[Elecraft] [K3S] mW TX for WSPR

Wed May 17 00:48:12 EDT 2017

The DX Engineering Magic-T combiner should work fine. 
Just be sure you don't too much power into it! Much less than 
one watt. 

The dual receive feature of DXplorer should do the trick for you. 

Same polarization antennas produce almost immediate good 
performance evaluation results. Evaluating the performance of 
antennas with different polarizations might take some effort. 

73 
Frank 
W3LPL 

----- Original Message -----

From: "Charles" <cbjesseenh at comcast.net> 
To: donovanf at starpower.net 
Cc: elecraft at mailman.qth.net 
Sent: Tuesday, May 16, 2017 10:40:09 PM 
Subject: Re: [Elecraft] [K3S] mW TX for WSPR 

Hi Frank, 

I think I see what you are suggesting - matching the power transmitted by each transceiver over a common antenna to assure I'm feeding two different antennas with the same TX power? 

I'm finding a Magic-T RX Splitter/Combiner https://www.dxengineering.com/parts/svp-sv-rsc-50 Can I use this to transmit as well? I'd like to give your plan a try. 

I was looking at the problem from a different perspective perhaps. Since the WSPRlite is a low output TXer (variable over 16 dB range up to 200mW, so I think that means 5mW to 200mW) I was looking to set that at 200mW on my random dipole antenna (two random wires, one E-W and the other W-E, joined by a 4:1 balun) and try to figure what power on my nearby 43ft Vertical gave the same profile on DXplorer.net. 

I think comparing a dipole to a vertical might be a interesting task, as it appears one is more "efficient" at night and the other during the day. The DX10 lines seem to invert at dawn and dusk on 40m. Two completely different antennas types cannot be equivalent a priori , I suppose! 

BRET/N4SRN 

----- Original Message -----

From: donovanf at starpower.net 
To: elecraft at mailman.qth.net 
Sent: Tuesday, May 16, 2017 5:40:31 PM 
Subject: Re: [Elecraft] [K3S] mW TX for WSPR 

Hi Bret, 

When using the DXplorer.net simultaneous receive measurement 
system, its best if you have the capability to start your testing 
by simultaneously transmitting through a Magic-T combiner 
into a single antenna. 

In less than 30 minutes you'll have enough data from DXplorer.net 
to calibrate out any power output difference between the two 
transmitters. After you've completed the calibration you're ready 
to connect each WSPR transmitter to the antennas under test. 

73 
Frank 
W3LPL 

----- Original Message -----

From: "MaverickNH" <cbjesseeNH at comcast.net> 
To: elecraft at mailman.qth.net 
Sent: Tuesday, May 16, 2017 6:37:31 PM 
Subject: [Elecraft] [K3S] mW TX for WSPR 

I'm trying to fiddle the TX power on my K3S using WSJT-X WSPR 1.7 on a 43ft 
Vertical to match the 200 mW output of a WSPRlite over a random wire dipole 
antenna, using the DXplorer.net simultaneous RX measurement system 
https://tinyurl.com/mthms72 . Is TX wattage continuous with rotation of the 
PWR knob? It has 0.1W decrements and I seem to find equal performance 
between 0.6 and 0.7W on the K3S and was curious if halfway between 0.6 and 
0.7W as I rotate the knob is 0.65W? I can imagine precision of TX power 
isn't accurate to more than +/1 0.1W but thought I'd inquire. 

Bret/N4SRN 

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