Using WSJTX to test your antenna system with your main rig and a PC is relatively easy, we've documented how to do this here: WSPRX. But you many not want to tie up your transmitter for this task, particularly if you want to run a test over a log period of time. 

QRP Labs sells the Ultimate3S which is a self contained multi-band and multi-mode beacon kit. Just connect the U3S to your antenna and switch it on, the beacon will then transmit regular digital mode message on the bands of your choice. These transmissions are picked up by other Hams around the world and reported on the WSPRnet website: http://wsprnet.org/drupal/wsprnet/map

This US3 beacon can be left running continually, it's perfect for testing antenna systems over time. It is highly configurable to suite your own needs (like adding multiple antenna connections for example).A receiver and amplifier options are also available to complement this kit. For more info go to: QRP Labs.

I have really enjoyed making and operating this kit. When completed, the Ultimate3S is a robust, useful and good looking addition to the shack.

There are no surface-mount components, the assembly is straight forward. However, care is needed during the build as there is little room for error. Components will need to be soldered to the PCB's, terroids will need to be wound. The final configuration can be a little tricky, for example: Plugs can be connected the wrong way round, it's easy to apply 12v and damage critical parts! With care issues can be avoided. If you do make an error then fixing problems can be tricky.

It took me over four months to get this kit working correctly (because I made mistakes), the basic unit could be completed in a day if you're careful and good at these things.

The instructions that come with the kit are excellent and need no further explanation. Below I've made some notes on how to avoid potential pitfalls and improve your building enjoyment of this great kit.

The the Low Pass Filter filter boards are tricky to make and they're easily damaged when handling. To avoid damage, use hot melt glue to secure them in place after testing.

Connectors

It's easier to use header pins and sockets to connect this kit up, soldering wires directly to the board can make things difficult during future testing and modification. Boxes of header pins and sockets are easily available from Amazon and are handy to have around the shack.

Error proofing

It's easy to connect things the wrong way round, or plug things in the wrong slot:

• Label plugs and sockets.
• Mark LPF's with their band
• Mark connector orientation with paint (i.e blob of red/green paint on one side of a connector)
• Make connections to a good standard, pull test connections to ensure they are robust

The enemy of those WSPR spots is drift. As soon as your Q3S starts to transmit, it'll heat up the crystal and you will get drift, this could stop you from logging any WSPR spots. So this is important.

There are two ways around this:

• Buy the OCXO/Si5351A 
• Protect your Si5351A from heat.

Protecting your Si5351A from heat is well documented on the QRP Labs website, but it not obvious and can be missed. This is what I did:

Add a heat sink

To protect your Si5351A from heat you can glue a lump of metal to the crystal to slow and absorb any temperature variations.

Add a heat box

I also built a box around my Si5351A using thick plastic card to make a small box. This worked very well.

Either way, solving heat related drift is going to be required for those WSPR modes, so you'll need to address this right away.

If you fit the programming pins during initial assembly you'll be able to flash your own micro controller very quickly should you ever need to do this. Much easier than having to add the pins later on.

I've included instructions on how to flash the AT328P below.

I did damage a couple of the micro controllers when setting up the U3S. It is far easier and cheaper to flash you own replacements, here's how to do it: 

The following hardware is required to flash your own Ultimate3S micro controllers:

• AVR USBASP programming lead (with six pin connector)
• A pack of ATMega 328P's
• A copy of the latest firmware - from the QRP-Labs website

Simply replace the 14 pin chip, the GPS chip and other components will probably be okay:

• IC1 74ACT08, 14-pin DIP chip

To remove this you'll need a solder sucker pump. The IC and pump can be purchased from Amazon or eBay. If you don't fancy doing this then use an alternative GPS as shown in the next section.

You will need to replace the power transistors if you apply voltage the wrong way round to the U3.

Re-flash the firmware.

Here are the U3S settings I used to get my first 20m, 40m and 80m WSPR spots. 

Note: You will always need your highest frequency LPF fitted in slot 1!

Physical setup:

• LPF 1 10m *** This LPF must be fitted, this must be the highest frequency***
• LPF 2 15m
• LPF 3 20m
• LPF 4 30m
• LPF 5 40m
• LPF 0 80m - Located on main PCB

• GPS fitted - QRP labs

U3S settings:

• 1]: 0  003,570,100 WSPR 23 1 - Relay 0, 80 metres
• 2]: 3  014,097,100 WSPR 23 1 - Relay 3, 20 metres
• 3]: 5  007,040,100 WSPR 23 1 - Relay 5, 40 metres
• Message: 73 DE #CS
• Call: [your call sign]
• Locator: [set by GPS]
• (Frame Start): 14  00
• GPS (mode Baud): 2  009,600
• GPS: 0  01
• Cal: 01  120
• Park: 1  000,001,600
• Time: [set by GPS]
• XW=0 x2=0 Tn=0 Iv=0 TxS=2

Note: All other settings can be left as they are.

If all is okay you will instantly receive spots following your first TX cycle.

I purchased two receiver kits but was unable to get either of them to work. After many hours of debugging, desoldering, and checking, I eventually gave up on the receiver project as it was just making me miserable.

However, I did get a raspberry pi working with WSJTX and an external sound card, so it would have been good if the receiver kits had worked.

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