Stick XPro Analyzer is on TV and Radio Broadcasting Center duty
10.08.2023
Stick XPro is on TV and Radio Broadcasting Center duty
Lviv TV tower
Stick XPro is on TV and Radio Broadcasting Center duty
Stick XPro is on TV and Radio Broadcasting Center duty
Stick XPro is on TV and Radio Broadcasting Center duty
Looking for an Antenna and Cable analyzer capable of withstanding intense radio frequency field levels, the chief engineer of the Lviv Radio and Television Broadcasting Center, Ukraine, Vladimir Ageev UR5WCW, went through a long way of unsuccessful testing devices from various manufacturers. The measurements he desperately needed were impossible to obtain due to instant overloads.
The RigExpert analyzer passed the challenge successfully first.
Which model worked perfectly, what problems it solved in the professional radio industry, and how – read the full story from a direct participant.
Another heavy rain triggered the activation of the SWR protection circuit on the 94 MHz FM transmitter installed on the Lviv TV tower, causing the output power to drop automatically.
We inspected the antenna’s standing wave ratio (SWR) at the transmitter end of the 50-ohm coaxial cable, which showed 1.8 instead of the manufacturer’s claimed range of 1.05-1.1. It was unacceptable.
The antenna is a phased array of four folded dipoles, with equal-length coaxial feed lines running from each to the splitter. The main feeder connects the splitter to the FM transmitter.
We had to climb up the tower to check the antenna’s parameters near it and the splitter.
Measurement and troubleshooting
The Lviv TV tower, a typical 3803-KM project, is sturdy and lattice-like. It broadcasts digital multiplexes, television, and FM radio signals. The TV tower is in a famous historical city place in Castle Hill. It stretches up to 192 meters. We had to climb 140 of them.
This time, I chose the Stick XPro analyzer for measurements. It is lightweight, compact, and waterproof, and its battery lasts long on a single charge. But, most importantly, according to my friend’s review, the analyzer is impervious to the high RF fields on the TV tower.
First, we checked the main feeder from the splitter with a 50 Ohm load at the transmitter end, and Stick Xpro, connected to it at the end of the antenna, showed an almost perfect SWR of 1.04.
Next, we investigated the SWR at the input of the splitter. Our suspicions about a malfunctioning antenna system were confirmed: SWR 1.87.
We individually evaluated the SWR of the four folded dipoles and their connecting cables. They all showed almost perfect values except for the last one: 1.87. The “culprit” was exposed.
To avoid damaging Dipole-4, we connected it to the analyzer using a jumper cable. The SWR confirmed its integrity and indicated a fault in the line between the dipole and splitter. We replaced the connecting cable with a new one, measuring the required length with Stick XPro. Re-measured the SWR.
Then, we turned on and retested the transmitter at nominal power. The system worked stably.
Important postscript
Given how many times we had to check SWR in our case, I would strongly recommend the Antenna and Cable Stick Xpro analyzer for another reason: factory calibration. It is ready to work from the moment you turn it on and does not need to be calibrated after each measurement.
