Search found 8 matches

by ProfessorRoach
Sat Aug 21, 2004 7:48 am
Forum: General Discussion
Topic: Engineering Mathematics
Replies: 5
Views: 1006

Re: Engineering Mathematics

This is an excellent text on DSP and the last chapters cover the engineering mathematics you need to understand, and it's chapters are free for download (After reading the free .pdf's I bought a hardcopy - $40) . This book was written for the beginner and explains equations and abstract concepts in ...
by ProfessorRoach
Wed Aug 11, 2004 2:20 am
Forum: Robotics
Topic: sources for television schematics?
Replies: 4
Views: 2453

Re: sources for television schematics?

WOW...I haven't heard that name for over 20 years (SAMS). Used to pick those up from North Am. Phillips.
Are you interested in any particular makes or models? Trying to bring some older sets back to life?
by ProfessorRoach
Tue Aug 10, 2004 4:27 am
Forum: General Discussion
Topic: wrong place for cap?
Replies: 8
Views: 1363

Re: wrong place for cap?

Correction:<p>My 2m yagi is centered at ~143.0955MHz <p>(@145 the FCC might be knocking at my door!)
Sorry, I was reading something while making last post.
by ProfessorRoach
Tue Aug 10, 2004 4:18 am
Forum: General Discussion
Topic: wrong place for cap?
Replies: 8
Views: 1363

Re: wrong place for cap?

The 50nF acts like a High-pass filter, that makes sense. I didn't think that the electric wave length was very significant (lack of freq. discrimination).
For those interested, I am using this to sketch patterns and do level checks, I have two yagi's, 2m (145MHz) and 6m (51MHZ).
by ProfessorRoach
Mon Aug 09, 2004 4:51 am
Forum: General Discussion
Topic: wrong place for cap?
Replies: 8
Views: 1363

Re: wrong place for cap?

Corrections:<p>The cap = 50000nF
I used 1N34's as opposed to 0A95's.
by ProfessorRoach
Mon Aug 09, 2004 4:44 am
Forum: General Discussion
Topic: wrong place for cap?
Replies: 8
Views: 1363

wrong place for cap?

I built the following very simple FSM and don't detect any RF, even a few feet away from my rig's antenna(thought I had noise p/u prior, but it tunred out to be miscalibration). Suppose the 50000 pF cap could should not be placed before the 1N34's? All RF meters or crystal sets I've seen don't have ...
by ProfessorRoach
Wed Jul 14, 2004 4:33 am
Forum: General Discussion
Topic: RF meter question
Replies: 3
Views: 672

Re: RF meter question

I'll bet on the 50kw station. I am not concerned with this noise from a measurement perspective. Good idea about a dipole for general direction. I will probably soldier up a good old 50 ohm RF SO-239 port to the antenna input, this way I can use my 3-element yagi. I'm 5-6 miles outside metro, so I'm...
by ProfessorRoach
Tue Jul 13, 2004 8:02 am
Forum: General Discussion
Topic: RF meter question
Replies: 3
Views: 672

RF meter question

Built a very basic RF meter with 2 1N34's, various ceramic caps, 25k pot. and 200 microamp analog scale. It's a simple level meter for leak checks and rough antenna pattern sketching, so it is not frequency discriminate. I am getting an ambient 3-5 microamp general background reading (without measur...