CASE STUDIES + FAQs

Below is a sample of a some antenna and transmission issues found using our airborne measurement systems. In most cases, once the client received their report on what was wrong with their transmission system, they were able to fix the problem and increase their overall RF performance.

In some cases, these antenna systems had been operating incorrectly for years.

  
 

SCENARIO 1: INCORRECT MAIN FEEDER PHASING

A common occurance in multiple feed antenna systems. These antennas are designed in such a way that the input to each part of the antenna needs to be fed with a specific amplitude and phase in order to direct the main beam of power to an intended depression angle. Phase is directly proportional to the length of these feeders. If installed incorrectly, it will effect the beamtilt and power distribution from above the horizon to below the horizon known as the vertical radiation pattern (VRP), meaning your target coverage area may be missed and your signal may be several dBs down on your designed beamtilt. 

 

SCENARIO 2: WRONG PANEL ORIENTATION

For directional arrays, incorrectly orientated antenna panels can cause the horizontal radiation pattern to be skewed or shifted in azimuth. This is usually only an issue if there is a significant deviation from the manufacturers designed pattern but could mean you miss your inteded RF coverage area even if deviations of 10 degrees are measured.

 
   
   

SCENARIO 3: UNKNOWN SYSTEM LOSSES

In some cases, all losses are not known throughout the RF chain. This may include combiner, switching frames, rigid line, coaxial feeder, power divider network and even internal antenna losses. This could equate to large signal losses. By measuring the effective radiated power (ERP), with great accuracy, we get a better understanding of the actual losses within the system. The example to the left shows two channels which were designed to radiate with the same amount of power. One channel is lower due to incorrect/unknown system losses.

 

SCENARIO 4: SEVERE MECHANICAL LEAN

A very difficult problem to diagnose using traditional land-based measurement techniques. However, now with increase in both accuracy and accessibility, we can diagnose excessive mechanical lean up to a resolution of up to 1 degree. This could be as a result of the physical antenna installation or it could be warping/leaning of the supporting structure. Downward tilt on one face and upward tilt on the opposing face are good indications that there is mechanical leaning of your antenna or supporting structure.

 
   
   

SCENARIO 5: INVERTED PANELS

Some antenna systems could be made up of hundreds of panels, and some may only consist of a few panels. In many cases panel antennas are quite symmetrical, this means it's easy to make the mistake of installing the panel upside down. Inverted panels usually create large nulls in your antenna patterns when there shouldn't be. Fixing this will result in significant improvement in signal quality.

 

SCENARIO 6: COMPLIANCY

Government regulators impose restrictions on the amount of power you can radiate in any direction around the transmitting antenna. This is usually the case when interference mitigation and broadcast market protection is needed. Most broadcasters will have a restriction on the ERP (Effective Radiated Power) they are allowed to radiate on a certain channel, this can now be measured accurately to ensure compliancy.

 
 
 

FREQUENTLY ASKED QUESTIONS

You want to be confident your rf transmission system is working as intended,right? Perhaps you need to install a new broadcast antenna system? How do you know for certain that it is installed correctly and gives you the performance you expect? We understand how difficult it is to accurately prove the performance of these complicated antenna systems, especially when a high level of accuracy is needed. Traditional land-based measurement techniques are limited, it's time to innovate. Here at SIXARMS, we are redefining the measurement tools needed to give you confidence that your rf system is working the best it can! Here's some questions we've been asked.

What does SIXARMS do?

We sell Airborne Radio Measurement Systems (ARMS). We give you the tools and help you verify the operation of your transmission systems. We have bundled over 3 decades of antenna and RF measurement knowledge into a versatile platform that is now far more capable than any previous measurement methods. 

What do you mean "verify the operation of our transmission systems"?

Our platforms allow you to fully characterise the transmitted signal from your antenna. The airborne system flies predetermined routes to gather enough data to allow a 'picture of health' to emerge. This confirms whether the installed system is as per the design. If not, it allows you to more easily diagnose what the potential issues may be, then correct them.

Great, but I don't know much about flying drones?

That's ok, you simply put your staff through a remote pilots course. You don't have to be a world champion drone racer. In fact, most of the flying is done without any human intervention. We'll provide training on how to carry out the measurements correctly, so that the data you captured is valid and you're able to setup the measurement. Our software solution takes the complexity out of the operation.

Thats fine, but we don't want to do these measurements ourselves, do you offer this as a service, independent consultant?

Yes, as well as suppling these airborne systems, we also offer a measurement service. We'll come and measure the antenna for you and provide you with a comprehensive report on the performance of your system. Perhaps even the performance of your competitors system too.

What's in the report?

Alot. We supply all measured data in a form that becomes useful. That is, we provide a 360 horizontal pattern and a number of vertical slices depending on the configuration of your transmitting antenna. These are compared directly to your manufacturers designed patterns. We'll also include the real radiated power and include the accuracy of the results. 

I've just installed a new broadcast antenna. Does it really need to be verified that accurately?

The choice is yours, however, there are a number of situations that are very difficult and time-consuming to diagnose should you only do some land-based verification measurements. If undiscovered, there may be areas of several dBs down in signal strength. Use the ARMS and a couple hours later (not days or weeks) and you know the performance of the antenna without any doubt. Even better, schedule the airborne verification while you still have rigging teams on-site, so that if issues are discovered, they can be rectified pretty quickly, saving a ton load of money. Ideally, do an airborne verification of your current antenna before you swap it out. That way you can confidently compare the before and after performance. Very useful when you need to shift frequencies but keep the same coverage envelope.

What protocols can you measure?

We're only limited by the range of the spectrum analyzer and receive antenna systems. Otherwise we are able to measure anything from 500kHz to 6GHz (higher in the future).