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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 3:22 am 
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Joined: Sep Wed 22, 2010 1:36 am
Posts: 434
Location: Sliver Springs NV.
Thanks for the reply Tom. I will install the chip and osc and try again.
The link failed as well. Tried it in two different browsers as too.


Flipperhome
It may be a dns problem like you say.
I just will have to wait for my IP to reset it.
I did not have the IC or osc installed. So no chance of having blown them.
YET! :mrgreen:
Thanks for the reply.
Mel W.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 3:48 am 
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:lol: Well no wonder there was no current draw :mrgreen:

I do think I'd start with more like a 1k instead of either the 220 or 390 ohm and slowly work down as you see how the voltage comes out. That is, if you don't use a regulator.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 6:15 am 
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Location: Sliver Springs NV.
Flipperhome wrote:
:lol: Well no wonder there was no current draw :mrgreen:

I do think I'd start with more like a 1k instead of either the 220 or 390 ohm and slowly work down as you see how the voltage comes out. That is, if you don't use a regulator.


That is my plan.
Thanks for the advice.
Mel


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 2:25 pm 
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Sam T wrote:
Here are a couple photos of my latest transmitter build.
The high voltage area is protected with acrylic.

Attachment:
DSCN1510.jpg


Attachment:
DSCN1507.jpg


I like the idea of using a meter like in 35Z5's separate thread, might have to try that.

-Sam T.


Hi Sam

That worked out nice...

Is that transformer something you bought or from a junk clock radio or similar? I have a couple that have cords made into them...


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 2:38 pm 
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Hi Tom,
The transformer came from the junk box, salvaged from something or other.
My wife likes the cigar box cabinet over the others I've done.
Wish I had a good/cheap source for the older style variable caps, with a shaft for attaching a knob.

Thanks again for all of your help.
-Sam T.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 7:06 pm 
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Location: Texas. USA
If you're willing to cover less than the whole BCB, and the upper end has better range anyway, radiodaze has some air variables for cheap. http://www.radiodaze.com/category/417.aspx

You could parallel sections in the 'lots of sections' job but that also increases the minimum capacitance, which may or may not be a problem depending on your coils.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Thu 22, 2012 7:53 pm 
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The variable cap is for peaking the antenna, the transmitter freq is controlled by the osc. at 1000, 1200 something or 1500 something khz. Tom's schematic calls for a 0 - 50pf variable. But you are right, I could just use the 75pf section of the $4 item on Radio Daze. Thanks for pointing these out!

-Sam T.


Image


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Fri 23, 2012 2:12 am 
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A 0-75pf tuning cap is likely a better choice especially if a shorter antenna is used, say something like a 3-4ft whip...

Tom


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Fri 23, 2012 2:36 am 
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Sam T wrote:
The variable cap is for peaking the antenna, the transmitter freq is controlled by the osc. at 1000, 1200 something or 1500 something khz. Tom's schematic calls for a 0 - 50pf variable. But you are right, I could just use the 75pf section of the $4 item on Radio Daze. Thanks for pointing these out!
Opps. I forgot which transmitter we were talking about :oops: as I tend to be obsessed with a variable LO and that's what I meant about the restricted range. I use the 170 pF variable on Beamus and just stay on the upper end of the BCB.

You're right that the 75pF section would be good for the antenna trimmer on this one but they've also got some trimmers and a couple of the plasitc 'transistor radio' jobs. Wander around the NOS section.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Nov Fri 23, 2012 4:41 am 
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Here's a later version schematic I posted to the temp gallery...


http://antiqueradios.com/gallery/v/temp ... 101112.jpg.

Tom


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 04, 2012 5:47 pm 
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Location: Fort Washington,MD 20744
bill hamre wrote:
Heard from hergi he is breadboarding as we speak.



OK so I am slow. I got mine working on a breadboard and I have to say it sounds good and covers well for just a few parts. I just use the transmitter section running off 7 AA cells. Now I have to stuff it in a box. :shock: I get about 10.6 mA draw when the antenna is peaked. Pin 7 has about 4.5V.

Doug


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 04, 2012 6:06 pm 
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Way to go Doug, guess we can call off the search party... :wink: I used my breadboard version most of the summer till I finally built the one in the satellite meter case...

Your current readings are fine, should be a good performer for you...

Tom


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 04, 2012 6:30 pm 
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I had oscillation problems at first but changing the layout and shortening leads cured it.
Thanks for the fun project! Thanks for the kit Bill!

Doug


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 04, 2012 8:37 pm 
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Pictures please.


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Thu 06, 2012 12:40 am 
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Sinced you asked so nicely Mike.
It's just a breadboard though.

Image

Doug


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Mon 10, 2012 7:28 pm 
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Where can I get the osc chip from.

_________________
Skip......


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 11, 2012 2:12 am 
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Location: Texas. USA
Mouser or surplus-electronics-sales.com


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Dec Tue 11, 2012 4:27 am 
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Bill Hamre should have the IC's and most of the parts avail as a kit, suspect he'll be along in the next day or so...


Tom


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Jan Mon 07, 2013 7:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 878
Location: Lima, Ohio, USA
bill hamre wrote:
Give us a couple of weeks and I'll get kits to everyone. In the meantime PM your mailing addresses.



Do you have anymore kits Bill?

Mike AA8RV


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 Post subject: Re: LM386N MK-XI BCB Transmitter
PostPosted: Jan Wed 09, 2013 8:17 pm 
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Location: Fairfield, OH USA
I'm interested in a kit, as well, if still available.

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Vinton Roush
Fairfield, OH


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