't last forever, but a good power supply almost will. Sorting a Portable battery powered set up should be fun, too, but you'll want to dial back the power a bit on that 857.

    As for antennas: get yourself some coax, a center insulator, and some wire. THHN 14 gauge from the hardware store will do the trick. You're really going to want an antenna analyzer too, as KF9BD said (others will disagree, but some of the best fun I've had in this hobby is building wire antennas in my backyard and my RigExpert is the ticket). Get outside and build a 20 M dipole. You'll need a way to get it up in the air. Once you've done that you can add some connectors to the ends of the dipole and add wire to make it a 20/40 linked dipole. At the end of this exercise you will have built something that outperforms about anything store bought, doesn't cost and arm and a leg, and you will have learned a lot along the way.

    Then, start learning Morse Code.


  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    For portable use at reduced power, the Bienno should be fine; for running 100W at home, it won't be.

    It's rated 20A max, and at that current will last about 15-20 minutes (transmitting time), even if you use their recommended charger which only provides 2A charge rate.

    I'd use either a much bigger battery, or just go for a regulated DC power supply which will allow you to operate as much as you wish without worry and without deeply discharging the battery.

    [It might be noted also: I have an FT-857D, but most 100W rated solid state transceivers are about the same in this respect -- they only provide full transmitter power at ~13.8Vdc (up to ~14.5Vdc). At 12Vdc at the "battery" end of the cable, power starts to be reduced, and there is always some voltage drop in the battery cable, fuseholders, fuses and internal connections so with 12V at the battery, you may only have 11-11.5V "inside" the radio, where it counts, at full load. My FT-857D under this condition reduces TX power to about 80W, which isn't bad, but it's not "full power." At 10.5Vdc, it shuts down completely and will not transmit.]
  5. K2CAJ

    K2CAJ XML Subscriber QRZ Page


    I have a 40Ah Bioenno battery that is rated for a higher current (I think 40A sustained?), that I bought to operate portable. I now use it pretty much all the time, at home or at work, and I rarely use my power supply. So yes, you absolutely can do that---although the 40Ah battery is not ideal for carting around in a backpack.

    Even so, I'd recommend starting with a reliable "boat anchor" power supply like an Astron RS-35a, which is cheaper than a battery of comparable output, and which will run reliably for a long time. Then you can save up your money for a battery that's best for whatever portable adventure you want to have. It never hurts to have a proper power supply (well, it may hurt your back, but other than that it never hurts.)

    Regarding the rest of your post:

    First, congratulations, and cool callsign. Make sure you label your transceiver as "THE RADIO OF DQQM."

    Second, homebrew antennas are cheap and fun and educational. They can be as compact or easily deployable as you make them, and there's some really impressive innovation out there. Check out, for example, KC8VWM's clothesline reel antenna, which is easy to deploy and pack away, and to adjust to an arbitrary length.

    Third, "End-fed wires or inverted vees, etc?" You won't have to commit to either one, and half the fun is trying out a bunch of ideas to see what gives you the most success. It also depends on what best fits your yard.

    I also agree with the others that an antenna analyzer is a huge help. Out of all the gadgets I bought, I think the most useful single item was an antenna analyzer for HF.
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    A Buddistick or Buddipole is okay for portable operating (hiking, camping, etc) but for home station use I think it's a ridiculous choice. These short, loaded antennas work best on the higher bands like 6m, 10m, 12m...but by the time you get down to 20m they're very compromised and on 40m crazy compromised -- just too small to be effective.

    Put up a dipole or inverted vee, or better still a rotary dipole (rigid, on a rotator, so you can steer it in a favored direction) and there are such antennas that can be homebrewed or purchased commercially. I have an old Cushcraft D4 which is a trapped aluminum rotary dipole that covers both 20m and 40m and is easy to install (although not particularly cheap) and can be turned by a heavy-duty "TV antenna" rotator like a Hy-Gain CD45 or Yaesu G800.

    As you'll find out for yourself, "height makes might" with antennas, and the higher above ground you can install any kind of horizontally polarized antenna, the better it works -- until it's very, very high (like >1WL, which on 40m would be >120 feet high). But I've used the D4 for Field Day portable operations when it's only up about 36' above ground (50' telescoping mast) and it was pretty good.

    An Alpha-Delta model DX-CC is a parallel dipole only 82' long that works well on 10-15-20-40m and "works" on 80m, but has limited bandwidth there. It's all pre-cut and mostly preassembled, and only takes maybe 10 mins to complete the assembly, and then just string it up as high above ground as possible and it will run rings around a Buddipole or any similar small antenna.

    For portable ops, easy-deploy and easy-remove antennas are the thing, but that should not restrict you at "home." I see you're in Orange County, NY which I know quite well since I grew up in northern NJ and the WX is the same in both places. At home, you want something strong and secure that will withstand snow, ice and wind and you won't have to be running outside in wintertime to mess with it.

    But for portable ops, a Buddipole isn't a bad choice. With a small 3' tripod and a mast, it can be set up in 10 mins or so, and it breaks down to something that can fit in a golf bag or whatever for transport. But there are dozens of choices.
  7. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    This antenna will do you much better than a Buddy Pole. It's essentially a 20m/40m fan dipole on a 12 meter heavy-duty fishing pole. Tuneable to other bands. It works really well for me, portable. The pole 12mHD pole is 7.5 pounds though. That is the only negative. If you have high trees over 12 meters, and a way to get a line that high, you don't need the pole.

    As per the battery, as mentioned, you'll need more power for home work. I run a 10Ah 12.8v Lifepo4, and although I can push it to 100w, it really is best to keep it at 25w to 75w. Not a lot of difference between 75w and 100w, anyway. For portable work, I'd get a 15Ah, if I were to buy again. For home -- I'd go 20 to 30Ah, minimum. Although I would rather have a linear power supply for any day except emergencies.

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