https://www.ahrdf.net/forum/ Mon, 27 Apr 2026 15:10:54 +0000 MyBB https://www.ahrdf.net/forum/showthread.php?tid=867 Mon, 23 Sep 2019 00:01:58 +0000 VK3RX]]> https://www.ahrdf.net/forum/showthread.php?tid=867 Moon Bounce Elint - CIA Historical Document]]> Moon Bounce Elint - CIA Historical Document]]> https://www.ahrdf.net/forum/showthread.php?tid=861 Fri, 13 Sep 2019 22:26:03 +0000 VK4ADC]]> https://www.ahrdf.net/forum/showthread.php?tid=861 From text edition for SEPTEMBER 15 2019 - VK NATIONAL NEWS BROADCAST ON VK1WIA : http://www.wia.org.au/members/broadcast/wianews/

Also in MP3 edition of news available at: http://www.wia-files.com/podcast/wianews-2019-09-15.mp3

Back on August 31, Richard VK7ZBX and Rex VK7MO completed the first VK7 to VK7 EME contact over a distance of 720,000 km even though their stations were only 22 km apart here on Earth.

Operations were at 10 GHz using the QRA64 digital mode.

Richard was running a 75cm dish and 60 watts  - to Rex running a 113cm dish and 90 watts.

At the time the Moon was nearly as close as it can get but even so this resulted in a propagation loss of 289 dB!!

However spreading was around 35 Hz producing an additional loss of around 3.4 db.  Signals were solid and a degradation test with added noise showed there was 5 dB in reserve.
On the following day the Moon had moved a further 1562 km away due to its elliptical orbit but this cost only an additional 0.1 dB But the spreading was now down to 3 Hz reducing the overall loss by around 3.3 dB compared to the day earlier.  With this extra 3.3 dB in hand Richard tried out a 60cm dish and just 30 watts and again a QSO was completed.
This time degradation tests showed there was nothing to spare.

This second QSO is believed to be between the smallest dishes ever to complete an EME QSO with power of just 30 watts at one end.

Critics might ask how we are sure the signal got to the Moon and back rather than direct between us.  The answer is that the signal took 2.5 seconds to arrive which relates directly to the time it takes at the speed of light to get to the Moon and back.  In addition Doppler shift calculated at around 20 KHz proved to be within about 5 Hz once it was automatically compensated - again confirming the signal was being reflected from the Moon.]]> From text edition for SEPTEMBER 15 2019 - VK NATIONAL NEWS BROADCAST ON VK1WIA : http://www.wia.org.au/members/broadcast/wianews/

Also in MP3 edition of news available at: http://www.wia-files.com/podcast/wianews-2019-09-15.mp3

Back on August 31, Richard VK7ZBX and Rex VK7MO completed the first VK7 to VK7 EME contact over a distance of 720,000 km even though their stations were only 22 km apart here on Earth.

Operations were at 10 GHz using the QRA64 digital mode.

Richard was running a 75cm dish and 60 watts  - to Rex running a 113cm dish and 90 watts.

At the time the Moon was nearly as close as it can get but even so this resulted in a propagation loss of 289 dB!!

However spreading was around 35 Hz producing an additional loss of around 3.4 db.  Signals were solid and a degradation test with added noise showed there was 5 dB in reserve.
On the following day the Moon had moved a further 1562 km away due to its elliptical orbit but this cost only an additional 0.1 dB But the spreading was now down to 3 Hz reducing the overall loss by around 3.3 dB compared to the day earlier.  With this extra 3.3 dB in hand Richard tried out a 60cm dish and just 30 watts and again a QSO was completed.
This time degradation tests showed there was nothing to spare.

This second QSO is believed to be between the smallest dishes ever to complete an EME QSO with power of just 30 watts at one end.

Critics might ask how we are sure the signal got to the Moon and back rather than direct between us.  The answer is that the signal took 2.5 seconds to arrive which relates directly to the time it takes at the speed of light to get to the Moon and back.  In addition Doppler shift calculated at around 20 KHz proved to be within about 5 Hz once it was automatically compensated - again confirming the signal was being reflected from the Moon.]]> https://www.ahrdf.net/forum/showthread.php?tid=477 Tue, 02 Jan 2018 22:34:04 +0000 VK2XV]]> https://www.ahrdf.net/forum/showthread.php?tid=477
Does anyone have any information about rain effects on Yagi arrays when used for E.M.E. on receive ?

During my 436 MHz observations of the Vela pulsar I notice when the antenna is wet there is a significant drop in received signal strength (during light rain the signal virtually disappears).  The antenna is a long Yagi (5.7 m).  I had thought that, while return loss is affected significantly, gain is less affected by water on the elements.  I have done some preliminary tests by keeping the driven elements dry, but the effect still seems to be there.  I ask for E.M.E. observations on this point as the loss of a few dB in sensitivity would be noticeable - just like my Vela pulsar observations.

Steve

Vela Pulsar observations...]]>
Does anyone have any information about rain effects on Yagi arrays when used for E.M.E. on receive ?

During my 436 MHz observations of the Vela pulsar I notice when the antenna is wet there is a significant drop in received signal strength (during light rain the signal virtually disappears).  The antenna is a long Yagi (5.7 m).  I had thought that, while return loss is affected significantly, gain is less affected by water on the elements.  I have done some preliminary tests by keeping the driven elements dry, but the effect still seems to be there.  I ask for E.M.E. observations on this point as the loss of a few dB in sensitivity would be noticeable - just like my Vela pulsar observations.

Steve

Vela Pulsar observations...]]> https://www.ahrdf.net/forum/showthread.php?tid=392 Fri, 08 Sep 2017 10:35:58 +0000 VK2ZIW]]> https://www.ahrdf.net/forum/showthread.php?tid=392 I've just converted my dish (2m) to a Short Backfire antenna on 70cm.
(because I thought it wouldn't be too hard, two days later...)
(Matching blues, definitely well below 50 ohms at the dipole feed)
(I scrapped the loli-pop feed in coax and went for a wide dipole only
to convert it to an unequal folded dipole)
Bandwidth about 1%, seems all in the feed.
Bandwidth fixed as per "Improved SBFA" in doc SBFA_GBT_187.pdf a 1998 Radio Astronomy article.
I just added the 10.78 inch front disk. I now have well over 10MHz.

Pixture on my website http://www.unixservice.com.au/hamradio/antenna/

So, does anybody do Circular on 70cm?
=== Answer, no ===
Circular,. HB9Q has Circular so as not to "miss" anybody. He asked for either H or V.

I've tried EME on five moon passes thus far. Nothing, absolutely nothing heard and nobody has heard me either.

Back to the Drawing Board.

2C39

Alan VK2ZIW]]> I've just converted my dish (2m) to a Short Backfire antenna on 70cm.
(because I thought it wouldn't be too hard, two days later...)
(Matching blues, definitely well below 50 ohms at the dipole feed)
(I scrapped the loli-pop feed in coax and went for a wide dipole only
to convert it to an unequal folded dipole)
Bandwidth about 1%, seems all in the feed.
Bandwidth fixed as per "Improved SBFA" in doc SBFA_GBT_187.pdf a 1998 Radio Astronomy article.
I just added the 10.78 inch front disk. I now have well over 10MHz.

Pixture on my website http://www.unixservice.com.au/hamradio/antenna/

So, does anybody do Circular on 70cm?
=== Answer, no ===
Circular,. HB9Q has Circular so as not to "miss" anybody. He asked for either H or V.

I've tried EME on five moon passes thus far. Nothing, absolutely nothing heard and nobody has heard me either.

Back to the Drawing Board.

2C39

Alan VK2ZIW]]> https://www.ahrdf.net/forum/showthread.php?tid=171 Tue, 23 May 2017 12:12:56 +0000 VK2ZRH]]> https://www.ahrdf.net/forum/showthread.php?tid=171 WIA honours achievers with awards at its AGM

The Ron Wilkinson Award went to Phil Moat VK4CDI for his 23cm band moonbounce (EME) experiments focusing [on] digital modes, resulting in the world record distance contact of 18,918.3 km with Aleksandr EA8DBM on 27/11/2015.

See: http://www.wia.org.au/newsevents/news/20.../index.php]]> WIA honours achievers with awards at its AGM

The Ron Wilkinson Award went to Phil Moat VK4CDI for his 23cm band moonbounce (EME) experiments focusing [on] digital modes, resulting in the world record distance contact of 18,918.3 km with Aleksandr EA8DBM on 27/11/2015.

See: http://www.wia.org.au/newsevents/news/20.../index.php]]> https://www.ahrdf.net/forum/showthread.php?tid=165 Sat, 13 May 2017 23:30:03 +0000 VK2XV]]> https://www.ahrdf.net/forum/showthread.php?tid=165
http://neutronstar.joataman.net/

...or see here for my own efforts...

http://nrarao.joataman.net/pulsar/

Cheers

Steve]]>
http://neutronstar.joataman.net/

...or see here for my own efforts...

http://nrarao.joataman.net/pulsar/

Cheers

Steve]]> https://www.ahrdf.net/forum/showthread.php?tid=30 Sat, 17 Sep 2016 14:17:19 +0000 VK2JDS]]> https://www.ahrdf.net/forum/showthread.php?tid=30 lets continue on with the experiments on 23cm EME. As you may know there was a long running thread exploring all aspects of setting up a moonbounce station for the quiet 23cm band on the old forum.
23cm is totally different to 2 metres. You can clearly see the trace of the station you are working, and there are very few spurious signals to cause confusion. Noise is very low.
So, who VK stations are experimenting at the moment?
Tonight there was VK3WRE, VK3NFI and VK4UH operational on 1296.075 working me. Dish sizes ranged from 2.5 to 3 metres.
Ralphs signal was audible at -16 and he has a 2.5 metre dish and 100 watts into a septum. Dean was struggling without a LNA at the feedpoint and got the occasional synch but no decodes.
Kevin is working on optimising his feedpoint position. Tonight he was quite a way off the optimum and nothing was heard, but at its previous spot he was only 3dB down on Ralphs signal. He had previously also worked Victor UA9YLU on his first active evening.
Another regular is Phil VK4CDI who has a good signal from his large dish. I get him at -13
In June we had Andy VK5FA doing some experiments and he was -19 using a 2.3metre dish.

We use JT65C for the time being, but there is a new mode out now that we may all move over to.

Equipment.
G4DDK VLNA2+ low noise rx amps are the go, vk5eme Preamps are good too, but need plenty of absorber material to tame them when mounting them in a box.
W6PQL amplifier bricks or the european types are the most used power amps. I have an Alan Devlin 160 watter here and a W6PQL 4 block.
Mount the LNA at the septum feedpoint , and mount the power amp at the back arms of the dish, or at the base of the mast piece (ground mount).
Radios used are IC910h or IC9100, some use transverters. Lock everything to GPSDO or a OCXO. The high stability option for the IC910h is good.

Software , use Joe Taylors WSJT. also use vk1od Owen Duffy's NFM program to do accurate sun noise vs cold sky measurements to optimise your antenna setup.
The best website to see realtime moonbounce activity on 23cm is HB9Q.CH, its where we hang out when actively running our stations to coordinate etc.
More info to follow
73 Dave vk2jds]]> lets continue on with the experiments on 23cm EME. As you may know there was a long running thread exploring all aspects of setting up a moonbounce station for the quiet 23cm band on the old forum.
23cm is totally different to 2 metres. You can clearly see the trace of the station you are working, and there are very few spurious signals to cause confusion. Noise is very low.
So, who VK stations are experimenting at the moment?
Tonight there was VK3WRE, VK3NFI and VK4UH operational on 1296.075 working me. Dish sizes ranged from 2.5 to 3 metres.
Ralphs signal was audible at -16 and he has a 2.5 metre dish and 100 watts into a septum. Dean was struggling without a LNA at the feedpoint and got the occasional synch but no decodes.
Kevin is working on optimising his feedpoint position. Tonight he was quite a way off the optimum and nothing was heard, but at its previous spot he was only 3dB down on Ralphs signal. He had previously also worked Victor UA9YLU on his first active evening.
Another regular is Phil VK4CDI who has a good signal from his large dish. I get him at -13
In June we had Andy VK5FA doing some experiments and he was -19 using a 2.3metre dish.

We use JT65C for the time being, but there is a new mode out now that we may all move over to.

Equipment.
G4DDK VLNA2+ low noise rx amps are the go, vk5eme Preamps are good too, but need plenty of absorber material to tame them when mounting them in a box.
W6PQL amplifier bricks or the european types are the most used power amps. I have an Alan Devlin 160 watter here and a W6PQL 4 block.
Mount the LNA at the septum feedpoint , and mount the power amp at the back arms of the dish, or at the base of the mast piece (ground mount).
Radios used are IC910h or IC9100, some use transverters. Lock everything to GPSDO or a OCXO. The high stability option for the IC910h is good.

Software , use Joe Taylors WSJT. also use vk1od Owen Duffy's NFM program to do accurate sun noise vs cold sky measurements to optimise your antenna setup.
The best website to see realtime moonbounce activity on 23cm is HB9Q.CH, its where we hang out when actively running our stations to coordinate etc.
More info to follow
73 Dave vk2jds]]>