ARCHIVE: Australian Ham Radio Discussion Forum ( AHRDF )

Greetings all.
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

Hi Dave and all, G4JNT has some good software that is good for sun noise
<!-- m --><a class="postlink" href="http://www.g4jnt.com/SignalMeasure.exe">http://www.g4jnt.com/SignalMeasure.exe</a><!-- m -->
I use it to cal the dish tracking system and set the feed focal point.

Cheers Ralph VK3WRE

Hi Dave,
Tnx for starting (continuing) the thread......Seems like 23cm EME is doing well in VK, a few more have dishes and should be on air soon, Phil VK4IIO springs to mind........Installed a 250W PA recently, but I am looking at the 400W SSPA fom DUBUS last year if I can source a PCB or better still, a kit.......

See you all on the moon

Phil

5Mx dish/septum feed with super VE4MA choke/250W SSPA/G4DDK preamp

Hi Phil,
Great to see you on here
Regarding the Dubus 400 watt amp using the Freescale MRF8VP13350N device from F1JRD
The pcb info can be sourced via email from <!-- e --><a href="mailtoUBUS@t-online.de">DUBUS@t-online.de</a><!-- e -->
Jeffrey WA6KBL is credited in the latest DUBUS with organising a set of PDF and DXF files for the board. its 4 inches by 3 inches.
just print them out on a printer and check measurements to ensure correct scaling.

73 Dave

Did see that, which brings me too the next question...where can you get low volume PCB's made?

Phil VK4CDI

Hi all,

I emailed off for the files and produced the gerbers and sent them off to 1 board house so far here is a run down of a quote i got back

Qty.(pcs)10, Unit Price($/pcs) $40.00, Setup Costs($) $240.00, E-test Costs($) $60.00, Freight Costs($)(DHL) $45.00

All the prices are in USD

I hope to find another board house for more quotes but seems few do Arlon 450.

If more people are interested im happy to look further for manufactures?

Matt

Matt can you upload the files here please.

Sent from my D5833 using Tapatalk

Another great evening tonight on 23cm moonbounce, with 2 new initials. OK1IL and IZ5TEP on 1296.065 JT65C.
No moon visible as it is cloudy here, so aiming was initially set with a digital elevation meter and a compass.
Azimuth is then adjusted by the audible strength of the return echos and the digital meter is used for elevation. Its all manually done, hands on, at the dish, out there with the mozzies and the dogs wanting to play ball etc as it gets dark.
Last weekend was a EME contest. Poor weather and work commitments restricted available time, so I only made 2 CW contacts into Poland and Russia.
The second leg of this contest is coming up shortly.
Also active is Kirk VK2MER and I am looking forward to another contact soon there Kirk.
Maybe we can tee up the vk4's and vk3's to join in, and Andy vk5fa too.
23cm is always interesting to experiment with.
The noise floor is so low compared to 2 metres. (unless you aim at trees)
73 from the doghouse, Dave VK2JDS

I just picked up this dish and have a set of board for a 300w amp on the way. So I might be able to join you soon.

I've put up 4 x 28 ele DL6WU's on 23cm and currently run 150w. Whats the chances of eme with that ?

Should be able to work bigger stations....you will be 3dB down because of your linear polarisation........circular is the norm....

Cheers, and look fwd to a QSO

Phil VK4CDI

Picking up a 2.4m TVRO dish tomorrow for free, so with some time and good management I may be joining you all on the moon in the next 12 months or so. Lots of reading to do to get my head around the best way to attack it all. I have a IC9100 with the 1296 module, but thats about it so VLNA (probably G4DDK) will be required and a SSPA (yet to decide on what I will get). Septum feed seems to be the way to go. Also need to make the AZ/EL tracking setup. May start with manual pointing using CCD camera and a monitor in the shack, as I have that stuff at hand. If the bug bits (and I belive EME is addictive from all reports) I will then look at a proper tracking setup.
I will no doubt be asking plenty of questions here as I progress down the slippery slope.

You will eventualy need a vk3hz riglock pll to fix the 9100 drift, but get going first and sort that out later.

Here i had a close lightning strike last friday eve, so have been putting the station through its paces to confirm if all is well.
Without moon to get echos from, and no sun (night time) the next best thing for receiver testing is to compare the noise from cold sky with the noise from a 50 ohm termnation.
With the dish pointed up into the night sky it just requires the 24 volts to be turned on and off to the transco sma relay at the rx feedpoint of the septum to switch between them.
The G4DDK vlna2+ is connected to the centre sma socket of the relay , with the septum on the NO port and the 50 ohm sma terminator on the NC port.
On receive the relay is powered up, so is the G4DDK separately, and its easy to drop power to the relay only.
Reduce (wind backwards) the RF gain of the IC910h so the Smeter shows S9. This prevents the agc from affecting readings.
I had measured 5.2dB difference prior to the storm. Now i measure just under 1dB using Owen Duffys NFM program.
The dural beacon 200kms away over the mountains is only just visible.
So, the vlna is working but at reduced gain. I swapped it for an older G4DDK lna version and saw an improvement to 4.8dB.
Dural beacon is more pronounced on the waterfall now, and barely audible using a BHI dsp audio processor.
With gain back to full on the IC910h i see 2 S points difference from cold sky to the 'hot' 50 ohm termination.
So, some diagnosis showed the biasing screwed up on the atf54143. Replacing it got the voltages back to normal.
These noise measurements can be improved with optimisation of the front end coils and the fet bias.
I hope this info has been of some use to you, how to test and optimise your feedpoint LNA without sun noise.
73 Dave

GD all,
Yep, that time of year, summer storms......
Nice explanation Dave.....
Watched the 5Mx dish bounce around fiercely last week during a big blow....Felt sure it was going to break and come down.....blew a mesh panel out, which may have helped save it. All repaired and tested for last weekends ARRL EME contest. What a fizzer compared to previous years.....only 8 QSO's for the two passes, only one CW station heard, previous tests CW band is like 20M.....Then the Elevation screwjack lost power......Later inspection revealed a grungy relay contact......All fixed and ready for the second leg of the test.

Hi all and thanks to Matt PP for his investigation on boards for the Dubus 400 watt 1296 amplifier design

Please add me to the list if there is going to be a "board Run" from a suitable manufacturer

Kevin VK4UH Brisbane

Any progress or news on a board producer for the DUbus 1296 400 watt design?

Could we start a list here for those who would like to put their names down to cost share a limited run for a board?

Not many of the usual companies have this substrate available

KJ

Might be easier to order the 300w pcb from Df9ic

Sent from my D5833 using Tapatalk

Wasn't aware he sold PCB's... I have made my own, but without plate thru holes, it gets a bit awkward milling the copper spreader.
First attempt blew both devices, only managed 80W for 10 in before the smoke escaped. In the process of redoing.......

Phil
VK4CDI

This weekend was part of the ARRL moonbounce contest, and there were lots of stations on.
I was up at 1 am sunday morning and 2am this morning to work the American window, and from 30 degrees down to moonset on friday warm up then saturday and sunday morning for russia, europe etc, england.
The cw end of the band from 1296.000 to 1296.040 was full of signals, sometimes several cw traces within a few hundred hertz of each other, especially around 1296.020 to 022.
The CW ops run lots of power, so small stations over here should be able to see them on the wsjt waterfall or spectran etc.
Big stations like HB9Q will gladly get on air for a sked for small yagi stations here, and you Will get his signal ! Have a google.

For the digital operators there were a long list of stations sitting in the HB9Q.CH logger, so no shortage of signals to look for.
Nearly all the digital stations I worked could have been worked with a 2 metre or 2.5 metre scrounged dish set up in your backyard.

Stations worked : NA : CW n4pz, wa6py, kl6m alaska. Digital were n5bf, wa3gfz, k2uyh, wa3rgq, w6yx, va7mm, kn0ws, va6eme.
EU : CW G4CCH, OK1DL. Digital HB9Q, sp5gdm, rw0ldf, g4bao, la3eq, with iz5tep, i5ydi, df2vj, df3ru and ok1il before contest
Oceania CW JA6AHB

You can do this too, and there are plenty of stations all around the world that reckon VK is rare dx. Moonset dogpiles for VK are common on large activity weekends like the one just gone.

You dont need fancy computer tracking and a mechanical nightmare if you set your radio and a laptop near the dish. Just aim manually and keep adjusting regularly.
73 Dave vk2jds

Greetings All.
Just F.Y.I. - I have moved home so have dismantled my 23cm E.M.E. station.... for now.
I hope to be back up and running 23cm E.M.E. early in the new year with a bigger dish and a new callsign

I definitely concur with Dave's comments: I started with a 1.8m dish, 45W and manual tracking. With that setup I worked quite a few on JT65, and a couple on CW.

But be warned: E.M.E. can become very addictive.