Review: Volt/Amp Meter

Volt-Amp Meter

Volt-Amp Meter

I was cruising a web site and found this little meter for the amazing price of only $4.20.  Such a deal, I thought.  But was it?  Maybe, depending on your application.

The meter reads 0-99 volts DC, and 0-10 amps DC and could be very handy if it was not for one small quirk.   The sample for amperage is taken from the Negative side of the meter.

Vendor Schematic

Vendor schematic of suggested hookup.

This may, or may not be a problem in your application, however it does require you to think about wire size, especially when working with a DC device drawing 10 amperes, DC. 

The meter also does not have a fast sample rate, so use on something like a Yaesu FT-857D in the single sideband or CW mode would not be too helpful. 

The meter seems to have about 350 mS refresh, and to be honest I was awful tempted to use a diode in place of the yellow lead and direct DC to a capacitor to stabilize the reading.  That would, however, cause some errors in the readings.  But maybe .1 of an amp or volt is not concerning to you.

The negative (ground) amperage measurement does rule it out for applications such as automotive, truck gear, etc.  I imagine with some MacGyvering you could put it into a project box for a bench power supply, or just to monitor a power supply output.  Another application could be a monitor on a solar or wind charging system, as long as 20mA doesn’t bother you when calculating losses.

The seller has these on sale at Aliexpress for only $1.88 each, and sometimes as cheap as $1.09.  So maybe it’s not entirely a bad deal.   They also have a voltmeter only in the same package.

Rear View of Meter

Rear view of meter


Wire Connections

Wire Connection


 

 

 

 

Seller’s Specifications on product

  • Working voltage: 4.5-30V DC
  • Note: The maximum input voltage can not exceed 30V, otherwise there is the danger of burning
  • Working current: 20mA
  • Display: 0.28″ Two color, blue & red
  • Measuring range: DC 0-100V, & 0-10A
  • Minimum resolution (V): 0.1V
  • Refresh rate: 100mS / times
  • Measure accuracy: 1% (± 1 digit)
  • Minimum resolution (A): 0.01A
  • Operating temperature: -15 to 70° c
  • Working pressure: 80 to 106 kPa
  • size: 48×29×21 mm

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Old School Console

Gates Studioette from the Ross Revenge

Today I found a reference to the Gates Studioette console.  Remember them?  This console resided in the pirate ship Ross Revenge, “The Boat That Rocked”.  If you’re not familiar with the history its well worth an hour of reading!   Radio Caroline was an amazing station.

My first experience with the Gates Studioette was a visit to then WAWR-FM in Bowling Green, Ohio.  The station was on 93.5, mono, and in a college town, Bowling Green, Ohio.  The announcer giving me the tour was Bob Ladd who later went on to own a station in Bellevue, Ohio, on 92.1.   I never forget the tour of WAWR.  It was awesome.

The console was typical of that era.  Tubes, step faders, but the interesting part was the construction.  Note how the chassis was made, the number of brakes made in the metal.  Knobs which you can actually handle.  Then there is the switching on the front as well as the escutcheon plates detailing the function.  Those, by the way, are steel and silk screen.

Today you don’t see that craftsmanship.  Recently I had to look for a console for work, and I was dogged by the fact every darn one of them is either a computer, or a production/stage mixer type of console.   OK, they look cool and futuristic, but they can’t be fixed at the component level, (you’re beholding to a manufacturer), or they don’t “feel” right.

Soon I’ll be starting on converting an old tube Yard, (circa 1958), to a modern stereo console.  The restoration will be interesting as the Yard’s old guts go, replaced by my own designed amps, but I want it to look like it did in 1958.  I’m also adding some options which include mix-minus for the Telos, and solid state relays for the On-Air light and remote starts.

The cabinetry will be the hardest part, as well as replacing switches and knobs.  Presently I’m trying to find a source for the Gates knobs uses at that time.   Due to our economy, (or lack thereof for the past several decades), we don’t make things anymore in this country.  So it’s going to be hard to find a company to make them.  I did find someone to make the switch knobs, except he didn’t have the dye they used to make colored caps.  Only black.

VU meters?  Try to find one.  Most are unobtanium due to the complex nature of the meter.  The specifications are rather narrow, and only new old stock is available.  If you buy any of the VU meters from China, they will likely be DC meters 500mA, and even with an AC to DC conversion, the ballistics are not right.

The bottom line is, after the Gates Yard is finished, I might start on a Studioette.  It’s a classic.  But to make it, it’s going to require learning metal braking, silk screening, and other jobs which we simply don’t do here in the United States.

 

 

April 1st is Here

April 1st is here, so I thought I would mention some pranks.

Yes, I like a good joke if it’s not mean or harms someone.

OK, so let’s look at a few from the past.

The Mackinaw Tunnel

I love the north, and hope to retire there if the locals don’t mind.  I’m an amateur radio operator, and during one long conversation with a friend in Alpena, MI, I had the opportunity to spin a tale.

As I was talking to my friend a mobile operator heading north broke into the conversation rather crudely.  He was sort of an excitable type, using CB lingo, with nothing to say good about the traffic and the way people up in the U.P. conduct their affairs.  From no late night carry outs, to lack of gas stations on each corner to fill up his brand new Escalade, nothing pleased him  I was about to ask him why he even ventured north when he didn’t like it.  That is, until he gave me the opening.

“What the hell is wrong with the traffic before the bridge?  They closed the damn bridge.  I’ve got places to go.”  His bitchy tones were getting me in the mood for some fun.

My friend Larry tried to tell him that they close the bridge during high winds, or ice falling from the bridge cables.  Despite this the fellow argued again and again about how primitive the area was, and how in Detroit was MUCH better as they had a bridge AND a tunnel.

Larry, a civil engineer, tried to explain to him what a 5# chunk of ice falling from 150 feet would do to his car, not to mention people inside.  But our dear Rochester Hills friend was having none of it.  He wanted across now, and there was no debate.  That’s when I talked to him.

“Have you thought about taking the private tunnel?”  I asked.   There was silence then he asked about it.  I could hear the reel on the fishing pole spinning.  I hooked me one!

I explained that they had a bad storm and closed the bridge for a few days.  Then after reopening it, a herd of jackalopes blocked all lanes for a few days, and they were on Governor Snyder’s endangered species list so you can’t disturb them until they crossed.  Jackalopes are small so they take up to a day to cross.  Then the timber trucks from the U.P. had to cross so they could make their deadline at the Grayling Toothpick Factory.  Because of situations like this the locals built a private tunnel.

The tunnel to the other side was one lane each way for cars only and the toll was a buck.  The guy was amazed that it cost only a dollar toll, but Larry jumped in and reminded him it was a private tunnel and not on the highway system.  He also said the locals didn’t want anyone to know about it, but it’s on Huron Avenue behind a bait shop.

The fellow thanked me, and I told Larry I would catch him later and turned off the radio not wanting any more questions.  I often wondered if anyone ever clued him in.

The Moose At My Radio

As I mentioned, I’m an amateur radio operator.  While on vacation on the North Manistique Lake I set up my portable amateur radio station, consisting of a Yaesu FT-857D,  tuner, and dipole antenna.  I then started talking to friends back south.

Some amateur operators like to collect grid squares, meaning locations across the United States within specific boundaries.   There is a map on QRZ.COM if you are interested in what they look like.

We’ve all had that person who hangs around, either at a party, or in a conversation.  That friend who says they just need to stop “for a second”, and 5 hours later they are still hanging around.

I was just about to shut down for the morning when I got called by a fellow on the radio who interrupted my conversation with someone else.  Apparently he needed my grid square for his count.  He asked where I was and I mentioned, “I’m at 46° 18′ 4” North by -85° 43′ 59” West, which is grid EN76dh.  I’ve got to sign off.  People are waiting for me.” 

The fellow took this to mean that we needed to strike up a long conversation.   After several exchanges, and reminding him each time that I needed to go, (and the fellow not taking the hint), I figured I needed to create some drama.

On my last communication with him I said.  “Can you hold on a second.  There’s a moose wandering into our campsite.  Wait …. the moose is coming toward me.”  I then made a snorting sound.  “Oh no!  The moose is eating my radio.  Someone needs to get this moose before …….

From this point on I didn’t transmit again, however the fellow I was talking with continued to call and ask questions for the next 20 minutes.  Priceless!

Erasing a Record

When I was a DJ I pulled a lot of pranks and told a lot of jokes on the radio.  One such joke was to explain how records worked.  After giving the explanation I mentioned that records were like audio tape and could be erased, but it only removed the vocals from the record.

Little did the audience know that some 45s pressed at the time had the full song on the A side, and then the B side was the instrumental without vocal.

So I started to play the Barry White song “You’re The First, The Last, My Everything“.  After playing about 15-seconds of the song, I stopped it and explained that I was about to erase the song’s vocal off the 45 RPM record.   I made a sound effect and then played the B side of the song.   It was surprising how many people thought you could erase a record.

Mr. Lyons

At one station I worked at we had a salesman who, honestly, looked like Conway Twitty, but acted like Herb Tarlek.   No, he was worse than Herb because this guy was always jazzed, and many of us suspected he was on uppers.  Good salesman.  Obnoxious creep.

On the morning of April 1st he came in the station to discover his usual mail and pink telephone message slips.  One of those was a slip that said “Call Mr. Lyons at 313-xxx-xxxx.   He wants to place a rather large ad buy for 26 weeks.”  He called and didn’t quite catch on until someone clued him in.  The number was for the cat house at the Detroit Zoo.

After he figured it out he was on the warpath to find out who pranked him.  This only lead to staff members finding pictures of lions, tigers, and bobcats in the newspaper and magazines, and depositing them in his mail, sales files, desk drawer, and anywhere he would discover them at a later date.

The Pettisville Drive In Theater

In the late 70s I worked briefly at a radio station in Archbold, Ohio.   Down the road a bit was a little town called Pettisville, Ohio.  The town at the time was probably only a thousand feet long in any given direction. It has a population of only 498 now, and I would bet it was a 1/3rd less back then.

One April 1st morning I announced that the town now had a drive in theater, and created some commercials to go with gag.  Movies like “American Hot Car Wax”, and “National Lampoon’s Animal Hospital”, and “The Catbox from Outer Space.”   Of course this was outright humor, and the tag line to all the commercials was “The Pettisville Drive In Theater.  You can come as you are, but keep your kids in the car.

Most people took the humor in stride, and thought it was funny.  But apparently some people took it seriously as after my shift I was summoned to the station owner’s office and told to knock it off as it was causing some concern in the small town.  Someone from the little town had called the owner saying that they didn’t appreciate the humor.

These same people had kittens over the Col Sanders Obit.

Toledo Edison Transmission Line Cleaning

At the same station, and as a public service, I reminded people in Delta and Swanton, Ohio, that they needed to place sandwich bags over wall receptacles and light fixtures with no bulb screwed in.   “Toledo Edison will begin cleaning their transmission lines out in the country by using compressed air in the wires.  We all know that birds sit on the wires, the transformers, and poles, and we all know what birds do from time to time.  So if you don’t want bird poo to accidentally get into your hours, cover any receptacles and sockets and you can confine the mess and throw it away.

After saying this on the air I had a lady call me and ask, “How will I know when it’s safe to take the bags off?”

I had to go back on the air and mention that cleaning was starting at 9AM, and would be done by 11AM, so if you didn’t have anything in your bag then it meant the utility probably preemptively vacuumed some of the wires a week earlier.

I also explained that some of the transformers had vac units in them, which was why some had brown stains down the sides.  (In reality it was rust).

At least I didn’t do what WEBN-FM had done for years, and broadcast a fake parade which usually got people out of their homes to find the non-existent parade in Cincinnati.

I miss this sort of thing on the radio.  Today with social media, and news organizations picking up stories without vetting them, a good DJ prank would be a welcomed relief to dull airwaves.