6m EME via wsjt

WSJT 65 (and variants) Discussion
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VK6KXW

6m EME via wsjt

Post by VK6KXW » Sun Jun 08, 2008 10:15 am

23:53 UTC Sat 07-Jun-08
Congratulations go to Lance W7GJ and EA/G8BCG Peter Talyor for successfully completing a JT65a moon bounce qso.
EA/G8BCG at his end quote off dxscape logger....
-27db hr by Lance on 50.190mhz
was only running 100 watts, 6m7j,5m coax,
rig on roof, antenna over ocean,
had 6 initials with this holiday set up !
http://www.g8bcg.org.uk/

What about you ... achieved moon bounce yet ?? Mmmmmm
Peter
VK6KXW
OF87jr

VK6KXW

Re: 6m EME via wsjt

Post by VK6KXW » Sun Jun 08, 2008 2:45 pm

Additional info from Lance,

Peter L. Jackson wrote:
> viewtopic.php?f=29&t=8002&p=3864#p3864
>
TNX Peter. That was the first time I worked Peter when his moon was setting out over
the ocean. The first time we worked was in November 2006, and the moon was setting
out over the land....but we STILL made it ;-) There were a few reasons why the
contact was possible:

1) Peter is an experienced operator and knows well how to use JT65A mode.
2) He had NO feedline loss (his rig was mounted up on the roof!)
3) He had a good yagi - the 6M7JHV
4) He had a great location with a clear shot over the ocean, for making great ground
gain.

I wish all my attempts at working new DXCC had a station like that! GL and VY 73, Lance

--
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8)
P.O. Box 73
Frenchtown, MT 59834 USA
QTH: DN27UB
TEL: (406) 626-5728
URL: http://www.bigskyspaces.com/w7gj
2m DXCC #11/6m DXCC #815

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VK5PJ
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6m EME via wsjt

Post by VK5PJ » Sun Jun 08, 2008 5:49 pm

I have tried and failed :oops: at my first few attempts to work Lance W7GJ. While I thought I had a fair chance to work him with the station AS IS, it would seem the 100 odd Watts and a single long yagi was no where near the mark for my location and the amount of ground gain available. Lance could not detect my signal off the moon but he was a fairly good decode here.

Yes I know, who was I kidding thinking I could be successful with no added effort? :!:

Next move is to :
1. Get a permit to use some more grunt on the TX.

2. Fix up the rats nest of interconnecting audio and control cables as my WSJT interface can not handle the added current of keying the P.A as well as the Tx.

3. Look hard and long at my aging antenna to see what needs a refurbishment, as I am told there are problems with the older M2's like mine, in the feedpoint area where he has used dis-similar metals and just force fitted them. Apparently once the goo that is pumped into the feed point box has dried out or leaked away, corrosion sets it and then there is a measuable resistance between the N connector and the driven element :twisted: )

The moral of this story, never under estimate the challenge of an EME contact.
Peter Sumner, vk5pj
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill

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Re: 6m EME via wsjt

Post by VK4GHZ » Mon Jun 09, 2008 12:53 pm

VK5ZLX wrote:3. Look hard and long at my aging antenna to see what needs a refurbishment, as I am told there are problems with the older M2's like mine..
With the Aussie dollar approaching parity, now is great time to buying stuff out of the USA.
I purchased my 6M7JHV when we were only getting 70 cents in the dollar.
At least the rising value of our dollar offsets inflation, etc. :D
Adam, Brisbane
http://vk4ghz.com | VK4GHZ on Youtube
Image Waiting for the perfect 2/70/23 multi-mode SDR transceiver

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Re: 6m EME via wsjt

Post by ZL1RS » Mon Jun 09, 2008 4:34 pm

There are several big 6M stations that are workable even without ground gain while using a single yagi and some horse-power on 6M (with the appropriate permit, of course 8) My own escapades with a home made 6 element yagi and Acom1000 have put a few of them in my log. At 4X/ZL1RS I worked several stations with the single yagi elevated to follow the moon and get away from the high local city QRN prevalent in Jerusalem ... just 9.5dBd and 1000W.

There are excellent commercial 6M antennas available ... and for those who like to homebrew their antennas at a fraction of the price, there are some good and proven designs at :

http://www.dk7zb.fox28.de/
http://www.yu7ef.com/LowTemperatureAnt.htm

The basic antenna construction rules apply ... follow the material sizes and element mounting methods as stipulated, including any through-boom correction factors if required! My personal preference is for the YU7EF designs with their 50 ohm feedpoint impedance allowing the use of a simple split-dipole driven element, direct coax connection, and "ferrite choke balun" ... but it definitely is a case of "horses for courses".

In recent weeks I've built the 3 ele 12.5 ohm DK7ZB 6M yagi, and after a small adjustment to the DE length (only because I used a different DE diameter), I achieved a 1.05:1 SWR, band noise peaking between 49 and 51Mhz, and have worked 9 stations in Europe on double hop Es from here in Addis Ababa, Ethiopia. On 2M, I built a pair of the YU7EF EF0211B and have 86 different 2M EME stations in the log ... running just 150W at this end! Pop (YU7EF) even included a photo of my little array on his EF0211B web page, and there are more pix on my own web site http://www.qsl.net/zl1rs/

For those who like to design their own or check their existing antennas/antenna designs, the antenna modelling software 4nec2 by Arie Voors at http://home.ict.nl/~arivoors/ is free and a good one. It is not the most intuative program to use, but the results compare well to the commercial antenna software offerings once you RTFM and get used to it!

73, Bob ZL1RS (for the moment, "guest operator" of ET3AA)
Bob, ZL1RS in the Bay of Islands at RF64vs
http://www.qsl.net/zl1rs

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Re: 6m EME via wsjt

Post by VK4ABW » Tue Jun 10, 2008 10:12 am

VK5ZLX wrote:I have tried and failed :oops: at my first few attempts to work Lance W7GJ. While I thought I had a fair chance to work him with the station AS IS, it would seem the 100 odd Watts and a single long yagi was no where near the mark for my location and the amount of ground gain available. Lance could not detect my signal off the moon but he was a fairly good decode here.

Next move is to :
1. Get a permit to use some more grunt on the TX.

2. Fix up the rats nest of interconnecting audio and control cables as my WSJT interface can not handle the added current of keying the P.A as well as the Tx.

3. Look hard and long at my aging antenna to see what needs a refurbishment, as I am told there are problems with the older M2's like mine, in the feedpoint area where he has used dis-similar metals and just force fitted them. Apparently once the goo that is pumped into the feed point box has dried out or leaked away, corrosion sets it and then there is a measuable resistance between the N connector and the driven element :twisted: )

The moral of this story, never under estimate the challenge of an EME contact.
Peter. Keep at it. The moon has good days and bad days. :roll:
Forms RO55 and RO77 are required for the permit, plus a small donation to the ACMA xmas fund.
Definately fix up the rats nest
I've also heard of dissimilar metal problems on the old M2s from several ops. Thats why i built my own..... 19.6dbd achieved :D

EME on 6......is always a challenge :)

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