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Thread: hidef tuner

  1. #21
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    If the feeders are run at anything other than their surge impedance the RF ammeters will read very low in many areas of feedline.

    They do not respond to reactive power either so if your tuner has appreciable J conjugate match happening the ammeter will not show it.

    If absolute maximum performance is desired on the two bands mentioned you might consider sticking the ammeter at some useful point and trying a stub and different tuning with a kilowatt carrier to see if you can increase feedline current any.


    Quote Originally Posted by 543 View Post
    Quick question about the thermocouple type ammeters. Does it matter if you're measuring at a high impedance point in the feedline? I think it does because the power is the same but no heating in a high voltage low current situation.

    I couldn't get a measurement with a 1.5 amp meter on 40 and 20 with 100 watts. The doublet arrangement makes for a high impedance at the tuner on those bands. I ended up making a pickup to use with a volt meter to balance the system.

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  3. #22
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    Ok. I never tried to maximize current with the balanced L. I just got both legs as balanced as possible and cured my rfi problems. I assumed there was only combination of L and C to get a match. You mentioned using stubs and tuning for max smoke in the past but I never tried.

    I did find multiple combinations on the link coupled job. I finally found less L and more C put the most current up the feedline line on 75m. When I got as much out of it as the balanced L I called it good.

    Pole pig mentioned that some of these old ammeters are defective. This one works as expected on 75m

  4. #23
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    We used RF ammeters exclusively for wattmeters back when surplus parts were everywhere but newer stuff was too expensive.

    Look at the following to understand why wacky antenna loads need huge conductors even if you don't care about RF AMmeters

    Take the ammeter and stick it in series with the coax center conductor and feed a dummy load or a perfectly matched antenna.

    The load will be 50 ohms.

    Power in Whats = I^R or I X I X R or whatever the meter sez times itself and again multiplied by 50.

    One ampere indicated = 1 X 1 X50 so one amp = 50 Whats

    Two amperes indicated = 2 X 2 X50 = 200 Whats

    3A = 3x3x50 =450 whats

    5A = 1250 Whatz

    My CB locals = a half dozen twats

    10A = 5killerwhats

    14A = just shy of 10KW which was a benchmark for what I was working on in 1985.


    Now, take the antenna load and make it 10 ohms instead of 50. Run some numbers and it will be apparent that antenna current will increase a lot more than might meet the eye.

    Where do you get 10 ohms of antenna resistance? Shortened antennas.

    How do cheesy commercial mobile antennas get around this? They use conductors that exhibit enough loss in series with the radiation resistance to make the system present 50 ohms to the transmitter.

    - - - Updated - - -

    Quote Originally Posted by 543 View Post
    Ok. I never tried to maximize current with the balanced L. I just got both legs as balanced as possible and cured my rfi problems. I assumed there was only combination of L and C to get a match. You mentioned using stubs and tuning for max smoke in the past but I never tried.

    I did find multiple combinations on the link coupled job. I finally found less L and more C put the most current up the feedline line on 75m. When I got as much out of it as the balanced L I called it good.

    Pole pig mentioned that some of these old ammeters are defective. This one works as expected on 75m
    Yes L/C ratios should match typical L/C ratios of link coupled RF AMplifiers in a link coupled tuner. See old ARRL handbook from about 1937 - 1960 or so for specifics. Dunno about older than 1937.

    Any panel meter made back when men were men will be designed for a specific panel mount. It may specify 1/8" steel or some thickness of aluminum.
    These meters are effected by their mounting. If you have one hanging in the breeze it may be reading differently than if it were mounted in steel.

    Always short RF ammeters when not reading but leaving in the circuit. It's easy to kill them when you do something stupid. Raising hand here. I've had them shipped to me with a short circuit connection by some buzzard hams who knew stuff. Same as turning a Bird 43 slug to the short circuit position during shipping. Y'all do know about that, yes?

  5. #24
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    That ac2iq cat has more rf knowledge in his farts than the Tyler ball clanger has in is everything he knows.
    Quote Originally Posted by HiDef View Post
    Makes me want to start a ham mis-information of the month section here.

    Tyler's video is interesting but it shows an open wire line connection surrounded by crap which would throw it off balance. Maybe it is just the camera angles.

    Any feedline sampling done near voltage maxima will have problems with accuracy. It only takes a few pF even on 4 mhz.

    The discussion on QRZ has already sunk below the noise level thanks to ham lore.

    One well respected poster who is very dedicated and runs several beacons thinks it's safe to quote W8JI.

    Well it isn't. JI posted this crap to discredit Richard Measures. It says a balun should be installed at the output of a tuning network. Well not if it's a symmetrical network but making AG6K look bad was more important than the truth. Fucking short people.....

    https://www.eham.net/ehamforum/smf/i...?topic=39865.0


    Then there's the old guy with a resume at the end of many posts. He wants everyone to know how many times he has been let go or the place he worked went tits up.

    He says increasing power can change the balance of an antenna system. Really?

    Sorry for him that he couldn't handle the math involved in electrical engineering but he should really stay away from any serious discussions that may evolve into theory.

    This guy likes to drift balanced wire antenna discussions toward the toilet saying that they are never balanced well in real life. Maybe in his life. Others have excellent results.

    Stick with rusty cars and get out of the way.


    Dunno if AC2IQ has results posted from his version of instrumentation regarding balanced feedline measurement but last time I looked it appeared he was on the right track. Hambone radio needs more people like him.

    Have a nice day.
    Quote Originally Posted by HiDef View Post
    Matching networks make my dick hard.
    Quote Originally Posted by pole_pig View Post
    I'm careful to avoid draining bottles that drain my wits when I'm working on stuff
    Quote Originally Posted by HiDef View Post
    If anyone hears about me using an end fed antenna please kill me.




    Trying not to choke on that 10 ohm smoke.

  6. #25
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    Quote Originally Posted by HiDef View Post
    We used RF ammeters exclusively for wattmeters back when surplus parts were everywhere but newer stuff was too expensive.

    Look at the following to understand why wacky antenna loads need huge conductors even if you don't care about RF AMmeters

    Take the ammeter and stick it in series with the coax center conductor and feed a dummy load or a perfectly matched antenna.

    The load will be 50 ohms.

    Power in Whats = I^R or I X I X R or whatever the meter sez times itself and again multiplied by 50.

    One ampere indicated = 1 X 1 X50 so one amp = 50 Whats

    Two amperes indicated = 2 X 2 X50 = 200 Whats

    3A = 3x3x50 =450 whats

    5A = 1250 Whatz

    My CB locals = a half dozen twats

    10A = 5killerwhats

    14A = just shy of 10KW which was a benchmark for what I was working on in 1985.


    Now, take the antenna load and make it 10 ohms instead of 50. Run some numbers and it will be apparent that antenna current will increase a lot more than might meet the eye.

    Where do you get 10 ohms of antenna resistance? Shortened antennas.

    How do cheesy commercial mobile antennas get around this? They use conductors that exhibit enough loss in series with the radiation resistance to make the system present 50 ohms to the transmitter.

    - - - Updated - - -



    Yes L/C ratios should match typical L/C ratios of link coupled RF AMplifiers in a link coupled tuner. See old ARRL handbook from about 1937 - 1960 or so for specifics. Dunno about older than 1937.

    Any panel meter made back when men were men will be designed for a specific panel mount. It may specify 1/8" steel or some thickness of aluminum.
    These meters are effected by their mounting. If you have one hanging in the breeze it may be reading differently than if it were mounted in steel.

    Always short RF ammeters when not reading but leaving in the circuit. It's easy to kill them when you do something stupid. Raising hand here. I've had them shipped to me with a short circuit connection by some buzzard hams who knew stuff. Same as turning a Bird 43 slug to the short circuit position during shipping. Y'all do know about that, yes?
    Thanks for the math lesson. I never figured out how to calculate rf amps across a load.

    I may not have have gotten an accurate reading on 75m. The meter was hanging on clip leads. Approximately 8 watts showed 1.5 amps on the feedline. That would be 3 to 4 ohms at the tuner. Around 20 amps at 1500 watts. Peak could hear me on 160 with 700 watts. A 40 mile trip and I was piss weak but I'll take it.

    I learned about the bird meters after I bought one. The guy shipped it with the slug in it but not shorted. Luckily it didn't get damaged.

    Somewhere along the way I figured out a panel meter needle didn't shake around as much if they were shorted.

  7. #26
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    thermocouple meter self repair.
    knowledge is power. RF amps in this case.
    http://www.tuberadio.com/robinson/Thermocouples/
    Electronic Innovations In Action - Setting Energy Traps in the Forbidden Band

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  9. #27
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    Not to mention the night I heard you was an extremely noisy night with shitty local conditions.
    Quote Originally Posted by 543 View Post
    Thanks for the math lesson. I never figured out how to calculate rf amps across a load.

    I may not have have gotten an accurate reading on 75m. The meter was hanging on clip leads. Approximately 8 watts showed 1.5 amps on the feedline. That would be 3 to 4 ohms at the tuner. Around 20 amps at 1500 watts. Peak could hear me on 160 with 700 watts. A 40 mile trip and I was piss weak but I'll take it.

    I learned about the bird meters after I bought one. The guy shipped it with the slug in it but not shorted. Luckily it didn't get damaged.

    Somewhere along the way I figured out a panel meter needle didn't shake around as much if they were shorted.
    Quote Originally Posted by HiDef View Post
    Matching networks make my dick hard.
    Quote Originally Posted by pole_pig View Post
    I'm careful to avoid draining bottles that drain my wits when I'm working on stuff
    Quote Originally Posted by HiDef View Post
    If anyone hears about me using an end fed antenna please kill me.




    Trying not to choke on that 10 ohm smoke.

  10. #28
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    "That story ends with defeat. They needed to use ssb to communicate." HiDef 2017

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  12. #29
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    Quote Originally Posted by mrsuburban View Post
    Click image for larger version. 

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    Quote Originally Posted by HiDef View Post
    Matching networks make my dick hard.
    Quote Originally Posted by pole_pig View Post
    I'm careful to avoid draining bottles that drain my wits when I'm working on stuff
    Quote Originally Posted by HiDef View Post
    If anyone hears about me using an end fed antenna please kill me.




    Trying not to choke on that 10 ohm smoke.

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  14. #30
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    I have 13VA's gay cb trophies somewhere over here..... Why, I do not know!
    Quote Originally Posted by 4-400 View Post
    Fat girls try harder, plain and simple, and blow-job enthusiasm is perhaps the area where that mentality gives them their greatest edge over their more bony-hipped sisters

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    Is 13VA gay?

    I AM THE RDX AFRO-AMERICAN
    THEY CALL ME LITTLE HECTOR, THE HUMAN STOOL SOFTENER....... AN ARMCHAIR ANAL ENTHUSIAST


  16. #32
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    Quote Originally Posted by 241 Mr Wonderful View Post
    Is 13VA gay?
    Yes, and he is a homosexual too..
    Quote Originally Posted by 4-400 View Post
    Fat girls try harder, plain and simple, and blow-job enthusiasm is perhaps the area where that mentality gives them their greatest edge over their more bony-hipped sisters

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    lol
    Quote Originally Posted by -=PEAKABOO=- View Post
    I detect shenanigans somewhere in this thread and my eyes hurt.

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