Amateur Radio Study Guides

Someone on #hamradio (on Freenode IRC) recommended these study guides for anyone looking to take the Technician or General class amateur radio exams:
KB6NU’s Manuals – available in pdf and for the Nook and Kindle.

Miami and Tampa Frequency Lists for the Wouxun KG-UVD1P

Hey, it’s me, I want to give you some good frequencies…

Miami Area Repeater Listing

Tampa Area Repeater Listing

Use KG-UV Commander to edit and transfer the files to the radio.

Under the hood: A Xantrex RMA.

The story so far: Customer returns dead Xantrex TR series inverter/charger. When he hooked it up, some kind of internal fault caused it to burn the battery terminal (see the burn there on the positive post?). It worked for a few minutes at 100 watts, but the output voltage was too low. After that, he put 400 watts on the unit, and it died permanently. I get it back in the shop and it doesn’t do anything but throw code F04.

 

BEGIN RUNNING THE GAUNTLET. It’s 11 am.

We’re a longterm customer of Xantrex here, so I would have thought they’d treat us well… Unfortunately, Xantrex is now just a subsidiary of electrical products giant Schneider Electric, who are officially Too Big To Care.

STAGE ONE:

The customer spent a good long time on the phone with Xantrex tech support, who finally told them to return the inverter to us. UPS delivers the unit a week after their driver electronically confirmed its delivery (WTF?!). I spend about 20 minutes on hold to reach the Customer Care group, who take down the info into … Nothing … They forward me to tech support.

Tech support takes down the serial number, purchase date, and failure description. An rma number is issued, however, I still need the shipping label to send the inverter back. I confirm my contact info and they inform me that it’ll be e-mailed.

It’s 1:30 pm now, and I await a response…

4:20 pm, and I get am email from the same person who took the call, asking me to send along the proof of purchase… Along with the serial number and fault description, because, oops. All that got entered into a great black hole. I fax the invoice over.

4:50 pm, I’m asked to fax the invoice again, and send it over immediately.

4:55 pm, I’m told that this entire process is complete, however, this was just the process of clearing the RMA through technical support, and I will now need to complete it through Customer Care.

End result: Most of a day wasted, still cannot confirm that a replacement will be sent our way if we ship a new inverter to the customer.

I should also add that in the past, Xantrex used to have a six ton cockblock in the way of me contacting their service department at all. Someone had established that our technical contact at work was the accounts payable department, and they refused to talk to me a second longer than it took to tell me to get accounts payable to contact them to continue the process. Funny they remembered this like an elephant, but filed today’s rma request in /dev/null! I had to establish contact with tech support by contacting them regarding an XW6048 that vomited fire with a loud buzzing sound at another customer, who had managed to open an rma on the unit.

Xantrex still threw me around on the phone for about 2 hours on that one, and I still don’t have the shipping label… I do, however, have it crated and ready to go home, with a hilarious and profane label sitting on the lid.

All of this is just part of the many reasons I like Outback Power better.

It’s done! As of about 7:30 pm, I got a couple of e-mails from Xantrex confirming that I just need to ship the dead inverter out, and the shipping label arrived! Hurrrrrrrrr…

Under the hood: Morningstar SunSaver MPPT.

Buckin' Bronco

This is the Morningstar Sunsaver MPPT charge controller, capable of pumping 15 amps into a 12 or 24 volt battery system from an up to 75V input. It’s fairly simple, though the 6P6C jack can be used for Morningstar’s Modbus system or Remote Meter to add more control, programming, and monitoring capabilities. The unit is driven by a Microchip PIC18???* microcontroller.

A typical MPPT controller consists of a switching buck or buck-boost converter with the input connected to the solar panel array, and the output connected to the battery system. A microcontroller monitors the solar array voltage and current (and multiplies them to calculate the power) periodically, and adjusts the switching of the converter appropriately to keep the input side voltage at the solar array’s maximum power point, Vmp.

Inside the Morningstar Sunsaver MPPT, there is… a switching buck converter with a micro… etc. Here you go:

* The conformal coating stuck to the top of the chip made it difficult to read. Like the flavor of PIC matters? XD

Control/Logic Board

No fans or other active cooling are needed. The inductor is thermally coupled to the back of the housing, which is a tall metal fin attached to the heatsink/base. The switching transistors are, undoubtedly, potted somewhere in there. The potted construction is also used on the SunSaver PWM controllers.

Simple, elegant, but here’s the big question: WHY does it cost $250?! Rest assured, I’m scouring the market for some *good* low cost MPPT controllers. This is just a very good and not quite as low cost controller!

Xantrex XW-MPPT-60-150: Squeezing 60 amps through a toothpick

It doesn’t smell too great in my office right now…. some Xantrex XW-MPPT-60-150 charge controllers just came back that are completely, totally burned up. SCORCHED. OWNED. PWNED. TEHPWNZRIATED.

All images are clickable for full resolution, as always (4000×3000 px)

First off, here’s why I think these blew up. Note the four small pins on the back of each contact of the large screw terminals. Each of them is probably 18 gauge… if even. It’s hard to judge since they’re square pins.

Up to 60 amps of current will flow through these little four-legged pieces of Chinese scrapmetal when the controller is running full tilt.

FYI, National Electrical Code requirements would call for AT LEAST 6 AWG assuming the conductors are copper — which they are not, they’re tin plated steel.

Aaaaaaand now, the results.

Burnt components and pieces of plastic fall out of the controller whenever it’s handled, and it’s left a wretched smell to permate my workspace. The copper PCB traces are still there and didn’t fuse, but the solder has melted away on them from the heating, and several components in the vicinity desoldered and fell right out of the controller.

Moar:

Topside. The top of the terminal block and delaminated PCB

Under the hood: The Outback FM80

Warning: Engineering porn ahead. All images are clickable to view in full resolution.

The Outback Power FM80 solar charge controller is a high performance MPPT controller which converts a solar array’s output (up to 150VDC, 64 amps) down to charge a 12, 24, 36, 48, or 60 volt DC battery string using a high efficiency switching buck converter and an extremely flexible microprocessor control system. It is field programmable from the front panel and can be linked to other system components using Outback’s communication buss and the MATE controllers for system logging and remote control.

It is extremely well built, and solid as a rock.

More photos below…

Continue reading »

gimme gimme shock treatment

(Special thanks to The Ramones)

An engineer came into the office today who will remain nameless mainly because I forgot his name. He told me of hijinks at the Dayton Hamvention in which he rigged a portapotty’s seat with conductive tape, a dc flourescent lamp driver, and a small solar panel on top of the ‘loo. When sunlight hit the panel, the seat became… Well, the least pleasant portapotty seat ever.

Now that’s … Special.

Heart Transverter

Well, this is new. Years ago, Heart Interface Corporation made a really nice line of renewable energy and vehicle ac inverters and inverter charger units. At some point, the company became Trace Engineering, which was then bought out by Xantrex, who promptly worked hard to make most of the better products and engineering go away in favor of nasty Chinese rubbish. 😛

Well, Heart Akerson is still around today in Costa Rica, and his new company, Heart Transverter, has a pretty fun product going.

Basically, it’s one green 2KW box of switching converters, software defined and highly programmable, with two dc input/output busses, one +50VDC output, one ac input, and one ac output… and it does… anything you want it to, including serving as a grid tie inverter, pv controller, charge control ….

A companion unit can be used for sophisticated load monitoring and control of six circuits.

It is designed and manufactured in Costa Rica, which is pretty amazing in itself.

The brains of the system are on a small remote control unit about the size of a sandwich, with a usb interface for programming.

Believe me, I’m most curious and intrigued. I didn’t get to see it running today, sadly. I’d love to see this in action.

I should add that the Heart Transverter logo is pretty cool. Yeah, I have a little obsession with how neat the old Heart Interface logo was 😛

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