Let's say that you've successfully built and now have working one of Tony Park's fine diminutive SoftRock SDR transceivers. You've installed and debugged the necessary software component(s) and jumped through all the hoops to get it on the air. Let's continue the scenario to the point where you've decided that the SoftRock SDR transceiver is an absolute wonder of technology and amazing for the price, but that you've decided you need a bit more output power to really enjoy it. What are your options? So do you spend a few hundred dollars to enhance a $79 SDR radio or in the true spirit of ham radio, try to find something far more reasonable? So what does it look like? The Texas Topper (or the round Tuna Topper designed to blend in with the Tuna Can series of kits) is small and easy to build. The square Texas Topper version is Altoid's tin sized, but the height of the plug-in filter board requires a much higher case. The Texas Topper Amplifier pictured here was built into an aluminum Radio Shack Project Case with BNC connectors for input and output and a lighted power switch. The top of the case must be removed to change band modules. Heavier 16 gauge wire was used for power delivery as recommended in the downloadable online assembly instructions.
I've found that the SoftRock RxTx Ensemble, if driven at full output, will produce almost ten watts of output from the Texas Topper. I've reduced my drive to about 700 mW and see a nice easy 5 watts of output and very little heat from the single heat sink.
One can build it for 'fast' or 'slow' QSK delay, but 'slow' is recommended and was how I built mine. I'm very satisfied with the break-in speed for my level of CW (about 15-20 wpm).
So, in conclusion, I have found the Texas Topper 5 watt amplifier from QRPme.Com to offer good value, an easy build and satisfying results. It seems to be a good match for the SoftRock SDR transceiver.
I'd love to hear what kinds of packaging you come up with for this little amplifier and how it works out for you. Please consider sending me any photos of your implementations.
Amateur Radio: K3RLL
TEXAS TOPPER AMPLIFIER
Here is one solution to the inherent lower output power from Rockmites and, more specifically to my needs, the SoftRock Series of SDR Transceivers.
Let's further just imagine that you're just not making all that many contacts with the sub-watt level of output power. Is this you, buddy?
Am I talking to you? (Smile)
There is the HFPacker V4 amplifier kit from Virgil Stamps for about $250 or so.
Then there are the inexpensive Ramsey amplifiers, but you may not like all that you've read about them.
Or perhaps you've been lucky enough to locate one of the old Ten Tec 405 Amplifiers designed to accompany the earlier Argonauts, but it would need more drive than that supplied by the SoftRock SDR transceivers or Rockmite level minimalist rigs.
You've probably read about the Palomar, the Chinese TC, the Saieng (sp?) and the RM Italy CB-type amplifiers but you are concerned about filtering.
And there is the new kid on the block, the HardRock-50 that seems to be garnering some positive attention but it currently costs $300.
Sadly, the Tokyo HiPower 45 watt amplifier, though pricey, is no longer available.
Enter the Texas Topper 5 watt version of Chuck W5USJ implementation of NB6M's Mini Boots original design. Available as an easy kit from Rex at QRPme.Com, the latest version of the Texas Topper is multi-band (though not 'band-switching') with plug in filter modules for 80, 40, 30 or 20 meters.
For something less than $40, Rex W1REX supplies a the kit with a single 40 meter band module. The remaining band modules available as an extra-cost purchase for about the price of the amplifier.
Left: Open case showing limited required wiring. Right: with top cover attached.
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