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Siltronix 1011D, Is it possible to convert for AM transmit?

Discussion in 'CB Radio Modifications' started by broncoman529, Dec 29, 2005.

  1. broncoman529 Active Member

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    I have a friend here in town who has a Siltronix 1011D and he wants to know if it can be converted to transmit on the AM mode instead of just receive. This guy on ebaY claims he has done it and does so at 60 watts , But we find it hard to believe:

    http://cgi.ebay.com/ws/eBayISAPI.dl...1&from=R8&satitle=5845729678&category0=&fvi=1



    So my question is: Is it possible? How hard is it to do? Where can the information be found so it can be done and done right? Please let me know.

    Thanks,
     
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  2. nomadradio Active Member

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    Uh Larry, the owner's manual explains how to transmit on AM mode. Won't do it very well, but it will. Uses the SSB modulator for AM. The front-panel carrier control "unbalances" the SSB "balanced" modulator, to insert a carrier for AM transmit.

    By chance, are you asking how to get it to transmit on the "CB" band as well as the 28.5 band?

    You'll find the the receiver on AM is a pain in the neck to use, if you are listening to more than one station on the frequency. Since the radio is still using the too-narrow SSB filter for AM receive, you'll need to "clarify" an AM station just right. Turn the tuning knob too far one way, and he'll be muffled and bassy. Too far the other way, and the receiver will slice his carrier off of his signal, and he'll sound as if HE's transmitting on SSB. Tune him in just right, and he'll sound okay. Until the next guy keys on the frequency. If the other fella's frequency is different by as much as a couple of tenths of a kHz (safe bet), you'll have to re-tune to HIS signal to clear him up. Listen to a channel with four people on it, and your hand will be glued to the tuning knob, each time someone different talks.

    As if that weren't a sufficient pain in the neck, the AM transmit is using the SSB modulator. This means that you have to keep the mike gain down, to match the carrier level. You'll see a carrier power between 15 and 25 Watts if you follow the instructions for AM transmit. True PEP will be between 50 and 80 Watts, more or less. Trouble is that as soon as your audio peaks exceed 100 percent modulation, it doesn't get loud, it gets "muffled". Crank the mike gain beyond that, and you'll sound like you're transmitting on SSB. Yes, it WILL transmit AM mode, but it won't get loud. At all.

    AM was an afterthought on this radio. SSB is what it was designed to do in the first place. SSB is ALL it really does WELL. So long as you don't need a noise blanker. Doesn't have one of those.

    And if you're asking about making it transmit on the "CB" band like it will on "28.5", that's easy. Find the rear-most section of the band switch. It's on the rear-facing side of the VFO enclosure, next to the 6GK6 driver tube. Bridge the two green wires that are connected to the switch deck. Or, move one of the green wires over to the lug where the other one is soldered. Once that's done, the transmit relay will work on BOTH bands, rather than JUST the 28.5, as the factory delivered it.

    There's a whole Yahoo group devoted to that model. Pretty sure it's called "Siltronix 1011 Bunch". Their files section has the manual, and other info posted.

    It's a pretty good SSB radio, once it warms up, and gets sufficient maintenance. It's a lame AM radio, no matter how you slice it.

    73
     
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  3. broncoman529 Active Member

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    I asked him the same thing if he wanted to do AM CB, But he said that wasn't all that important. He was more interested in being able to transmit AM on it. I don't think he has the instruction book for it, But he ran into that person on ebaY while looking for extra parts and pieces for the Siltronix 1011d that was transmitting on the AM mode and it peaked his interest. It's funny because all the adjustments you would have to make on the Siltronix to make it sound half way decent is just like when I use my Technical Materiel Corporation GPR-90 shortwave receiver to tune in SSB, Not that it is hard to tune in ssb it just has a billion different ways to make a distant station sound good. Thanks for the info, I will definitly relay it to him. We have quite a few people around my area that are into the older equipment and like to tinker, But do not want to destroy anything. We like to see older unused rigs get back on the air, The more we save the more there will be in the future for others.

    Thanks,
     
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  4. kd5drx Member

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    old silky

    We called those silky's back in the day and they will work on AM real well. You have to find a AM filter for it which at this day in time may be hard to do but try MACOM comunications in Michigan they have allot of the old stuff from that area in stock. If you can find the filter it is fine with out it it's hunt and peck with the tuneing as previecly stated in this thread. I had 2 of them along time ago and they worked good. The only real draw back is they drift real bad for the first hour or two there turned on once they get fully warmed up they do ok. Good luck and keep it original they make great 10 meter rigs for the new guys just starting or the freebander that wants a good sideband rig.
     
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  5. my2995dx Member

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    silly 1011d

    you can convert the 1011d they are set up to recieve am no transmit you have to run a jumper wire off the back of the band switch.Right in front of the final tube there is only two wires on it.You have to jump them but they are a pain in the butt.Get a manual for it to load and tune if you do it wrong you could be looking for a new 8950 tube and there hard to find unless you know someone who has a good one i have 2 of the 1011c and 1011d
     
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  6. mikeydoodle Member

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    Hi all

    Does anyone know what is the replacement tube for the 8950 in the 1011D
     
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  7. kd-5-bgt W9WDX Amateur Radio Club Member

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    The tube is M-2057,

    Depending on what brand of tube you get you might have to cut a hole in the back of the radio for the tube to fit in place.

    I had a 1011d with a M- 2057 in it made by Maco and it did fit without the hole,but it was a tight fit
     
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  8. BJ radionut Supporting Member

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    Maco no longer exists

    Maco or Majestic Communications(Memphis, Tenn) has been sold. They no longer deal in equipment or parts. They are listed only as a tower equipment and metal fabricators.
    The rights to the Maco antennas has been sold and are still available.
    The radio service/parts house has been disbanded.
    They no longer even have a web-page...unless the name has been modified they no longer appear on any directory I have found lately.
    All the Best
    BJ
     
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  9. WR0220 Active Member

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    Installing a fan to provide air flow across the 8950 greatly reduces/eliminates drift. Using the existing holes of the cover you can install one on the inside of the cover without having to modify. Use a 120v fan and you can power it through the on/off switch. I have to agree that they're a pain in the back side on AM.
     
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  10. n0zna W9WDX Amateur Radio Club Member

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    Dont run the sil1011 over 5 to 7 wts dead key,swing dosent matter....i ran one on am/ssb for years 73s de jw
     
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