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Thread: ALC cable to linear?

  1. #1

    Default ALC cable to linear?

    I want to upgrade to a linear amp for a little more punch. My transceiver is an old Yaesu FT-847 which has an STBY out jack to connect 4 different linear amps (HF, 6m, 2m & 70cm amps) It also has a ALC jack out, but the manual says I need a Si diode in-line in the positive line of the RCA cable at the amp end, but it does not specify the value of the diode needed. Does anyone know what value Si diode I should use? I have a 1000v/10A diode. Will that work?

    My second question has to do with an email from Ameritron. They said I do not need to use a ALC cable at all, because my FT847 only puts out 100 watts; just use my STBY cable to connect to their ARB704 interface. Is this wise? Should I use an ALC connection cable between my transceiver and a linear or not?

  2. #2

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    Quote Originally Posted by MitchellB View Post
    I want to upgrade to a linear amp for a little more punch. My transceiver is an old Yaesu FT-847 which has an STBY out jack to connect 4 different linear amps (HF, 6m, 2m & 70cm amps) It also has a ALC jack out, but the manual says I need a Si diode in-line in the positive line of the RCA cable at the amp end, but it does not specify the value of the diode needed. Does anyone know what value Si diode I should use? I have a 1000v/10A diode. Will that work?

    My second question has to do with an email from Ameritron. They said I do not need to use a ALC cable at all, because my FT847 only puts out 100 watts; just use my STBY cable to connect to their ARB704 interface. Is this wise? Should I use an ALC connection cable between my transceiver and a linear or not?
    Hello Michelle,

    The one question I have is, Is the RF Linear Amplifier Tube or Solid State (Transistors)? Generally all RF Linear Amplifiers produce the Negative Voltage that feeds back into the FT-847 transceiver. After studying the Operators Manual I see that RCA Cable where they inserted the Diode, you'll need to build one, apparently YAESU Parts no longer stocks the cable. I believe your 1000VDC at 10 Amps is slightly an overkill. I would use a 1N4004A or NTE 116 http://www.nteinc.com/specs/100to199/pdf/nte116.pdf in place.

    Dan
    WA9WVX

  3. #3

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    Quote Originally Posted by WA9WVX;35360

    The one question I have is, Is the RF Linear Amplifier Tube or Solid State (Transistors)?

    I believe your 1000VDC at 10 Amps is slightly an overkill. I would use a 1N4004A or NTE 116 [url
    http://www.nteinc.com/specs/100to199/pdf/nte116.pdf[/url] in place.

    Dan
    WA9WVX
    Thanks Dan. I do not have a linear yet. I am still shopping. I am leaning towards a tube amp like the Ameritron AL811 due to costs. I am not opposed to buying a legal limit used amp, but I am not sure I want to chance buying someone else's boat anchor since I only know enough about electronics to make me dangerous. I have a STBY cable and just ordered a used Ameritron ARB704 interface from fleeBay. I figured I would have to make my own ALC cable (if I need to use one), but was surprised at the email from Ameritron that I did not need one. Seems like a simple cheap enough cable, compared to the costs of a linear. But the FT847 manual did not tell me the value of the diode needed in the cable. Thanks for the diode suggestion. I'll probable get some of those.
    KX4AU

  4. #4

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    Hello Michelle or is it Dalmer M Badgett,

    As you might imagine I'm a bit confused who I'm really consulting with as I went out to the QRZ.com website and discovered this information.

    At this time I would hold back from purchasing a Solid State 1500 W RF Linear Amplifier because you'll need a +50 VDC at 50 to 60 Ampere Power Supply and these are NOT inexpensive compared to a traditional Tube Amplifier. An ARB-704 will interface with your FT-847 transceiver and practically any RF Tube Amplifier and I believe it does the ALC Detecting / Converting to the lower -4 VDC that the FT-847 requires. Since you have stated, "since I only know enough about electronics to make me dangerous" that doesn't give me a Warm & Fuzzy Feeling so be very careful when you're dealing with a high power RF Amplifier as they're Very High Voltages within the Amplifier cabinet. Safety First! These voltages are high enough to kill an individual ... I've always worked around these kind of voltages in my former career in Electronics & Radio Communications. You can make some mistakes but learn and respect the High Voltage!

    Dan
    WA9WVX
    Elgin, Illinois

  5. #5

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    Quote Originally Posted by WA9WVX View Post
    Hello Michelle or is it Dalmer M Badgett,

    As you might imagine I'm a bit confused who I'm really consulting with as I went out to the QRZ.com website and discovered this information.

    At this time I would hold back from purchasing a Solid State 1500 W RF Linear Amplifier because you'll need a +50 VDC at 50 to 60 Ampere Power Supply and these are NOT inexpensive compared to a traditional Tube Amplifier. An ARB-704 will interface with your FT-847 transceiver and practically any RF Tube Amplifier and I believe it does the ALC Detecting / Converting to the lower -4 VDC that the FT-847 requires. Since you have stated, "since I only know enough about electronics to make me dangerous" that doesn't give me a Warm & Fuzzy Feeling so be very careful when you're dealing with a high power RF Amplifier as they're Very High Voltages within the Amplifier cabinet. Safety First! These voltages are high enough to kill an individual ... I've always worked around these kind of voltages in my former career in Electronics & Radio Communications. You can make some mistakes but learn and respect the High Voltage!

    Dan
    WA9WVX
    Elgin, Illinois
    I'm not sure where you got the Michelle from. Friends call me by my middle name, Mitchell, and my log in name is MitchellB, but you are right about my first name being Dalmer. Generally I'll answer to Hey You also. I was five years old before I knew my name was not dam-it-boy.

    I used to be a welder in my former life, so I know about the heat, sparks and the funky dance routine electrical energy can create, but it never hurts to be warned. Thanks.

    So with the ARB704 interface, you agree the ALC cable is not needed?

    If I buy new, I am leaning with the Ameritron AL811 (600 watt max out), which I believe has the power supply built in. That will about max out my toy funds right now, but I am not in a large hurry and may save up for something nicer.

    If I buy used, I'm still trying to familiarize myself with what ever I run across as to value, condition and whether it will work with what I got. I do not have a problem replacing components, but I am not real good at figuring out what needs to be replaced when it is not working. Thanks for the tips and sorry you got confused about my name.
    Mitchell

  6. #6

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    Hello Mitchell,

    OOPS! My mistake on your name ... I looked at your Avatar and assumed (this is very dangerous) that you were a girl / woman, then researching your call letters on QRZ.com I was even more confused. This was strictly my fault and I'm truthfully Sorry it happened.

    Okay I just skimmed over the AL-811 RF Amplifier specifications and MFJ says it produces 600 W PEP Output "almost 2 S Units" which is a lot of baloney being 600 W PEP Output will increase your 100 W PEP from the FT-847 transceiver a + 6 dB to 400 W PEP Output or 1 S Unit plus an additional 200 W PEP Output which is equal to a +3 dB or .5 S Units. Don't get me wrong as the average ham station needs 600 W PEP RF Output to be heard on the other end with our current Propagation / Band Conditions.

    Years ago will say in the 1970s, 1980s & 1990s it was possible to turn your transceiver on 20 m any time day or night with 100 W PEP RF Output and work people all over the world with +10 to +20 over S9 signals, the HF Bands were HOT with the higher Sun Spot numbers and these were average conditions. If the Sun Spot numbers increased which they would from time to time, your signal reports would be +40 to +50 over S9 using only 100 W PEP RF Output so as the Sun Spot decreased there were only two ways to improve your signal, by adding a RF Amplifier and/or putting up a Multi-Band Beam Antenna or both.

    I just read that you'll need a PNP-5M Interface Cable between your ARB-704 Box and the FT-847 transceiver and a homebrew RCA (M) with a Diode to another RCA (M) Connector for the ALC Function to insure everything works correctly with the Ameritron AL811 RF Amplifier.

    Please don't use a heavy duty welding torch on these miniature connectors as I envision them to melt using too much heat. If you have a 50 to 100 W Ungar Soldering Iron and some 60% / 40% Solder that will do the job. The newest Tin Solder is Junk, the connections break all of the time and this is something you don't want to use. Newest doesn't mean it's better, it's only Rohs compliant for the manufactures. Thirty Five years in the Electronic Industry & working for Motorola on Land Mobile Products taught me a whole lot about components and soldering techniques. Good Luck on this RF Amplifier Purchase and installation.

    73,

    Dan
    WA9WVX
    Last edited by WA9WVX; Tue 17th Oct 2017 at 02:24.

  7. #7

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    Quote Originally Posted by WA9WVX View Post
    Hello Mitchell,

    OOPS! My mistake on your name ... I looked at your Avatar and assumed (this is very dangerous) that you were a girl / woman, then researching your call letters on QRZ.com I was even more confused. This was strictly my fault and I'm truthfully Sorry it happened.

    Okay I just skimmed over the AL-811 RF Amplifier specifications and MFJ says it produces 600 W PEP Output "almost 2 S Units" which is a lot of baloney being 600 W PEP Output will increase your 100 W PEP from the FT-847 transceiver a + 6 dB to 400 W PEP Output or 1 S Unit plus an additional 200 W PEP Output which is equal to a +3 dB or .5 S Units. Don't get me wrong as the average ham station needs 600 W PEP RF Output to be heard on the other end with our current Propagation / Band Conditions.

    Years ago will say in the 1970s, 1980s & 1990s it was possible to turn your transceiver on 20 m any time day or night with 100 W PEP RF Output and work people all over the world with +10 to +20 over S9 signals, the HF Bands were HOT with the higher Sun Spot numbers and these were average conditions. If the Sun Spot numbers increased which they would from time to time, your signal reports would be +40 to +50 over S9 using only 100 W PEP RF Output so as the Sun Spot decreased there were only two ways to improve your signal, by adding a RF Amplifier and/or putting up a Multi-Band Beam Antenna or both.

    I just read that you'll need a PNP-5M Interface Cable between your ARB-704 Box and the FT-847 transceiver and a homebrew RCA (M) with a Diode to another RCA (M) Connector for the ALC Function to insure everything works correctly with the Ameritron AL811 RF Amplifier.

    Please don't use a heavy duty welding torch on these miniature connectors as I envision them to melt using too much heat. If you have a 50 to 100 W Ungar Soldering Iron and some 60% / 40% Solder that will do the job. The newest Tin Solder is Junk, the connections break all of the time and this is something you don't want to use. Newest doesn't mean it's better, it's only Rohs compliant for the manufactures. Thirty Five years in the Electronic Industry & working for Motorola on Land Mobile Products taught me a whole lot about components and soldering techniques. Good Luck on this RF Amplifier Purchase and installation.

    73,

    Dan
    WA9WVX
    My avatar is an old chalk drawing I did as a teenager of Linda Ronstadt and Emmylou Harris, so I'm impressed you even noticed it.

    I thought I might need the PNP5M interface cable, but I found a schematic of the ARB704 and decided I could just the old Yaesu CT61 cable (which I have) instead. That way I would have connections for a 2m, 6m and 70cm linear amp later on down the road if I wanted to add them. Where if I used the PNP5M, it uses the same STBY jack from my FT847 but without using the other 3 pins according to the email Ameritron sent me. I'm still not sure if I'll need the ALC cable with this setup or not though.

    I am getting pretty good distance with my setup as it is when conditions are good. I have broken 5000 miles and just this weekend talked to some folks in the AZ QSO party from here in NC. However, I was hoping that a 300 watt or so boost or just a single S unit in talk power from a small linear, may give me a little more clear talk power to those distant stations that I can hear; maybe understand me better and pick me out of a pileup. Last night I heard several contacts from Jamaica clearly, but they seemed unable to hear me, so if I had a little more power, maybe they could have heard me. ?????? I just got a DX Engineering catalog in the mail yesterday and some of those linear amps in there cost more than I paid for my old truck!

    Thanks and thanks for the soldiering tips

  8. #8

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    Hello Mitch,

    You're quite an artist as I looked closer at that Chalk Drawing and I'm impressed. I was thinking that you could probably do some real nice portraits with Oil Paints and Brushes. I'm not that talented although in my younger days, I could free hand do mechanical drawings that were almost as good as the mechanical drawings off of draft board. Some of my managers were impressed although now I cannot draw a thing because my lack of hand muscles -- old age taking it's toll on my body.

    Well I agree with your thinking since you have that Yaesu harness that will help with the 600 W PEP RF Amplifier. You want to use 400 W PEP RF Output to see a minimum of +6 dB or 1 S Unit on the other end where ever that station might be. I'm not sure whether the distance between NC to Jamaica might cause your signal to fall short or skip right over the targeted country. You didn't mention whether you have a multi-band beam antenna or just wire and how high these would be for the take off angle.

    I'm using a 80 thru 6 m Carolina Windom OCF Dipole mounted at 80' with most of my signal going North and South but a month ago Mother Nature came down in the form of Lightning, hit the 120' tower and jumped over hitting my 2 m / 70 cm vertical and my OCF Dipole blowing up both transceivers ... OUCH! September was a bad month for me, first the Lightning hit and then I was taken to the local hospital for Pneumonia / Congestive Heart Failure, these two conditions are so close with the symptoms it's difficult to say which one I had. I've been in the hospital with these conditions so many times I've lost count. I've almost changed my home address from my home to the local hospital. Now if they would allow me to hang some antennas on their roof and bring in a HF transceiver I'd be fine with that.

    BTW, You'll want the ALC connected between your transceiver and the RF Amplifier which prevents flat topping the SSB signal on Transmit. You'll ONLY need a maximum of -4 VDC feeding the transceiver and you should be able to adjust the Transmit ALC for the middle of the meter scale. Distorted Transmit signals will make enemies for you which You don't want.

    73,

    Dan
    WA9WVX

  9. #9

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    Thanks for the compliment on the pic. Growing old sure ain't for the faint of heart. My wife was forced to take a flu shot last week where she works (she gets to retire in 3 months). The next day she got the flu and then I caught it from her. She got better in a couple days, but I am still fighting if. Sorry to hear about your hospital visit and hope all works out for the good soon. Maybe you can take a handheld in there and at least talk on your local repeaters.

    I also use a Windom cut for 40-6m pointing north/south, but it is not nearly high enough (only sitting on a 20' pole at the off-center), but tied off in a tree about 35-40' up. However I am surprised it does as well as it does. I used to have a homemade fan dipole. but the Windom has a lot less tie offs to dodge when mowing and seems to do just as good if not better. I am thinking about buying another 10' section of pipe and at least raising the off-center up to 30', but just not sure if I can get away with it without using extra tie offs. I mostly talk on 40m. I keep a ground block in my shack that I can disconnect my antennas from my radios and screw them into the ground block when weather gets boomy. However, I would feel safer if l put the short to ground block outside the house. I got some inline lightening arresters I keep meaning to install in my coax outside as well, but haven't got around to it yet.

  10. #10

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    Hello Mitch,

    I know exactly what you mean with these Flu bugs ... when my XYL (WB9YCW) gets one, no matter what I do to avoid catching it, I normally do and in my case it hangs on for 2 weeks. She's always in the holiday spirit and says, It's better to Give than Receive! I've got to get her out of that mode.

    As far as your OCF Dipole being at 20,' no sense to raise it since it's working so well. I've got a friend who lives at the base of the Smoky Mountains in Tennessee that uses a IC-735 transceiver and a Collins 30L1 600 W PEP RF Amplifier and has worked stations all over the world using that combination of equipment, He an excellent CW Operator running 35 to 40 WPM has his DXCC and loves to contest. So when you do decide to purchase the AL800 RF Amplifier, I think you'll do just fine.

    I'll need to add RF Surge Protectors at the base of my tower to prevent the Lightning from entering the house. I need to locate a pair of "N" Type connectors for my older 7/8" Heliax for the 2 m / 70 cm band and dig out a pair of PL-259A connectors for the HF bands, ground them to my tower which has 1/2" Ground cable to my Ground Rod ... that's going to be quite a project to do for me to get done with my health problems. Getting old really Sucks ... Enough said. Well, I better cut and hobble away.

    73,

    Dan
    WA9WVX

  11. #11

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    I admire anyone that can do CW. My CW skills are far from being of much used to me yet. It is a slow learn for me. I go though a few months of trying real hard to learn and give it up for a few months and go back again for more tortured learning. Right now I am in one of those off months where I have given up again. I was to the point I knew all the letters, numbers and some of the punctuation, but I had to receive very very slowly between characters to decipher them. I could send better than receive. I'll go back and dive into to it again at some point, maybe when the weather turns cold.

    I got my ARB704 interface yesterday and connected it to my FT847 STBY connection to test to see if the interface XMT light would switch on when I keyed up the transitive and it did. So I'm assuming it works, but I do not have an amp to test it with yet.

    Yea, I feel your pain about the getting old. My last antenna I put up was my 40-6m Windom and I tried to rope it off so that I would not need to climb a ladder to fix it in the future. One end is roped though a pulley on the top corner of the house that I can lower it to the ground and the other end is a rope pulled up though a tree that can also be lowered. The off-center feed line is supported by 20' of pipe that is tied against our picnic shelter, that I can be laid down if needed and I buried the coax underground so my lawnmower would not chop it up. Unfortunately my 2m & 70cm ground plane antennas are mounted to the peak & eves of our house an require a 24ft ladder to get to. However they have worked fine for over 20 years and only had to come down once a few years ago when I made aluminum soffits, fascias and eves around the house and install gutters and downspouts. The intention was to later install vinyl siding next, but that has not happened yet and I doubt my crappy knees will let me now. Besides, my wife has a long list of other Honey Dos she still thinks I'm able to do.

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