Driver to drive?

[Rich Grise]

On Wednesday 06 October 2004 01:17 pm, Jamie did deign to grace us with the
following:

Frank Raffaeli wrote:

mndflmr <mndflmr@hotmail.com> wrote in message
news:<n9j6m09u104h3rbod7ermst3jc421ltqon@4ax.com>...

Hello all,
Recently I purchased a low-power VHF transmitter kit from Ramsey.
After building this kit, I have discovered that it will not work for
my purpose. I am trying to transmit audio and video about 20 feet from
a satellite receiver to my bedroom. The power output from the
transmitter is so low that the picture quality is very poor. I am a
novice and I am hoping the experts that use these newsgroups can help
me. I will post a link to the Ramsey kit manual. Will some of you
guys please take a look at this manual, and suggest some simple
(hopefully) methods to increase the power of this transmitter? There
is no chance of interference with the neighbors, as my nearest
neighbor is far away. Any help would be greatly appreciated. If you
want to email the response, please send it to mndflmr@hotmail.com

Here is the link to the kit manual:
http://www.ramseyelectronics.com/downloads/manuals/TV6.pdf




Something is broken. Either at the transmitter or receiver. A
mis-matched antenna couldn't possibly account for a poor quality
picture at 20 feet. I presume this transmitter is designed to transmit
a signal via antenna to source and not over transmission line. Here
are some probable causes:

1) The transmitter output stage is broken.
2) The receiver is not working (see how well it picks up other
stations).
3) The antenna at either end is disconnected.
4) There is Radio-frequency interference (RFI) such as from a
computer.

Frank Raffaeli

Its my guess that the Transmitter has insufficient bandwidth and power
for that broad of a signal.
one must not forget the amount of band space a single channel takes.

Did the OP go through the alignment procedure? Did the OP bother with
antennas at all?

Did either of you read the kit doc?

Thanks,
Rich

 

[Spehro Pefhany]

On Mon, 4 Oct 2004 21:32:10 +0100, the renowned John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that Spehro Pefhany <speffSNIP@interlog
DOTyou.knowwhat> wrote (in <vk83m050pc7drdi4jtc3a1m90nenj04l19@4ax.com&gt
about 'The Rational Mind of Fred Bloggs', on Mon, 4 Oct 2004:

http://www.bartleby.com/65/co/conspira.html
Seems a bit more than talking about the weather is required...

I believe that is not so in English law, or at least it is arguable that
planning a legal act is still a conspiracy.

But anyways:-

Etymology: Middle English, from Middle French conspirer, from Latin
conspirare to be in harmony, conspire, from com- + spirare to breathe

I visualize people huddled together whispering to each other. According
to the OED (not a legal definition), it's possible for one person to
conspire.

Well, one person can aspire, expire, perspire, respire and suspire, so
why exclude conspire.

Because it doesn't inspire. But thanks for the list. There's at least
one that is very useful these days <suspire>.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Boris Mohar]

On Mon, 04 Oct 2004 01:10:18 GMT, Rich Grise <null@example.net> wrote:

On Sunday 03 October 2004 11:18 am, Roy McCammon did deign to grace us with
the following:

This is my own whimsy only.

I'd be one of the open range animals on the back lot;
not particularly dangerous or interesting. The visitors
would ask each other "what does he do?".

I feel like the wizened old bachelor chimp, who watches the other
animals play, and contemplates space flight.

Cheers!
Rich

I would be your flea

--

Boris Mohar

 

[Frank Bemelman]

"Winfield Hill" <Winfield_member@newsguy.com> schreef in bericht
news:cjv6ct0e9r@drn.newsguy.com...

Mike Monett wrote...

ChrisGibboGibson wrote:

John Larkin wrote:

[snip]

Comparing the results with a 10 digit meter I got accuracy
within 0.005% of the Vrefs I was using. That's quite amazing
for a dollars worth of comparator and discretes.

10 digit DVM? Who makes that?

Keithley, circa early 80s

Really? 6.5 and 7.6 or even 8.5 digits, but 10 digits?

Note, 6.5 or 7.5 digits lets one measure to better than 1ppm
resolution, yet 0.005% is only 50ppm, or 5.5-digit territory.

Or did he mean a 10 digit price tag

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

 

[John Larkin]

On 6 Oct 2004 11:52:10 -0700, geoffreygallo@yahoo.com
(Blahblahblahblahblahblah) wrote:

Greetings friends,

At issue is an approach to amplifier design, a quest for a
part or chip, and inquiry for your suggestions.

The Impossible Amplifier specification;

Source Impedance; 200 to 1000 ohms
Source Signal Level; 1 to 20 microvolts (differential)
Load Impedance; 50 ohms, balanced (single ended)
Spectrum covered; DC to 200 Mhz
Gain over spectrum; 10,000 +/- 3 dB

* The purpose of the amplifier is to make visible on an oscilloscope
nanosecond-scale microvolt-scale events at a level above the 1
millivolt noise floor of the scope.

* Dropping all components below 1 MHz may be an option, if necessary.

* Single transistor preamps at the source are feasible if pluto-like
temperatures are ok.

* I'd like to get it all on a single board using as few components as
possible.

* Costly parts are ok.

Rather than re-invent the wheel(tm), I thought I'd ask you folks and
see what comes of that. Thanks !
- Geoffroi le Gallo

It may be impossible. A 50-ohm resistor has 13 uV RMS thermal noise in
this bandwidth.

John

 

[Clarence]

"Rich Grise" <null@example.net> wrote in message
news:JMW8d.6696$r3.5272@trnddc05...

On Tuesday 05 October 2004 11:09 pm, xray did deign to grace us with the
following:

On Wed, 06 Oct 2004 05:12:05 GMT, "Clarence" <no@No.com> wrote:

"xray" <notreally@hotmail.invalid> wrote in message
news:90p6m01k67o1e4e2bgheo9hs3617fpggta@4ax.com...
On Wed, 06 Oct 2004 03:00:23 GMT, xray <notreally@hotmail.invalid
wrote:

If your considering moving, pack your bags.

Oh, and I forgot to criticize you're grammar.
--------------------------------^^^^^^--------

He-he!

Get a clue, idiot.

You may have noticed that sarcasm is wasted on those who need it the most.

Like they say, don't cast your pearls before swine, although applying that
to some of the blockheads around here is more of an insult to swine.

Yes I did notice. But sometimes it helps to tweak their nose, or perhaps tie a
can to their curly tails! But he still doesn't get it!

 

[John Larkin]

On Wed, 06 Oct 2004 15:39:12 -0400, Mike Monett <no@spam.com> wrote:

Another issue is that you can't take n-bit data and digitally
correct it to n-bit data without nasty artifacts, missing codes
and ghastly differential linearity.

I'm not sure I understand. A sensor produces analog signals. You
digitize this to whatever accuracy needed, then use a polynomial or
lookup table to get the corrected value. The output is monotonic and
within whatever error tolerance you determine. There are no nasty
artifacts, missing codes or differential nonlinearity problems. So
where's the problem?

How could you possibly take n-bit readings, apply a polynomial
correction, and get n-bit data without missing codes? And how could
you maintain fractional-LSB differential linearity? After all, the
only thing you can do is add or subtract multiples of one LSB.

Sheesh.

John

 

[Spehro Pefhany]

On Wed, 06 Oct 2004 19:32:28 GMT, the renowned Rich Grise
<null@example.net> wrote:

And good cross-language puns are rare.

The problem is that few can understand them, good or not.

Q: How many eggs do you need to make an omlette?
A: One is an oef.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Wouter van Ooijen (www.vo]

Buy a TTL data book. They make great bedtime reading!

I am still reading the various PIC datasheets. When I am finished with
those there is still AVR, COP8, PSoC, ....



Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
Webshop for PICs and other electronics
http://www.voti.nl/hvu
Teacher electronics and informatics

 

[Dave VanHorn]

Have a look here, I think it will answer your questions.

http://www.dvanhorn.org/Micros/All/Crystals.php

I have 20MHz PIC16C745, should I still use 6 MHz chrystal?

You should use a crystal that is 20MHz or lower, and fits your other
requirements like generating baud rates accurately, or letting you reach
particular ranges with your timers.

What should
be C1 and C2 values? Or/and, how do I calculate the values of C1 and
C2?

Thanks!

--
KC6ETE Dave's Engineering Page, www.dvanhorn.org
Microcontroller Consultant, specializing in Atmel AVR

 

[Rich Grise]

On Tuesday 05 October 2004 10:09 pm, ftls1@uaf.edu did deign to grace us
with the following:

HI,All

I have an oscilloscope in hands and I want to let it access to the
internet then I can "see and operate" it from distance (in an intranet
actually).BUT-this oscilloscope could obtain a dynamic IP address,
which is private IP address. This is the first step, next I must tell
this IP and MAC to the administrator to get a new IP address.
Here is the problem:
I must know the MAC or physical address because in my area the network
administrator only assigns IP address combined with MAC address.

How can I solve it?

Buy the way , it's a Tektronix one with E-scope function.

Do you have the ability to set the settings on the scope? Just set it

for DHCP, and tell the sys admin that you have a DHCP device you're
plugging in. His DHCP daemon will assign an IP address, and retrieve
the MAC address, so he can run his script and update his configs. ;-)

Have Fun!
Rich

 

[Rich Grise]

On Tuesday 05 October 2004 09:57 pm, Julie did deign to grace us with the
following:

Robert Morein wrote:
I've heard about the legal cases regarding "laptop burns", and I laugh.
The brains of the victims must be a little unusual. Most of us readily
sense if something is uncomfortably warm.

It isn't an immediate burn, but a burn as a consequence of extended heated
contact, not unlike a sunburn.

I heard an urban legend about some guy who was driving at night in the
winter somewhere, and he was tired. So he pulled over, but just so he
wouldn't freeze, he left the engine idling, with the windows open enough to
let all the CO out. Unfortunately, he had fallen asleep with his foot right
up against the heater outlet, with hot air blowing directly off the heater
core onto his foot. The guy that told me this said that when the guy woke
up, his foot was completely cooked. It does sound plausible, after all,
especially if his feet were numb when he fell asleep.

<vaudevillian aside>
Didn't say whether or not he ate it. <rimshot>
</vaudevillian aside>

Cheers!
Rich

 

[Ken Smith]

In article <4cf981af6ctonyw@ledelec.demon.co.uk>,
Tony Williams <tonyw@ledelec.demon.co.uk> wrote:

In article <cjvnt0$id3$1@blue.rahul.net>,
Ken Smith <kensmith@green.rahul.net> wrote:

I just designed in the 600V PTC circuit breaker from BC
components. You can guess what I just found out today. Thats
right, Vishay bought BC components and are cancelling that
product line.

Any chance of a replacement in the Raychem Polyswitch range?

The Raychem Polyswitches can't stand the voltage.

Since Raychem got bought out, there products are harder to find.

Bourns is claimed to have something but you can't find it on their web
site. I think someone's kid did the Bourns web site. Its fancy but
fairly useless.

--
--
kensmith@rahul.net forging knowledge

 

[Ken Smith]

In article <cZP8d.714$P25.445@newsfe3-gui.ntli.net>,
colin <no.spam.for.me@ntlworld.com> wrote:

"Robert Baer" <robertbaer@access4less.net> wrote in message
news:41638894.50804@access4less.net...
Ken Smith wrote:

Do you know of any way to protect a signal output line against some
idiot
connecting it to 440AC or 600VDC yet meeting the following:

Shoot all known idiots? it does sound like a very silly thing todo.

The birth rate for idiots is too high. You can't kill them all.

Applying the wrong voltage is a simple miswire away in a system where
440AC and/or 600VDC and data co-exist.

--
--
kensmith@rahul.net forging knowledge

 

[Ken Smith]

In article <ck0lft01fm4@drn.newsguy.com>,
Winfield Hill <Winfield_member@newsguy.com> wrote:

Ken Smith wrote...

... Some of you may not remember that Siliconix made a 2N4867A that
was a very low noise JFET. It was, I believe, a selected 2N4867 part.

That was in a TO-18 package, far too expensive to compete in the
long haul. Siliconix sent us to their J201 series for TO-92 and
SST201 series for sot-23 versions of the die, which they still make.

The J201 didn't work for us. We ended up talking Interfet into producing
(selecting) fets for us that are tuned to our need.

Surely there are other suitable PTC manufacturers?
"Don't all me Shirley"

Raychem's patents
expired a few years back, didn't they?
I think so.

Schurter,
I'll look.

Bourns,
I have looked but there were web site problems.

Littlefuse,
I have looked.

Cooper Bussman,
I've looked here too.

etc
My PC at home has an "etc" directory.

. And the pacific-rim companies listed on the
Global Sources website, like Fuzetec, Jenn Feng, Electric, Shenzhen
Sunzone, Dongguan Richwell, Photosphere (Photo-Top), Sinyork, TOA,
Jya-Nay, and Supertech.

Fusetec looked a little hopeful.
I've also got info coming from Stetron

--
--
kensmith@rahul.net forging knowledge

 

[Nicholas O. Lindan]

John Larkin wrote:

You can do the reverse: feed back a bit of the ramp voltage into the
guts of the current source such as to increase the current as the ramp
runs. This adds a t-squared term to the curve, nearly compensating
shunt resistance ...

The modern solution is to figure it can be fixed in the software and
toss the problem over the partition.

As long as the measuring system is repeatable and monotonic anything
can be fixed in software. A few 5th order splines and away you go.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com

 

[Pooh Bear]

Pete wrote:

I am completely newbie to microcontrollers, and that's probably why I
don't understand when Microchip's documentation for their sample
application TB055 says "C1 and C2 values selected according to crystal
load capacitance". The sample is at
http://ww1.microchip.com/downloads/en/AppNotes/91055C.pdf and the
picture is right at the beginning of the sample.

I have 20MHz PIC16C745, should I still use 6 MHz chrystal?

You can use an crystal frequency up to a MAX of 20MHz.

What should
be C1 and C2 values? Or/and, how do I calculate the values of C1 and
C2?

Values for C1 and C2 ( which will be the same ) can be found from the
crystal maufacturers data. Typically likely to be in the range 20-30pF.

Most 6MHz crystals I've come across require about 30pF. Higher frequencies
tend to require slightly less capacitance.


Graham

 

[Ken Smith]

In article <5b08m0pbkn3e5nm6rkj9lk86hacrdh5i9i@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:
[...]

Now, connect one end of a bipolar TVS or a couple of, say, 15V Zeners
in series opposition to the NO contact of the relay and the other end,
through a series diode and a resistor to the base of an NPN transistor
and through another series diode and resistor to the base of a PNP
transistor. Connect the emitters of the transistors together and to
one end of the coil of the relay, and connect the other end of the
relay coil to ground. Connect the collector of the NPN to V+ and the
collector of the PNP to V-. Connect a timer in there somewhere so
that when you get an overvoltage on the output it holds the relay open
long enough so that you don't overdrive the Zeners.

The reaction timne of the relay is a bit of a problem.

Or use a latching
relay and a loud, intermittent beeper that won't shut off until a
manual RESET is set. That ought to wake the morons up!

You've obviously never met these morons. I'd bet that it would be sent
back with a note that it was DOA and beeped as soon as power was applied.

--
--
kensmith@rahul.net forging knowledge

 

[Pooh Bear]

boki wrote:

Dear All,
I try to use many Bluetooth devices at the same time for my
PC/NB, when enable them individually, they will work good(The only no
good is sound quality of Bluetooth earphone). If I enable them all,
the mice move speed will drop down(like a mice taking stone) until I
stop another Bluetooth device, then the mice work normally.

The Bluetooth bandwidth is limited?

Yes, Bluetooth devices 'share' the bandwidth, so the more that are in use
in a given location, the less bandwidth each one has. It's only 732 ?
kbits/sec max available anyway, so I'm sure we'll hear plenty more about
problems with Bluetooth devices as they become more widely used.


Graham

 

[Rich Grise]

"Glen Walpert" <gwalpert@notaxs.com> wrote in message
newsrn7m0tf82a2rjcj13sscuh7occ8f5m1k5@4ax.com...

On Wed, 6 Oct 2004 01:49:11 -0400, "Robert Morein"
nowhere@nowhere.com> wrote:

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:mFfMHMBKz3YBFwq3@jmwa.demon.co.uk...
clip
On the other hand,
explosive rupture of a battery pack close to the abdomen could,
concievably, be lethal.

Yes, but the probability is probably lower than that of being fatally
kicked by a horse.
--
The two probabilities are not in the same universe of discourse because I
don't ride horses. OTOH, I am in close proximity with lithium packs.

I am pretty sure John assumed you don't ride horses when he assigned
the lower probability to the exploding battery pack. All computer
lithium battery packs include a thermal fuse in direct contact with
one or more cells, so a cell explosion requires multiple simultaneous
failures including at least a low impedance short across the battery
and thermal fuse failure. I have never heard of even a single
occurrence of laptop battery pack explosion, and there are a lot of
them out there. On the other hand, I know several people who have
been kicked by horses .

http://www.slackersguide.com/movies/Horse.mpg