Just a quick note to let you know that DX-Sherlock now provides satellite-specific real-time maps and QSO lists.
Have a look at http://www.vhfdx.info/spots/map.php?Frec=SAT http://www.vhfdx.info/spots/map.php?Frec=SAT&Map=W2L &Map=W2L
I hope you like it.
73. Gabriel - EA6VQ
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow Antenna.
Of course, it is. You just need to make a schedule with someone on the other side of the link with enough Antenna Gain. You also need to be running the new digital text messaging mode called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain values based on the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
The Arrow antenna (Model 146/436-10) has 3 elements on the 2-meter band, so its maximum theoretical "Element Gain" is 4.5 dBd.
With the invention of the JT65 protocols, thousands of Amateur Radio stations running a Single Yagi 2-meter antennas, now have access to the Moon and EME contacts.
To make a contact on Moon bounce, the "Total Antenna Gain" from both stations is added up and will need to be in the approximate range of 25-30 dBd. With this gain and the average transmitter power of (100-400 watts) you will have a 10-20+ percent chance of completing a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus on the antenna Gain.
The amount of Total Antenna Gain required depends on the mode you wish to use. The wider the mode, the more gain that is required. The mode JT65B is a very narrow mode and requires less gain. I am not going to go over all of the details of JT65 in this article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi + 8-Yagi) FM 60-70 dBd (16 + 24) Guess
The Mode JT65B requires approximately 30 dB of Total Antenna Gain for an EME contact. If we assume the average 12-element 2-Meter Yagi has 10.5 dBd (round to 11 for easy math) of "Element Gain", then the more Yagi's you stack, the more gain you will have. In EME lingo, 1x12 means, you have One Yagi, with 12 elements, 4x12 means you have a stack of 4 yagis with 12 elements each (48 elements total) and an approximate gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi (17 dBd) station will have approximately 28 dBd Total Antenna Gain. The 4xYagi stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150 watts (10 watts if hand held).
If you are running the maximum 150 watts on your Arrow antenna, you should be able to work stations with 32 to 64 Yagi's. There are not very many 64 Yagi stations out there, however Dave W5UN has been active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5 watts and your Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will reduce your performance by 12 db. To compensate for the reduce power, you will just need to find a station with a bigger antenna.
There is another big gun on EME. Two weeks ago, Arecibo was on EME, running CW, working EME stations on the 440 band. The antenna used at Arecibo is a simple 1,000 foot dish. The actual gain for 2-meters is not known, however I will assume it is more than 64-Yagi's.
So here is your chance. Make a schedule with Arecibo and go for QRP, EME, with a held Arrow antenna, or if you know of any good contacts at Arecibo, send me the data and I'll try to arrange a schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made Yaesu FT-736R) http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That is ok for 50' EME runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
A few comments for accuracy (no criticism intended on what WF1F wrote). I have been on 2m-eme since 1998 and have used digital mode since 2003 when it first was made available. Insertions (below)
At 04:36 AM 4/1/2010, MM wrote:
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow Antenna.
Of course, it is. You just need to make a schedule with someone on the other side of the link with enough Antenna Gain. You also need to be running the new digital text messaging mode called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain values based on the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
This is not entirely accurate. Yagi antennas increase gain in direct relationship to length of boom and not exactly a function of number of elements. I run four ten-element yagis with a total gain of 17.6 dBd (19.2 dBi). One such yagi has 11.6 dBd (13.2 dBi). It is 21-feet long (eme'rs usually refer to wavelengths for boomlength, i.e. 3 WL)
The Arrow antenna (Model 146/436-10) has 3 elements on the 2-meter band, so its maximum theoretical "Element Gain" is 4.5 dBd.
With the invention of the JT65 protocols, thousands of Amateur Radio stations running a Single Yagi 2-meter antennas, now have access to the Moon and EME contacts.
The rest of this pertains to 2-meter eme. 432-eme will take more antenna gain since the path-loss is higher at increase frequencies. This means antenna gain requirements go up (approximately 6-dB more for stations working eme on 432). The norm for two CW EME stations is 18-dBi with 1000w on 2-meters and 24-dBi with 1000w on 432. (subtract 1.64 dB to convert antenna gain to dBd).
The requirements drop significantly for running JT-65 instead of CW: 144-eme: 13-dBi with 600w (min) 432-eme: 19-dBi with 600w (min) this is for two such stations working each other. This not easy at this level and may take several hours spread over several days to make one contact for stations so equipped.
I ran my four yagis with 125w (at the antenna; 170w at the amplifier) and made contacts with single yagi stations running 600w. I now have 600w. This is on 2-meters.
To make a contact on Moon bounce, the "Total Antenna Gain" from both stations is added up and will need to be in the approximate range of 25-30 dBd. With this gain and the average transmitter power of (100-400 watts) you will have a 10-20+ percent chance of completing a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus on the antenna Gain.
The amount of Total Antenna Gain required depends on the mode you wish to use. The wider the mode, the more gain that is required. The mode JT65B is a very narrow mode and requires less gain. I am not going to go over all of the details of JT65 in this article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi + 8-Yagi) FM 60-70 dBd (16 + 24) Guess
Don't even give any thought to using FM for eme; it is too wide in bandwidth to get reasonable sensitivity in receive. SSB has only been done with one or two super-sized 2m-eme stations; it is more common with large stations on 1296-eme. I expect to work 1296-SSB with my 16-foot dish running 300w with stations running dishes >25-feet.
EME is done on CW or JT-65, predominately. Using an Arrow you will HAVE to use JT-65.
The Mode JT65B requires approximately 30 dB of Total Antenna Gain for an EME contact. If we assume the average 12-element 2-Meter Yagi has 10.5 dBd (round to 11 for easy math) of "Element Gain", then the more Yagi's you stack, the more gain you will have. In EME lingo, 1x12 means, you have One Yagi, with 12 elements, 4x12 means you have a stack of 4 yagis with 12 elements each (48 elements total) and an approximate gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi (17 dBd) station will have approximately 28 dBd Total Antenna Gain. The 4xYagi stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150 watts (10 watts if hand held).
If you are running the maximum 150 watts on your Arrow antenna, you should be able to work stations with 32 to 64 Yagi's. There are not very many 64 Yagi stations out there, however Dave W5UN has been active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5 watts and your Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will reduce your performance by 12 db. To compensate for the reduce power, you will just need to find a station with a bigger antenna.
There is another big gun on EME. Two weeks ago, Arecibo was on EME, running CW, working EME stations on the 440 band. The antenna used at Arecibo is a simple 1,000 foot dish. The actual gain for 2-meters is not known, however I will assume it is more than 64-Yagi's.
Arecibo will be doing 432-eme, NOT on 2-meters! However, one could try their 6-element UHF Arrow antenna with preamp (absolutely necessary) to try hearing Arecibo which has 58 dBi (56 dBd) gain on 432-MHz. In a recent test folks with small yagis 7-10 elements were able to hear Arecibo. Arecibo will be running 500w (from last reports). it is not known if they plan to run JT-65; the focus is using SSB with other large dishes around the world. Average sized 432-eme stations (8-yagi and up) are expected work them (maybe requiring the use of CW for smaller stations). If you have 100w+ on 432 you might try CW with Arecibo with a small yagi (ONLY IF you can hear them, first - DO NOT Transmit if you cannot hear Arecibo).
I will be using 100w with my 16-foot dish (24-dBi gain).
BUT I REPEAT Arecibo will NOT be using 2-meters; ONLY 432.045 MHz (plus/minus for the expected QRM of stations wishing to contact them).
Arecibo will be doing eme on April 16-18 at times limited by their Moon view (they can only point down to 70-deg elevation). I will reprint the times once I find the e-mail that cited the exact operating times.
So here is your chance. Make a schedule with Arecibo and go for QRP, EME, with a held Arrow antenna, or if you know of any good contacts at Arecibo, send me the data and I'll try to arrange a schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made Yaesu FT-736R) http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That is ok for 50' EME runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
I have done very limited EME on 2m using JT65. My one good QSO was with W5UN who probably has the best EME setup on the planet. I was using a Cushcraft 13B2 and 160 watts. I also almost completed with RN6BY using this same setup but he had moonset at his QTH before we got the final sequence completed. The 13B2 has 13 elements on a 15 foot boom and Cushcraft advertises it at 12DBd or something like that. I have tried with other big stations using that same setup and was unsuccessful. I did not have an external preamp.
To use a 3 element arrow would really be pushing it, even for running with W5UN. I would think you would need at least 300 watts if not more, and an external preamp to even have a shot.
73s JOhn AA5JG
--- On Thu, 4/1/10, Edward Cole kl7uw@acsalaska.net wrote:
From: Edward Cole kl7uw@acsalaska.net Subject: [amsat-bb] Re: Arrow and EME? To: AMSAT-BB@amsat.org Date: Thursday, April 1, 2010, 11:46 AM A few comments for accuracy (no criticism intended on what WF1F wrote). I have been on 2m-eme since 1998 and have used digital mode since 2003 when it first was made available. Insertions (below)
At 04:36 AM 4/1/2010, MM wrote:
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow
Antenna.
Of course, it is. You just need to make a
schedule with someone on
the other side of the link with enough Antenna
Gain. You also need
to be running the new digital text messaging mode
called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain
values based on
the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
This is not entirely accurate. Yagi antennas increase gain in direct relationship to length of boom and not exactly a function of number of elements. I run four ten-element yagis with a total gain of 17.6 dBd (19.2 dBi). One such yagi has 11.6 dBd (13.2 dBi). It is 21-feet long (eme'rs usually refer to wavelengths for boomlength, i.e. 3 WL)
The Arrow antenna (Model 146/436-10) has 3 elements on
the 2-meter
band, so its maximum theoretical "Element Gain" is 4.5
dBd.
With the invention of the JT65 protocols, thousands of
Amateur Radio
stations running a Single Yagi 2-meter antennas, now
have access to
the Moon and EME contacts.
The rest of this pertains to 2-meter eme. 432-eme will take more antenna gain since the path-loss is higher at increase frequencies. This means antenna gain requirements go up (approximately 6-dB more for stations working eme on 432). The norm for two CW EME stations is 18-dBi with 1000w on 2-meters and 24-dBi with 1000w on 432. (subtract 1.64 dB to convert antenna gain to dBd).
The requirements drop significantly for running JT-65 instead of CW: 144-eme: 13-dBi with 600w (min) 432-eme: 19-dBi with 600w (min) this is for two such stations working each other. This not easy at this level and may take several hours spread over several days to make one contact for stations so equipped.
I ran my four yagis with 125w (at the antenna; 170w at the amplifier) and made contacts with single yagi stations running 600w. I now have 600w. This is on 2-meters.
To make a contact on Moon bounce, the "Total Antenna
Gain" from both
stations is added up and will need to be in the
approximate range
of 25-30 dBd. With this gain and the average
transmitter power of
(100-400 watts) you will have a 10-20+ percent chance
of completing
a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus
on the antenna Gain.
The amount of Total Antenna Gain required depends on
the mode you
wish to use. The wider the mode, the more gain
that is
required. The mode JT65B is a very narrow mode
and requires less
gain. I am not going to go over all of the
details of JT65 in this
article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi +
8-Yagi)
FM 60-70 dBd (16 + 24) Guess
Don't even give any thought to using FM for eme; it is too wide in bandwidth to get reasonable sensitivity in receive. SSB has only been done with one or two super-sized 2m-eme stations; it is more common with large stations on 1296-eme. I expect to work 1296-SSB with my 16-foot dish running 300w with stations running dishes >25-feet.
EME is done on CW or JT-65, predominately. Using an Arrow you will HAVE to use JT-65.
The Mode JT65B requires approximately 30 dB of Total
Antenna Gain
for an EME contact. If we assume the average 12-element 2-Meter Yagi has
10.5 dBd (round
to 11 for easy math) of "Element Gain", then the
more Yagi's you
stack, the more gain you will have. In EME lingo,
1x12 means, you
have One Yagi, with 12 elements, 4x12 means you
have a stack of 4
yagis with 12 elements each (48 elements total) and an
approximate
gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi
(17 dBd) station
will have approximately 28 dBd Total Antenna
Gain. The 4xYagi
stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150
watts (10 watts
if hand held).
If you are running the maximum 150 watts on your
Arrow antenna, you
should be able to work stations with 32 to 64
Yagi's. There are not
very many 64 Yagi stations out there, however Dave W5UN
has been
active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5
watts and your
Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will
reduce your
performance by 12 db. To compensate for the reduce power, you will just need
to find a
station with a bigger antenna.
There is another big gun on EME. Two weeks ago,
Arecibo was on EME,
running CW, working EME stations on the 440 band.
The antenna used
at Arecibo is a simple 1,000 foot dish. The
actual gain for
2-meters is not known, however I will assume it is more
than 64-Yagi's.
Arecibo will be doing 432-eme, NOT on 2-meters! However, one could try their 6-element UHF Arrow antenna with preamp (absolutely necessary) to try hearing Arecibo which has 58 dBi (56 dBd) gain on 432-MHz. In a recent test folks with small yagis 7-10 elements were able to hear Arecibo. Arecibo will be running 500w (from last reports). it is not known if they plan to run JT-65; the focus is using SSB with other large dishes around the world. Average sized 432-eme stations (8-yagi and up) are expected work them (maybe requiring the use of CW for smaller stations). If you have 100w+ on 432 you might try CW with Arecibo with a small yagi (ONLY IF you can hear them, first - DO NOT Transmit if you cannot hear Arecibo).
I will be using 100w with my 16-foot dish (24-dBi gain).
BUT I REPEAT Arecibo will NOT be using 2-meters; ONLY 432.045 MHz (plus/minus for the expected QRM of stations wishing to contact them).
Arecibo will be doing eme on April 16-18 at times limited by their Moon view (they can only point down to 70-deg elevation). I will reprint the times once I find the e-mail that cited the exact operating times.
So here is your chance. Make a schedule with
Arecibo and go for
QRP, EME, with a held Arrow antenna, or if you know of
any good
contacts at Arecibo, send me the data and I'll try to
arrange a
schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made
Yaesu FT-736R)
http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That
is ok for 50' EME
runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
Sent via AMSAT-BB@amsat.org.
Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur
satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73, Ed - KL7UW, WD2XSH/45
BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
----- Original Message ----- From: "Edward Cole" kl7uw@acsalaska.net To: AMSAT-BB@amsat.org Sent: Thursday, April 01, 2010 6:46 PM Subject: [amsat-bb] Re: Arrow and EME?
The rest of this pertains to 2-meter eme. 432-eme will take more antenna gain since the path-loss is higher at increase frequencies. This means antenna gain requirements go up (approximately 6-dB more for stations working eme on 432). The norm for two CW EME stations is 18-dBi with 1000w on 2-meters and 24-dBi with 1000w on 432. (subtract 1.64 dB to convert antenna gain to dBd).
73, Ed - KL7UW, WD2XSH/45
Hi Ed, KL7UW
I agree completely with you except (subtract 1.64 dB to convert antenna gain to dBd).
The gain of a 1/2 wave dipole is 2.14 dBi = 1.64 time in power so that to convert the antenna gain in dBd you must subtract 2.14 dB to the antenna gain expressed in dBi
An antenna gain of 12.14 dBi is equivalent to an antenna gain of 10 dBd
Best 73" de
i8CVS Domenico
I have been doing some reading on this also. Although I have not yet made any EME contacts, I have been uncovered the following:
1. Moonrise/moonset will enhance signals because of ground reflections, something like 6 dB. Many folks intentionally use moonrise and moonset attempts for this reason.
2. Mast mounted pre-amp is essential
3. Higher frequencies need more gain (so I have been told). But the 440 MHz part of the arrow antenna should have a LOT more gain than the 2 meter part.
4. Low loss coax is very important, esp at VHF. Keep the runs short and use something equiv to LMR 400 (50 foot of the good stuff is probably under $100, and worth it.
5. Definitely try to set up a sked with W5UN. If you can hear him, then you are halfway there!
6. Monitor websites like http://www.chris.org/cgi-bin/jt65emeA
7. 2010 appears to be a promising year for EME, here is a good calendar: http://www.vhfdx.net/w5luu.html
Mark Lunday WD4ELG Greensboro, NC - FM06be wd4elg@arrl.net http://wd4elg.net http://wd4elg.blogspot.com
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of MM Sent: Thursday, April 01, 2010 8:37 AM To: AMSAT-BB@amsat.org Subject: [amsat-bb] Arrow and EME?
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow Antenna.
Of course, it is. You just need to make a schedule with someone on the other side of the link with enough Antenna Gain. You also need to be running the new digital text messaging mode called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain values based on the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
The Arrow antenna (Model 146/436-10) has 3 elements on the 2-meter band, so its maximum theoretical "Element Gain" is 4.5 dBd.
With the invention of the JT65 protocols, thousands of Amateur Radio stations running a Single Yagi 2-meter antennas, now have access to the Moon and EME contacts.
To make a contact on Moon bounce, the "Total Antenna Gain" from both stations is added up and will need to be in the approximate range of 25-30 dBd. With this gain and the average transmitter power of (100-400 watts) you will have a 10-20+ percent chance of completing a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus on the antenna Gain.
The amount of Total Antenna Gain required depends on the mode you wish to use. The wider the mode, the more gain that is required. The mode JT65B is a very narrow mode and requires less gain. I am not going to go over all of the details of JT65 in this article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi + 8-Yagi) FM 60-70 dBd (16 + 24) Guess
The Mode JT65B requires approximately 30 dB of Total Antenna Gain for an EME contact. If we assume the average 12-element 2-Meter Yagi has 10.5 dBd (round to 11 for easy math) of "Element Gain", then the more Yagi's you stack, the more gain you will have. In EME lingo, 1x12 means, you have One Yagi, with 12 elements, 4x12 means you have a stack of 4 yagis with 12 elements each (48 elements total) and an approximate gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi (17 dBd) station will have approximately 28 dBd Total Antenna Gain. The 4xYagi stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150 watts (10 watts if hand held).
If you are running the maximum 150 watts on your Arrow antenna, you should be able to work stations with 32 to 64 Yagi's. There are not very many 64 Yagi stations out there, however Dave W5UN has been active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5 watts and your Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will reduce your performance by 12 db. To compensate for the reduce power, you will just need to find a station with a bigger antenna.
There is another big gun on EME. Two weeks ago, Arecibo was on EME, running CW, working EME stations on the 440 band. The antenna used at Arecibo is a simple 1,000 foot dish. The actual gain for 2-meters is not known, however I will assume it is more than 64-Yagi's.
So here is your chance. Make a schedule with Arecibo and go for QRP, EME, with a held Arrow antenna, or if you know of any good contacts at Arecibo, send me the data and I'll try to arrange a schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made Yaesu FT-736R) http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That is ok for 50' EME runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Another very important thing is polarity. the ability to change polarity can easily me a completed QSO or one where not a peep was heard.
In the late 80's early 90's I had a small station of 4 eight element 2 meter yagis. I think they were a W1JR design?
anyway I mounted them in a way that i could rotate them in polarity also.
It was amazing I never thought i could do moonbounce with them but just for kicks was listening down at the bottom of the band one day and heard someone CQing and wortking someone off he moon. of course it was W5UN. but a random call when he finished and we had a complete QSO in the log with no repeats solid exchange both ways!
what make this amazing was I was using a kenwood TS700 rig into a old KLM (remember KLM amps?) a 70 watt one that was tired and only putting out about 35 watts, into a run of rg 213 50 feet to the antenna, no pre amps at all. and on CW by ear! no filters either just the standard 2.XX whatever wide filter. But the polarity made all the difference! In horizontal mode i heard NOTHING. but somewhere inbetween H and V he wa solid copy and he had no problem hearing me too.
I eventually went on to work about 30 other stations as small as other 4 yagi stations. The ability to make polarity changes is a GIANT advantage!
Joe WB9SBD
The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com
On 4/1/2010 12:11 PM, Mark Lunday wrote:
I have been doing some reading on this also. Although I have not yet made any EME contacts, I have been uncovered the following:
- Moonrise/moonset will enhance signals because of ground reflections,
something like 6 dB. Many folks intentionally use moonrise and moonset attempts for this reason.
Mast mounted pre-amp is essential
Higher frequencies need more gain (so I have been told). But the 440 MHz
part of the arrow antenna should have a LOT more gain than the 2 meter part.
- Low loss coax is very important, esp at VHF. Keep the runs short and use
something equiv to LMR 400 (50 foot of the good stuff is probably under $100, and worth it.
- Definitely try to set up a sked with W5UN. If you can hear him, then you
are halfway there!
Monitor websites like http://www.chris.org/cgi-bin/jt65emeA
2010 appears to be a promising year for EME, here is a good calendar:
http://www.vhfdx.net/w5luu.html
Mark Lunday WD4ELG Greensboro, NC - FM06be wd4elg@arrl.net http://wd4elg.net http://wd4elg.blogspot.com
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of MM Sent: Thursday, April 01, 2010 8:37 AM To: AMSAT-BB@amsat.org Subject: [amsat-bb] Arrow and EME?
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow Antenna.
Of course, it is. You just need to make a schedule with someone on the other side of the link with enough Antenna Gain. You also need to be running the new digital text messaging mode called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain values based on the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
The Arrow antenna (Model 146/436-10) has 3 elements on the 2-meter band, so its maximum theoretical "Element Gain" is 4.5 dBd.
With the invention of the JT65 protocols, thousands of Amateur Radio stations running a Single Yagi 2-meter antennas, now have access to the Moon and EME contacts.
To make a contact on Moon bounce, the "Total Antenna Gain" from both stations is added up and will need to be in the approximate range of 25-30 dBd. With this gain and the average transmitter power of (100-400 watts) you will have a 10-20+ percent chance of completing a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus on the antenna Gain.
The amount of Total Antenna Gain required depends on the mode you wish to use. The wider the mode, the more gain that is required. The mode JT65B is a very narrow mode and requires less gain. I am not going to go over all of the details of JT65 in this article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi + 8-Yagi) FM 60-70 dBd (16 + 24) Guess
The Mode JT65B requires approximately 30 dB of Total Antenna Gain for an EME contact. If we assume the average 12-element 2-Meter Yagi has 10.5 dBd (round to 11 for easy math) of "Element Gain", then the more Yagi's you stack, the more gain you will have. In EME lingo, 1x12 means, you have One Yagi, with 12 elements, 4x12 means you have a stack of 4 yagis with 12 elements each (48 elements total) and an approximate gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi (17 dBd) station will have approximately 28 dBd Total Antenna Gain. The 4xYagi stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150 watts (10 watts if hand held).
If you are running the maximum 150 watts on your Arrow antenna, you should be able to work stations with 32 to 64 Yagi's. There are not very many 64 Yagi stations out there, however Dave W5UN has been active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5 watts and your Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will reduce your performance by 12 db. To compensate for the reduce power, you will just need to find a station with a bigger antenna.
There is another big gun on EME. Two weeks ago, Arecibo was on EME, running CW, working EME stations on the 440 band. The antenna used at Arecibo is a simple 1,000 foot dish. The actual gain for 2-meters is not known, however I will assume it is more than 64-Yagi's.
So here is your chance. Make a schedule with Arecibo and go for QRP, EME, with a held Arrow antenna, or if you know of any good contacts at Arecibo, send me the data and I'll try to arrange a schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made Yaesu FT-736R) http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That is ok for 50' EME runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Good points Mark, comments MM
--- On Thu, 4/1/10, Mark Lunday mlunday@nc.rr.com wrote:
From: Mark Lunday mlunday@nc.rr.com Subject: RE: [amsat-bb] Arrow and EME? To: "'MM'" ka1rrw@yahoo.com, AMSAT-BB@amsat.org Date: Thursday, April 1, 2010, 1:11 PM I have been doing some reading on this also. Although I have not yet made any EME contacts, I have been uncovered the following:
- Moonrise/moonset will enhance signals because of ground
reflections, something like 6 dB. Many folks intentionally use moonrise and moonset attempts for this reason.
MM: I have heard the same comments and some theories. The Ground Gain is very much dependent on your local Geography. I live 30 miles from the Massachusetts coast line. I can work Mir/ISS on 2-meters to the North East all the way into the Ocean with solid copy. However, my Geography does not favor the Moon. I cannot hear any JT65B signals on 2-Meters until the moon is more than 10 degrees above the horizon. Will your location benefit from Ground Gain, the only way to find out is to try it. You may get lucky.
Mast mounted pre-amp is essential
Higher frequencies need more gain (so I have been
told). But the 440 MHz part of the arrow antenna should have a LOT more gain than the 2 meter part.
- Low loss coax is very important, esp at VHF. Keep
the runs short and use something equiv to LMR 400 (50 foot of the good stuff is probably under $100, and worth it.
MM: I now call RG-8 style coax 10-Millimeter coax. When comparing Name brand coax in the 10-millimeter size range, the loss at 2-meters (100 feet), will be very similar. If your loss is too high, the next step is to go with thicker cable. The Diameter of the cable, is one of the limiting factors. The LMR-400 has possibly the lowest loss of all of the flexible 10-millimter coax cables, and it does not kink like the Belden 9913. LMR makes several sizes of thicker cables, with lower loses. Just like your antenna, Size is important, so too is the size of your coax.
Typical loss values for 100 feet at 145 MHz LMR-400, 1.5 dB loss, 10 mm RG-213, 2.5 dB loss, 10 mm LMR-600, 0.9 dB loss, 14 mm
- Definitely try to set up a sked with W5UN. If you
can hear him, then you are halfway there!
Monitor websites like http://www.chris.org/cgi-bin/jt65emeA
2010 appears to be a promising year for EME, here is a
good calendar: http://www.vhfdx.net/w5luu.html
Mark Lunday WD4ELG Greensboro, NC - FM06be wd4elg@arrl.net http://wd4elg.net http://wd4elg.blogspot.com
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of MM Sent: Thursday, April 01, 2010 8:37 AM To: AMSAT-BB@amsat.org Subject: [amsat-bb] Arrow and EME?
Arrow Antenna and EME:
It is possible to work Earth Moon Earth with an Arrow Antenna.
Of course, it is. You just need to make a schedule with someone on the other side of the link with enough Antenna Gain. You also need to be running the new digital text messaging mode called JT65B
Link for JT65 http://www.physics.princeton.edu/pulsar/K1JT/
Definitions: In this document I will refer to all antenna gain values based on the number of elements.
Example: A Single half-wave Dipole = 0 dBd Elements 2 = 3 dBd Elements 4 = 6 dBd Elements 8 = 9 dBd Elements 16 = 12 dBd
The Arrow antenna (Model 146/436-10) has 3 elements on the 2-meter band, so its maximum theoretical "Element Gain" is 4.5 dBd.
With the invention of the JT65 protocols, thousands of Amateur Radio stations running a Single Yagi 2-meter antennas, now have access to the Moon and EME contacts.
To make a contact on Moon bounce, the "Total Antenna Gain" from both stations is added up and will need to be in the approximate range of 25-30 dBd. With this gain and the average transmitter power of (100-400 watts) you will have a 10-20+ percent chance of completing a 2-way EME JT65B link, with another station. Note: There are many other factures used in EME gain calculations. For simplicity, we will just focus on the antenna Gain.
The amount of Total Antenna Gain required depends on the mode you wish to use. The wider the mode, the more gain that is required. The mode JT65B is a very narrow mode and requires less gain. I am not going to go over all of the details of JT65 in this article, look it up.
Gain required by mode: (All values are approximate)
JT65 28-30 dBd (1-Yagi + 4-Yagi) CW 30-40 dBd (4-Yagi + 4-Yagi) SSB 40-50 dBd (8-Yagi + 8-Yagi) FM 60-70 dBd (16 + 24) Guess
The Mode JT65B requires approximately 30 dB of Total Antenna Gain for an EME contact. If we assume the average 12-element 2-Meter Yagi has 10.5 dBd (round to 11 for easy math) of "Element Gain", then the more Yagi's you stack, the more gain you will have. In EME lingo, 1x12 means, you have One Yagi, with 12 elements, 4x12 means you have a stack of 4 yagis with 12 elements each (48 elements total) and an approximate gain of 17 dBd.
1-Yagi = 11 dBd 2-Yagi = 14 dBd 4-Yagi = 17 dBd 8-Yagi = 20 dBd 16-Yagi = 23 dBd 32-Yagi = 26 dBd 64-Yagi = 29 dBd (W5UN)
A Single-Yagi station (11 dBd) calling a 4-Yagi (17 dBd) station will have approximately 28 dBd Total Antenna Gain. The 4xYagi stations are very common on JT56B EME.
Let's go back to the Arrow Antenna:
We need 30 dBd of total antenna gain. The Arrow antenna has 4.5 dBd. The Arrow also has a Maximum power limitation of 150 watts (10 watts if hand held).
If you are running the maximum 150 watts on your Arrow antenna, you should be able to work stations with 32 to 64 Yagi's. There are not very many 64 Yagi stations out there, however Dave W5UN has been active on JT65 EME recently.
If you want more of a challenge, you can try QRP at 5 watts and your Arrow antenna. Reducing you power from 150 watts to 5-10 watts, will reduce your performance by 12 db. To compensate for the reduce power, you will just need to find a station with a bigger antenna.
There is another big gun on EME. Two weeks ago, Arecibo was on EME, running CW, working EME stations on the 440 band. The antenna used at Arecibo is a simple 1,000 foot dish. The actual gain for 2-meters is not known, however I will assume it is more than 64-Yagi's.
So here is your chance. Make a schedule with Arecibo and go for QRP, EME, with a held Arrow antenna, or if you know of any good contacts at Arecibo, send me the data and I'll try to arrange a schedule and try it from my station.
Other Hardware: A good Receiver Preamp (similar to ARR) http://www.advancedreceiver.com/
A good SSB 2-meter Transceiver (the best ever made Yaesu FT-736R) http://www.xs4all.nl/~ketel/ham/ft736.htm
Good Coax (RG-8 coax is 11 Millimeter coax. That is ok for 50' EME runs, for longer runs use 12+ Millimeter coax)
73
WF1F www.marexmg.org
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (7)
-
Edward Cole -
Gabriel - EA6VQ -
i8cvs -
Idle-Tyme -
John Geiger -
Mark Lunday -
MM