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SSB Carrier Supression

Discussion in 'General Electronics Chat' started by Space Varmint, Dec 3, 2008.

  1. Space Varmint

    Space Varmint New Member

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    Wait a minute. Flat are you looking for these parts? Why don't you get them from either Digi-key or Mouser. Mouser is really cheap on allot of this stuff. Now you will need to go to Amidon for the cores. These will be the inductors if you want to do a limited amounbt of shielding. The donut shaped cores have a self shielding property. You can get away with it to a degree but you will notice if some stages are too close you may have to angle some of the cores. Maybe set them perpendicular to each other to keep down the interaction. Still, shield as much as possible.
    Once you get the "Flyer" from Amidon you will see how many windings it will take to make say a 200 micro-Henry inductor and so forth. Trust me, the things are magic!
    Where you will still need to always shield are places like in a transmitter, of course you want the frequency oscillator and any buffer stages separate and shielded well so no energy from your amps get back to the oscillator or it will cause "splatter". In the receiver it is necessary to isolate the mixers as much as possible and filters sections.
    You could get all the rest of your parts at Mouser who I think is the cheapest but Digi-key is good on allot of parts and they got everything.
    Also if you want more specific radio application parts such as RF power amp transistors and high power variable caps, then RF Parts is a very good source and they are great on their prices. You can easily find things like matched pairs of power transistors because they assume part of their business is repair. Final power amps are often of a push-pull variety.
     
  2. Space Varmint

    Space Varmint New Member

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    Got several QSOs yesterday and when using a receiver as a communications device, you will look at it in a different way. There is something I had been noticing lately and I guess band conditions where really good so it was even more evident.
    Sunday nights are Broadcaster's heaven night. High power broadcasts everywhere. My mixer was getting hit so had it was heterodyning to beat the band even with the preselector. I put a 22 ohms resistor right across the coupling cap to the rf front end amplifier with a switch to ground and switched it on and pulled signal right out of the congestion.
    I ran into a strange phenomena where I am using a two-way switch that is sealed to select between transmit & receive to antenna. I really prefer a knife switch but don't have one. Anyway this cotton picker was couple some rf back from the receiver to the transmit signal and I was using a seperate power supply for the receiver that I built into a plastic box. So I put another power cable on the transmitter power supply and regulated it down to the proper voltage and cleared it right up. After that, all my contacts gave me a 599 (the best) signal report. :)
     
  3. flat5

    flat5 Member

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    "Flat are you looking for these parts? Why don't you get them from either Digi-key or Mouser"

    Well I guess you have not looked at their site.
    Futurlec, The Electronic Components and Semiconductor Superstore
    You can't beat their prices + low shipping and no minimum.
    Such as:
    300 1/4W 5% Carbon Film Resistors in mixed values. $2.45
    Multimeter with two temp. probes $5.95 (I don't expect it to be great)
    Yes, the list (and a few more) are parts I'm considering to order from Futurlec.

    I don't know what wire sizes are handy to have on hand for coils.
    I guess 30, 28, and 24. These I'll get locally.
    I want to try to find a European supplier for Amidon or equivalent.
    Hopefully in Holland.
     
  4. dave

    Dave New Member

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  5. JimB

    JimB Super Moderator Most Helpful Member

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    Try here: JAB Electronics Micrometals & Farite Cores

    JimB
     
  6. Space Varmint

    Space Varmint New Member

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    Man, I'm gonna have to check them out! But what do you have against Amidon? I mean, they are like the industry standard as far as the ARRL is concerned. I get along just fine with Amidon products. They got every kind of core you could ask for.
     
  7. Space Varmint

    Space Varmint New Member

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    Oh yeah! I got me some MC1496's in today. Guess I will do this modulator right. Some of these guys pick at me and I give 'em hell back, but it doesn't mean I don't listen to them. They do have some good suggestions every now & then.

    Not sure if it's more "now" or "then".... if you know what I mean ;)
     
  8. flat5

    flat5 Member

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    I was very happy with the MC1496.
    Amidon Has a minimum order and shipping will cost more than necessary. The site Jim suggests should suit me better. (Thank you, Jim!) They accept Paypal too. No minimum, low shipping cost. They sell lots of goodies :)
     
  9. Space Varmint

    Space Varmint New Member

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    I did not realize they had a minimum. I guess I always order enough.
     
  10. flat5

    flat5 Member

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    What turned me off is I could not get the "Free" booklet.
     
  11. Space Varmint

    Space Varmint New Member

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    Why not? Don't tell me you got to order parts first. Oh boy ;(

    Hey, I just got a Hartley oscillator to run at crystal frequency. I'm gonna try to warp the crystal frequency down to lower sideband. Wish me luck.

    Do you remember JAN crystals? You could unscrew them and shave them down a little for new freqs.
     
  12. Mikebits

    Mikebits Well-Known Member

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    Wow, that is awhile back I guess. Crystals need to be airtight or the leads oxidize inside changing the frequency.

    I once went to a crystal plant. I was surprized to learn that they grew the crystals and they did not dig them up from the ground. Afterall Quartz is a mineral, but a quartz crystal is homegrown. Go figure.
     
  13. Space Varmint

    Space Varmint New Member

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    Yeah, that was a while back. I had an old Knightkit T-60 transmitter and you plugged the crystals right into the face of it. The pins were thick like tube pins. Inside the crystals they just had two metal plates that pressed against the crystal itself.
     
  14. Mikebits

    Mikebits Well-Known Member

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    I kind of remember seeing those back in my navy days. I would think shaving the crystal would be a hit and miss proposition as far as tuning goes. As I remember, the crystals are fairly brittle. You would need a real sharp blade I imagine.
     
  15. Leftyretro

    Leftyretro New Member

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    I actually recall grinding crystals like those. We would use toothpaste and gently grind in a circular motion and then clean them up. You could gradually raise the frequency a few khz at a time. Now to lower the frequency material needed to be added and there were various mythical methods but I don't think they worked well or reliably. The advice was to always pick a crystal that was less then you needed and grind it down until you got what you wanted.

    Now today I look at these SMD crystal packages and I'm just amazed that they could shrink the crystal to such a small size.

    Lefty
     
  16. Mikebits

    Mikebits Well-Known Member

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    New material with a tighter lattice I would suppose, but I really dunno.
     
  17. Leftyretro

    Leftyretro New Member

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    Well as I recall I think a crystals frequency is determined by the thickness of the material and not it's physical size, so I guess it's not been a problem getting them in small packages once they could grow and cut the blanks to those dimensions. It's been awhile so I'm not current on crystal tech, but they were always my favorite electronic component for some strange reason. :rolleyes:
     
  18. Mikebits

    Mikebits Well-Known Member

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    It is a pretty interesting technology. We have some pretty smart folks on this otherwise planet full of dummies:)
     
  19. Space Varmint

    Space Varmint New Member

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    I'll tell what's blowing me away. I got this VXO going using a Hartley configuration and no matter what I do so far, the frequency wants to only warp up. I change the variable cap and when it hits the exact Xtal freq. it wants to stay there as I keep tuning the cap. The I get far enough past it and it jumps way down in freq. Definately not resonating the crystal.

    Keep playing I guess.
     
  20. flat5

    flat5 Member

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    Hey SV, I had a T-150 Transmitter that I assembled from a kit.
    Knight T-150 Product Reviews

    To get it to work on 6 meters I had to use a battery to bias the 6146s or they got quite orange. Nothing else I tried worked. This was in 1964, I guess. Don't think I ever used the crystal socket :)
     
  21. Space Varmint

    Space Varmint New Member

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    Aaahhh...that's funny. I guess I can call you "old man". I love hearing "OM" in a CW QSO. Well they worked. What's really funny is the receiver I used back then. An old Hallicrafters, I can't even remember the model number.
     

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