- We needed to test how bad the harmonic output level was when
we input 2 tones directly into the broadband amplifier. We had
previously measured the harmonics when sending 2 tones through
dana's phase shifter and then into the tx. This had very high
harmonics since the two tones were both applied to the lo input
of a mixer.
What we did:
- The mesh was in the 5 MHz position
- we transmitted at 5.125 MHz rcp.
- no 430 tx,
- interim correlator recorded gr 430 receiver to check for
- 11:54 50 kw each tx
- 12:00 up to 450 KW. left running to check for stability
- 12:24 stopped so christiano could give a platform tour !!!!
- 13:20 started 2 tone test.
- 13:26 -7 -7 siggen drive,
- 13:25 off
- 13:29 -4,-4 siggen drive (into combiner,filter)
- 13:31 off
- 13:32 -3,-3 siggen drive
- 13:34 off
- 13:35 -2,-2 siggen drive
- 13:37 off
- 13:39 operator error, skip
- 13:42 -1,-1 dbm siggen drive
- 13:45:30 tried 0,0 dbm.. but tx tripped.
- 14:04 airline trip
- 14:12 bring up . lots of arcing
- toggled a few broad bands off, on to stop arcing.. mainly tx
- 14:14 75KW each tx..
- 14:18 arcing tx 6 off,on stopped arcing
- 14:20 arcing tx 1 off,on stopped arcing
- 14:23 arcing. tx 4 off on stopped
- 14:30 done
HF output power
Plots showing hf tx drive and
output power (.ps) (.pdf)
- page 1:
- Top: hf rf coupler output vs hour of day
- Each color is a different tx.
- middle: output power in KW
- bottom: synth drive amplitude (in dbf)
- page 2: hf drive power vs hf output power
- the output power (in KW) vs input drive power (in dbf) is
plotted for each tx.
- values that lie below the trend, occur when an rf off occurs
during a spectrum analyzer power average.
dbf Drive for 50 KW output.. 5MHz
Generator power vs
The data from the 3 running generators was
used to measure how much generator power was needed to drive the 6
Generator output power vs hf
output power (.ps) (.pdf)
- Top: generator output power vs time.
- middle: total rf output from 6 hf tx
- bottom: gen power vs hftx output power
2 tone test
We tested the harmonics generated on output
when we input 2 tones directly into the broad band input
The setup was:
- siggen 1: 5.115 Mhz
- siggen 2: 5.125 Mhz (delta= 10Khz)
- we varied the output amplitude of the the two siggens.
- siggen1,siggen2 combined in a splitter -> 5 Mhz
filter -> tx 3 cable to broadband
- We measured the loss through the combiner, filter.
- 4.2 db loss.. so -5 dbm out of each siggen gave -9.2
dbm for each tone on the spectrum analyzer (before
begin sent to the broad band)
The observing cycle was:
- -7 dbm each siggen output
- -4 dbm each siggen output
- -3 dbm each siggen output
- -2 dbm each siggen output
- -1 dbm each siggen output
- 0 dbm each siggen output .. but tx 3 tripped (probably
exceeded the power level)
Plots showing the harmonic levels
from the 2 tone input. measured at the rf coupler (tx output)
- Page 1: rf coupler output in dbm
- Each frame is a different 2 tone drive level (the levels are
for a single tone)
- Each color is a different Tx. Green tx3 had the 2 tones. All
the tx coupled from the dipoles back into the rf couplers.
- The dashed horizontal lines are spaced every 10 db.
- The tones are at 5.115 and 5.125 Mhz.
- for the stronger drive levels 3*f0 - 2*f1 is stronger than
- Page 2: tx output power in KW (linear scale)
- Only tx3 tone power is visible. All the harmonics are less
that 1 KW.
- Page 3: The harmonic levels for each tone output power
- each frame overplots the harmonics from all 6 tx.
- You can see the harmonics from tx3 and the coupling levels
into the other dipoles.
- In general tx4 (dipole 90 from tx3 on the same tower) has
the lowest coupling.
- Page 4: single tone output power vs broadband single tone
- The dashed horizontal lines are spaced every 5KW.
- The max value was 47 Kw for 1 tone
- This was for -1 dbm drive at siggen.
- 2*47 = 94KW total tx output
- When 0dbm siggen drive was tried, it tripped tx3. The
output was over 100KW.
- For the last few db drive increase, the output power is not
increasing as fast as the input..while the harmonics increase.
- For the highest single tone output level (47.6 KW) the
harmonics were 20 db down
- For 46 KW single tone output, the harmonics are down 25 db.
processing: x101/190509/hftest.pro, hf_190509.pro
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