Re: [K3S] mW TX for WSPR

Posted by MaverickNH on May 16, 2017; 10:40pm
URL: http://elecraft.85.s1.nabble.com/K3S-mW-TX-for-WSPR-tp7630731p7630733.html

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: [hidden email]
To: [hidden email]
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" <[hidden email]>
To: [hidden email]
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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