Archive for radio

If tubes could speak…

This one’s probably been around the block a few times. I was initially kinda worried because the fins looked roughed up but after some unscientific testing to make sure I could blow through them and fit a cable tie down between the fins to ensure there was a good pathway, I went ahead and installed it, and it came up just fine with a perfectly good stack temperature…

NO EXCUSES ON DA BOWL

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These holes seem to be a common feature of some part of the remanufacturing process

The old tube went soft pretty quick. Don’t they have pills for that now?

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And here’s what that goes in, a Harris/GatesAir 25,000 watt FM transmitter.

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To swap it, you release a hose clamp holding a big collet on the movable top plate of the cavity so you can slide that plate blocker/chimney up, then release the hose clamp holding it to the tube (bottom), slide it up then clamp it again out of the way. Then you can carefully disconnect the plate voltage supply cap and somersault the tube upside down above the socket and remove it. I wish I’d taken a video of how bizarre this all looks.

Cooling air is forced both through holes in the socket and out of the cavity through the tube’s plate cooler after entering from the blower duct.

The two big fat orange wires – GatesAir / Gates / Harris Broadcast really likes that fat orange wire – are the filament supply, 10vdc Max at 150 amps. The HV, ~9500vdc at about 3 amps and change, comes in on a piece of RG-213 coax from this off board power supply.

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First person shorting stick wielding view

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Rectifier modules

A little dust but not too bad. The dust seemed to really like gathering on anything live with plate voltage. Eww. A more through cleaning will occur soon.

And the award for silliest front panel design goes to….

The QEI Model 691 FM modulation monitor!

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It always makes me think of Pokey The Penguin comics.

Please feel free to use this photograph to torture graphic designers.

Sorry about the stray marks, I’ve been asked to respect the secret identity of my client. You’re not cleared for that. Fnord!

The Florida Repeater Council Meltdown

If you are a US licensed amateur radio operator, please take a moment to read the following:
FCC Part 97.205

§ 97.205 Repeater station.

(a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of a Technician, General, Advanced or Amateur Extra Class operator license may be the control operator of a repeater, subject to the privileges of the class of operator license held.

(b) A repeater may receive and retransmit only on the 10 m and shorter wavelength frequency bands except the 28.0-29.5 MHz, 50.0-51.0 MHz, 144.0-144.5 MHz, 145.5-146.0 MHz, 222.00-222.15 MHz, 431.0-433.0 Mhz, and 435.0-438.0 Mhz segments.

(c) Where the transmissions of a repeater cause harmful interference to another repeater, the two station licensees are equally and fully responsible for resolving the interference unless the operation of one station is recommended by a frequency coordinator and the operation of the other station is not. In that case, the licensee of the non-coordinated repeater has primary responsibility to resolve the interference.

(d) A repeater may be automatically controlled.

(e) Ancillary functions of a repeater that are available to users on the input channel are not considered remotely controlled functions of the station. Limiting the use of a repeater to only certain user stations is permissible.

(f) [Reserved]

(g) The control operator of a repeater that retransmits inadvertently communications that violate the rules in this part is not accountable for the violative communications.

Part H omitted because it is not relevant here but you must refer to it if you’re near Arecibo Observatory.

So now we continue.

Photo: hamsexy.com – in the aftermath of the infamous Dayton Volcano

The Florida Repeater Council was originally established to fill a need to facilitate the voluntary frequency coordination between amateur radio repeaters. This ensures that repeaters on the same or adjacent channels do not interfere with the use of one another and promotes more reliable communications using the repeaters.

In addition, as the coordination agency recognized by the American Radio Relay League, they supply their coordinated repeater listings for inclusion in ARRL publications such as the neat little pocket repeater directory books.

Unfortunately, at some point, egos flared, communication broke down, and it became the worst sort of bullshit secret society. (Communication? People using amateur radio are supposed to— communicate?)

I first became aware of this as an ongoing problem as early as 2000. At the time there were a lot of hams active in the Miami-Dade community and the need was there for several good repeaters with countywide and wide area coverage. When the trustees of these repeaters were approaching the Florida Repeater Council for coordination, either nothing would happen… or they would get coordination, but only if they were personal friends of the then regional coordinator, Nilo W4HN. Very mysterious.

In some cases they’d get coordinated to frequencies already in use.

For a while the FRC also had a statement on their website that suggested that uncoordinated operation of an amateur radio repeater was in violation of federal law. This statement is perfectly negated by the actual federal law, which I have included above for your convenience. Read it if you haven’t already. Trust me, FCC Part 97 is the LEAST painful piece of the FCC rules I have ever read. This was removed after a couple of years and I’m not sure exactly when, so I can’t put up a link to it for you to laugh at them with right now. Oh well.

After a couple years of frustration with this, some of my friends who were being repeatedly screwed over by the FRC by not receiving coordination and then having highly, uh, effective, Papertron 4000* repeaters coordinated onto the same frequencies they applied for, they attempted to attend the FRC’s regular yearly meeting at the Melbourne Hamfest to complain and attempt to get this fixed while they were there in person.

Well…. the meeting was also a mere piece of paper, in a sense. The Platinum Coast Amateur Radio Society had assigned them a time and a forum room at the hamfest. As I recall, it was something like Saturday at 2 PM.

Saturday at about 10:30 AM, an announcement went out over the Melbourne Civic Auditorium’s PA system that the FRC meeting was due to begin in five minutes. The forum room was currently occupied with another event, and none of the FRC board of directors were in attendance. 15 minutes or so into the meeting, it was announced where they were—

At a hotel conference room about a half hour drive away.

Needless to say, nobody was very pleased with them for this.

Eventually Nilo retired his position as director for our region, and the Dade Radio Club of Miami recommended that I apply for this position. I sent off an email to the president of the FRC (now deceased, listed as deceased but still as president on the FRC webpage and never replaced because they haven’t held elections in over a decade.)

We continued to have no coordinator for a couple of years, and during this time, not only were new coordinations impossible, but existing coordinations wouldn’t even expire if the trustees were not sending in updates or notified the council that they were unable to continue operations! Not to turn this into YET ANOTHER “Miami-Dade sucks moldy donkey nuts” post, but around this era, access to good repeater sites was very rapidly dwindling away to nothing due to property flipping, so there was just almost nowhere to put them. Yet, they continued on forever on paper. (This is what I was getting at with that “Papertron” comment above.) There were PAGES of paper repeaters, especially on the 70cm band.

You can’t take it with you. Or can you?

I heard nothing back for about a day then my phone rang off the hook. I got calls and emails from each of the directors insulting and berating me for daring to apply for this position, as to be qualified as a member of the FRC, I would need to be trustee of a previously coordinated repeater, and by attempting to join incorrectly I was now permanently disqualified from ever coordinating one.

I have never answered a caller with that much FCC part 97.113(a)4 disapproved language before. Here I was politely offering to volunteer to assist in coordination activities and they saw this as if a personal attack. Amazing.

You can see above that there is one actual coordinator listed, Dana. Dana holds ALL the data on FRC coordinations, and he was very difficult to work with. If he left, so did every repeater coordination in the state. And that’s … likely what would happen.

Finally, after the FRC’s dealings got even uglier, an effort was coordinated to bring about reform to the organization. They met at the Orlando Hamcation and pulled some of their old tricks – change of venue AND started the meeting earlier than the published time. What happened there was spectacular — the board of directors decided to eject all members (who were paying dues to be in there!). Since this meeting I’m told they’ve also been searching out the hams who joined the petition for reform and removing their repeater coordinations. This is going to be uhhhh grrrrrrrr-eat for the data they supply to the ARRL.

This is the full meeting on video.


Enhanced audio here.

Sounds like a RAGEQUIT to me.

So where does this leave amateur radio in Florida?

…. The same place where it always was. Loss of a repeater coordination organization actually makes almost no difference. The bands just aren’t that clogged, and there just aren’t that many places to put up repeaters, so with a bit of due care, hams can work together to avoid interference between their repeater systems. If you’re not sure if a pair is in use, listen to it for a while, at least with a good mobile radio (driving to the top of a tall parking garage can help).

And, for that matter, if you have an active repeater – PUBLISH IT! There are several directories that are community based.
RepeaterBook.com and RadioReference.com should be used, among others. If you run an open repeater and it uses CTCSS access, set the ID to tell listeners which tone to use, or follow the standard for your area. To be honest, while the little pocket books from the ARRL were neat, their use and relevance has faded nowadays.

And don’t send your contact information to the FRC if you don’t want angry phone calls. Been there, done that, laughed my ass off at them behind their backs.

iShartMedia quality

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iShartRadio quality:
[Booby Trap commercial]
“This is a test of the Emergency Alert System.”
[Tootsie’s Cabaret commercial]

Heard on WBGG-FM about 1:18 AM. No data bursts were sent. Not even a period of silence.

Let’s not even think too deeply here about what a sin it is to put spots for two rival businesses of the same type in the same stop set. It’s very disrespectful to your advertisers. Then again if they had any respect they wouldn’t be cutting spots in a studio where the equipment has a distinctly audible whining hiss.

Amateur Radio Testing Sessions in Miami-Dade

This is an unofficial listing and you may want to confirm with the club before going for a testing session!

For any amateur radio exam session, please be sure to bring photo ID, the exam fee (unless you’re going to a Laurel VEC session which has none) and a calculator. Calculator apps on a smartphone don’t cut it here. What kind of silly borks do you take us volunteer examiners for? Ha!

 

For whatever odd reason, the testing sessions in Miami-Dade County have sometimes disappeared from the master database on the ARRL website.

 

These are the clubs I’m aware of that regularly host exam sessions:

Dade Radio Club of MiamiTesting sessions monthly in Doral.

Contact: Mike Jasinski, KE4DP@arrl.net

Second Monday of the month, starting 7:00 PM at the Miami-Dade County Emergency Operations Center / Fire Rescue headquarters, 9300 N.W. 41 Street, Doral FL.
Upon arriving, drive up to the front of the building and go left to the gate. If this is closed, ring the intercom and tell the guard you’re there for the Dade Radio Club meeting.

Everglades Amateur Radio Club – Testing sessions monthly in Homestead.

Second Friday of the month, starting 7:30 PM at the South Dade Agricultural Center, 18710 SW 288th St., Homestead, FL.

Contact: Ryan W4NTR, ryan@bbnx.net

Special Events with testing:

South Florida Tropical Hamboree – Originally a Miami event, now held in Fort Lauderdale, but I’ll include it anyway.

Amateur Radio Testing January 8 in Palm Beach

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Picture entirely unrelated

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

I can’t even

It stopped working after I touched it

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I don’t know why

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I fixed it

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I don’t know how

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But it’s all good.

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Good night everyone. Don’t break it again like I did.

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.