[TowerTalk] possible 15M EME ES5TV to K3LR QSO on April 27.

TexasRF at aol.com TexasRF at aol.com
Wed Feb 6 12:46:57 EST 2013


Hi Tim, I will check out the date and elevation angles on both ends. It may 
 well be that the angles are not compatible for eme. To work, it would have 
to be  approaching moonset for ES5TV and shortly after moonrise for you. 
The elevation  changes about .2 degrees per minute so 5 degrees elevation 
happens about 25  minutes before moonset and after moonrise.
 
On 6m, eme is often done with the 2nd and 3rd elevation lobe so you might  
want to do a computer run for both ends to see if one of the higher lobes 
can be  used. This is pretty tedious stuff and explains why many skeds are 
just done  multiple times to see if happy coincidence happens empirically. Of 
course we all  do some crazy things in the name of being part of a "first".
 
On the ionosphere issue, I am guessing that an open band will attenuate the 
 eme path quite a bit. One way to get a handle on this is to monitor 
background  galactic noise on a dead band vs open band. The difference in noise 
levels would  be due to attenuation differences as the noise passes through 
the  ionosphere.
 
I will let you know about the numbers for April 27.
 
73,
Gerald K5GW
 
 
 
 
 
In a message dated 2/6/2013 7:58:49 A.M. Pacific Standard Time,  
k3lr at k3lr.com writes:

Hello  Tonno,

If April 27th works out - I can be very ready to try this. That  is a good
open day for me. Maybe Gerald, K5GW can double check path loss  calculations
for EME on 21 MHz at that day/time for both QTH's to see if  this 10 minute
window might work on April 27 15 meter EME QSO according to  his program. 

We can have a multi Skype session web link going on April  27 - so guys can
see both ES5TV and K3LR ends live during the experiment  EME time.

The coordinates on the K3LR QRZ.com page have 1 second  accuracy for the 15
meter tower. At K3LR, the four high OWA long boom  stacked array has modeled
gain (with ground) of 21.9 dBd at a take of angle  of 4.5 degrees. The feed
system is very low loss - 200 feet of 1 5/8"  Andrews Heliax, so most of the
1500 watts in the shack makes it to the  antenna port power divider mounted
on the tower at the mid point of the  array.

I do not know if 15 meter EME be done during daylight hours when  the band 
is
likely to be open. Others may know that  answer.

73,
Tim K3LR

-----Original Message-----
From:  Tõnno Vähk [mailto:tonno.vahk at gmail.com] 
Sent: Wednesday, February 06,  2013 8:57 AM
To: k3lr at k3lr.com; towertalk at contesting.com
Subject: RE:  [TowerTalk] 15m monster finally up - EME and Video

Thanks Tim,

I  got a good program suggestion - MoonSked by GM4JJJ.

Not being very  familiar with this stuff yet I can calculate windows for us.

Basically  I am looking for moments when the moon is from 0 to 5 degrees in
both  locations and both are in darkness. It is not an easy criteria  to
fulfill.

The first slight chance opens on April 27 from ca 0210  to 0220z while I 
have
sunrise on 0230z already which might mean the band is  already open at 0210.

In summer we almost don't have common darkness so  I guess that rules summer
out. And now looking all throughout the year  there is no other time.

So we only seem to have a 10 minute window in  the whole year, Tim!:)

Is my logic correct here? Or could it be that it  could be done during
sunlight? In the sunspot minimum  perhaps?

73
tonno

-----Original Message-----
From: Tim  Duffy [mailto:k3lr at k3lr.com] 
Sent: Tuesday, February 05, 2013 11:50  PM
To: 'Tõnno Vähk'; towertalk at contesting.com
Subject: RE: [TowerTalk]  15m monster finally up - EME and Video

Hello Tonno!

Congrats on  a very FB installation! Your EME video is outstanding!

If the moon  times line up with you, there is enough gain with the 15 meter
28 element  array at K3LR to do EME. I'd love to try a two way 15 meter  
QSO.

http://www.k3lr.com/2007/photos/15mtower.jpg

http://www.k3lr.com/2011/CQ11CW/IMG_3300.jpg

73,
Tim  K3LR

-----Original Message-----
From: TowerTalk  [mailto:towertalk-bounces at contesting.com] On Behalf Of 
Tõnno
Vähk
Sent:  Tuesday, February 05, 2013 7:49 AM
To: towertalk at contesting.com
Subject:  Re: [TowerTalk] 15m monster finally up - EME and Video


Now all I  have to do is to find someone interested in attempting real 15m
EME QSO  (anyone done that before?) who would have coinciding sunset/sunrise
and  high gain antenna on  15m.

73

Tonno

ES5TV




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