Thirteen antennas you can actually buy in Poland — from one that will fit on a balcony to a five‑metre column for a mast. Pick a model from the list or click a bar on the drawing: on the right I’ll show a photo, the parameters, gain converted to dBd and what to watch out for with that model.
Want to build an antenna instead of buying one? Calculate the dimensions in the antenna calculator, and the loss in the cable in the cable calculator.
The drawing is to scale — the figure on the left is 180 cm tall. This is the most important thing when choosing a base antenna: the difference between “fits on a balcony” and “I need a guyed mast” is four metres in this comparison.
Manufacturers quote gain in dBi — relative to a theoretical isotropic antenna. On the air and in descriptions of directional antennas you more often see dBd, referenced to a simple dipole. The conversion is simple and fixed: dBd = dBi − 2.15. That’s why the “6.5 dB” on the X-300 box is in practice 4.35 dBd — two and a half times less impressive, but honest. In the tables below I give both figures.
The second point matters more than the number itself. The gain of an omnidirectional antenna doesn’t come out of nowhere — the antenna doesn’t amplify the signal; it stops radiating it up and down, flattening the pattern at the horizon. The longer the column, the thinner the “pancake”:
The antenna itself is only a third of the story. Below are the things that in practice decide whether you’ll get through — ordered from the one that most often wipes out the premium paid for a better model.
On 70 cm 20 metres of RG-58 loses 6.6 dB — roughly the entire gain of an X-50. The extra you pay for a longer collinear then turns into heat, not range. The same run in H-155 costs 2.7 dB, in Ecoflex 10 — 1.9 dB.
Calculate your cableN is sealed and has lower losses on 70 cm, UHF (SO-239) is cheaper and available everywhere. With two metres of cable the difference is negligible; with twenty metres and operating on 70 cm — not so. Diamond in “N” versions gives an N connector, Comet is SO-239 as standard.
The manufacturer quotes a permissible wind speed: 217 km/h for the X-30, but only 145 km/h for the five‑metre X-510. An antenna that long acts as a lever — it’s the mount and the tube that determine the strength, not the antenna itself. At 3 m and above: a steel mount, a tube with 2 mm wall thickness or more.
The most common reason why an antenna stays in the box isn’t technical. Before you hang anything on an apartment block, check what your housing association actually requires and what it cannot require.
Antenna and the housing associationAn antenna bought “just in case” can be worse than a shorter one chosen for a specific repeater — especially in hilly terrain. First see what’s within your reach, then estimate the link budget.
Repeater mapManufacturers’ sheets: the Diamond Base Station/Repeater Antennas comparison and product sheets on cometantenna.com. Lengths and weights converted from feet and pounds, wind speed from miles per hour — hence the “uneven” values.
Product photos from the manufacturers, provided by their distributors. The technical drawings are mine — drawn from the same dimensions, to a single scale for the whole comparison.
Indicative, checked in August 2026 with Polish distributors. I verified seven of the thirteen directly; I estimated the rest within the same brand and tier — hence ranges rather than exact amounts.
Spotted a mistake or your antenna is missing? Write to me — I’ll fix it.
