Home Made Oscope

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Sambuchi
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Home Made Oscope

Post by Sambuchi » Mon Jan 23, 2006 8:52 pm

Just curious...

I have been searching the web for an o-scope to look at a composite video signal. The old Tektronics still run well over $200.00 My price limit.. :)

So I came across a way to use your parallel port, little hardware and free software to do the job. I am about to build my first scope this week.

I was curious if someone knows of a decent o-scope supplier or has tried making a homemade o-scope that worked!

I am aware that my home made o-scope will be limited around 200kHz signal but $20 sounds better than $200.00

Thanks

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Chris Smith
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Re: Home Made Oscope

Post by Chris Smith » Mon Jan 23, 2006 9:17 pm

For the $150 range, try "Fair Radio Sales" of Lima Ohio.

Good ole Teks,.. 20mhz and better can be found on occasion.

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Re: Home Made Oscope

Post by Robert Reed » Tue Jan 24, 2006 12:14 pm

Sam
If you are talking TV composite video signal--you will need a bandwidth of at least 4.5 Mhz.

rshayes
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Re: Home Made Oscope

Post by rshayes » Tue Jan 24, 2006 1:06 pm

The later Heathkit scope line had several models that were solid state, used flat screen CRTs, and had 5 to 10 MHz bandwidth. These may be available at electronic swap meets and on Ebay in the $20 to $30 price range. Construction was fairly open and used printed circuits boards with generic types of transistors. If the power transformer, HV power parts, and CRT are good, the rest should be repairable.

The old Tektronix scopes (500 series) were good instruments, but some models used parts that are hard to get (tunnel diodes and matched tubes). Size and weight would make the shipping charges alone on these quite expensive.

The newer, portable series (400 series) are also good scopes, but they also use special parts that would also be hard to find (nuvistors,HF transistors, miniature potentiometers, and special switches).

<small>[ January 24, 2006, 01:06 PM: Message edited by: stephen ]</small>

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jwax
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Re: Home Made Oscope

Post by jwax » Tue Jan 24, 2006 5:02 pm

I bought my HP1740 dual trace on Ebay for $70 plus $30 to ship.
Find "IT" on Ebay!

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philba
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Re: Home Made Oscope

Post by philba » Tue Jan 24, 2006 8:06 pm

I bought my tek 2225 (60 mhz dual trace) off ebay for about 100 over a year ago. only used by a little old researcher to do spectrograms on sunday...

A good used analog dual trace 100 mhz scope can be had for under your budget. I prefer Teks but HPs are ok too. don't bother with storage scopes, the old ones use storage tubes which are almost impossible to replace and the newer digital ones are way pricey.

A quick spot check revels many scope for below your budget but who knows what the end prices will be. try watching ones you are interested in.

<small>[ January 24, 2006, 08:08 PM: Message edited by: philba ]</small>

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Sambuchi
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Re: Home Made Oscope

Post by Sambuchi » Tue Jan 24, 2006 9:28 pm

Mr. Smith thanks for the outpost.. looks like they hae been been around for a while

Mr. Reed .. good point. You made me do more homework and you are correct. I scoped my B/W Cammera at work with a Tek O-scope "NTSC trigger". And the frame that i was looking at was about 150kHh but that will change with more Black and White in one frame.. Brrrr. But I sill think I will be able to see the Vertical and Horizontal syncs

NTSC STANDARDS

Horizontal Scan Frequency 15,734.26Hz

Vertical Scan Frequency 59.94 Hz

I will have an external tigger.

jwax,stephen and philba thanks for the info.. E-Bay was my starting spot in finding a O-scope.. and could not find one that was resonable "cheap .. like me!!".. The names of scopes are great information and I will look around town for one.

Thanks for the post..keep them coming and I will respond with the outcome of my scope with pictures.

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Re: Home Made Oscope

Post by Robert Reed » Tue Jan 24, 2006 10:39 pm

Sam
Also NTSC standard--Video is Fc to 4.5 Mhz ; sound is FM moulated on its own carrier at Fc + 4.5 Mhz. But don't worry if you buy any used scope manufactured in the last 40 years as they will all have at least a 5 Mhz bandwidth. They havn't produced < 5 mhz scopes since the dark ages.

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Re: Home Made Oscope

Post by rshayes » Tue Jan 24, 2006 10:47 pm

Some examples of the Heathkit model numbers are IO-4205, IO-4210, and IO-4510. Try searching Ebay for "heathkit oscilloscope", note the model numbers, and then do a Google search for sites with information on Heathkits to determine the specifications.

The ones on Ebay seem to be getting bids in the $10 to $15 range, but the final bids might be a little higher. The shipping might cost more than the scope.

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jwax
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Re: Home Made Oscope

Post by jwax » Wed Jan 25, 2006 3:33 am

Search Ebay for "Analog Oscilloscopes".

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Re: Home Made Oscope

Post by jwzumwalt » Sun Feb 05, 2006 3:07 am

While this will not help you on this project, there is a home made Audio scop that attaches through a computers sound card. Best part of it is it's free!

linux http://linux.maruhn.com/sec/oscope.html
ms http://www.hitsquad.com/smm/programs/VA/
JZ

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Re: Home Made Oscope

Post by Dean Huster » Mon Feb 06, 2006 6:53 am

You should be able to find a Tektronix T921 or T922 (15MHz single- or dual-trace respectively) T932 or T935 (30MHz single- or dual-timebase respectively, both dual trace) scopes on ebay for a song. All in the T900-series have TV triggering built in, which may be nice considering your interest in video. Any Tektronix oscilloscope or scope plug-in with "Option 5" will have "TV triggering".

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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Sambuchi
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Re: Home Made Oscope

Post by Sambuchi » Wed Feb 15, 2006 10:30 am

Hello all.. thanks for the posts so far..

This project has blown into several other smaller projects... i'm guessing another month. Just to let you guys know that I'm still working on it and still looking at E-bay...

I have some bids out there right now..

thanks for the info.

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Re: Home Made Oscope

Post by thesprocket » Sat Feb 18, 2006 4:54 pm

On a wee bit of a tangent...

I have been doing some cleaning, and am thinking of unloading some NI-DAQ (data aquisition) hardware, can I post a "for sale" in this forum?

Moderators, please advise. Thanks.

Robert Reed
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Re: Home Made Oscope

Post by Robert Reed » Sat Feb 18, 2006 5:35 pm

thesprocket
Please dont attempt any ads on this forum, as it might open upflood gates we would all be sorry for. However the idea of a buy/sell/swap shop in another location would be very appealing. If you contact the moderator/webmaster, why not suggest this to them. I think you would have plenty of support behind you.

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