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2m/70cm SSB/FT8

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by WB0FTY, Jan 14, 2018.

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  1. W0AAT

    W0AAT XML Subscriber QRZ Page

    Anyone serious about VHF+ will run a brick amp and they can be bought pretty cheap used. It is not advanced or uncommon at all! And an IC-251a impressive? The thing is a dinosaur! And on VHF+ aluminum before amplification! Antenna gain is cheaper than amplifier gain!
     
    WD4IGX likes this.
  2. NQ1B

    NQ1B Ham Member QRZ Page

    "Impressive" meant the 2M5WL. It's a significant project to put up a tower and rotor that can support and turn an antenna that size. I don't even have room to swing one without hitting a tree. :rolleyes: I agree that brick amps are not expensive in absolute terms, but unlike HF amps each one only works on a single band, so you have to be "serious about VHF+" to go that route. I'm sure you've noticed that the number of hams "serious about VHF+" is a tiny and declining fraction of all hams.

    Antenna gain is not cheaper than amplifier gain. That's a myth, and I don't know where it comes from.

    Example from HF: I bought an SB-220 (used) and did some minor repairs on it, totaling about $700. That gives me 10 dB of gain on bands 80-10 meters. I also bought a hexbeam (new) for about the same price, then had to spend additional funds to get a military mast and rotor. If I had found a source for a used hexbeam, the total installed cost would probably have been about the same as the 220, but it only gives about 3 - 4 dB gain on 20-10 meters. (Of course, it gives that gain on receive as well as transmit, and some F/B as well.)

    Example from VHF: Your 2M5WL is currently $462 at DX Engineering. The cheapest new rotors I've seen for ham use (ignoring the cheap TV rotors I use for small antennas) run about $350 new. I won't guess what it costs to buy a tower and do the full installation, but it's going to be siginificant, and many hams don't have the skills to do it. On the amplifier side, a TE Systems 1412G puts out 160+ watts for $440 new, and doesn't require any towers, rotors, concrete-pouring skills, or other major accessories.

    I don't see any way to argue that antenna gain is cheaper than amplifier gain until you get past the 500 watt level. When you start looking at legal limit amps, then the cost per watt rises dramatically. But of course that's also true on the antenna side once you get past a minimum tribander (on HF) or basic 2-meter yagi (on VHF).

    The cheapest 10 dB bargain in amateur radio is a 1 kw amplifier. The next cheapest 10 db is a serious tower with monobander yagis at a good height (50 ft+). The next 10 dB after that gets really expensive...
     
    KA0HCP likes this.
  3. WB0FTY

    WB0FTY Premium Subscriber QRZ Page

    Cathy you are right. It is expensive and I feel blessed the LOML of 50 years gave me her blessing to purchase a new FT-991A radio. I have always bought used because of money. I just upgraded my main rig from a FT-101 with Kenwood TS-590S. Being able to add this new 991A to the mix feels good. Being on a fixed income it is hard. Would love a 50 ft tower, with a stacked set of M2 25 element yagis, running 400 or 500 watts to go along with this new radio but I do the best I can with what I have. LOL I figure as long as I can still have fun and especially learn something along the road that is all I can ask for. Thanks again for the responses and info.
     
  4. W0AAT

    W0AAT XML Subscriber QRZ Page

    Aluminum is cheaper than amplifier on VHF! 2m5wl is ~15db gain, 15db amplifier is a 50 in 300 out, TE1452g is closest at 25 in 350out and is $700!

    2m5wl can be support by a simple mast if needed, wind load is not that high. Can turn it with a smaller rotor, or even armstrong like I did for a year!

    Amps can be built cheaper of course W6PQL has a very affordable 1kw 2m amp kit for $468, add his low pass filter and a power supply and relays and you are on the air. Then there is building a tube amp. Been there done that used a microwave over transformer to power it. 4CX250 plumber delight with all surplus parts I got dirt cheap. Total I had in that was under $300 and I used it for a couple years before I smoked the power supply transformer...

    And if you haven't guessed by now, VHF+ ops are crazy!

    Tower? Used Rohn 25 sections are $25-50, get 2 and a sleeve top, and a damaged section to set in the concrete if you want to go cheap. Dig a 2x2x4' deep hole and set the bottom in on gravel, add concrete and then stack the rest of the tower, total tower cost? Under $300 if you scrounge!
     
  5. NQ1B

    NQ1B Ham Member QRZ Page

    Yes, I've noticed that. :D But then all hams are crazy in our own ways!

    Good to know that a mast can be adequate. I paid about $100 for a section of strong military mast that supports my hexbeam, and I'm sure that could support the 2M5WL. So that would be about $562 total if you don't use a rotor.

    Perhaps you'd like to come dig the 2x2x4' hole on my property for me? Hint: I live on a granite quarry in the mountains, in a town that was built on the granite industry. You will hit bedrock and huge boulders in less than 2' of depth.

    You're assuming that digging a hole means a few hours with a shovel, but for some of us, it means hiring it done, or at least hiring serious power digging equipment.

    If you're going to scrounge to build the antenna and support, you have to compare costs with scrounging on the tube side. As you pointed out, that drops the amplifier price further. I tend to use new pricing in discussions like this because they can be looked up and verified objectively, and they are open to everyone, whether they have scrounging opportunities or not.

    I'm glad you've had good success at reasonable cost at getting a good station going. It's not equally easy for everyone to do this. I'm happy that I was able to put up a 2M9 on a mast and TV rotor fed by a TE 1412.
     
  6. W0AAT

    W0AAT XML Subscriber QRZ Page

    On granite I would use a standard rohn base and drill holes and epoxy in bolts! Modern construction epoxy is as strong or stronger than concrete. Or if you can get down 2' go that far, epoxy rebar into the granite then pour a smaller base.
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Not so much. My old buddy Bob Cunningham, the original K1XR, installed a 100' 25G tower on his property in one weekend...in NH, where the ground is about as you describe. I helped him do that. It took two days, mostly for dealing with the guys and turnbuckles.

    It took one cement pier, one Rohn pier base, and 90' of 25G tower sections. A pier point base requires no excavation and no concrete, but you do need to have guy points. In our case, there were hundreds of strong trees around, so we mostly guyed to the bases of them, down low on their trunks.

    We installed a pair of long-boom 2m yagis on that with zero issues.
     

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