Palstar BT1500A
$$$$·
| Frequency | 1.8-29.5 MHz (160-10 m); widest matching on 20-160 m, narrower on 10-15 m |
| Bands | 160m, 80m, 40m, 30m, 20m, 17m, 15m, 12m, 10m |
| TX power | 1500 W (A manual antenna tuner, not a transmitter. Rated 1500 W PEP SSB/CW, and 1000 W on 100 percent-duty modes. Matching range about 2500 +/- j2500 ohms on 20-160 m and 1000 +/- j1000 ohms on 10-15 m.) |
| Modes | manual balanced-line (Double-L) antenna tuner with cross-needle SWR/power meter |
| Weight | 7.7 kg (17 lb) |
| rf input | SO-239 coax input from the transceiver, through a ferrite 1:1 input balun |
| antenna | Balanced-line output terminals for open-wire / ladder-line feeders (the tuner is inherently balanced) |
| meter | Built-in illuminated cross-needle power/SWR meter (Active Peak, Peak Hold and average; 300 W and 3000 W ranges) |
| power req | None for tuning - it is a passive manual tuner; only the cross-needle meter's lamp uses a small DC supply. |
The right tool for an open-wire-fed antenna: a genuinely balanced 1500-watt tuner with two tandem roller inductors, so it tunes ladder-line antennas without the heating, loss and occasional damage that plague coax tuners fitted with an output balun. Its switchable dual-section capacitor gives a very wide matching range across 160-10 m, it has an excellent peak-reading cross-needle meter, and it is heavily built American metalwork.
It is a specialist, designed to do one thing - tune balanced (ladder-line) feeders - so it is not the tuner for a coax-fed antenna or for someone who wants a general-purpose unit. It is a manual tuner (hands-on tuning every band change), it is large and heavy at 17 pounds, and at around $995 it is a premium price for a single-purpose tuner.
The Palstar BT1500A is a premium, truly balanced 1500-watt Double-L tuner built specifically for open-wire and ladder-line fed antennas, which it handles far better than a coax tuner with an add-on balun. It suits an operator running a doublet or loop on balanced line at up to legal-limit power; those with coax-fed antennas should use a standard coax tuner such as the Palstar AT2K instead.
The Palstar BT1500A is a specialized antenna tuner built for one job: matching antennas fed with balanced line (open-wire or ladder-line), at up to 1500 watts. Most tuners are coax (unbalanced) designs with a balun added at the output to feed balanced line, but a center-fed doublet on random-length ladder line can present wildly varying impedances, which makes that balun run hot and lossy and can even damage it. The classic solution, as QST's antenna columnist has noted, is an inherently balanced tuner, and that is what the BT1500A is.
It uses a Double-L network with two precision ceramic-body roller inductors mounted in tandem, giving a genuinely balanced match, plus a massive dual-section capacitor (960/65 pF, rated 4.5 kV) that can be relay-switched between the input and output side of the network and between low and high bands to maximize the matching range. The result covers 160 through 10 meters (1.8-29.5 MHz), with its widest range on 20-160 m. A ferrite 1:1 balun feeds the SO-239 coax input from the radio, and the balanced output terminals go to the ladder line. An illuminated cross-needle meter from Palstar's PM2000A wattmeter shows power and SWR with Active Peak, Peak Hold and average readings on 300- and 3000-watt scales.
It is heavily built in 11-gauge iridite-treated aluminum, measures about 13 by 6 by 16 inches and weighs 17 pounds, is made in the USA, and sells for around $995. Being passive, it needs no power to tune. It is rated 1500 watts PEP (1000 watts on continuous-duty modes).
It is a single-purpose specialist: the tuner to choose if you run a doublet or loop on balanced line. For coax-fed antennas, Palstar's standard manual tuners such as the AT2K or the two-control AT2KD are the right choice.