Interference concerns due to Silvus Technology doing RF testing East of Woodley.

Jason asked me to look possible interference happening at our field recently. 

I had a long technical conversation with David Brown, one of the engineers involved with doing testing of an audio video networking system near our Apollo 11 field  (East across Woodley.) 

I also visited their location to observe a test in progress. I had just left our field before the testing started and visited it after. There were no reports of loss of control by those flying today. (Tuesday 7/23/19)

The frequencies used for testing are in the 2200 and 4400 MHz range (2.2 & 4.4 GHz).

The transceivers used are hand held type FCC type accepted and licensed. The antennas are Omni Directional (360deg) whip type, not highly directional Their frequencies and low power levels are far away from what should cause any interference to our 2.4 Ghz systems.

Typically SPECTRUM......2.400 to 2.425:  FUTABA..........2.426 TO 2.450  Is used.

They do have a 4.4 ghz link system transmitter but it’s almost 2 times higher than 2.4ghz and is pointed south east. One would have to fly over/East of Woodley to be in its path. Something we don’t usually or should not do!

Their testing was concluded Wednesday, 7/24/19 at 12 noon and should anymore unexplained crashes occur, we’ll have to look elsewhere. 

It’s still possible their presence could be a catalyst (mix) of many frequencies present at our location, but not a direct interfering transmission. Mix related frequencies require a mix of many that result in new ones not actually being transmitted.

This catalyst could come from a overhead passing aircraft transmitting something in our band or other, or some link frequency traveling across the valley and our field.  

Safety wise it’s a good reminder that like in the past with 27, 72, 53 & 54mhz, (6meter band), 2.4 ghz may at some point become unreliable due to over population of the frequencies.

A good reason to be aware of a possible link failures and failsafe conditions at any time,

 David has agreed to notify me (for the club) if any future tests are conducted. He also fly’s drones and is a paid member of our club. He’s very aware of safety.

Glen Roe 

Chairman of the Board of the valley flyers foundation.

Volunteer tech/electrical RF advisor for the Valley Flyers

Letter of Agreement with Van Nuys Air traffic Control & Valley Flyers to keep Apollo Field open