Joey Gill /
10.09.2013 12:00 AM
Harris’ Maxiva UAX Low-Power Transmitter

Harris Maxiva UAX

The physical world has its limitations— things can only get so small. Nowadays, we’re all quite accustomed to seeing technology pack more features into smaller packages. Why should the world of solid-state transmitters be any different? Evidently that is what the designers at Harris Broadcast were thinking when they came up with the Maxiva UAX Compact Class transmitter. It features a built-in exciter, drive chain and remote access/control, all in a 2RU package.

FEATURES
The solid-state Harris Maxiva UAX is part of the company’s “Compact Class” of transmitters, with power levels from 5 to 50 watts, and as tested, providing frequency-agile UHF coverage from 470 to 862 MHz. The unit weighs about 25 pounds, adds less than 65 dBa of acoustic noise (as measured from one meter in front of the transmitter), and is air-cooled via internal fans with a front-to-rear airflow. It takes AC power between 110 and 230 volts at frequencies between 47 to 63 Hz. Rear panel ports include RF output, RF input sample for RATC, transport stream inputs (two, configurable as SPMTE 310M, DVB-ASI or DVB-T2MI). There are also a couple of ports for DVB-ASI hierarchical modulation and a 10 MHz reference input, as well as for a PPS reference, along with a DHCP-enabled RJ- 45 Ethernet for networking. Front panel ports include a 10 MHz reference output (SMA, 50 ohms), 1 PPS reference output (SMA, 50 ohms), RF monitor output (SMA, 50 ohms) and 1 RJ-45 Ethernet for customer access.

The front panel also features an LCD screen along with Status, Power and Setup buttons immediately below. To the right of the screen is a “menu control wheel” and buttons for remote enable/disable, output power adjustment and an on/off control. Seven status LEDs provide a quick status check of TS input, drive chain, power amplifier, supply power, output, system and mute.

The transmitter also includes a built-in GPS option to support single-frequency network operations, full remote control capability including Web-based HTML, GUI interface, SNMP and parallel/monitoring.

As mentioned, the Maxiva has dual transport stream inputs with manual/auto switching and Real-Time Adaptive Correction (RTAC). It supports DVB-T/H, DVB-T2, ATSC, ATSC-MDTV, ISDB-Tb, CMMB and CTTB modulations.

As a transposer/translator, the Maxiva supports all COFDM and ATSC standards and has a digital, tunable RF input filter. As a gap filler, its features include powerful adaptive echo cancellation with up to 15 dB gain margin for exposed stations and difficult situations and a very low processing delay.

The Maxiva features Harris PowerSmart Technology inside, and offers high power and efficiency, utilizing new 50-volt LD-MOS devices. Its exciter offers the Apex M2X technology platform.

IN USE
When the Harris Maxiva arrived, I mounted it in my test rack and attached the supplied directional coupler with dummy load. Next, I connected my station’s SMPTE 310 stream to the input and applied AC power. The LCD screen was easy to read and the information was simple and direct. The display provided forward and reflected power figures (it indicated “0” and “0” values for these at power up). I raised the forward slowly, leveling it off at about 22 watts. At this level, reflected power measured only about 12 mW. All was well. However, what channel was I on?

Below the power display was the menu display list, including On-Air Data, Digital Signal Path, PFRU (Precise Frequency Reference Unit), Up/Down Converter, LPU, Battery Backup, Transmitter I/O, Revisions, Fault Log, System Settings, Adaptive, Transmit Power Settings, Remote Comms and Defaults.

Under the PFRU, I was able to find “Center Frequency,” and noted the frequency, 582 MHz. This didn’t please me, as I like transmitting on UHF Channel 36. Therefore, I killed the RF output (habit), and using the menu navigation buttons, I selected the center frequency setup and changed it to read 605 MHz and then pressed “enter.” Voila, I was on Channel 36, where my station belongs.

I raised the power and connected a little consumer DTV to the directional coupler output (using a paper clip as an antenna) and there were all three channels that we regularly broadcast.

After having successfully put this unit on the air without reading any instructions, I figured the next order of business should be to gain remote control via the Ethernet port.

I scrolled down the menu to find “Remote Comms,” and under that menu I found “Rear IP address.” After connecting my laptop to the unit using a crossover cable, I typed the address into my Chrome browser. A log-on screen appeared, wanting a pesky “User Name” and “Password.” There was a box to click as a guest with “View Only” privileges. When I clicked there, I was able to pull up the GUI and look but I needed control!

At this time I took the instructional CD from the box and loaded it into my desktop PC. Once the PDF loaded, I searched “User Name” and once again, I had the keys to the gate: “admin-admin” were the magic words. The remote GUI proved to be slick, simple and intuitive. I was able to raise and lower power, and all of the status info I needed for remote control was displayed.

SUMMARY
Over the next few weeks, I let the little transmitter sit in my office and cook. I did adjust the power down so that the dummy load wouldn’t get too hot, but the unit never missed a beat. The “Output” LED indicator responded to a low RF condition when I lowered the drive, and I checked the TS LED by unplugging the SMPTE 310 feed.

I next unplugged and powered up the system several times to see what would happen in a power bump, and it always came right back up to normal.

This is a really complete transmission system in a 2RU package, and one that you don’t have to go to a training program to learn how to deploy.

My regret was in not being able to put it on the air.

Joey Gill is chief engineer at WPSDTV in Paducah, Ky. and has been with the station for 30 years. He has worked in television since 1977. He may be contacted at respond2jgill@yahoo.com.

FAST FACTS

APPLICATION
Low-power transmitter, repeater and gap filler

KEY FEATURES
Compact, solid-state technology, multifunction operation

PRICE
MSRP as tested, $9,950

CONTACT
Harris Broadcast
800-231-9673
www.harrisbroadcast.com



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