WSPR-TX XP Plus Transmitter - autonomous WSPR TX

WSPR‑TX XP Plus is a standalone WSPR transmitter covering bands from 136 kHz až po 70 MHz, vybavený integrovaným GPS modulom, ktorý zabezpečuje presný čas a výpočet Maidenhead lokátora bez potreby manuálneho nastavovania.

How to determine propagation conditions using WSPR?

Zisťovanie podmienok šírenia pomocou WSPR is very effective and simple. Here's how to do it:

🔍 What is WSPR?

WSPR (Weak Signal Propagation Reporter) is a digital mode developed for monitoring and mapping the propagation of radio waves. Each WSPR signal is:

• very narrow (6 Hz),
• transmitted with low power (typically 0.1–5 W),
• decodable down to -28 dB SNR.

Using a network of receivers around the world, we can track, odkiaľ a kam sa signály šírili, na akom pásme a v akom čase.

🧭 How to determine propagation conditions via WSPR

1. Visit the WSPRnet.org website

Go Displays the map and table of captured WSPR transmissions.

• Displays the map and table of captured WSPR transmissions.
• Filter by volacieho znaku, pásma, doby a lokátora.

2. Monitor propagation from a specific station

• Search for your own callsign or callsign of another WSPR TX station.
• Uvidíš, where your station was received (tzv. “spots”).
• Suitable for monitoring band openings – for example, when new connections appear on 10 m, you know the band is opening.

3. Use the tool from HB9VQQ

• 

  Through https://WSPR.hb9vqq.ch data can be processed and analyzed in a clear form

4. Use software like WSPR in the WSJT-X package

• You can receive WSPR signals with your own RX and upload spots to WSPRnet.
• Alternatively, you can also transmit and track where you were received.

📈 How to evaluate propagation?

• Denné grafy (e.g. number of spots per hour) will show, kedy je pásmo otvorené.
• Smer a vzdialenosť spotov ukazujú, aký typ šírenia nastal (e.g. F2, sporadic E, tropo…).
• Comparing multiple bands (e.g. 20 m vs. 10 m) helps to understand, ako sa mení MUF.

🛠 Example of practical use

You have a WSPR transmitter (e.g. from ZachTek, QRP Labs alebo PC + SDR) on 20 m:

• You start transmission every 2 minutes.
• Na WSPRnet.org you monitor where you are heard.
• You gain an overview of current conditions – e.g. that signals are going to JA, ZL, or just in Europe.

✳️WSPR-TX XP Plus Transmitter

🔧 Key features

• Works completely autonomously after configuration (you only set the callsign via PC once) – no computer is needed after turning on.
• Napája sa z 5 V USB power supply, s príkonem cca 250 mA pri vysielaní (100 mA v pohotovostnom režime) – vhodné aj pre mobilné využitie s powerbankou alebo USB nabíjačkou.
• RF output approx. 250 mW, ideálny pre kontinentálne až medzi­kontinentálne WSPR spojenia závislé od podmienok šírenia.
• Dimensions of the compact module ~100 × 66 × 20 mm, weight approx. 40 g.

➕ Extended version 'Plus'

The “Plus” model adds to the basic XP:

1. Wi‑Fi connectivity (currently without functional firmware, but potentially for NTP synchronization or remote configuration).
2. Vstup pre externý frekvenčný referenčný signál (eg 10 MHz OCXO), which increases frequency accuracy if the reference signal is in the range of 8-18 dBM.

🛠 Open development and expandability

• Softvér aj schémy sú open-source and available on GitHub, allowing for custom enhancements and experimentation.
• The module is supplied already assembled, except low‑pass filtra, ktorý si používateľ dokúpi alebo zmontuje samostatne podľa požadovaného pásma – filter nie je súčasťou základného balenia, ale je predávaný samostatne (ak je potrebný pre funkčný RF výstup).
• An optional is available for convenient band switching Mezzanine LP4 karta, ktorá umožňuje ovládať až štyri filtre (band-hopping).

⚙ Usage and function

1. 

   Pripojte externú GPS anténu (3 m cable, part of the package).

2. Set the call sign via USB configurator.
3. Connect the antenna and power supply - TX will start transmitting autonomously in a random WSPR frequency 'slot' at a 2-minute interval.
4. GPS will take care of time and position synchronization - the module automatically generates the correct Maidenhead grid.

💵 Price and accessories

• Base model price WSPR-TX XP Plus je $79 (excluding VAT for EU customers)).
• Low-pass filters and Mezzanine accessories are sold separately, prices are listed in the ZachTek store

🧭 Who is it for?

WSPR-TX XP Plus is ideal for radio amateurs, experimenters, and mobile stations who want to transmit to the WSPR network simply, reliably, and minimally without unnecessary settings. Thanks to open firmware and compact design, it is an accessible and flexible tool for modern QRP WSPR experiments.