Search found 1252 matches

by rshayes
Sat Jun 14, 2014 10:11 pm
Forum: General Discussion
Topic: Old Magazines
Replies: 2
Views: 2780

Old Magazines

Maybe this is redundant. It has been a while since I have viewed this forum. I recentlt stumbled on a web site that has scans of old radio and electronic magazines (www.americanradiohistory.com). This site appears to have pdf scans of most of the issues of Popular Electronics, Electronics World, and...
by rshayes
Thu Nov 17, 2011 1:56 am
Forum: General Discussion
Topic: The disappearing 9V, C, D, Battery?
Replies: 12
Views: 2390

Re: The disappearing 9V, C, D, Battery?

If I remember correctly, Home Depot usually has displays selling name brand (usually Duracell, sometimes Eveready)alkaline batteries in several packages. The larger quantity packages are usually AAs or AAAs, but 9V, C, and D cells are usually available in packages from 2 to 4 batteries. Harbor Freig...
by rshayes
Thu Nov 17, 2011 1:47 am
Forum: General Discussion
Topic: Lights of America does not play well with GFCI
Replies: 20
Views: 2865

Re: Lights of America does not play well with GFCI

If the ballasts were recently made, they are probably electronic ballasts. There seems to be a push to eliminate the magnetic ballasts for energy conservation reasons. The electronic ballasts are basically switching regulators arranged to give a constant current output. The switching is done at a hi...
by rshayes
Mon May 16, 2011 11:12 pm
Forum: General Discussion
Topic: Tube Data
Replies: 7
Views: 2220

Re: Tube Data

The tube that I have appears to have a date code. It is stamped "68 22", which I assume means the 22nd week of 1968.
by rshayes
Wed May 04, 2011 12:05 am
Forum: General Discussion
Topic: Flipping video
Replies: 12
Views: 2369

Re: Flipping video

The hardware required ti do this is relatively cheap. The design of the hardware will be expensive if only a few units are needed. The basic problem is that NTSC video is a serial data stream and at any given time the value of only one pixel is available. This is probably not the pixel needed for a ...
by rshayes
Thu Apr 21, 2011 7:38 pm
Forum: General Discussion
Topic: Inductors for Receiver
Replies: 14
Views: 3513

Re: Inductors for Receiver

The antenna specified is very short compared to a wavelength (less than 1 meter compared to 1000 meters wavelength at 300 KHz) and probably has a very high impedance. The low capacitance/high inductance tuned circuit may be an attempt to load the antenna as little as possible and thus maximize the s...
by rshayes
Tue Apr 19, 2011 2:56 am
Forum: General Discussion
Topic: Tube Data
Replies: 7
Views: 2220

Re: Tube Data

The tube that I have is labeled WX 5078P1. It came out of an EICO Model 435 oscilloscope, and all of the documentation on that model indicates that it used a WX 5013P1. I suspect that the tube that I have is actually a WX 5013P1 and that it was mislabeled by Westinghouse.
by rshayes
Sat Apr 16, 2011 4:53 am
Forum: General Discussion
Topic: Inductors for Receiver
Replies: 14
Views: 3513

Re: Inductors for Receiver

Amidon is basically a distributor. You can get more detailed information (including application notes) from manufacturers' web sites (Examples: Micrometals for powdered iron cores, Ferroxcube and Fair-Rite for ferrite cores). Easiest cores to get are probably toroids and possibly the EC series of po...
by rshayes
Sat Apr 16, 2011 3:53 am
Forum: General Discussion
Topic: GEIGER MULLER TUBES, WHERE DO I FIND ONE THESE DAY
Replies: 5
Views: 1576

Re: GEIGER MULLER TUBES, WHERE DO I FIND ONE THESE DAY

Fair Radio Sales lists two types surplus geiger tubes (type 5879 and type 5980). Prices are $ 46.00 and $ 35.00 respectively. A search for "geiger" will bring these up.
by rshayes
Sat Apr 16, 2011 3:48 am
Forum: General Discussion
Topic: Understanding digital electronic meter ranges
Replies: 5
Views: 1589

Re: Understanding digital electronic meter ranges

Measurements in the microhenry range are probably better done with a "Q" Meter or an RF Bridge. A rough measurement can be done by using a parallel capacitor to form a resonant circuit and measuring the frequency with a Grid Dip Meter. Normal test leads can cause considerable errors in inductance me...
by rshayes
Sat Apr 16, 2011 3:36 am
Forum: General Discussion
Topic: Tube Data
Replies: 7
Views: 2220

Re: Tube Data

Dean- That was a good suggestion. Unfortunately, the ARRL apparently does not believe in CRTs. The CRT table in the 1960 edition was rather short (about 3/4 page) and after 1968 the CRT data table was deleted entirely. A few CRTs had base connection diagrams but no characteristics after 1968. None o...
by rshayes
Mon Apr 11, 2011 2:47 am
Forum: General Discussion
Topic: Tube Data
Replies: 7
Views: 2220

Re: Tube Data

The only Westinghouse CRT that I ever encountered was a WX5078P1. This was used in the EICO Model 435 oscilloscope, a kit oscilloscope sold in the 1960's.. It was a 3" flat face electrostatic deflection type. I have never been able to find a data sheet on that CRT either. I have also never seen a li...
by rshayes
Sat Apr 09, 2011 4:33 am
Forum: General Discussion
Topic: I need a small, cheap 277vac to 12vdc LED driver
Replies: 17
Views: 2852

Re: I need a small, cheap 277vac to 12vdc LED driver

You probably want a control transformer for safety reasons. Otherwise, all of the wiring will have to be insulated for the full line voltage and meet the other requirements for conductors carrying line voltage. The most likely control voltage would be 24 VAC and the LEDs can probably be hooked in se...
by rshayes
Sat Apr 09, 2011 4:21 am
Forum: General Discussion
Topic: GEIGER MULLER TUBES, WHERE DO I FIND ONE THESE DAY
Replies: 5
Views: 1576

Re: GEIGER MULLER TUBES, WHERE DO I FIND ONE THESE DAY

The Russian tubes seem to be the most commonly available. Prices seem to be in the $25 to $50 range. At one time, American tubes were available on the surplus market for $5 to $10. These seem to have disappeared. The CK1026 was an inexpensive tube that was sold for a new price of a few dollars in th...
by rshayes
Sat Apr 09, 2011 4:09 am
Forum: General Discussion
Topic: Inductors for Receiver
Replies: 14
Views: 3513

Re: Inductors for Receiver

I once measured the inductance of a trigger transformer used to fire flashtubes. As I remember it, the inductance was in the 10 mH range and the stray capacitance was surprisingly low, on the order of a few pF. These are not specified for inductance and may be hard to get, and might require modifica...