In a previous article on K8EZB station upgrades, I mentioned plans to add an Acom A1200S amp and 04AT tuner to my existing IC-7610 based station. This proved to be a bit more of a project than first thought. Some details below.

Ground System:

I had not previously used an amp in any of my stations, so I sought some advice from those with experience at this. All advised that a good ground system is even more important when using an amp, so I went to school on amateur radio ground systems. My main resource was the ARRL Grounding and Bonding book. After reading this carefully and consulting several other publications, I decided to install two ground rods interconnected with the electrical service ground rod, for a total of three ground rods. I was reluctant to drive in the new ground rods with a hammer or hammer drill, so looked online for alternatives. I came across several YouTube videos showing a “hydraulic” method using water pressure to make a hole for the rods, and decided to try this method. I purchased two 10 ft sections of copper plumbing pipe and attached a fitting to one end which allowed the connection of a garden hose. Using no more water pressure than is available from a common hose spigot, I was easily able to insert about 8 ft of each copper pipe into the ground using only water pressure. A few gentle taps with a hammer left about 6 inches above the ground. Ground rods were spaced apart about 20 ft and interconnected with heavy solid copper wire buried just under the surface. An Alpha Delta surge protector and DXE copper ground clamps were used to finish-off outside portion of the system. Exterior cables/components were installed in 2.5 in PVC pipe and irrigation system boxes for protection and easy access.

Grounds at the station operating table use a copper bus bar from KF7P Metalwerks, with each piece of equipment connected to the bus bar with 1” copper straps from Georgia Copper, also used to connect the station bus bar to the main Erico ground bus.

RFI:

Despite careful attention to grounding, I experienced two instances of RFI at higher power levels when using the amp. In one case, RF was getting into my station computer UPS, and in the other case, into my DSL modem/router. These problems were fairly easily solved by similar but different methods. Both solutions used generous application of ferrite beads and homebrew common-mode RF chokes wound on mix 31 ferrite toroids from KF7P Metalwerks and applied as suggested in an excellent paper by W1HIS. Getting the RF out of the router required, in addition to the RF chokes, relocating the router a considerable distance from the RF source and powering through a small UPS. All this took some patient research and sleuthing, but finally paid off.

Amp and Tuner Issues:

After doing considerable homework researching amps in the 1000-1500 watt class, I selected the Acom A1200S amp and companion 04AT tuner. One key requirement was a solid-state amp. In addition to the Acom, I initially considered the Elecraft KPA-1500, Flex PGXL, and Palstar LA-1K with Palstar HF Autotuner. I eliminated the KPA-1500 due to price (significantly more expensive for relatively small power output advantage), fan noise complaints, and reports of early failures. The Flex PGXL was made from unobtanium, not available for at least 8-12 months even after being introduced two years previously, and was the most expensive of the lot by a wide margin even without a more unavailable tuner. Both of the Palstar units had a mix of favorable and unfavorable reviews and, to my eye, a clunky looking industrial design. Although the Acom A1200S has had teething problems in the past, recent reviews have been mostly favorable, the price was very competitive, the industrial design appealing, the tuner nicely integrated, and the fact that DXE handles U.S. service made this choice fairly easy. However, all has not been wonderful with this choice. Due to a significant number of “nits” in the design, documentation, operation, and factory support of this product, I can give it no better than an “adequate” rating at this time (3 on a scale of 5). Most significant is a firmware bug I discovered when using the amp with recent vintage transceivers (IC-7610). The amp/tuner does not handle the digital modes correctly when executing a “Tune” cycle, and returns the transceiver to an incorrect mode at the end of a Tune, requiring the operator to manually reselect the correct transceiver mode; not a huge deal, but shouldn’t be necessary in equipment at this price point. I have communicated this issue to Acom in Bulgaria, and they acknowledge the problem, which they believe can be corrected with a future firmware update, however no visibility yet of the timing for a firmware fix.

The 04AT tuner incorporates a 4-port antenna switch and can be located remotely (closer to the antenna feed point) if desired. Antennas are selected from the amp front panel controls.

Despite the issues outlined in this update, I now have things settled down and working well. I still believe the Acom amp to be the best choice of those considered and actually available now. The Acom amp and tuner basically convert the IC-7610 into a 1200 watt transceiver, with band/mode changes executed quite transparently with the click of a mouse.

Rick, K8EZB