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Hello smart people,?

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So I assembled an Ultimate 3s WSPR kit. I booted it up, hooked it up to a dummy load, and everything worked as it should. But then, a thought.?

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What am I supposed to do for an antenna?

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My main station uses a ZS6BKW dipole, and my first thought was to take a piece of coax, solder the main wire to the "RF" pin, twist the shield wires of the coax into a single strand and solder that to the neighboring "gnd" pin, put a connector on the other end of the coax and use it to hook it into the ZS6BKW. But then, another thought.?

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How am I gonna tune this??

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No problem, I said. The ZS6BKW is resonant for me on 40 meters, so I put in the low-pass 40m filter, and gave it a go. Everything looked and acted like it should, but when I looked on , no contacts.?

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Then I took my IC-7300, dialed it down to 1 watt, and tried it on WSPR. Plenty of contacts, no problem, so I figure if I can get a signal to the ZS6BKW with the Ultimate 3s, I'll be ok. But I have no idea what to try next.?

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I'll include that it includes the GPS receiver, which seems to be working fine.?

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I have a feeling my problem is something simple, and I'm gonna feel dumb when I get it, so please be easy on me if I'm coming across as a noob.?

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But any help would be appreciated.?

On Sat, Apr 26, 2025 at 09:04 PM, DS wrote:

No problem, I said. The ZS6BKW is resonant for me on 40 meters, so I put in the low-pass 40m filter, and gave it a go. Everything looked and acted like it should, but when I looked on , no contacts.?

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Then I took my IC-7300, dialed it down to 1 watt, and tried it on WSPR. Plenty of contacts, no problem, so I figure if I can get a signal to the ZS6BKW with the Ultimate 3s, I'll be ok. But I have no idea what to try next.?

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Erm, I bet you've used the PC version of WSPR / WSJTX and applies the dial freq to your SSB rig,

and then used the same dial freq on a U3S ?

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Nah, U3S uses direct freq mode, RTFM.

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So if you're using 40m, dial in 7.040.130 on the U3S and see what happens.

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I bet that's your issue ;-)

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= Andy =

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Also there are other settings to get right, and for mine it takes a few transmission windows to get it sufficiently calibrated to fall into the 200 Hz span. I presume also you have a gps connected for proper timing.?

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The 3 most important items in WSPR:

1. CLOCK - Start on the 2-minute window

? ? Setting the Sys. Frq. and Ref. Frq. frequencies close is important.

??? Using the GPS is the ideal way! It takes care of both, but mainly the Ref. Frq. for TX accuracy

2. Frequency in the WSPR window

??? Dan's comment addresses this.? But that only works if the Ref. Frq. is set.

??? If not, the GPS may take some time to adjust it into "view"

3. Drift - mostly temperature of the Si5351 crystal and TCXO module

? ? Temp controlled crystal ??

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Another issue is that if you are using a GPS and don't get the Sys. Frq. and Fre. Frq. close, it may take awhile to get it working.

Make sure settings for Sys. Frq. and Fre. Frq. are according to the manual for the crystal you are using.

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Now try a receive test.

Set the IC-7300 and WSJT-X to receive only on 40m without an antenna (MAKE SURE TX is OFF) and the RX window (waterfall) is wide (not just 1400 - 1600.

?? Bins/pixel: 3 and Start at: 0 Hz should give a wide audio band.

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Then ENABLE the 40m TX window on the U3S with the desired antenna and let it transmit on 7.040.130 as Andy suggested.

You should see a signal now, and it should be decoded.

If you don't see a signal, dial around to see if the transmission signal is outside the audio signal.

If not post the new information.?

?? The U3S TX frequency?

?? The IC7300 dial frequency?

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-------
Robert Giuliano

KB8RCO