Dumb EME question #1

[VK3IH]

Probably the first of a series of dumb EME questions...

I have read up a lot BUT the question is:

Do you have to 'see' the horizon (or close to it) from Moonrise to Moonset to increase chances of contacts?

I live on a nice big hill but it is cluttered with the normal house/sheds/trees etc. I have a location in mind for a dish that has great Moonrise/East aspect all the way to North that will not 'see' the West/NorthWest/Moonset below about 30 degrees so well. Is this an issue or should I select another spot which has Moonset/East access but has large trees to North nearby (+ which will require more set up as the shed nearby is rough).

any advice appreciated

Paul VK3IH

[VK5PJ]

Hi Paul,
there are a few assumptions here, seeing the horizon is an advantage for extending the maximum distance of stations you seek to contact (as far as position on the earth goes) but in reality if both stations can see the moon at the same time it is not an issue.

A high angle to the horizon can be restrictive if you are seeking to take advantage of 'ground gain' in the contacts you are working. (in phase reflections from you antenna from the ground in front of you, search ground gain in google for more info)

Some times for smaller stations (like mine) ground gain can be the make / break factor in getting through to some stations.

I too have a limited western horizon (big hills) so have consoled my self to just accept the limitations of that direction and as long as I have a common moon window with the other station, a contact will happen at some point

You may find it is better to get a manageable location for the antenna rather than one that is difficult to work with and then focus on having some fun.

Note: I am a small time very occasional EME operator so others may disagree with my opinions.

Edit- I forgot to mention, you should grab a copy of the VK3UM moon prediction package and enter in some data for your home QTH, I think it can be set up with your horizon view and it will help you understand what impact it has. -Edit

Regards,

[VK3BJM]

G'day Paul.

At what frequency do you intend to operate?

73,
Barry
VK3BJM

[VK2JDS]

Hi Paul and Peter,
When the moon rises and sets in its northernmost declination having a good view to the horizon to the northwest gives you european coverage, northeast gives you america and canada etc and this is the most active time.
When the moon declination is such that it rises in east and sets due west you can work south africa to the west and south america to the east but there is not much activity at these times.
Its not necessary to have any northerly horizon as the moon will track 30 degrees or so upwards but you will be able to work Japan, New Zealand, Russia etc.
So the best option is to get northeast and northwest clear as low as you can as that will give you the most contacts, provided your antenna placement allows easy operation of your aiming and controls. I ended up building a small shed/hut next to my dish and all the gear is installed in it to allow easy dish aiming whilst in the middle of a contact. I just dash out and re-aim each minute, or over on CW, while hearing the radio clearly.
The lowest I can aim to the northeast and northwest is 7 degrees due to distant timbered ridgelines.
Nearfield trees and buildings are your worst problem.

73 Dave vk2jds

[VK3IH]

"When the moon rises and sets in its northernmost declination having a good view to the horizon to the northwest gives you european coverage, northeast gives you america and canada etc and this is the most active time"

That is what I suspected... getting Northwest view will require it to be either mounted at the shack on an over tall mount or shoot through trees or a relocation 150m from the operating shack. The only other issue with this site is it will be visible to my only neighbour...... Good point about trees to North, they may be out of moon view so to the dash and aim technique which will be my method to start with.

I need to make some observations...

Any advice on signal degredation on 1296 through vegetation? (row of Cypress trees mostly 60m away) is it catastrophic for EME ?

I intend to use 1296Mhz as I no longer have my 10Ghz transverter.


Paul

[VK4TI]

Wet foliage will kill most signals , perhaps your neighbour might appreciate some trimming on the fence line ? , it's been ages since I played but some remote controlled steerage
( electirc rams from ebay ) and a boom mounted inexpensive cctv cam makes life easier , remember high as you can and to prove it stand on your roof , quite amazing what a few meters can do . Hope it goes well .

[VK2JDS]

Those trees will greatly attenuate the weak signals you are looking for, also they are noisy.
Nearfield trees are bad, farfield trees on a ridgeline a kilometre away with the moon setting into those trees will reduce your self echos to near zero however you may still hear strong stations through them briefly.
Mounting large dishes on tall poles isnt a good idea when storms and high winds turn up, also manually aiming a tall dish is difficult, i already have to climb a ladder to aim this 5metre dish at low elevations, when its fully cloudy you will be searching for echos by moving the dish slightly left or right of your calculated azimuth, pressing the morse key or whistling into the microphone and listenning for echo, looking at spectrum waterfall screen etc. Motor drive with an accurate tracking system makes things heaps easier, when you eventually get time to implement it in the future. For the time being you can remove the elevation uncertainty by using a digital elevation meter available from hardware stores. That way only hunting azimuth is required. On clear days and nights a camera will do.
Are you going to gippstech?
73 , Dave

[VK3IH]

VK4TI - the row of trees are mine the problem is they are 20-30m high cypress trees leaning over a 20m long shed.....

Dave JDS, yes I thought the high mounting would be tricky and no doubt lead to some movement of the dish. I live in a very windy area to add to the decision making.

I will be at Gippstech all day Saturday, would love to talk to you there.

Maybe I should post some pictures (but seem to leave and get home in the dark at the moment!)

Paul VK3IH

[VK4TI]

I understand the trees are attractive , and make rubbish over the place and more work , personally they would shrink over night getting a chance to thicken and blossom whilst remaining shorter

[VK5TX]

The photos are of my view of the moon raise and moon set. Pass the trees is open land. Would it be worth trying eme on 2m?

I am located in woomera.

[VK3ZAZ]

The photos are of my view of the moon raise and moon set. Pass the trees is open land. Would it be worth trying eme on 20m?

I am located in woomera.

That's question #2

Ground gain is everything on 6M band plus extensive antenna gain.
And the 11M25WL was the ultimate single yagi for its day, 53 feet long 12 db genuine gain
and low angle or radiation,
all the VK3 F2 6M records also were set using it.
It was not elevated
I am talking CW not robotic modes.

[VK3BJM]

The photos are of my view of the moon raise and moon set. Pass the trees is open land. Would it be worth trying eme on 2m?
I am located in woomera.

I'd suggest you download a copy of the latest version of Doug's, VK3UM, EME Planner. He's added a rather dandy new function called "Monthly Data", which includes a good graphical representation of how much variation in Moon Rise and Set Azimuth you can expect from your location. Just add your location details to the Planner and let it do the work.

http://www.vk3um.com/eme%20planner.html

For instance, from my location this month, moon rise Az varies between 65 and 112 degrees, and moon set shifts between 247 and 292 degrees. That's about 45 degrees variance during the month. The trees might be in the way only for part of the month. In which case, put up the Yagi, have a go when the trees aren't in the way, and that will be a baseline to see what (if any) attenuation they introduce. They don't look as bad as ancient cypress hedge would look.

At least they're not going to be wet trees very often, which would be worse for your signal...

I can guarantee you'll be popular with the Moonbounce crowd!

73,
Barry
VK3BJM

[VK5TX]

Thanks. As far as I can see the gird square has never been activated

Sent from my D5833 using Tapatalk

[VK3DXE]

Absolutely give it a go on 2m. Those trees shouldn't affect too much unless they're wet.

Provided you have a reasonable 2m yagi (10dBd+) and no major issues with local noise, then have a listen on 2m at moonset, as there are a lot of big guns in Europe that you should hear, even on a very modest setup.

Aim for a period of low degradation so as not to be disappointed. This page is excellent for planning your operating schedule: http://www.mmmonvhf.de/eme.php You want to be listening when the RED line is indicating the lowest figures. Also note that the page also grabs any post with "CQ" in it off the loggers and posts them down below. Also watch the N0UK logger (MMMonVHF also has a link to it down the page) to see who is where and to get an idea of who/where/what/how big you can hear.

Also be aware of the effect of Ground Gain. Be patient and you'll see (provided you're hearing anything) signals peak quite strongly at certain elevations and also drop right off when the moon passes through your GG nulls.

Also note that WSJT gives you real-time moon az/el data too, as well as the calculated degradation figure for your location. When I was living in inner Melbourne, 2km from the CBD, depending on the azimuth at moonset, I would often have speaker copy on my single yagi during GG peaks and with the degradation figure <2.5dB.

[VK5TX]

So after playing with the VK3UM software. The photo above shows the difference window of the moon.

[VK3IH]

So here is a panorama of the preferred location (?) it's at the edge of the cattle yards not far from the shack and power.

As you can see some Cypress trees are inconveniently placed.....

what does everyone think?

Paul

[VK2JDS]

looks like you are blocked for europe which is the main source of contacts, but the US and VE should be good.
see how you go
73 Dave

[VK3IH]

If you move back down the hill things improve to the west OR see front paddock view, this would not be as popular here or with neighbours.....

[VK2JDS]

Moonset north-west gives me most contacts. The moon drops from 15 degrees to 7 quite fast, but thats when all the action happens. This weekends new contacts were germany and italy on 23cm, they had 3metre dishes.
Just get the dish up and have some fun. Minimal mechanicals, aim manuaĺy, have fun with hands-on moon tracking.
73 Dave

P.s. if anyone wants to see and hear what 23cm EME is like then PM me or email vk2jds@hotmail.com.

[VK3HJ]

I've been following this thread with some interest, as I too find the thought of EME contacts fascinating. The moon is, I believe, currently the only satellite that would offer us the possibility of longhaul international contacts on VHF/UHF.

But, as I suspected, my station location does not offer a clear horizon in any direction. The other day, I noted that I lost about an hour of moonrise, due to the terrain and horizon clutter. Moonset would be worse, so I would not be able to see the moon at low elevations, ever.

Perhaps one day I might see if I can hear my own signal off the moon at a higher elevation, on 2 m. Otherwise, I could possibly set up on the top of the range further back in the property, but not until summer time!

I guess I'll just stick to HF/MF. I do rather well with HF/MF DX here. USA and Ecuador most evenings lately on 160 m. Can't complain, eh?

73,
Luke VK3HJ