Rádioamatér, ktorý hľadá kvalitný balun, a durable antenna or reliable grounding, often ends up being a compromise. Either he buys a cheap product without documentation, or he pays for a professional technique that is not made for amateur bands. Belgian eshop RF.Guru is trying to fill this gap. Behind the shop is a radio amateur and VF engineer, who first measures his products himself and only then offers them further. The offer today ranges from ferrite cores for a few euros to complete ones Prevádzač v 19″ skrini.
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Why was RF.Guru created?
Zakladateľom je Joeri Van Dooren, ON6URE, who introduces himself as an RF engineer and antenna designer. In a small family team, Jonas Van Dooren is in charge of mechanical solutions and Jonathan Van Dooren is in charge of purchasing, logistics and administration. The same ON6URE is also worth otvoreným firmvérom OpenX6X00 pre transceivery Xiegu X6100 a X6200, which we already wrote about on the portal.
The beginning of the store has a very practical story. A reliable active loop antenna failed during a storm due to water entering it. According to the authors, this was a failure that could have been avoided with better designs. Added to this was frustration with antennas that bend easily, transformers without proper documentation, and manufacturers for whom weather sealing is an afterthought. The team therefore decided to produce technology that it would use itself.
"RF.Guru exists because good RF engineering should survive contact with both the measurement bench and the weather."
The philosophy of the store is VF technology, which is explainable, measurable and suitable for real installations. This includes documented parameters, measured assemblies and construction ready for outdoor assembly. Another principle is also important: the technical question should reach a person who understands the system, and not end up in an automatic answer. In addition to its own products, RF.Guru also sells goods from other brands, such as Amphenol Procom, Mastrant, Knipex and Schaffner.
News and interesting things from the last time
Kategória noviniek obsahovala v čase písania 78 položiek a dobre ukazuje, kam sa sortiment posúva. Pre telegrafistov je tu SmartCW, kombinácia jambického kľúča, CW trenažéra a rozhrania s pripojením USB-C, tlačidlom PTT, konektormi pre pastičku a výstup CW. Stojí 99 €. Za rovnakú cenu sa predáva VFO-Knob, a tuning knob with a touch display for the transceiver. The OpenX6X00 firmware counts with it via the TCI protocol, so it can also be used for remote debugging Xiegu. For quieter moments there is a miniature telegraph key µKey s kapacitným dotykom.
The CurrentScout HF current meter (€139) is also interesting. Such a meter is suitable, for example, for finding phase currents on the jacket of a coaxial cable, which are often the cause of interference in a shack. The Common mode Noise Reduction Kit for €69.99 is designed to suppress them. Among the novelties, we also find the Horizon1090 active antenna for ADS-B with an integrated SAW filter and a series of USB power supplies with low noise and galvanic isolation.
Swag for radio amateurs
A small category of accessories has a rather symbolic character. It offers an RF.Guru cap for €19, a coaster with an embossed logo and two rulers for the workbench. The 15-centimeter one is marked HAREC Bench Ruler, which is a nice detail for a radio amateur with a test according to harmonized requirements. Rulers cost less than two euros, so they can be added to a larger order.
Hotspots for analog operation
RF.Guru hotspots differ from regular MMDVM modules in that they are analog. A finished system image is available for SvxLink on Debian Bookworm, which also supports EchoLink. Digital hotspots and AllStarLink are only on the wish list for now, according to the store. So anyone looking for DMR or C4FM needs to look elsewhere.
The basis is the Analog HotSpot for VHF and UHF with a power of 500 mW for Raspberry Pi 4 and 5 from €289. There is also a version with 4G/LTE for the 70 cm band for €349 and a separate fourth-generation transceiver board with a power of 500 mW or 2 W. The system image on an SD card costs €22. For testing with minimal radiation, the NoTenna2 termination "antenna" for 2 W. The hotspots also include an assortment of power supplies, from official Raspberry Pi supplies to low-noise supplies.
Building your own converter
For clubs and groups considering their own converter, the category with boards, extensions (HAT) and control units is of interest. Vrcholom je analógový simplexný prevádzač pre 2 m s výkonom 30 W v 19″ skrini s výškou 2U za 1 084 €. Samostatne sa dá kúpiť aj prijímač pre 2 m v rovnakom prevedení za 720 €.
Those who want to assemble the converter themselves can find the SVXLink TRXrptr HAT for Raspberry Pi from €129, the SVXLink Receiver1 receiver boards for 2 m and 70 cm at €153 and the VHF/UHF transceiver module with a power of 2 W for the Raspberry Pi 4. Bandpasses for 6 m (30 to 70 MHz), 4 m (70 to 72 MHz) and 70 cm cost 89 each €.
Among the printed circuit boards are also smaller useful modules. These include broadband LNA so ziskom +20 dB pre 50 MHz až 1 GHz s ochranou proti ESD za 19,50 € a LNA pre LoRa APRS on 433 MHz. The receiver input protection with galvanic isolation and limiter for 1 to 400 MHz for €94 is worth paying attention to. Designers will also appreciate the development board µPico Stick s mikrokontrolérom RP2040.
Baluns and ununs
Baluny sú jadrom vlastnej výroby a je to vidieť už na pomenovaní. Pri každom výrobku je uvedený výkon s označením ICAS alebo CCS. ICAS (Intermittent Commercial and Amateur Service) zodpovedá prerušovanej prevádzke na SSB a CW. CCS (Continuous Commercial Service) znamená trvalú záťaž. Pre digitálne módy alebo RTTY v conteste je preto rozhodujúci údaj CCS.
The offer of current baluns and chokes 1:1 starts with the single-core type for 100 W and bands 160 to 10 m from €129. It continues through the four-core types for 5 kW at 40 to 10 m to the version for 10 kW ICAS for the entire KV from €247. There are also specialized baluns for hexbeam, spiderbeam, vertikály, smerovky a rotačné dipóly, balun pre VHF and VHF up to 1 kW and baluns to antenna tuners, including the transition from coaxial cable to open wiring. For assembly, a set made of stainless steel INOX 316 is used from €45.
Ununy covers the common cases of wire antennas in the range of 1.5 to 30 MHz. The 9:1 ratio is for non-resonant wires of random length, 4:1 for multi-band monopoles and wires, and 1:2 for short verticals to lower bands. They are produced in versions for 2.4 kW and 3.6 kW. For demanding users, there is a six-core Unun 4:1 for 160 and 80 m with a power of 8 kW from €300.
Surge protection and grounding
Ochrana stanice tvorí samostatnú skupinu. Zaujímavý je Open-Wire & Coax Bleeder for 3 kW CCS from €180, which removes static charge from the antenna on both the open line and the coaxial cable. Coaxial completes the offer surge protection Bourns for high frequencies for €118.55 and lightning rod for active receiving antennas for €83.22.
Earthing includes a universal stainless steel earthing pin from €83, a galvanized earth rod 65 cm long for €12 and tinned copper braided flexible jumpers with M6 bolts. The shorter one has a length of 15 cm and a cross section of 10 mm², the longer one is 25 cm and 15.09 mm². For problematic soils, there is an earthing mixture in a six-kilogram bucket for €59.
Filters: power supply, ferrites and duplexers
Interference from photovoltaic inverters is one of the most frequent complaints at KV today. The Schaffner FN2200-25-33 filter for 1200 V DC for €130, designed to suppress interference on the side of the solar panels, aims at this problem. For the mains side, there is an EMC Schaffner filter for 60 A and 520 V AC. A module with protection, slow start-up and filter for 30 A with Powerpole connectors is designed for 13.8 V power supply.
FT240 and FT140 ferrite cores are sold in grades 31, 43, 52, 61 and 77, mostly for €4.50 to €18. The store also lists indicative ranges: material 31 for approximately 0.1 to 10 MHz, material 43 for 5 to 50 MHz, and material 61 for 50 to 500 MHz. Anyone who needs to quickly suppress the phase current without disconnecting the cable reaches for a split core made of material 31.
For converters and more complex VHF/UKF installations, Amphenol Procom six-cavity duplex filters for 2 m (50 W) and 70 cm (25 W or 50 W) are available for approximately €478 to €508.
Maintenance of antennas, masts and mooring
Small things that extend the life of the antenna include silicone vaseline for sealing the connectors (100 g for €17) and Würth assembly pastes. According to the store, aluminum paste is non-conductive and protects against corrosion. Copper paste CU 800 is conductive and therefore suitable for screw connections and ground connections. M&P silicone sleeves are used to seal coaxial connections.
The masts are represented by a telescopic carbon mast in three lengths from €139, which is suitable for both wire antennas and portable operation. There are also galvanized tile load frames for a 60.3mm diameter pipe and 1×1m rubber tiles. Such a solution makes it possible to build a mast on a flat roof without drilling. The Fibox ARCA cabinet with IP66 protection will be used for external wiring.
Mooring is based on the Mastrant system: ropes of various thicknesses, sleeves in three directions for masts with a diameter of 10 to 60 mm, pulleys, tensioners, eyelets and a set with 30 m of rope for €35.99. For verticals, there is a stainless steel plate for radials with 32 holes for €99. The tools category includes Knipex and Bahco hand tools.
Wire antennas, end-fed and POTA/SOTA
Wire antennas form one of the widest groups. Antennas EFHW fed at the end of a half-wave radiator, they are produced as single-band and dual-band, for example 160/80 m and 80/40 m in an inverted L configuration for 4 kW or 40/20 m for 3 kW. For those who want more single-wire bands, there are 22, 37 and 51m EFLW antennas for 2.4kW. A compromise between the two is EFOC antennas with off-center feeding for 3.6 kW.
The classics will find doublets with open line 600 Ω for 9 kW from €114 and inverted V dipoles for 9 kW from €115. GRA carbon rods are intended for portable operation within POTA and SOTA. The CF5200 model has a length of 5.12 m for the 20 m band (€129), the CFP2600 model measures 2.48 m and is intended for 10, 6 and 4 m (€89).
Verticals, loops, active and VHF antennas
The IronWave range of fixed KV antennas stands out: IronWave6 for 40 to 10 m (3.4 kW, from €259) and IronWave9 for 80 to 15 m (3.6 kW, from €304). The offer is completed by VertiCore for 20 to 4 m, multi-band VertX for 20 to 10 m, XentrX for 40 to 6 m and a V-shaped SolidV dipole. Delta loops are designed for DX with a low radiation angle: multi-band DeltaRex (3.6 kW, from €377) and single-band SolidDelta.
Active receiving antennas are probably the best-known part of the assortment. EchoTracer3 is a broadband E-probe for 10 kHz to 1.5 GHz from €209. OctaLoop3 and OctaLoop3 Mini shielded loops, TerraBooster2 ground loop and shorted loaded SkyTracer2 active dipole cover 500 kHz to 30 MHz. VerticalVortex3 is an E-probe designed for the lower bands of 1.5 to 10 MHz. A practical addition is the RX Power Disconnect module for €39, which disconnects the power supply of the active antenna during transmission via PTT or RCA.
The VHF and VHF offer mainly consists of basic Amphenol Procom antennas for 2 m, 70 cm and dual-band. Mobile operation is represented by the dual-band antenna Larsen KG2/70CXPL for mounting through glass. For hand stations, there are Nagoya antennas and our own RF.Guru MonoBand HT. The ISM category includes antennas for 433 and 868 MHz from manufacturers Barracuda, Meteor and Larsen, and there is also a GPS antenna.
Coaxial cables, connectors and tools
Cables are divided according to use. For 50 Ω systems, there are EXTRAFLEX-BURY-7 and -10 for direct grounding, flexible 7.6mm STEALTH-FLEX-7 and POTA-FLEX-7, and Teflon RG142 with silver conductors. It is suitable for winding baluns that have to withstand high power. For satellite technology there are 75 Ω INTSAT and DIGISAT cables.
The N, UHF (PL-259), BNC, and F connectors are sorted by 5, 7, 10, and 13 mm outer cable diameters for easy selection. They cost approximately €1.60 to €12. In addition, transitions to the panel, twelve types of reductions and ready-made connecting cables with PL-259 connectors from 25 cm to 48 m. For assembly, there is a Knipex stripping tool, crimping pliers for BNC, F and RCA and cable cutters. The artificial load is represented by the NoTenna model for 10 W.
Power supply 13.8 V and Powerpole
The basis of the power supply is the Mean Well industrial power supply for 13.8 V and 26 A (360 W) for €109. Portable operators will be pleased with the HAMPwr+, which produces 14.8 V at a power of 50 W from USB-C PD. This allows the QRP transceiver to be powered from a power bank with USB-C PD support.
Voltage distribution is handled by Anderson Powerpole APP-45 connectors with silver-plated contacts for 30 A and 45 A, Iwiss crimping pliers and PowerHub4 and PowerHub8 hubs for 45 A. The offer is completed by flat two-core cables with a cross section of 0.5 to 2.5 mm² and a car socket with a PP45 connector.
Amplifiers, APRS, Raspberry Pi and more
Lineárne zosilňovače are represented by two models: LA145 for VHF with a power of 80 W for €229 and LA435 for UHF with a power of 60 W for €449. Category SDR receivers was empty at the time of writing. RF.Guru focuses more on active antennas that belong to SDR receivers.
For APRS, there is a 433 MHz LoRa car tracker with 400 mW power and 13.8 V supply for €96, together with LNA and suitable antennas. The Raspberry Pi category offers both the Raspberry Pi 4 and Zero 2 W, power pole extensions 12 to 24 V and a range of USB cables. The Teltonika RUT241 router will serve for remote access, and the Hammond polycarbonate box for the exterior will be used for building your own devices.
Conclusion
RF.Guru is not a shop with everything, but a shop with a clear focus. It is the strongest where it can apply its own construction: baluns and ununs with both ICAS and CCS performance, durable KV antennas, active receiving antennas and analog solutions for hotspots and converters. A well-thought-out assortment of accessories is built around it, from ferrites to grounding to Powerpole power supply.
Prices are in euros and are current at the time of writing. Several products have a "from" price that depends on the variant, and some items have been sold out. It is therefore worth checking availability directly on the shop.rf.guru website before ordering. Anyone dealing with interference in a shack, planning a new wire antenna or building a converter will find a lot of useful information there.