ad: Hamcrazy-1

All HF band amps , without tuni coils ?

Discussion in 'Radio Circuits, Repair & Performance' started by KD0CAC, Apr 26, 2012.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: L-rfparts
ad: K3QNTad-1
ad: l-gcopper
ad: Subscribe
  1. KD0CAC

    KD0CAC Ham Member QRZ Page

    I have been looking at getting an HF amp that can do 160m - 10m .
    I have heard from some that you may need to tune some of the coils to work some bands ?
    So with 160 , 80 , 60 , 40 , 30 , 20 , 17 , 15 , 12 , 10 - that could be a 10 position switch ?
    Or fewer position switch but tuning some positions for either of 2 close bands - what I would like to avoid ?
    With some bands being wide , especially when looking at top to bottom CW & phone , I can under stand that may be too much , but say just the phone portion of each band .
    Thinking that when I get proficient with CW , someday , that CW should be good for lower power .
    Is that only available in auto-tune amp ?
    So far I have had older tube amps , that I have picked up either butchered or blown up with 5 positions , Heathkit SB-200 , Collins 30L-1 and now a Yaesu FL-2100B - not finished yet .
    Thanks John
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Here in the U.S. we wouldn't need coverage on 60m or 30m, since our power is limited by regulations. Some day that might change, but for now it is what it is.

    There are some bandswitched amps that do include separate switched positions for all the bands except 60m (and maybe 30m), like this one (HF-2000):

    Or this one (Alpha 8410):

    These are not "auto tune," they just have bandswitches and input/output networks selectable for all the bands without compromising or trying to share the same network on two adjacent bands.

    Not difficult to do, just adds cost.
  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    Thanks Steve , yes I know about the power limitations on 60m & 30m , just didn't think about it while posting the question .
    Thats what I was thinking , but just wanted to double check .
    I've seen the comments about the AL-80B being good bang for the buck .
    And the ones you just mentioned are too much for me at this time , but so is the 80B .
    I am also thinking about collecting parts to build something vaguely like the ones 2 you mentioned , to try to keep cost down and still have my cake to eat :)
    Thanks again .
  4. KO6WB

    KO6WB Premium Subscriber QRZ Page

    You could get a soild state amplifier with automatic band switching. No tuning but your antenna system better be able to handle the amplifiers need for a low SWR. There are several manufacturers out there. Like Elecraft (kind of expensive), Ameritron (ALS600 for home use), check Tokyo High Power, the Yaesu VL line. I'm sure I missed some but if you look around you'll find them. Every one of them can be very expensive compared to the same power levels in a tube amplifier. There are some tube amplifiers that will do a band change with no tuning. Can't remember who has that but those are really expensive.
    Good luck
    Last edited: Apr 27, 2012
  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    Gary , I like the manual tuners , to be able to tune the tune to a finer point .
    But the reasoning in this post is cost is higher on the high power auto-tuners .
  6. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Auto-tune tube amps are expensive because they're very complicated.

    Nobody really needs an auto-tune amplifier.

    "Bandpass tuned" amps are a bit simpler, like the old Alpha 374 or 78 series. They don't auto-tune, but they include bandpass circuits that allow them to run full power into a reasonable load without tuning.

    I wouldn't homebrew either of those, they just add a lot of cost for no great reason.

    Tuning's easy. With either my Ameritron or homebrew amps, takes maybe 5 seconds. I know life is short, but I have the 5 seconds.
  7. KD0CAC

    KD0CAC Ham Member QRZ Page

    What I had in mind was building a manual amp , with maybe more switch positions .
    As far as the tuning I am talking about , its the individuals tuning coils in the back of most of the amps I've been in , for tuning each switch position and tuning for the band you want , leaving out another nearby band .
    At my station , most of my DX contacts are between 17m through 10m , I do not here near as many DX on the lower bands ?
  8. KO6WB

    KO6WB Premium Subscriber QRZ Page

    I have an Ameritron amplifier and it covers all the MF and HF bands. I have driven it with 10W on the 60 meter band and the amplifier puts out 100W. This is perfect for that band. I use the 80 meter selection for this. I tried the 40 meter selection and it would only put out 30W. My band selector switch has only 6 positions.
    To hear the DX on the lower bands you need to be awake at night and not have any thunderstorms active. You can sometimes capture DX during grayline. This is the time a little before sunset/sunrise or a little after. I have worked Japan on 40 meters during the morning daylight hours. This was not a grayline contact. For it to be a grayline contact both stations are in the zone of the sunset/sunrise. The zone can be a couple of hours wide. There are some operators that know exactly where the grayline possibilities are for each week or even day of the year to various locations. I'm not one of those. If you look up grayline on the net you will find sites that have graphic displays of the Earth and where the grayline zones are at any time of the day. Due to the tilted axis of the Earth the grayline varies and new locations come up on a daily basis.
    Have fun.
Thread Status:
Not open for further replies.

Share This Page

ad: k1jek