K5CM FMT May 9, 2012 (9 PM CDT)
K5CM 20 - 14054689.000
W60QI 20 - 14056223.332
It seems Marvin's 20 meter FMT transmitter is working great. He had a very good signal in Oklahoma and his signal was measured with good accuracy by most.
Several capitalized on the K5CM reference signal. W3JW, K6IQL, N7EP, and WB6BNQ all had zero error with AA6LK, VE2IQ, and W8XN having 5 millihertz or less error. It would seem, at least for these stations, that the Doppler was stable over at least 200 Hz of frequency difference. We will do more testing to see if these and other stations can duplicate these interesting results.
Thanks to WB6BNQ, AB4RS, and KA1BQP for providing complete wave files and to WA1ABI for providing call up snips.
Thanks to all that participated.
|AA6LK||SV||CM98kw||I'll be lucky to get close this time, as I discovered after the test that my Z3801A had been in holdover mode for several hours and unable to acquire satellites. Used my error from the "reference" frequency to correct my entries. To add insult to injury, the PG&E pole tranformer that feeds my house began its yearly 3-week ritual of generating S9 hash when the outside temps are in the mid 80's. W6OQI was very weak but managed to pick him out during a brief lull in the din.|
|AB4RS||VA||FM18hw||Forgot to let my radio warm up and stabilize, so the AF slewed over about 1 Hz over the course of the test. Kind of makes it hard to do long, deep FFTs. Delta reference method, using HP 3336C locked to 10MHz reference from Trimble Thunderbolt. Tuned to AF using Yaesu FT-897d, analyzed using SpectrumLab. Don't have particularly high expectations for my accuracy on this one.|
|K5CM||OK||EM25ir||Great signal Marvin. You were pounding in at s9+10|
|K6BZZ||AZ||DM33xb||Good sigs from K5CM both directions. W6OQI sig very weak east and barely perceptible NW. I will be better prepared next time for a two tone test, if you do that again. Thanks for the FMT.|
|K6IQL||KS||EM28nq||Good fun as always. Signals very weak into KS and had trouble finding K5CM at first, but the 200 Hz spaced CW signals showed up on SL and identified the test signal for me.Lots of doppler (+/- 1 Hz) and phase shift on K5CM and less so on W6OQI. Usual setup- audio beat method, SL for frequency measurement, RB clocking home brew DDS synthesizer, 75A4 rcvr. Phase sorting. Thanks again for a fun evening - 73 john k6iql|
|K6OQK||LAX||DM04ud||Connie's westbound 20-Meter signal was very stable. Over the period of the westbound test including callup and keydown the signal only varied about 10 degrees in phase shift (referenced against my GPS) as seen on the 1:1 Lissajou display. This either means that the Doppler was really steady in direction for that period and I'm way off, or I'm lucky. Marv's signal was also very stable, but then we're only about 7 miles apart. Burt, K6OQK|
|KA1BQP||RI||FN41||Signals were good, although I almost lost Marvin when he pointed northwest. I picked the reference signal up on the wrong sideband. I had to do some fancy math to figure the correction factor. Measure with a micrometer, mark with chalk, cut with axe! Tnx Connie & Marvin for another great FMT.|
|KG0HY||NE||EN20||Signals from K5CM were bad, but from W6OQI were just right. Still use a WinRadio G313 HF receiver. I used IF filters down to 50Hz. Calibrated receiver to CHU and WWV. Antennas used were HF vertical and HF yagi. DE KG0HY, Casey|
|KX0O||MO||EM38ci||Interesting format thanks again for the fun. Very unusual behavior with W6OQI tonight... two distinct peaks nearly 1 Hz apart. the upper peak seemed to be cleaner and more stable so I threw out my initial reading almost exactly 1 Hz Lower. I suspect the ionosphere was playing a trick on me or there was 1 Hz spur in his signal. Will be interesting to see.. either I am really close or really far away. I have never seen two distinct peaks with such separation. Will learn something, no doubt, as always. Thanks again, Doc|
|N2GL||OR||cn85kp||Took average WWV reference readings before and after but finally used GPS 10 MHz as a reference. 80m dipole to GPS SLM to SpecLab.|
|N4AU||AL||EM62vp||Thanks guys for the practice. K5CM signals about the same level here and 26 mHz difference in calculations. W6OQI was very strong (S9+) with East signal but weak on NW signal. I had a difference in calculations on them of 57 mHz. Here using a KW TS570 with Speclab and spreadsheet.|
|N5DM||STX||EL29fs||20m signals from OK to STX nearly impossible. Not sure what was wanted on this FMT but...Lower f : 14054501.950 Hz Upper f : 14054691.000 Hz Difference f : 189.050 Hz|
|N7EP||WWA||CN87uk||Interesting FMT with the usual 1-2 of Hz Doppler into Seattle. The Doppler from W6OQI was the worst. I hope I figured out K5CM's dual transmissions. I finally got both spectragraphs to look about the same. Thanks for all your efforts. Earl, N7EP|
|N8OB||OH||EN80ko||Fun as usual and not on my Ham Radio Club meeting night. TS-2000 and Spectrum Lab software.|
|NO5K||STX||EM10CM||Nice test between the storms here. Now raining cats and mice. Interesting short burst on 14054688.072 early in W6OQI's transmission. Measured K5CM Ref Carrier: 14054499.969E and 14054499.977W. Good signals, the antennas was connected for this test.|
|VE2IQ||ON||FN15nt||Thought K5CM's east run was easy - then I looked at his west run, now I'm not sure anything is easy. W6OQI measured about same for east, west but I suspected a large negative doppler so added 400 milliHertz out of the blue.|
|VE3OAT||ON||FN25eg||Was able to hear all four transmissions. The signal in the NW beam from W6OQI appeared 500 mHz higher than his E beam. For K5CM the W beam signal was only 300 mHz higher than the E beam.|
|W3GXT||MDC||FM19||Big SID's during the day upset the band. W5CM signal was fine. W6OQI was a no-show,I did not see any signal at all. Thanks for holding the event.|
|W3JW||VA||FM17TN||Gud strong signals from both stations with beams east. Very useable sigs with beams W and NW respectively. East-to-West shift on Connies signal was minimal (in the order of a millihertz). However on Marvin's signal, with the antenna direction change I saw a shift (up) in the order of 175 millihertz. In the case of Marvin's signal, I was using the typical single signal narrow span setup for Spectrum Lab. For Connie's two signal transmission I widened the spectrum lab window to encompass both signals and worked with the difference only (if I had been measuring Connie's signal with the "single signal" spectrum lab setup, I suspect I would have seen considerable shift in the signal during the period of the test.|
|W4UK||SC||EM93an||I observed K5CM "reference" as 0.193 high, so subtracted this amount (presumed Doppler error) from the "unknown" signal to come up with my reported value. This is my first time using Spec Lab (FLDIGI previously). Hope I am using it correctly. Thanks again for the fun tests. Jerry W4UK|
|W5PDB||OK||EM06vp||From Flex 1500 / HP 3330B reference. No correction for Flex DDS error. The DDS design is unknown to me. -- Thanks for the test! 73 Paul|
|W6OQI||LAX||DM04vf||It was fun to have a 20 meter FMT. I noticed Doppler on K5CM but slower moving than on 80 and 40 meter FMTs in the past.|
|W7FU||WWA||CN87xo||A new comer to FMT. Want to get into the game, so reduced the moving parts and used locally generated reference signals. GPSDO: SDR, synthesizer, and a swept AF SA on 'max hold' function. Thanks to the Connie and Charles for staging tonight's wonderful exercise. And thanks to Earl, N7EP, for all his mentoring.|
|W8XN||MI||EN82DG||Great idea for an FMT, many thanks!|
|WA1ABI||RI||FN41jp||Good signals from both stations. Thanks Connie and Marvin.|
|WA2DVU||SNJ||FM29ob||Good sigs - 20/9 no doppler for a change!|
|WA6VPL||SB||CM94sq||Submitted entry was made using K5CM ref tx on 14054500. Also, measured his ref tx with my own ref and obtained 14054499.380, 0.620 Hz low. Measured unknown with my own ref and obtained 14054689.129, again 0.620 Hz low. Oddly the two differences match. Is this Doppler effect or is my calibration off? W6OQI was very rough copy at this location. Using Spectrum Lab software to analyze the data.|
|WB6BNQ||SDG||DM12||Grey-line issues and very weak signal on W6OQI|
K5CM 20 Meters (9:00 CDT)
|Call||Section||Grid||TX Frequency||Measured Freq||Error in Hz||Error in PPX|
W6OQI 20 Meters (9:20 PM CDT)
|Call||Section||Grid||TX Frequency||Measured Freq||Error in Hz||Error in PPX|
*Ground wave / Direct, range of W6OQI
K5CM audio snip by WA1ABI
W6OQI audio snip by WA1ABI
W6OQI audio snip by K5CM
Example of how to measure the difference between two signals with Spectrum Lab.
Although this technique works fine, It is best to average the entire period using SL to write the difference to a file every second or more. Using the averaging, the reading was dead on.
Transmitting equipment used by K5CM for this FMT:
A HP Z3801 GPS frequency source clocks a HP-3336B and a PTS-250. The outputs are combined and feed to a 10 db transistor amp which drives a 12BY7 / pair 6146. Then to the final amplifier, a Dentron 2500 running 300 watts out. There are no mixers or any device in the chain of amplifiers that might impact the accuracy of the GPS frequency source. As a reality check, I periodically log the frequency source against WWV and other GPS referenced sources. I monitor each transmission with a completely separate receive system to look for any instability or short term drift.
I typically see considerably less than 1 mHz difference at 10 Mhz when comparing two Z3801's or a Z3801 and a Thunderbolt, over a 10 to 10,000 second period.
160 - Vertical
80 - New Sloping dipole. Sloping down from 140'. (favors West, North, East)
40 - Standard Dipole hanging between two 80 foot towers. (favors East, West)
20 - 4el SteppIR at 70'
Current W6OQI FMT transmitting equipment for this FMT:
My Transmitting setup consists of a HP Z3801 clocking a HP 3336B which drives a Johnson Viking I transmitter, the output of which is attenuated by a 6 db attenuator, to then drive an Icom PW-1 amplifier to about 500 watts. The antenna is an inverted Vee which favors north and south from the Los Angeles area.
Note: Because I put the results up quickly, there will be mistakes, so don't hesitate to point them out quickly.
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