Search found 1469 matches

by dyarker
Fri Nov 10, 2017 3:11 pm
Forum: General Discussion
Topic: New to me Old Ham Transceiver
Replies: 5
Views: 844

Re: New to me Old Ham Transceiver

...(but then what is the heater switch for).
because tubes are hard to beat for transmit output and driving the output tube. Everything else in the unit can be transistor or LSI ICs.
by dyarker
Sun Oct 29, 2017 6:27 am
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 1417

Re: Iron wire inductor

Ever thought you knew something till you tried to explain it? After almost an hour I came up with: E field is 90 degrees from the M field (in space at transformer, not phase) Your iron wire idea tries to give a low magnet field impedance (reluctance?) in the same geometric plane as the electric fiel...
by dyarker
Sat Oct 14, 2017 1:55 pm
Forum: General Discussion
Topic: Blinking red LED with a coin [button] cell
Replies: 6
Views: 1041

Re: Blinking red LED with a coin [button] cell

To meet thickness limit put the two CR2477s side by side with a wire (or flat metal strip) from bottom of one to the top of the other. Or stack two CR2330s. They are a touch less than 1/8 inch thick each. How you would solder them together I don't know, because solder does not "wet" the metal batter...
by dyarker
Sat Oct 14, 2017 8:57 am
Forum: General Discussion
Topic: Blinking red LED with a coin [button] cell
Replies: 6
Views: 1041

Re: Blinking red LED with a coin [button] cell

CR2477s are only 3V when brand new and under no load. They are considered "dead" when voltage is down to 2V. The blinking LEDs I found are 3.5V minimum to 14V maximum. Your circuit with one CR2477 might last a week, if it worked at all. I suggest two CR2477s in series. That would be 6V new, 4V dead....
by dyarker
Tue Oct 10, 2017 3:39 pm
Forum: General Discussion
Topic: USB Power
Replies: 7
Views: 1138

Re: USB Power

You can measure directly using a USB power dongle and a resistor load You can???????? I thought a power control IC in the USB device negotiated with power IC in USB port for current range when cord is plugged in. If device tries to draw more than negotiated range, then port shuts down to save the P...
by dyarker
Sat Sep 09, 2017 10:04 am
Forum: General Discussion
Topic: replacing parts on printed circuit
Replies: 10
Views: 1343

Re: replacing parts on printed circuit

60/40: melts between 183–190 °C (361–374 °F)

Not even close! You need a new iron.

Cheers
by dyarker
Fri Sep 08, 2017 4:54 pm
Forum: General Discussion
Topic: LED stays on 24/7
Replies: 35
Views: 3974

Re: LED stays on 24/7

I think he meant "All the other breakers..." An unusual posibility I've been hesitant to say - Does the LED bulb glow when the room is dark? No? Then maybe - White LEDs are really blue LEDs with florescent coating inside the lens. Is there light with strong blue component in the room? (beam of sun l...
by dyarker
Fri Sep 08, 2017 12:16 pm
Forum: General Discussion
Topic: replacing parts on printed circuit
Replies: 10
Views: 1343

Re: replacing parts on printed circuit

Does it get hot?

You wouldn't believe the number of times tha answer to "Is it plugged in?", is "Oops, no!" :grin:
by dyarker
Fri Sep 08, 2017 5:10 am
Forum: General Discussion
Topic: replacing parts on printed circuit
Replies: 10
Views: 1343

Re: replacing parts on printed circuit

I argee with Gerty. Wattage and tip size of iron?

You did not specify capacitor type. But the 12W, 1/16" diameter tip I use for soldering IC pins won't touch electrolytic cap leads on wide traces. For that I use a 50W iron with 1/8" diameter tip.

Cheers,
by dyarker
Tue Aug 29, 2017 12:13 pm
Forum: General Discussion
Topic: Effects of loss of analog TV broadcasting on viewing
Replies: 12
Views: 1708

Re: Effects of loss of analog TV broadcasting on viewing

Yes, learned long, long ago that analog degrades more gracefully than digital.

Or,

As signal to noise ratio goes down, digital remains closer to perfect, then suddenly becomes unusable. Analog stays usable long after that.

Does not only apply to TV.

Cheers,
by dyarker
Mon Aug 21, 2017 10:27 am
Forum: General Discussion
Topic: What keeps me up late!
Replies: 48
Views: 6499

Re: What keeps me up late!

... so I can be sucked-in to its vortex.
Goodbye. ((that's just in case you're successful :smile: ))
by dyarker
Wed Jul 26, 2017 7:03 am
Forum: General Discussion
Topic: What keeps me up late!
Replies: 48
Views: 6499

Re: What keeps me up late!

An alternate possibility on the envelope - You put the contents inside, and suspect it might be over weight. You don't want it to come back; so either you weigh it yourself, or take it to the Post Office. With the measured weight and postal chart the correct postage is lookedup. Then stamp, or stamp...
by dyarker
Wed Jul 19, 2017 8:34 am
Forum: General Discussion
Topic: Lightning rods...
Replies: 24
Views: 2588

Re: Lightning rods...

Try some more today.

https://en.wikipedia.org/wiki/Lightning_rod seems pretty informative

Is the rebar part of above construction? If yes then No, could break the concrete during a strike. If no then still no due to rust and iron has a higher resistance than copper, even without rust.

Cheers,
by dyarker
Tue Jul 18, 2017 2:58 pm
Forum: General Discussion
Topic: Lightning rods...
Replies: 24
Views: 2588

Re: Lightning rods...

No
Yes
Above, yes
Not burned home

(Longer answer wiped by internet.)
by dyarker
Tue Jul 18, 2017 7:50 am
Forum: General Discussion
Topic: TONE DECODER
Replies: 3
Views: 898

Re: TONE DECODER

Perhaps those are ABCD ? No. Coin tone is mix of 1700Hz and 2200Hz in the U.S.. Highest tone in high group of DTMF is 1633Hz. "ABCD", "#" and "*" were/are used for specialized functions in different systems. (i.e. the U.S. military system used A thru D for precedence dialing.) Still other tones wer...