One of the most common issues at any flying field has been Frequency control and we know that all AMA sanctioned fields are required to have some type of frequency control system in place. Even with these control systems in place you are never 100% sure that no one is on your channel. This is where the new 72Mhz Frequency Checker from Hobbico comes in.

The Hobbico frequency checker is inexpensive, street price of $49.99 and very simple to use. All you have to do is take it out of the box, add 3 AAA batteries and turn it on. As it scans through each of the channels you will see the individual LED's light up. If it finds the channel active it will leave the LED light on as it continues to scan the rest of the channels. It takes the checker about 15 seconds to scan all the channels before cycling through them again.

The checker has a scanning range of 300 feet but you can increase its range to 1000 feet by buying the additional external antenna ($8.99). It is also small and light that you could carry it around in your shirt pocket.

Field Test

Now this sounds good but how well will this actual work out at the field. I received the checker the day before a competition that my club was hosting so I figured that this would be a great time to try it out. Since we were going to have someone controlling the transmitter impound and frequency board, I though the checker would be a good double check to make sure no stray transmitters were being turned on.

I started out using the checker without the external antenna to see how well it would work and it actual worked pretty well. I could watch as the competitors checked out their transmitters and see on the checker when they turned them on and off. I didn't get any stray channels showing up during this time so I was pretty impressed with it's performance.

Next I plugged in the external antenna and turned the checker back on. During the first cycle the checker showed that channel 34 was active. This was a bit of a surprise since all the transmitters where impounded and turned off. So I figured that we were picking up a stray signal on that channel but when it cycled through again it showed 34 off and now 35 on, then it showed 35 off and 36 on. It cycled through this pattern a couple of times before clearing. It would do this for about a minute, then disappear for awhile and then start up again. This pattern stopped once I removed the antenna but would reappear as soon as I re-attached the antenna. Now I had no real way of knowing if there was anything on these channels or if it was some glitch with the checker and the antenna. It would have been nice to have had a second checker with me to see if both were doing the same thing at the time. No one was flying on these channels which was probably a good thing but if there was I could have used their receiver to see if they were getting any glitches with their plane.

After getting home from the competition I tried the checker and had the same issue with the external antenna. I live over 20 miles from our flying field so I shouldn't be seeing the same behavior as I did at the field if it was caused by some type of stray signals.

I've used the checker a few more times at our field and at a few other locations and had similar results with the external antenna. I don't know if these are stray signals or a glitch but from reading Hobbico's Tech Notice it seems possible that this is more of a glitch with the system then it is from picking up a signal.

Conclusion

Overall I really like the Hobbico frequency checker since it’s inexpensive and it’s small size makes it easy to keep in my flight box or carry it in a shirt pocket. This is a great help to have at a competition as another way to monitor the frequencies that should be in use.

If you should run into the same problem that I had with the first unit just contact Hobbico for a replacement one. They were very helpful when I contacted them about the problem.

This frequency checker is well worth it's $49.99 price tag and nice addition to one's field box.