Hilltop rfi monitoring system

oct 2002

The current daily plots are:

Daily plots encompassing the previous day. There are 4 sets of the plots:

The average plots are just the average over the day for each frequency bin.

plots are just the average over the day for each frequency bin.

The image plots are frequency vs time for each band.



are frequency vs time for each band.

One plot has no bandpass correction







The 2nd set has the minimum channel over the day used to flatten the baseline. This distorts the true bandpass for channels that always have interference but is it good for removing the standing waves in the cables for the higher frequencies.



rms/mean.



For each channel of each band, the rms is computed for the entire day and then divided by the mean value. This is a sensitive indicator of interference (except for rock stable tones).



.pdf plots are created (2 plots per file) which give the best resolution and can be blownup.

plots are created (2 plots per file) which give the best resolution and can be blownup.

.gif plots are also provided for users that prefer them (although they are much lower resolution).

images by frequency for last 8 days:

The 0 to 10Ghz data is split into two files



Low freq (0 to 1450 Mhz)



High freq (1600 to 10000 Mhz)

Each page holds the 8 dynamic spectra for a single frequency (coming from the last 8 days).

There is one set with no bandpass correction and a second with the bandpass correction.

The image stretch (0 to 255) is done on the logarithmic data.



the date is printed on the upper left of each dynamic spectra as yymmdd.

The freq is plotted as the x axis in Mhz

Not much rfi is seen above 6500 Mhz

the gain in front of the spectrum analyzer is not sufficient to overcome the spectrum analyzer noise.







Notes on the images:



3200-3240. This rfi has the same time dependence as the aerostat radar.

This rfi has the same time dependence as the aerostat radar. 30nov10.





3200-1260 = 1940 .. so the aerostat may be mixing with the cell phone rfi.



This is probably in our system...

6500 noise step.

The spectrum analyzer uses different bands.



The spectrum analyzer uses different bands.

There is a band edge at 6500 Mhz. The higher band looks like it has a higher noise temp.

1400 Mhz band standing wave :

: period is 8.02 Mhz



This is a standing wave distance of 18.7 meters (61.3feet) in free space.49 feet if index of refraction=.8.



It may be the cable from the antenna to the box. The bpc version removes this.

4000-6500 Mhz extra noise during day (08:00 to 18:00)



30nov10



more easily seen in bpc version.



above 6500 it probably disappears because Tsys of the spectrum analyze goes up.



I wonder it this is a heating problem?



if so why does it start at 4000? The system uses the same components 2000 -> 10000.

2300-2650 monitoring the ism band

The plots are updated 4am each morning for the previous day/month.



Each file contains one month worth of data

Each page shows one day's worth of data

The spectra are taken about every 20 minutes. They are plotted on a db scale with an offset for display purposes.



The bottom trace is the first plot of the day (usually midnite start of the day).



The top trace of the day is usually midnite (end of the day .. unless the hilltop monitor system has trouble during the day).



Vertical dashed lines have been drawn at 2380 and 2400 Mhz (for reference).

The data read from the hilltop monitoring at sband has an offset of 3.6 Mhz.



This was determined by looking at the center of the 2380 xmter signal.



If you look at this data with imgui, the interference will be 3.6 Mhz higher than these plots..

licensee's below 2380 Mhz (aug17)

call

company

freqRange

wqy2338

att

2305-2310

2350-2355

wqy2339 att 2310-2315

2355-2360

wqy2340 att 2315-2320

wqy2341 att 2345-2350





att : [2305-2320],[2345-2360]



Monthly plots of ism band from hilltop monitoring system:







Notes 2020:

200301: hilltop monitor fails.. no more plots ...





Notes 2017:

170503: 2370 rfi appears.. continues through at least aug17

did geographic fcc license search 15aug17 within 200 km of ao, no one is licensed for 2370 band.



continues till 20sep19.. off the air from maria.





as of 18nov17 still not back on the air.



Notes 2015:



150101: ism below 2400 Mhz

150301: below 2400 Mhz jumped up to 2425

150318: 2425 moved back down to straddle below 2400. occurred during 430 xmter run

150810: jumped from below 2400 to have lower edge exactly on 2400 Mhz.

151229: 2370 rfi appears. looks like it moved up from 2345





Notes 2011:



dual band rfi 2360-2340 seen when our 430 Mhz radar is active.



jan: 110112: 2380 Mhz rfi appears (micro wave link from radio rendentor tower).



feb: radio rendentor tower turns off misbehaving micro wave link 22feb11. 2380 Mhz rfi goes away.

mar: 24-28mar Ao430rdr.

may:Ao430rdr on:05,19,26,

jun: weaker rfi 2380



jul: Ao430rdr :07-09,12,14,16,21,27-31

aug:

Ao430rdr: 01-11,19-20,25-30.



2408 band shifts down by 10 Mhz for 20 minutes on 31aug



sep:

Ao430rdr 15-16

oct:

05: 2390 band appears for about 3 hours. appears when 2530 band goes off.



Found licences for 2525-2530 and 2535-2540 (ana G Mendez tv broadcast) but no one at 2532.





08-12: 2408 band shifts down by 10 Mhz.



processing: x101/111012/ismrfi_hilltop.pro

Monitoring the 1325 band by month

the data from 1200 to 1410 Mhz is used (this contains most radars)

two dynamic spectra of all of the 1 minute peak holds during the month for this band is made



the vertical is day of month.



The imgall spectra flags all of the radars



the imgPS image flags the punta salinas frequency channels



the avgSpc: is an average spectra for the month.



top flags all radars





bottom flags punta salinas radars.



monthly dynamic spectra,.average spectra from hilltop monitor 1325 Mhz band

year

jan

feb

mar

apr

may

jun

jul

aug

sep

oct

nov

dec

2020 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2019 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2018 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2017 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2016 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2015 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc 2014 imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc imgAll imgPS avgspc

processing: x101/rfi/hilltop/mk1325month.pro

Pictures of system

History



080520: unused kl2500 control board 11 switched for bad board 11. System back online.



080506: kl2500 switch controller board 11 error.. system brought down to lab

121017: lightning

blows up 20mhz to 1ghz amp at output (between sw10 and sw11)



High freq amp at antenna not working.

121024:



high frequency data not being taken. (antenna amp in the lab).



Low freq data is being taken



FO amp 1 is not longer in. using straight thru. Gain has decreases for all but first 3 bands





Changed attenuation settting





Before if followed the ref level setting.







Now it can be specifed 0,10,20.. or -1 to follow the ref level setting (which usually left it at 10db)







edited setuplf.dat so used attn 0db for all low freq bands except first.

121105:

high freq data started again (should have started it on 01nov12 but i didn't update the setup.dat file)



Now using attn db=0 for all high freq (except the first band 1600 to 3000 (to block sband xmiter).

130917: mv147 board used to acquire the data died. installed an mv167 board.

new board had 32 mhz cpu.. eprom was setup for 25 Mhz.. so was running 32/25Mhz faster in waiting for spectra.



131026: temp fix timing problem. Just changed ticks/sec in integration wait..



140303: fiber optic amp port 4 switch 10 died on 25feb14



This was the straight thru mode position (switch 10,11 port 4).





It was being used by the low freq bands (since 2- 1ghz amp is not in)



Moved straight thru to sw10,11 port 3.a



also made port 1 straight thru (the amp is not in).



edited:



rfiRcvLib.h-RFIRCV_FOAMPID_BYPASS now index 2.. which is port 3







rfiRcvDat.h - rfiRcvFOAmpTbl. index 2 swpos 3, changed cfr,bandwidth to straight thru





/share/rfidata/data/setups.h - explicitly set foamp to 3 for < 1ghz if's

140912 - took 167 out.. used for pnt cpu. installed 25 Mhz167 board.



the eeproms were set to 32Mhz cpu and this was a 25 Mhz cpu. I ran cpuspeed() to correct this, but i forgot to reboot the computer (it sets the ticks/sec at boot time). So we ran until 07oct14 with longer integrations (80 secs) rather than 60.

141007: rebooted rfi crate so correct cpuspeed in use. not integrating for 60 secs.

141114 (8am) -> 141117 (8am) the spectrum analyzer was not changing the setup.

deleted the 1411 14->16 files.

150824 - vme rfi crate power supply fails.. no data till 31aug15

150831 - intfMon program now run on linux.

150902 : ac unit in rfi shack replace.. it had been blowing warm air for awhile

looking at the 1325Mhz rfi plots.. june looked ok, july starts to show a gain change during the day, and aug has it more pronounced.. so the ac probably started failing in jul15.

191122 : 620-830 filter. moved sw4,7 swnum 2 to sw4,7 swnum 4 (swnum2 wasn't working).



schematics

Schematic of electronics inside huffman box (amps, filters, switches) (.pdf)



notes on schematic

191122 - 620-830 Mhz filter. was sw4,7 position 2 move to position 4. this band hasn't worked since jan18.



change in aosoft/include/rfiRcvDat.h then recompile aosoft/src/vwconvert/libsrc/rfircv/ and intfMon.c



antenna input: sw 1



sw1-pos 1 - low freq input





sw1-pos 2 - noise diode high





sw1- pos ? - noise diode low (has attenuator inline with diodej







sw1-pos5 - outside of box a5 (ant 5) has high freq attached.







i think the a5 goes directly to the a-5 outside box is high freq cable. I think it goes directly to the 1-10ghz amp.



sw10,11 switch between amps. These are referred to as the fiber optic amps.



sw11 shows 4 positions. This switch has at least 5 positions (since the high freq single connects to pos 5).



diagram of high frequency mast (.pdf)



System modification history for the 1 - 10 Ghz receiver:

Notes:

Noise floor 2.2 Ghz is the daily average connector to the full receiver.

The cable is 50 feet of low loss heliax. 3.2 db loss at 2 Ghz to 8db at 10Ghz.

Since apr02 there have been harmonics of the 1950 cellular phone band. At 3900 Mhz the level was -25 dbm in oct, -33 dbm in june, and not there before 29apr02 (with a noise floor of -58 dbm).

Log of changes to high freq receiver date ampA ampB ampC R1

db R2

db Noise

Floor

2.2Ghz Noise

Flr

3.5Ghz Notes 04nov12















hi freq system was off 20oct12-04nov12. ant,ampa brought down to lab after lightning strike.Found broken cable inside box with amp A. replaced cable, installed.

Started running high freq with 10db attn out for all freq above 2200. Doesn't make a difference in the noise floor. Should think about putting it back in

17jan08















system reinstalled on hilltop. monitoring restarted.

15may07















spectrum analyzer brought down for maintenance during painting shutdown.

10jan06













New ac in rfi shack. Old one was failing. 19sep05 replaces replaced

replaced





noise floor looks ok, but signals absent. 26aug05 blew blew

blew





general power outage,lightning 29oct02 Found that 50 ft cable connector at box had come

loose (the shield). Tightened it up. 23oct02 g=25db g=25db 0 3 0 -58 -60 didn't change by 20 db.. 22oct02 g=25db g=dbdb g=30db 3 10 -44 -45 added swept elbows box to specAnalyzer

added R1

replaced short cable R1 to input of box. 9sep02 g=25db

1.7Nf g=25db

1.7Nf g=30db

2.8Nf 0 10 -41 -42 back on the air, system saturates

with 1.9Ghz birdie 22aug02

amps blown, off the air 01aug02 0 -50 -42 16may02 0 -50 -48 back on the air, not sure which amps were installed 29apr02 0 -58 -57 blew out 30apr02 25feb02 0 -55 -57 24sep01 0 -55 -56

Noise floor:

We then measured the noise floor with the high frequency antenna, ampA, and the 50 foot cable plugged into the spectrum analyzer (the 10db pad was always in) to see how much more gain we needed to get above the spectrum analyz noise floor. Finally we plugged in the whole high freq receiver (ampA,cable,3db pad, ampB(25db) and recorded the noise floor. The spectrum analyzer steps bands near 6500 Mhz.

Noise floor measurements 29oct02 freq (Mhz) ref

Level

dbm rbw

Mhz spectrum

analyzer

floor(dbm) antenna

ampA,cable

floor(dbm) antenna

full rcvr

floor(dbm) low freq 100 0 .1 -78

500 0 .1 -76

1000 0 .1 -75

1300 0 .1 -75

1400 -20 .1 -79

hi freq 1000 0 3 -63 -63 -64(800Mhz) 2000 0 3 -62.5 -62 -57 3000 0 3 -62 -62.5 -60 4000 0 3 -63 -61 -61 5000 0 3 -62.5 -62.6 -60 6000 0 3 -62 -62 -61 7000 0 3 -58 -58 -58 8000 0 3 -56 -56.5 -56.2 9000 0 3 -56 -56 -57 10000 0 3 -56 -56 -57

Amp A with the 50 foot cable is not above the spectrum analyzer noise floor.

Amp A, cable, 3db pad, ampB(25db) is above the noise floor at 2ghz but by 3 ghz the noise floor is being set by the spectrum analyzer. We probably could use 10db more but may then have problems with harmonics.





