One Becomes Two

Last November, I wrote about the initial thoughts we had to bring more capability to KL2R as a multi-two station.  After considerable research and planning, the efforts are coming to fruition in time for the spring contest season. 

Station Master

The Microham Station Master serves multiple functions. It ties together the Microkeyer II, bandpass filters, and SixPak antenna switch into a powerful, centrally-controlled system at each position.  The SM is far more than your standard band decoder.  You can build extremely sophisticated logic for switching, timing (to avoid hot switching), and miscellaneous device control.  To get started, you have to define bands and then associate these bands with specific antennas or antenna groups.  You can even build virtual rotators with fixed antennas on a tower, multiple Beverages, or a four-square, for example. 

A nice feature of the band definitions is the ability to limit transmissions to specific frequency ranges.  For instance, in a phone contest you might want to specify only the legal phone sub-bands.  In that way you avoid inadvertently chasing multipliers into the non-US segments.  The Station Master will simply not allow you to transmit there, thereby avoiding a possible OO card or FCC notice.

The two Station Masters control their respective sides of the SixPak 6x2 antenna switch at the tower along with bandpass filter arrays.  Two ports, A and B, with DB-25 connectors provide plenty of outputs for switch control.  Eventually we will add a second SixPak to the entrance to the shack to select antennas not going through the tower switch and thus consolidate all inputs to the radios to two coaxial lines.

The Bandpasser

At one position, the W3NQN bandpass filters are combined with an FM-6 switch from Array Solutions.  The SM selects the appropriate filter by applying +12 VDC to a specific pin on the switch's DB-9 connector.  The assembly is effective, of course, but bulky.  For the second position,  Hamation's AS-419 Bandpasser proved to be just the ticket.  It is a compact, book-sized unit with filters for all the non-WARC HF bands rated for 100 watts at 100% duty cycle.  Control can be asserted manually through front panel buttons, or remotely with a band decoder, in this case a Station Master.

Seeing Double

The fall contest season has begun in earnest with some good band conditions and fun to go along with them.  To make things a little more interesting, we made some changes inside the shack.

With KL1JP's FT-950 sitting idle in the shack most of the past year, we decided to beging experimenting with SO2R in earnest by using dual FT-950s in recent RTTY, CW, and SSB contests.  We're not quite where we want to be yet.  The DX Doubler sitting on the shelf for several years was drafted into service, and it is simply not up to the task assigned.  That doesn't  mean it's not a fine SO2R controller.  It just doesn't suit our needs very well.  We're exploring other options, especially the Microham micro2R controller.

Automatic switching of bandpass filters is another big need.  Essentially, though, we need two filter switch boxes.  We have individual W3NQN BPFs purchased from Array Solutions, and strapping them together using their FM-6 matrix switch seems like a good way to go.  It's only $185.  However, what to do for a second switched filter set?  The FM-6 populated with NQN filters is a whopping $945, and the Hamation FilterMax III is $975.  So the Dunestar Model 600 filter system seems a much more affordable choice at $449.  Hopefully Santa will be generous in a few weeks with a wise filter system investment.

Of course, the second radio really needs an amplifier.  So far, the ACOM 1010 has proven to be a real winner for its price.  While a full legal limit, no-tune amp would be nice, the budget is very constrained.Therefore, we may be trolling for a used ACOM after the New Year.

It's the Power, Man

In November, KL2R purchased an ACOM 1010 amplifier from Array Solutions.  I really enjoy doing business with AS, and the ACOM line has a good reputation.  The 1010 fit the bill, as in budget.  Array Solutions cut us a break on shipping to Alaska to offset the "free shipping" benefit to Lower 48 hams.  I could not have been happier.

The amp remained idle until WPX CW, which was planned as a test run for Field Day using high power and generators.  Neal W7USB loaned a Generac 7 kW generator with 240 VAC output more than sufficient to drive the ACOM 1010.  After some fiddling to get the T/R delays set well for the FT950 and Microkeyer II driving it, we were off to the races.  The shack was quite hot, 85F, as a result of an extraordinary heat wave over Memorial Day.  As the ambient temperature increased, the G2 LED began to flash with more frequency.  The manual says it is an indication of overdriving or a need to adjust the amplifier tuning.  Neither was the case, and the error persisted even with 20 watts drive from the Yaesu. Oddly enough, switching to standby from operate while G2 flashed would trip the amp into fault mode. A number of causes are under investigation.  This remains a mystery, and the problem repeated itself during Field Day.  I need to complete testing on stable, commercial mains.

Mini Stack Match Arrives

A box from Array Solutions perched on my desk one morning a few months ago.  I was excited.  KL2R had just taken delivery of a Mini Stack Match:

The Stack Match principle allows you to phase two, three, or more antennas while maintaining a constant 50 ohms.  A number of configuration options are available, including both-in-phase (BIP) and both-out-of-phase switching for ultimate stack flexibility.  Being on a tight budget, I opted to purchase a two-antenna Mini Stack Match (BIP only) and use 2x1 coaxial switches to switch it in and out of line.

Although I've had limited time to test it, its value became immediately obvious.  I had begun to notice the 20 and 15m paths to East Coast stations were, at times, slightly skewed to the north instead of the normal due east, thus making it difficult to work those stations using the usual NA C3 at 55 feet.  This was particularly true in the early morning and evening. The European C3 pointed north was somewhat better, but I found it frustrating to have to toggle back and forth between the tri-banders to get them to hear me.  When I hooked up the MiniStack Match, voila!  The combination of using both antennas in the stack saved time and trouble of switching, and I could work across the entire US and Canada much more easily.  Another advantage I have found is that I no longer miss those brief openings to EU and AF when I happen to be running US/VE stations on 20m.  It's the best money I have spent in a long while.