Intro:

History: 

• 02dec15: dana and i looked for this rfi from the 12meter site.
• Strongest rfi peaked up when pointing in the general direction of the  HQ/radioRedentor towers.
  
• 13jan16: azimuth swings showed lots of rfi below 5150 MHz. It also showed the azimuth direction where this rfi was strongest (in the cband receiver).
• 18jan16: dana and i went back to the 12meter site. We again saw the rfi below 5150 peaking up in the HQ/radioRedentor tower direction. This time the direction was the same to within a few degrees of the tower (from google maps).
• 19jan16: dana and i went out to the HQ/radioRedentor towers
  

The road trip

• We tried the rest stop on route 10, but it is now blocked off with a cement divider.
• First stop was the intersection of 6612 and routine 10
•  coordinates:   18.31576, 66.68288
• This is west,northWest of the towers.
  
• We looked at hq,radio redentor towers at cband and 2380 MHz..
• 2nd stop was across from colmado torres up R611 on the way to the HQ tower
• coordinates:     18.28576, 66.68934
• We looked out at yiyi's tower, and the tower to the east of yiyi's tower using 5100 and 2380
• The final stop was at the base of the HQ/radio Redentor towers:
• coord: HQ: 18.2887, 66.6606, radio redentor: 18.289535, 66.660439

Radio Redentor Emissions:

• Top Plot: pointing at the RadioRedentor tower from the first stop (intersection R10 and R6612).
• Black is a 5 sweep avg, red is a peak hold. the RBW was 1MHz.
• The dashed green line is the lower edge of the U-NII band.
• The internet channels are usually 20MHz wide.
• The signal was maximized when we pointed at the HQ/radioRedentor tower direction.
• Bottom plot. This was standing between the HQ and Radio Redentor towers.
• The rbw was 3MHz.
• the signal was about 15 db stronger when we pointed at the RadioRedentor Tower (compared to pointing at the HQ tower).
• We also went under the RadioRedentor tower (to shield us from the radio Redentor tower) and pointed back at the HQ tower. The signal was about 20db lower than when pointing at the Radio Redentor tower.
• Why are the relative signal strengths so different  between the two plots?
• Talking with some of the ksXpress workers we met at the towers:
• different frequencies are used to cover different sectors. This directional dependence is probably what caused the large relative power differences.

• We explained the rfi problem we were having with emissions below 5150 MHz. They volunteered to turn off their 5 GHz xmiters for a test.
  
• While monitoring the RadioRedentor tower from below it, they turned off their 5 GHz xmiters.
• I saw no change in the 5 GHz rfi coming from the tower.. so it looks like it wasn't them.
• They told me that other Internet providers using the tower were:
  
• dm wireless
• 4net

    We need to coordinate turning off the 4net and dmWireless 5 GHz xmiters while monitoring the tower to see if it is them..

It is interesting to note that we've had trouble with ViVinet (old name for KSXpressnet) and 4net before..

• on 04jun13 during a road trip to yiyi avila's tower, these two companies were found to be broadcasting illegally below 5150 MHz.

5 GHz rfi coming from yiyi avila's tower

• From the 12meter site we didn't see any.
• From our first stop on the road trip, yiyi's tower was blocked by mountains
• On the 2nd stop of the road trip (colmado torres)  we were able to get a clear look at yiyi's tower.

• The rbw was 1MHz.
• the clouds lifted before this data was taken and we could clearly see yiyi's tower.
• The rfi peaked up when pointed at yiyi's tower. It was weaker when we pointed at the tower to the east of yiyi.
• While talking to the workers from KSXpressnet, they mentioned the 4net also had internet service being broadcast from yiyi's tower.
• Looking back at the 04jun13 trip to yiyi's tower, 4net was broadcasting around 5100 or 5110 MHz back then..
  

Summary:

• strong rfi below 5150 MHz is coming from the radio Redentor tower.
• When ksXpressnet turned off their 5 GHz xmiters (on the radio redentor tower) , i didn't see any of the strong rfi go away
• If their emissions  were overlapping with someone else, i might not have noticed the change.
• DMwireless and 4net are also using the radio redentor tower to provide wireless internet services.
• We have had trouble with 4net in the past (04jun13 on yiyi's tower).
• When looking at yiyi's tower, there is rfi at 5110 to 5130 coming from his tower.
  
• i was told that 4net is also broadcasting from yiyi avila's tower.

Todo:

• Coordinate with radio Redentor tower engineer to turn off 4net and then dm wireless 5 ghz  radios.
• I'm not sure if we should be at radio redentor tower or not when this is done. if we rely on the cband receiver, we might miss some rfi because of the azimuth dependence.
• using the 12meter site is probably not optimal since many of the birdies we saw at the tower, were not seen at the 12meter site.
  
• The azimuth spins also showed some weaker rfi with different azimuth dependence.
  
• This may be the reply signal from house back to the tower.
• We need to make sure that not only does the tower not transmit below, 5150 MHz, but they should not request the home users to reply at frequencies below 5150.
• After radio redentor is cleaned up, we should look again at yiyi's tower for emissions below 5 Ghz,.