AM Newbie. Questions Inside.

Discussion in 'Amplitude Modulation' started by N4AXE, Sep 13, 2016.

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  1. N4AXE

    N4AXE Ham Member QRZ Page

    Greetings,

    I'm still a young nut in this hobby generally speaking. The longer that I have been involved the more I have wanted to build a modest am station for 80/40m use. I have an 80m skyloop that is just begging for some AM useage. I have experimented a little in using my ft950's am mode along with my als-600. It's just 250w and I realize its not "true" AM.

    I have contemplated building a class E transmitter, and I have considered purchasing some heavy iron that needs some love. So far what I have found available for purchase has been at a premium. Justifiably so given the condition of the equipment. None the less out of my price range making it prohibitive.

    For those of you in the know my question is this:

    Should I build a simple heavy iron AM station from scratch?

    Should I build a class E station from scratch?

    Is there a such thing in this day and age as an "affordable" starter AM station?
    (I realize the word affordable is quite subjective, and in the end you always get what you pay for, but for a moment please suspend the need to say something overly smartass in response.)

    I am open to any suggestions that are helpful at this point. I'd rather move forward with some guidance from the old pros than learn the hard way all by myself.
     
    N6YW likes this.
  2. N2DTS

    N2DTS Ham Member QRZ Page

    If you do not have a huge junk box, building a big AM transmitter is going to take a long time and cost a lot.
    You may be able to pick up something that works for a reasonable price, modify something to work on AM, or use what you have.
    The AM out of your FT950 is 'real AM'.
    Many use a flex (the 5000 is good) or whatever into a big amp.
    100 watts on 40 works very well much of the time, and on 80 its ok at times, not during prime time maybe.

    You can get something like a multi elmac AF67 or even a DX60 and mod it and feed it into an amp, find a dx100, valyant, or globe king for a reasonable price,
    or network for a rig.

    SDR's work very well, you can screen modulate something very easy, pick up a broadcast transmitter cheap sometimes, or just buy an AM station.

    I like building, so that is why I do AM, if you have parts, its easy to put something together.
     
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  3. VK3YE

    VK3YE Ham Member QRZ Page

    I would start with a medium power CW transmitter. Preferably using FETs and a 30v supply rail. Eg



    Then I'd be looking at some sort of modulation schemes. Again solid state would be cheaper/easier.

    Maybe using old power transformers.

    It might be worthwhile researching what HF pirate broadcasters use as their stuff is designed for long duty cycles and can be fairly simple.

    http://worldwidedirt.tripod.com/gproject.html
     
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  4. WZ5Q

    WZ5Q Ham Member QRZ Page

    Howdy Ben,
    Building your own Heavy Metal Transmitter from scratch is fast becoming a lost art in itself. There really are not that many amateurs doing it these days. Most people will buy already built transmitters, have them built by someone else, or find a Broadcast Transmitters and re-task it for Amateur Operation.
    I think the major reason for this is parts availability and the cost. You just can't find everything you need like you used to, and if you do, the cost is sometimes staggering. I have been collecting specific parts for my Heavy Metal Homebrew for the last 16 years and still don't have everything I "want". I have everything I "need" and am in the process of building it, but in some instances will have to use parts that hopefully I will be able to change out at a later date as the ones I "want" become available.
    Hamfests are the #1 place to find most of the small parts for the build. You can usually find small iron there as well. eBay is another great source, as well as QTH and the other web swap shops. The Big Iron and hard to find small parts are a different story. This is usually by word of mouth between amateurs and hardly ever advertised. If it is advertised, it is usually quite expensive. Then there is transportation and shipping cost issues to deal with.
    Another great source of parts is Broadcast Transmitters, but a lot of amateurs (me included) have a hard time ripping into and stripping them for parts if there is an once of life left in the old girls.


    This is what most are doing these days. I hear of more amateurs building these from scratch then anything else. Parts seem to be readily available and the cost reasonable. I have no experience with these type of rigs and will leave it to others to comment on this subject.
    I try to keep the "sand" out of my AM Transmitters. :D


    Yes! There are a lot of options to get your feet wet for sure. First you need to figure out what direction you want to go, as in Hollow State (glass) or Solid State (sand).
    In Glass, Brett gave some excellent choices mentioning the AF67, DX-100, DX60, & Valiant. There is also the Viking & Ranger. These perform very well in front of a Linear Amplifier for legal limit.
    The next bigger step would be a plate modulated transmitter of some sort like what Brett also mentioned the Globe King 500 or a military transmitter like the BC610 or T-368. These can usually be found for decent prices.

    You have lots of options and just need to do some research and figure out what you really want. You will learn a lot by repairing and modifying these rigs.

    Learning the hard way is sometimes the better way, for me anyway. ;)
    The most important thing is to have fun doing it!

    73
     
    Last edited: Sep 13, 2016
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  5. N6YW

    N6YW Ham Member Volunteer Moderator QRZ Page

    Ben
    Welcome to our humble Am Lounge here, where you will find the finest cadre of principled and
    talented people thoroughly infused with the AM addiction. All of the above postings are true and whatever
    your destination, whether it's home brew or vintage, re-purposed BC rigs etc, you will find the answers here.
    I like the idea of getting a starter AM rig that is running, and it doesn't have to be a heavy plate modulated
    rig either. Screen (Girlie) modulated transmitters are also fun and can sound excellent.
    Like you I also used the Yaesu FT-950 with very good results and it's a real AM rig, a carrier and 2 sidebands.
    It's a real good sounding transceiver.
    My best advice is to read a lot, talk to people and as mentioned above, network with people and go to the
    hamfests. DO NOT overlook local ads like Craigslist etc. There are a lot of great deals to be had but also
    beware of buying junk or taking on more than you can handle or have time for... this AM hobby can become
    a full time headache if you let it get away from you.
    Building a self contained low power CW transmitter and adding a modulator, like a mono hifi amp, is a real
    kick and can sound excellent. My friend K6JEK built an amazing Class E transmitter that rivals any BC
    rig I have heard. Many of us have bought restoration projects and enjoyed the learning process in bringing
    them back to life and of course that satisfaction is hard to beat. As for a BC rig like a Collins 20V, Gates,
    Bauer, etc. Those require a certain "need for speed" and the space. It's not everyone's goal and can be very
    daunting depending on your skill sets.
    If I may, allow me to suggest the military route as an alternative. I have owned the BC-610, and currently
    own the T-368-E and they are wonderful and represent the state of the art for those periods, but they are heavy
    and require a good understanding in keeping them running. My favorite is the Collins ART-13, which I own and
    use every day. Get one, build your own power supply unit, add a couple of simple mods and you have one of the
    greatest inventions ever put on the air. Auto-tune, a pair of 811-A's modulating a single 813 and excellent audio
    will bring you much joy and satisfaction.
    There are so many choices so have a look around and see what "excites" your interest.
    We are here to help!
    73 de Billy N6YW
     
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  6. N2DTS

    N2DTS Ham Member QRZ Page

    There is also the super senior class e rig (K7DYY).
    http://wireless-girl.com/Projects/AMTransmitters/K7DYYtransmitter.html

    The new icom 7300 sounds quite good, should be a lot of fun, and can be used for any mode.

    You can also use a modern radio to drive the grid of an amp and plate modulate that.
    All sorts of ways to get on the air.
    Networking and ham fests are a good way to go, as people get older and start downsizing, stuff has to go someplace.
    It won't be too long before you will not be able to give the stuff away.
     
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  7. WA3VJB

    WA3VJB Ham Member QRZ Page

    http://netohio.com/k7dyy.com/order.html

    I've heard several of the K7DYY transmitters and they do sound good.
    But at about $1500, they're not at the price point it sounds like you need.


    Sadly, one of the best markets to buy a transmitter is among the older licensees who are selling their homes and downsizing. I would recommend posting some want ads on this AM Forum, and the two AM gathering points on Facebook, as well as other websites and reflectors that cater to "vintage" and "military" gear. There's a lot out there, not being actively sold, and your interest could shake something loose.

    Good luck
     
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  8. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    The last great wave of newcomers are in their mid 60s now. Yes, there are a few younger folks, some in their 30s and maybe a couple in their 20s, but new younger blood has slowed to a trickle. As our generation morphs into worm food, there will be an abundance of this equipment with nowhere to go, and most of it, unfortunately, will end up in the landfill.
     
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  9. N4AXE

    N4AXE Ham Member QRZ Page

    First of all thank you to everyone for being so helpful and diverse with your suggestions. Quite a lot more options than I had first suspected. I have several new avenues to explore before my next post here. I will be keeping an eye out on the sites with trade/for sale sections and looking for the AM hangouts around the web as well to keep an eye out for any good deals or fixer-uppers.

    I like the idea of building a small cw rig and then looking at modulation schemes. I have been very interested in the "lets build something 1.0" regen ssb radio. I have built a few of the tuna can cw radios from qrpme and I'm about to start building a Michigan Mighty Mite ala Manhattan style construction. I figured that would be something simple to get my feet off the ground outside of "kit" building.

    Again thanks for the advice and direction it is appreciated. Now to do some more research with the new found information.
     
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  10. N6YW

    N6YW Ham Member Volunteer Moderator QRZ Page

    Ben
    Excellent!
    If you have any questions feel free to post them on this forum. We are collectively happy to help.
    73 and gud luck,
    Billy N6YW
     
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