WWW.RFCOMMS.CO.UK is an R&D advisory/design/supplier to Commercial organisations requiring RF antenna matching solutions. With over 50 years of HF/VHF Communications knowledge we design and manufacture the highest quality HF 2 > 30MHz and VHF 30 > 78MHz RF matching transformers some using up to 16 cores per unit and made to Mil 810G specification. Power levels of up to 5 kw can be offered on some configurations. We offer Current & Voltage baluns, and Un/Uns plus custom made RF chokes for optimum attenuation required in the HF spectrum for noise and returned RF plus antenna symmetry. NOTE: Commercial sales only.
“UPDATE JUNE 2020”
COVID 19 CRISIS: We are open for commercial business but due to postal restrictions we can only deal with couriers for overseas customers.
HF & VHF Matching Units
HF: High impedance matching transformers produce single and/or multiple RESONANT frequencies. The transformers can be made in various configurations from 49/1 to over 72/1 with minimal insertion loss (1.3db) using special ferrite cores. The antenna is a 1/2 wave length single long wire and is called “The Resonant End Fed”. Using this technology single or blocks of resonant frequencies can be created for day/night time operation.
VHF: The VHF (30 > 78MHz) versions are available in 4 banded ranges as listed below.
Above & Below: New 125 watt 2 > 30MHz or 50 watt 30 > 78MHz matching units (higher power units available for VHF), low through loss (1.3db) on HF and zero loss on VHF, 50 ohms, uses half-wave length of wire for required single or banded frequency range. 2 > 30MHz or 4 banded VHF frequency ranges 30 > 45, 35 > 50, 45 > 60 and 55 > 78MHz, extremely efficient, no grounding required. Ruggedized enclosure IP68, resin potted. BNC or “N” type connectors suggested.
Below: UV protected enclosure which is resin potted, stainless steel mounting and line strain relief eyes, PTFE SO239 with options of BNC or “N” type connectors, heavy duty Mil spec line connector post. Made to your specific requirements. MOQ
Below: Small lightweight 705HF units available for low power commercial transceivers like the QMac HF90
Above: Multi-cores wound with Mil spec DEF 210 PTFE wire. BNC, SO239 or “N” type sockets. Stainless steel line support strain relief and rear mounting. Cores are resin potted for stability and IP rating. High quality and low cost. MOQ
Below: Small lightweight 705VHF 30 > 78MHz L/C units. BNC, SO239 and “N” type sockets available.
Below: Strong UV protected 50mm dia tube enclosures
Guanella Current Baluns
Above: The 4/1 Guanella Current balun, multi-core, extremely high quality: Other versions include un/un and voltage versions, all fully resin potted.
NEW CORES-NEW IDEAS
We are currently studying the use of FSCP (Fully Sintered Crushed Powder) which is a loose powder available in Zinc/Ni/Mn, this can be mixed with a polymer such as nylon and compounded to produce non breakable cores with irregular shapes, it also offers the choice to make high precision HF/VHF cores.
After many months of experimentation with new core materials and new designs we have now produced outstanding results offering superb balance and excellent return loss. The new designs are mostly multi-core units using PTFE Mil spec wire in PTFE tube and are available in both voltage & current configurations with different ratios available.
A perfect match: eg: 50 > 200 ohms
New custom made cores with a new Ni/Zn mix has given us ultimate control of return loss and provides a perfect solution for the ultimate unit. 2 to 16 cores are used depending on the ratio, I or V configurations, and power requirements.