North Texas W5HN NTMS. Microwave Society W5LUA. Presented at Central States VHF Society Elk Grove Village, Illinois July

Transcription

1 2304 EME by Al Ward W5LUA Presented at Central States VHF Elk Grove Village, Illinois July

2 The Bands Band Frequency Range Weak signal work in NA 33 cm 902 to 928 MHz 902 MHz 23 cm 1240 to 1300 MHz 1296 MHz 13 cm 2300 to 2310 MHz 2304 MHz 2390 to 2450 MHz 9 cm 3300 to 3500 MHz 3456 MHz 6 cm 5650 to 5925 MHz 5760 MHz 3 cm to MHz MHz 1.25cm to MHz MHz and MHz.6 cm to MHz MHz.35 cm to MHz allocation changing Not all countries have same allocation as us.. 2

3 and MHz Most operation between and MHz UK can only operate at 2320 MHz - no allocation at 2304 MHz Japanese operate at 2424 MHz - no allocation at 2304 MHz 2320 MHz is primary terrestrial frequency in Europe VKs can only operate from 2300 to 2302 so MHz was chosen. Other stations then transmit on MHz A little complicated but do-able Crossband operation requires extra receive converters 50+ stations operational 100 over time Minimum Station Requirements 2.4m Dish, 100 watts So..Why go up in frequency? 3

4 Path Loss According to the Radar equation, the path loss increases by 6 db every time the frequency is doubled However dish gain also increases by 6 db every time frequency is doubled Since we gain the same 6dB on both receive and transmit and assuming we use the same power and the same NF as we go up in frequency, our echoes will improve as frequency is increased this is in fact what we see! 4

5 The transition from 1296 to 2304 MHz Noise figures are very comparable most sub 0.4 db. Power levels of 200 watts are easily obtainable at 2304 MHz and can be more easily mounted at the feed offering a bonus on 2304 over 1296 minimal feedline loss. Very efficient i feeds from OK1DFC, RA3AQ and WD5AGO Easier to track the moon because now we are able to see moon noise why is this? VK3UM program to analyze path loss 5

6 VK3UM EME Performance Calculator

7 Bottom Line With similar equipment on 13 cm and the same size dish, the echoes will be nearly 5 db stronger on 2304 MHz than they were on 1296 MHz plus we can now track the moon better because we can now see noticeable moon noise And it gets even better as we go higher in frequency! 7

8 American Stations on 13cm First 2304 EME contact was between W4HHK and W3GKP in 1970 Since then W5LUA, W3IWI/8, VE4MA, W7GBI, KD5RO/2, K9KFR, K5PJR, WB0TEM, NU7Z, WA8WZG, WA6PY, WA9OUU, WA9FWD, VE6TA, K2UYH, NA4N, WD5AGO, WW2R, W9IIX, WA5WCP/1, K5GW, WA5WCP, KL6M, KH7X, WA5WCP/7, K7XQ, WA8RJF, W7BBM About 30 out of nearly 100 worldwide were in NA That number has dwindled dl d over the years We need more NA activity on 13cm! Calls in red are presently active from NA 8

9 WD5AGO 8ft Dish for 2304 MHz 9

10 WA5WCP 10ft Dish for 2304 MHz 10

11 DL4MEA 1296/2304 Dual Band Dish Feed 11

12 VK7MO 3M Dish on 1296 & 2304 MHz 12

13 5 Meter Dish at W5LUA Used for EME on 902 MHz 1296 MHz 2304 MHz 3456 MHz 5760 MHz MHz May use on 222 and 432 MHz Also considered use as a 2.5M offset fed dish for 24 GHz 13

14 Multi-Band Feed System

15 AZ EL Mount for 5 Meter Dish Hydraulics for elevation drive Prop pitch rotor for azimuth drive US Digital Absolute Encoders for readout and K5GW tracking program 15

16 Prop-Pitch Motor for Azimuth 16

17 2.4m Offset Fed Dish at W5LUA I use mine on 24 GHz and 47 GHz RW3BP uses his 2.4M offset fed dish from 47 GHz down to 1296 MHz VE4MA uses his from 47 GHz down to 3400 MHz Dish has potential use on 80 GHz 17

18 AZ-EL for W5LUA 2.4 Meter Dish 18

19 3M (10ft) Diameter Dish 1296 MHz 3dB BW 5.3 degrees 1 db BW 3 degrees First null at +/-9 deg. Gain 30 dbi at 55% efficiency Need to be within a couple of degrees 2304 MHz 3dB BW 3 degrees 1dB BW 1.7 degree First null at +/-5 deg. Gain 35 dbi at 55% efficiency Need to be within a degree Less is always better! 19

20 Azimuth Rotator Options Ham-M and Tailtwister can only get you with 4 to 5 degrees due to the break wedge not good enough Yaesu G-2800DXA or equivalent with friction break is an option Old prop pitch rotor Motor and gearbox Linear actuator 20

21 Knowing Where We Are Pointed Potentiometers used in bridge circuit with a regulated 5V supply pot linearity a big issue 10 turn pots a better solution WW2R has a digital readout board that will work with potentiometers US Digital Absolute Encoders are a very good solution but pricey use a shaft encoder for AZ and an inclinometer for EL connect to pc through the USB or RS-232 port read by programs like K5GWs and F1EHNs resolution as high as.01 degree Less expensive option is US Digital s incremental encoders which can be read by W2DRZ s controller board K1RQG and K2DH use this setup with excellent results 21

22 WA8RJF Digital Level Modified for Elevation Readout Unmodified Modified for remote operation Will read to 0.1 degree 22

23 Moon and Sun Tracking Software F1EHN VK3UM K5GW Nova / Realtrack 23

24 F1EHN Tracking Software with Doppler Calculation l & RX Tuning

25 VK3UM EME Planner and Tracking Software

26 K5GW Tracking Software with Doppler Calculation & RX Tuning

27 The Doppler Effect Doppler effect is the change in frequency of a signal that occurs as a result of the source and the observer moving relative to each other. Since the relative angular velocity of the earth is faster than the orbit of the moon, the doppler is at a maximum at both moon rise and moon set and zero around zenith. Therefore at moon rise the doppler shifted signal will be highest in frequency (positive) gradually decreasing to zero offset from the transmitted frequency at zenith and continuing to decrease to its lowest frequency (negative) at moon set. Slight hook effect at the edges of the earth 27

28 Doppler vs Frequency Doppler does scale with frequency. While doppler may be several hundred Hz at 2M, it is over 3 khz at 1296 MHz and greater than 100 khz at 47 GHz 28

29 F1EHN EME Program at W5LUA Moon rising at W5LUA and near zenith at LX1DB Self Doppler at LX1DB Mutual Doppler Self Doppler at W5LUA 29

30 Faraday Rotation According to Skolnik s Radar handbook.. The Faraday rotation of the plane of polarization can be 2 to 5 revolutions in the UHF range, but since it scales as 1/f 2, is negligible at and above L band L band is defined in Skolnik as 1000 MHz to 2000 MHz and UHF is defined as 300 to 1000 MHz If we scale from 144 to 432 MHz the effect is 1/9 If we scale from 432 to 1296 MHz it is another 1/9 We know that time between signal peaks on 6M can be about 5 minutes, and 15 to 20 minutes on 2M and up to hours or days on 432 MHz so. In terms of what we hear, does this scale the time in between max and min signal strength or the level in db between max and min or both? Most likely it is scaling the amount of rotation of a linear polarized signal and decreases significantly at 902 MHz and higher 30

31 How do we analyze the performance of our systems? By noting the signal to noise ratio of our echoes By measuring sun noise and moon noise and other noise sources By measuring ground to cold sky or 50 Ω to cold sky ground is typically y 290K Where as cold sky may be as high as 3000K at 6M and 300K at 2M, cold sky at 1296 MHz and higher is typically 25K or less We can measure all these values in relative dbs 31

32 RF (MHz) cm Equipment LNA XVTR DEMI DB6NT IF (MHz) FT-100, FT-847, etc FRG-9600, etc DEMI front-end not as broadband as DB6NT, may not cover 2424 as well 32

33 RF (MHz) cm Equipment LNA XVTR DEMI DB6NT IF (MHz) FT-100, FT-847, etc FRG-9600, etc DEMI front-end not as broadband as DB6NT, may not cover 2424 as well RF (MHz) LNA HB 2302/04/20 XVTRs DEMI 2424 System at W5LUA IF (MHz) LO IF (MHz) 144 Flex 5000A IF (MHz) 26 SDR SDR-1000 IF (MHz) 44 Flex 5000A 33

34 LNAs WD5AGO LNA Prefer less than 0.4dB NF and 25+dB gain at feed requires 2 gain stages With isolation relay strive for less than 0.6 db NF at feed Designs by W5LUA, WD5AGO & DB6NT WD5AGO & DB6NT supplies built and tested units Kits by DEMI & G4DDK & DB6NT 34

35 Modified 200 W Spectrian 2304 MHz SSPA by N5AC Another option - G4DDK uses an Ex-Lucent ipam 3G power amplifier at W output 35

36 VA-802B Klystron at W5LUA Tube is capable of running 1 kw output, I run mine at 400 watts output 36

37 EME Net Meets Saturday and Sunday Mornings at 9AM Central time on MHz NET Control is K1RQG Also available via the internet courtesy of K0TAR Weekly NET notes also available from K1RQG by ing Joe at Also informal activity during the week on MHz starting at 9AM Central 37

38 432 MHz and Above EME Newsletter Edited and distributed monthly by Al Katz, K2UYH since 1972 send reports to Available from Rein W6/PA0ZN now W6SZ via the internet at Available from Warren Butler in.pdf format 38

39 International EME Conference The EME conference is held every 2 years. The location is generally in Europe or America with one event hosted in Brazil. The conference is an excellent event for meeting the folks that we work via the moon plus the technical forums are a great way to learn more about our exciting part of the hobby. The 2008 Int l EME Conference was held in Florence, Italy The 2010 Int l EME Conference will be held in Dallas, in August about a year from now. 39

40 Coordination of Activity Band by band activity weekends and many contests during the year best to stay tuned in to the newsletter, net notes, reflectors and the 20M net. Bands like 1296 MHz have considerable activity each month. Improved random activity on 2304 and more recently 3400 MHz. Best to coordinate other bands with individual operators known to be active 40

41 When is the Best MW EME Activity? Perigee when the moon is closest to the earth High declination best for northern hemisphere activity most hours of moon Perigee and High declination not always occurring at the same time of the month Stay away from new moon Mainly weekend activity unless retired 41

42 Moonbounce Reflectors Moon-Net - help.htmlhtml EME-net - telia 42

43 IW2FZR on 1296 and 2304 So you don t think you are good enough at CW? Check out Dario s hand key! Now look closer! 43

44 IW2FZR Homebrew Key Now this is dedication! by doing what you have to do to make the contact! And Dario is still very active with great signals on 1296 and 2304 MHz! 44

45 JA8ERE, JA6CZD & JA4BLC on 2424 MHz 45

46 Lunar Orbiter on 2271 MHz 46

47 Websites for more Information VE1ALQ - F1EHN - h / W2DRZ - K2AH W1GHZ

48 HB9Q Loggers 48

49 Receiver Sensitivity Tsystem = Tantenna + Treceiver Tsys = Tant + (Noise Factor - 1) * To Noise Factor = inv log ((NF(dB) / 10) If NF(dB) = 3 db then Noise Factor = 2 If NF(dB) = 2 db then Noise Factor = 1.58 Etc. Also T is in Kelvins or K 0K = -273C, 273K = 0C, 290K = 17C 49

50 Receiver Sensitivity Example Tsys = Tant + Trcv Tsys = 25K + 170K = 195K for a 2dB NF Tsys = 25K + 75K = 100K for a 1 db NF a system sensitivity improvement of 2.9dB which is just 10 log 195/100 = 2.9dB Tsys = 25K + 35K = 60K for a 0.5dB NF a further system sensitivity improvement of 2.2dB 2dB for a total of 5.1dB for a 1.5dB reduction in NF Tsys = 25K + 28K = 53K for a 0.4dB NF At this system NF another 0.1dB can provide an additional.54 db system sensitivity improvement! 50

51 Noise Floor Noise Floor= -174dBm/Hz + 10 log(bw) Hz + 10 log (NF + Ta/To 1) where NF is noise factor expressed asa ratio and To = 290K and Ta which is also in kelvins is the equivalent antenna temperature which could be as low as 25K on 2304 MHz If Ta = To then the noise floor changes db for db with the noise figure If Ta is less than To then we start to see some drastic improvements in receiver sensitivity when noise figures go below 2 db 51

52 Noise Floor Example Noise Floor= -174dBm/Hz + 10 log(bw) Hz + 10 log (NF + Ta/To 1) Ta = 25K For 2 db NF (1.58 noise factor), noise floor = dbm in a 1 Hz bandwidth For 1 db NF (1.26 noise factor), noise floor = dbm in a 1 Hz bandwidth (Δ = 2.8dB) For 0.5 db NF (1.12 noise factor), noise floor = dbm in a 1 Hz bandwidth (Δ = 2.3dB) For 0.4 db NF (1.096 noise factor), noise floor = dbm in a 1 Hz bandwidth (Δ = 0.5dB) Total improvement when decreasing noise figure from 2 db to 0.4 db is = 5.6 db 52

53 Slides will be uploaded to after the conference Hope to work you on 2304 MHz Any questions? 73 Al Ward W5LUA l b l 53

54 How do we compare sun noise readings? Converting (S+N)/N to S/N S + N N = S N + 1 Therefore S N = S + N N Convert dbs to ratios, then substitute in equations (S+N)/N S/N 20 db db 10 db 9.54 db 7 db 6.03 db 5 db 3.35 db 3 db db 2 db db 1 db db _ 1 Since we have very low sky noise on the microwave bands, we measure our sun noise and moon noise over cold sky. When comparing sun noise readings among amateurs with different systems in order to determine one s performance versus someone else, itis common place to compare these readings. At low S meter readings the measured level is actually signal plus noise and when we compare it to the noise level we must first convert (S+N)/N to S/N before making relative db comparisons 54

55 Examples Converting (S+N)/N to S/N S + N N = S N + 1 Therefore S N = S + N N Convert dbs to ratios, then substitute in equations (S+N)/N S/N 20 db db 10 db 9.54 db 7 db 6.03 db 5 db 3.35 db 3 db db 2 db db 1 db db _ 1 If station A is measuring 20 db of sun noise and station B is measuring only 10 db of sun noise then the difference is = db or a change in sensitivity of db. Now comparing station C who is receiving 10 db of sun noise to station D who is receiving only 3 db of sun noise then the difference is = 9.56 db or a change in sensitivity of still nearly 10 db for a 7 db drop in sun noise. 55