EVERYTHING FOR ELECTRONICS
READY TO DIVE INTO
Thank you, thank you, thank you!
For some time now, I have been
sitting on the fence thinking I need to
figure out how to create my own PCBs
using expresspcb.com. I have been
reluctant to wade into those waters,
however, because of my inexperience
with this aspect of electronics. Just last
week I recall thinking to myself, “I wish
someone would write an article that
would step me through the process.”
The June issue of Nuts & Volts just
arrived! So, thank you very much. I
think it's time to go “swimming.”
Response: You are welcome, you
are welcome, you are welcome!
Thanks for taking time to read the
article. I’m glad it was useful to you.
I would like to thank you for the
well-written article “PCB Basics: From
Your Brain to a Finished Board,”
appearing in the Nuts & Volts June
2008 issue. This is exactly the sort of
basic how-to article I need to advance
my own skills.
I have a question. When you click
the “Order Boards...” option, is
ExpressPCB smart enough to know
whether the board needs to be two
layer or four layer and default to what
the design actually needs?
Response: Thanks for reading!
When you begin your design, you
should set the board type to two or four
layer. The program is not smart enough
to determine the type of board to use
versus the design criteria.
There are things you can't do in
two-layer mode that apply only to
The order program will pick up
four-layer things that can't happen in
two-layer boards and post an error for
10 August 2008
you to correct them.
You'll sometimes get the four-layer
component in two-layer board errors
when you reuse components that
have been laid out in a four-layer board
design. For instance, if you reuse a
component from a four-layer board
that has been attached to one of the
internal four-layer planes, that will flag
an error in a two-layer design as the
planes don't exist.
Hope that helps, and again, thanks
GIVING THE WRONG
I have enjoyed reading your
magazine for a few years now, since
all the other electronic magazines have
dissappeared. But I have also noticed
sometimes that answers to some of
the readers questions are not always
correct and lead me to believe that
whoever gave the answer does not
know as much as they think. I have
emailed in several times with my views,
but have not seen any results. Today, I
would like to give a simple comment
on the digital TV questions.
I have been an electronics
technician/broadcast technologist for
about 25 years; I think this gives me
some insight to comment on this.
As far as the simple explanation
on how they can fit three digital TV
signals in the same space as one analog
channel — it is really simple. THEY
SEND LESS INFORMATION!!!! It has
been a couple years since I have
worked in the broadcast industry, and
there are probably many people out
there that can give a more in-depth
explanation, but here is mine.
In the early 1990s at one place I
worked, we were testing coax cable to
handle digital TV signals in the studio
environment. The analog bandwidth
needed was 6 MHz minimum, the
equivalent digital signal ran at 270
megabits per second. End result:
You need much more bandwidth to
send the same signal in digital format
This creates large problems. To use
continued on page 92
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