• ### Longwave Loop on Ground

Today I tried receiving 472 KHz with a loop laying on the ground.  Transmitting setup the same as last experiment.  Loop of 1 meter X 5 turns resonated by 2800 pF approximate tuning capacitor.  Max signal = 3 mV, noise a buzz at .002 mV.  Slightly less signal than last time, but much less noise.  And no need to dig holes.

• ### Longwave Experiments

I intend to perform a series of longwave experiments with ground contacts or limited antennas.  Here is the first, varying frequency only at a range of 25 yards with an input signal of one volt.  Earth contacts were what was readily available.

20 KHz received signal 0.1 mV, noise .02 mV

137 KHz received signal 2mV, noise .05 mV

472 KHz received signal 3.5 mV, noise .008 mV.

As you can see, 472 KHz was clearly superior.  That is where I shall concentrate further experiments.

• ### The Shape of the Electron

http://physicsdetective.com/the-electron/#:~:text=The%20electron%20is%20a%20spinor,%E2%80%9Cexist%20as%20standing%20waves%E2%80%9D.

I have been in this silly business for 50 years and this is the most cogent explanation I have seen for the nature of the electron.  Perhaps you will enjoy it too.

• ### FTL <> Info to the Past

A common objection to faster-than-light communications is that it would permit sending info to the past, thus putting effects before causes.  Let's look at that.  On my perfectly ordinary radio, I can send a dit from Florida to Australia at 0000 UTC.  The Aussie will get it at 0000 plus 72 milliseconds.

Now if I were a whiz-bang physicist (I'm not), I could invent a system that had no delay at all.  Send at 0000, receive at 0000.  But still, nothing in the world would make that dit show up at 2359.  Effects remain after causes.

• ### A Fan for the Drake T4X

Key Idea:  Run a 12 volt fan on 6 volts for low noise.

Details:  Get a fan about 3 inches square and tie or bolt it to the back of the final cage.  I used lacing tape, but ty-raps are probably easier.  The lamp behind the frequency scale has one terminal connected directly to the 12.6 VAC filament supply.  Put a single rectifier diode on that terminal.  Put the anode on the terminal and the cathode on the red fan wire.  Ground the black fan wire.  Leave enough slack in the fan wires to get the final cage off without trouble.  The fan runs almost too quiet to hear.

• ### Audio Output Transformer for Drake R4A

If your Drake R4A (ham radio) has blown its output transformer, a possible replacement is the Hammond 166G6B.  Although nominally the same size as the original, the new transformer is slightly larger and will go above the chassis in front of the can capacitor.  Connect the 120 volt winding in the plate circuit and the 6.3 volt winding to the headphone jack.  If the radio now squeals loudly, reverse the plate circuit leads.

N.B.  You will have your fingers in high voltage wiring.  Unplug the radio before you do anything.  If you are not comfortable with this work, find someone who is.

Another Note:  This modification is not intended to "improve" the sound of the radio.  Opinions of how the radio sounds better are as common as elbows.  This mod is to save a fine radio that would otherwise go in the trash.

• ### What Doesn't Cause Sporadic-E Short Skip

Today, I decided to investigate whether strong thunderstorms tend to cause sporadic-E clouds in the ionosphere above themselves.  So I looked at the storm data for Okaloosa County, Florida and the stored ionograms for Eglin Air Force Base located in that county.

In short, no.  Since 2009, a recorded thunderstorm only has about a 20% chance of being associated with a sporadic-E ionogram.  In looking for short skip, the better way is to look in the morning (local) in June, July or August.

My thanks to the National Climate Data Center, The US Air Force, and Lowell Digisonde for providing the data.

• ### Fooling Yourself with Quantum Mechanics

Here's how to deceive yourself in three easy steps:

1.  Use Newton's gravity equation to calculate the position of a planet.  It works fine, but in its most common form contains the assumption that all the mass of the planet is concentrated at a single point in the center.

2.  Use Schrodinger's equation to calculate the position of an electron.  Still works fine, still contains the same assumption.

3.  Conclude from step two that the electron is a point particle.  Don't notice that the assumption is also the conclusion.

• ### MMANA-GAL Easter Egg

MMANA-GAL (the basic edition) is free antenna analysis software.  MM is for Makato Mori, the initial author.  Or maybe it's for Method of Moments, how the software works.  GAL is for some German fellows who translated it and brought it to the non-Japanese speaking world.

Some of its best features are hidden under the tabs for Tools, then HF components.  Here is a section to calculate loading coils, LC matching circuits and three different flavors of stub matches.

If you do antenna designs, you should try it.

• ### Propagation Velocity Outside Coax

No, this isn't like the sound of one hand clapping. Several popular ham antennas depend on multiple sections of coax, which act alternately as radiators and delay lines. The velocity of propagation in the delay lines is well known, being 66% for solid dielectric coax and 80 to 82 percent for foamax. But what about the sections where the signal travels on the outside of the coax in order to be radiated? How should we calculate the length of those sections? I did some quick experiments to find out. All measurements were made at 200 MHz over a dirty workbench:

Tinned copper number 22 wire was the fastest at 95%.

PVC coating of any kind slowed things down to 92%. This was equal for number 22 PVC coated and for the outside conductor of Belden 1694A coax. It compares pretty well to the widely published 93% for plastic-coated wire.

NOTE: These results were taken in the middle of a wire and to not include end effect. Including end effect and VP, a practical antenna might be 10-13% shorter than a free-space wavelength.

• ### Thanks to EngineerAllen

My thanks to EngineerAllen, my very first follower. Welcome aboard & I'll try not to dissapoint.

04/24/2017 at 13:06 1 comment

"I calculated the inverse of the impedance," Tom admitted.

"I tuned in Glen Miller's Orchestra!" Tom cried with abandon.

"I want to go solo," said Diana Ross, making a Supreme sacrifice.

"I can't find the obsolete navigation station," Tom said disCONSOLately.

I built a NiFe battery," Tom said with irony.

"I'm afraid I blew out the LED," Tom hinted darkly.

"The QRN all went away!" Tom cried ecstatically.

"I designed a single-sided PCB," Tom said, smiling thinly.

"I touched the high voltage lead," Tom said crisply.

"The filaments have been on long enough!" Tom said heatedly.

"Nobody took care of the lead-acid battery," Tom said dryly.

"The turntable is a little slow," Tom said flatly.

"I need to replace every electrolytic capacitor in the set," Tom said caustically.

"It's drawing plenty of beam current, " Tom said amply.

"I recalibrated the audio generator," Tom said in measured tones.

"The flip-flop can be either high or low," Tom stated.

"I must raise my antenna!" Tom shouted in a towering rage.

"I wish I could read the Billboard top forty," Tom moaned listlessly.

"When I was in Army, I was a code technician," Tom said cryptically.

"I won't buy a circuit breaker," Tom refused.

"I'd better repeat the SOS message," Tom said remorsefully.

"I made a new contract with NBC," Tom said resignedly.

"I used to be on Allen Funt's TV show," Tom said candidly.

"Besides TV, I did still pix for MGM," Tom snapped.

"The singer is right in the middle of the stereo perspective," Tom deadpanned.

"I don't remember who voiced Bugs Bunny," Tom said Blancly.

"For God's sake roll off the bass!" Tom boomed.

"The phonograph needs a new needle," Tom said bluntly.

"I have to turn my aerial upside down," Tom said flippantly.

"Soft soldering isn't for outdoors," Tom said brazenly.

"What tool measures high voltage?" Tom wondered probingly.

"My transmitter uses natural quartz crystals," Tom said stonily.

"I don't need any more vintage radios," Tom said Crosley.

"This circuit has no resistance," Tom said shortly.

"I was cleaning my oldest set, but I ran out of alcohol," Tom said dispiritedly.

"I can imitate a gallop with coconut shells," Tom said hoarsely.

• ### Standoffs, Coil Forms & Test Probes

Standoff insulators, small coil forms, and test probes are all in stock at your local office supply. Just look for the cheap Bic pens with the clear plastic barrels.  Also, for some reason, drugstores insist on labeling coil dope "clear nail polish".  Wide dental floss is a good substitute for cable lacing tape.

• ### I just joined the Electronics Webring, I hope.

Powered by WebRing. <center><table bgcolor=gray cellspacing=0 border=2><tr> <td><table cellpadding=2 cellspacing=0 border=0><tr><td align=center> <font face=arial size=-1>This site is a member of WebRing. <br>To browse visit <a href="http://ss.webring.com/navbar?f=l;y=chipveres;u=defurl"&gt; Here</a>.</font></td></tr></table></td></tr></table> </center>
• ### Opinions Are Like Elbows

Most folks have a couple. One of mine is that the best time to homebrew some radio equipment is *right now*. A lot of us old timers mourn the loss of Lafayette or Allied with their doorstop-sized wishbook catalogs. We conveniently forget that we couldn't afford 90% of the stuff in them back then either.

More recently was the demise of Radio Shack. I do miss them for a place to get a part quick on Sundays.

Now let's assume the glass is half full: I recently made a mail order from Digikey on Thursday and it came in on Saturday. Not quite instant gratification, but close enough. Their Schemeit allows my tiniest projects to have a drawn and inked schematic that comes out of the laser printer on my workbench. Were they to try to print out their catalog, I couldn't lift it. How's that for a wishbook?

We still have one local electronics supply. Most towns probably do if you hunt hard enough. The prices are high, but they have to be to keep the doors open. And they do provide instant gratification.

SPICE gives us a quick way to try out our latest brainstorm without needing to order any parts at all. Spec sheets for the most obscure parts appear instantly from that same printer.

And the parts. Oh, my gosh the parts. A complete RF synthesizer on a chip for \$7. Computers for \$50. Complete VHF low noise amp kits for \$10. This stuff was beyond Buck Rodger's ample imagination when I was a kid.

The best time is now.

• ### New Power Supplies for the HP 8647A

The HP 8647A is an excellent signal generator with a lousy power supply. Here is how to use an Artesyn LPT-103-M and an XP-Power EML30US36 to replace the dead original. CAREFULLY use a jeweler's screwdriver & magnifying glass to set the XP-Power to 38 volts. Remove the original and put the new ones in its place with standoff insulators. A slice of ballpoint-pen barrel will do.

ALL THE USUAL DISCLAIMERS: I'm not making any money on this. I won't be responsible if you blow up your PSUs nor your signal generator. I'm trusting you to be a skilled Electronics Tech. I won't be responsible if you electrocute yourself. I won't be responsible if you do a swandive into a raincheck.

• ### PSU for Opamp Regen

Here is the power supply for the upcoming opamp regen. Three things are worth noting. 1. It is not necessary to use separate diode bridges for the positive and negative supplies. One will do, but I saw that after I built the board. 2. The power switch is after the transformer, rectifier & filter so I do not need to add a noise source to the cable going to the front panel. 3. The pinouts of the 7812 and 7912 are different. Do not confuse them.

**