Amateur Radio Testing January 8 in Palm Beach

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Are you around Palm Beach and want to take the exam to become an amateur radio operator or upgrade to a higher license class? See below.

Still need to study or take a practice exam to see if you’re ready? Check out HamStudy.org.

Bring photo ID and a calculator to the exam session. Since this is a Laurel VEC session, don’t bring the exam fee, as there is none. 😉

Dear Amateur,

This Sunday the Palms West Amateur Radio Club Laurel VEC team will be giving exams for all classes of Amateur Radio licenses.

Come and test with us on Sunday, January 8 at 10:00 AM at Fire Station #28, 1040 Royal Palm Beach Blvd, Royal Palm Beach 1 block south of Okeechobee Blvd.  There is no charge, and you do not have to register.

If you are coming to upgrade, please bring a copy of your license and a photo ID card, like your driver’s license.  There is no charge for testing!

If you know of someone who has been studying to become a ham, bring them along, even if they feel they need to do more studying.

And if you are a VE, please let me know if you can come and help.

73, John, K2CIB
RadioWhiz at gmail dot com

Oh it’s one of those new age free energy amplifiers

This is from the schematic to a Tytera MD-380 radio.

Shown here is the mic preamp. I was curious to see what this looked like as transit audio quality and level are said to vary a lot from one radio to the next.

Unless I’m missing something – there’s no way for DC voltage to get in there and let those transistors do their job.

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Annotated to show where capacitors block DC:

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Looks like Miami traffic at rush hour--- it ain't getting in or out.

I’m considering buying one to play with but. .. uh… only somewhere with a good return/exchange policy.

Another day, another dehydrator

Previously I posted about the Dielectric dehydrator. Here’s another common model, the Andrew / CommScope …. Newer models are controlled by this honking weird motherboard.

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This thing's some engineer's iron clad job security

Basic parts:

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Upper left: black top hat is the air inlet filter that Andrew claims is accessible from the front panel (big fat lie), twist cover and pull off to open. Felt element is easily cleaned. Do not oil, use dry.

Pump: A field rebuildable diaphragm pump.

Center left: vent valve.

Bottom left: Spaghetti Junction.

Center bottom: output pressure regulator.

Bottom right: Coalescing filter bowls. Accessible at front panel.

Right: Molecular sieve unit and air tank.

Top center: Humidity sensor, pressure alarm switch, power input, air output.

Just so you know I didn’t simply open this for fun, here’s what happened on this unit.

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Sliiiiiiimeeeeeee!!!!! The vent valve was blocked and the unit couldn’t drain, so it threw a humidity alarm.

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Water was building up in the coalescing bowls and not being purged. That line at the bottom leads to the vent valve.

How it works: The spaghetti board starts the pump. Air passes left to right through these filter bowls, actually going through them backwards best I can tell. That is to say it enters the inner part of the fiber filters. Believe it or not there is a good reason for this. It then flows through the molecular sieve unit which absorbs moisture, passes through a check valve (where?), and enters the storage tank. From there the regulator allows enough air to pass and pressurize the line. Usually it’s set to like 3 psi.

The tank pressure is gradually increased up to 40 psi at which point the controller stops the pump and opens the vent valve.

When this happens, the pressure in the molecular sieve drops rapidly with outflow to the input side. This causes water droplets to form and be ejected. The water blows back into these two bowls and is vented along with the air via the drain.

Since this is taking place backwards, the bowls are backwards so the droplets will hit the filters on the proper side and fall downwards.

There’s method to the madness, see?

To return the unit to service, I backwashed the vent valve with the air coming from the pump and a snot rocket launched out and went….. Well, it’s never been seen since. Who knows.

It works now, that’s the important part.

And now some hot electronics porn. Here’s a Harris Broadcast ATSC receiver….
Hardcore model.

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Top left: RF and IF board. Right: 8VSB demodulator. Bottom: big mama power supply.

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The 8VSB demodulator.

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Video stream decoder and video output

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Pin count anyone?

This. Unit. Was. Not. Cheap. To. Build. Daaaaaaayuuuummmnnnn

I accept your challenge

I wish to test this claim.

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"15,000 watts"

Can I borrow a big ass shortwave rig for a moment? I’d like to see how many milliseconds this lasts before becoming a plasmoid cloud of hissing metallic gas.

Don’t leave your radio near me

Because I’ll start playing with it.

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The only thing that prevented my coworker from winding up with memory channels named after colorful air-entrained car wash products is that I really didn’t like that touchscreen user interface. A+ for cleverness though. I’ve heard the Yaesu System Fusion digital mode on these radios works very well and sounds great.

A sad state.

I never liked how Pandora sounds. Their audio compression is pretty lossy; some quality was sacrificed to ensure smooth streaming on lousy mobile data connections.

The ad insertions aren’t coordinated with the programming either, but this isn’t such a big deal as most of them are just dry reads; it’s not like booming tones and overprocessed voice comes yelling out of there. It’s just a little odd to have everything come to a sudden pause of just some lady reading a spot over silence in between power metal ballads. Granted this also means your classical stream won’t launch you through the roof when a spot plays…

But yeah, terrestrial radio is dead and burned thanks to the new Neilsen PPM encoding systems that cause audio defects to the point of stripping guitar chords out of some songs, eight minute stop sets of ads that come across with great… Mountains of acoustic fnords… before you are returned to a six song music library that you can’t hear properly anyway.

Not that I’m bitter. Just a little bit. Okay, I am.

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Pissing and moaning.

Amateur Radio Exam Resources

This isn’t a comprehensive guide by far but these are the resources I like to guide people to if they’re interested in taking the licensing exams for amateur radio in the US.

Ham radio. Get it? Yeah... I'm that bad
Sorry, I had to drop this silly dad joke on you. I just had to.

KB6NU’s No Nonsense Study Guides – Free downloads available of PDF versions, ebook versions also available for Amazon Kindle, epub, etc…

HamStudy.org – an interactive study system based around generating practice exams

For practice exams:

AA9PW’s practice exam generator

Android exam generator app free and no ad garbage. Yay.

iOS app for practice exams

So, once you can take a practice exam and pass it reliably, find out where to take the real thing near you:

ARRL Exam Session Search

Some exam sessions are walk-in, others may require advance reservations.

What to bring to the exam session:
Photo ID
A calculator (ideally not a graphing calculator)
Your FRN number, if you have one already. This can make the filing process with the FCC faster and easier. You can apply for an FRN number ahead of time. It is not necessary to have an FRN number ahead of time, it just makes things easier.
The exam fee ($14 at the time I wrote this – not needed if you’re at a Laurel VEC session)

Once you successfully pass the exam, if this is your first license, you will need to wait for your call letters to be assigned before you go on the air. If you have an FRN number, go here and search by your FRN number each business day. Continue until it comes up. Celebrate. 😀

QRZ.COM maintains a daily list of all new/changed licenses where you may also find yourself.

Good luck and see you on the airwaves 🙂

A tale of amplifiers.

Here’s a story I’ve been meaning to tell for a while.

Once upon a time, there was a wonderful isle of dreams, and a television station built upon it. To carry the sounds to accompany its magically delivered pictures, there was a set of audio distribution amplifiers.

And oh baby what amplifiers they are….

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The guys on the right. Ignore the dark power lights, they're soldered in incandescent...

And their, uh, not the best side

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The company stuck around until 1985

And now the heart:

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Those of you who are like me will also notice, this is six individually transformer isolated outputs and one transformer isolated input.

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Fairly simple amp stages.

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The dual power supply. One regulator on each end. This is the older design; the newer one has two separate regulator cards.

These lived happily until one day, one regulator card let out a biiiiiig fart.

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For comparison, this is what the other end looked like:

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Oh how it stank that morning on the wonderful isle of dreams!

The finest nose on the isle located the stench and an engineer set to restoring the precious music of the angels to flow beyond it. Fortunately he found only two channels still in use, each feeding one output… Thus:

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Emergency passive near unity gain audio distribution system.

This engineer was haunted from that day by the knowledge that some very mission critical audio still runs through that stack and the amps aren’t getting any younger.

However, they are, at least, better than the modern equivalent.

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I'll just take my chances with the old Ramko Research shit boxes, thanks

Well look at that… A Daven.

Penny & Giles, eat your conductive plastic hearts out.

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The tab at top is the cover lock; push it and turn to remove it for cleaning and service

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Big silver contact studs lead to the resistors inside.

In normal service these would be lubricated with Daven oil. This is a total mystery to me — it’s been out of production for decades, and I have no idea what a proper substitute would be.

The only other place I’ve seen rotary switches this hardcore are in avionics.

The Daven step attenuator was used in older broadcast consoles — I’m not sure on the details but I’ve heard that WVUM had one.

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