Baluns (Brands, Designs, Losses, DIY Loops, etc.) - Page 8 - Canadian TV, Computing and Home Theatre Forums

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post #106 of 817 (permalink) Old 2009-02-11, 04:35 PM
 
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Channel Master 0265DSB preliminary schematic..

I fixed a few glitches and uploaded a revised version
which may be found here:

http://freepdfhosting.com/cd7267a855.pdf

The pdf hosting site deletes files after 30 days so this
will turn into a pumpkin at that time.
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post #107 of 817 (permalink) Old 2009-02-11, 06:39 PM
 
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I forgot to thank you for all the work you put in tracing out that circuit. It's interesting and nice to have.

I was just at Fry's a little while ago. They had a cheaper CM preamp ($30) I hadn't seen before. It has a gain of 13 dB, if I recall correctly, and a noise figure of 3.5 dB. The single 300-ohm input is via a thick, heavy-duty, captive balanced line a couple feet long that terminates in large spade lugs. The injector is a small satellite type with a cable shrink-wrapped at the power socket. The cable runs to a wall wart.

The more familiar CM preamp (I forget the number now but it's been discussed here) was $60.

Brian
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post #108 of 817 (permalink) Old 2009-02-11, 07:33 PM
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I was having some trouble with that PDF for some weird reason so I PM'ed uhmgawa - the result is that I saved the image and scaled it bigger, so its now available here:

http://www.user.dccnet.com/jonleblan...er-0265dsb.png
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post #109 of 817 (permalink) Old 2009-02-12, 12:42 AM
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Quote:
They had a cheaper CM preamp ($30) I hadn't seen before. It has a gain of 13 dB, if I recall correctly, and a noise figure of 3.5 dB.
Yeah, they have that one over at summitsource and solidsignal too. Its still better than the Radio Shack preamps.

My builds/plans (not the latest models) are located here.
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post #110 of 817 (permalink) Old 2009-02-12, 02:45 PM
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Quote:
Originally Posted by uhmgawa View Post
I fixed a few glitches and uploaded a revised version
which may be found here:

http://freepdfhosting.com/cd7267a855.pdf

The pdf hosting site deletes files after 30 days so this
will turn into a pumpkin at that time.
Are those typos in the resistor values, e.g. "4K7 ohm"???

Stampeder: Your image is blurry and nearly illegible....
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post #111 of 817 (permalink) Old 2009-02-12, 04:50 PM
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Quote:
Are those typos in the resistor values, e.g. "4K7 ohm"???
Heh, actually Ive seen some resistors labeled like that, and I went WTH ???

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post #112 of 817 (permalink) Old 2009-02-12, 05:21 PM
 
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Quote:
Originally Posted by holl_ands View Post
Are those typos in the resistor values, e.g. "4K7 ohm"???
No that is as intended. It is a fairly common convention
of replacing the decimal point with a (less likely to get
lost in the noise) units/multiplier. So in the above example
4K7 -> 4.7K, 3V3 -> 3.3V., etc..
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post #113 of 817 (permalink) Old 2009-02-12, 05:22 PM
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Originally Posted by holl_ands
Stampeder: Your image is blurry and nearly illegible....
Is the original PDF working properly for you, and is it clear enough?
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post #114 of 817 (permalink) Old 2009-02-12, 06:50 PM
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Uhmgawa's original comes through just fine....
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post #115 of 817 (permalink) Old 2009-02-17, 01:21 PM
 
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Channel Master 0265DSB schematic update..

Three locations exist where SMD resistors are stacked. The values
of the obscured resistors were calculated via series current, and
were within 5% of EIA standard values. Updated schematic is here:

http://freepdfhosting.com/1e7ee1e7dc.pdf

Note: this pdf hosting site deletes files after 30 days so this
will turn into a pumpkin at that time.
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post #116 of 817 (permalink) Old 2009-02-17, 02:10 PM
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Mirrored here, where there is no deletion deadline:

http://www.user.dccnet.com/jonleblan...-schematic.pdf
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post #117 of 817 (permalink) Old 2009-02-17, 02:54 PM
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DYI balun???

mlord:

I completed my DYI b4b antenna, and recive most HD channels, however I'm looking to squeeze more gain, should I attempt the DYI 1/2 wavelength balun, or just buy a balun.


I believe the RS one I bought is about 5 db. No real info on it..
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post #118 of 817 (permalink) Old 2009-02-17, 06:15 PM
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I believe the RS one I bought is about 5 db. No real info on it..
Yeah, pretty much overpriced crap, heh.

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post #119 of 817 (permalink) Old 2009-02-17, 07:04 PM
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300ohm:

What about you, you suggest I make my own, is it better?
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post #120 of 817 (permalink) Old 2009-02-17, 07:26 PM
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For outdoor use, a Channel Master balun at $1.99 (U.S) is a good bet.

My builds/plans (not the latest models) are located here.
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