U3s surprise #40m #wspr


jakob@...
 

Hi WSPR fans,
I built a U3s a few months ago and run it now with about 1 watt on 40 meters. I usually get quite some DX spots in Australia, NZ, Japan, Brazil, Europe, and sometimes Antarctica and Africa. My box has an extra switch for the PA so I can switch off transmission without stopping the whole unit when I reconfigure the antenna, which I did yesterday evening. This morning the map showed only two spots from my station, one in Utah 917 KM, and one to California 650KM. All the DX from the previous days is gone. I found the cause quickly, I forgot to switch the PA power on yesterday. But I was puzzled that I got two spots on the first skip with no PA power. My antenna is an inverted windom. I measured the xmit power with the PA power off on the U3s and found that -7.6 dBm power (170 microwatts) feeds the antenna through the non-functioning PA. This is QRPPPP. Amazing!
Happy WSPRing!
73 de AA0JR Jakob Arizona


BrianB
 

Jacob,

I’m not surprised at your success.

A while back a number of us participated in the “Under 1mW Challenge” which was a totally informal fun event. My U3S here in California was heard all over the US, Canada, Australia, and China.

73,
BrianB 


David R. Hassall WA5DJJ
 

Dear Jakob,
I have a documented 1uW contact on QRSS for 1,164 miles between me and W4HBK in Pensacola, Florida back on May 17, 2014.   QRSS and other weak signal modes do travel much farther than we ever imagined.   The total test between WA5DJJ and W4HBK is documented on my website at: http://www.zianet.com/dhassall/BILLIONMPW.html It was a team effort between Bill W4HBK and I and I have not seen anything since to top it.   I doubt that it can be done on WSPR but that is an assumption made without testing the theory.   Propagation is astonishing sometimes and a lot of it's actions we take for granted. 
Take care and have fun. Try some QRSS with that U3S between those WSPR Transmissions and be prepared to be amazed again at where your signal goes.
73/74 Dave WA5DJJ
ALL BAND QRSS SUPER GRABBER http://www.qsl.net/wa5djj/


jakob@...
 

Thanks, David for the instructive info. I am definitely interested in ultra-low-power transmission and propagation. Thanks for the tips as well.
73
Jakob


David Wilcox K8WPE
 

Propagation is always there.  Mostly it’s the electrical noise that is so high we can’t hear the weak signals.  Take your rig out in the middle of a golf course at night or even early in the morning and see how the signals jump out at you.  And I am reminded of the guys that go to upper Canada to nowhere to listen for non directional beacons once a year.... they hear things we have never thought of hearing. 

Wouldn’t it have been fun to have two QCXs back in 1900 across the pond from each other and a high dipole?  Kerosine lamps and telephone wires don’t make much noise.  The rare automobile spark coil would be heard for miles back then. 

Just thinkin’

David J. Wilcox K8WPE’s iPad

On Jun 25, 2020, at 10:31 AM, David R. Hassall WA5DJJ <dhassall@...> wrote:

Dear Jakob,
I have a documented 1uW contact on QRSS for 1,164 miles between me and W4HBK in Pensacola, Florida back on May 17, 2014.   QRSS and other weak signal modes do travel much farther than we ever imagined.   The total test between WA5DJJ and W4HBK is documented on my website at: http://www.zianet.com/dhassall/BILLIONMPW.html It was a team effort between Bill W4HBK and I and I have not seen anything since to top it.   I doubt that it can be done on WSPR but that is an assumption made without testing the theory.   Propagation is astonishing sometimes and a lot of it's actions we take for granted. 
Take care and have fun. Try some QRSS with that U3S between those WSPR Transmissions and be prepared to be amazed again at where your signal goes.
73/74 Dave WA5DJJ
ALL BAND QRSS SUPER GRABBER http://www.qsl.net/wa5djj/