AMATEUR RADIO SALES


FINAL CLEARANCE

VISUAL VSWR METER WORTH £30 FREE

WITH PURCHASES OVER £100

COLLECTION ONLY

VISUAL VSWR METER FREE

WITH PURCHASES OVER £100 COLLECTION ONLY

OR FREE

50MHz 250W RESONANT END FED ANTENNA WORTH £40

CONTACT


COMMERCIAL ITEMS STILL AVAILABLE:

ORDERS AND QUOTATIONS WELCOME

CONTACT


2/4/2024: POSTCODE PRIZE WINNERS FEB/MAR NR9 & DN33

Email for pricing as there are many options available, like sockets, power levels, special ceramic insulators etc

mailto: G4ICD@BTINTERNET.COM


BALUNS/CHOKES/UN-UNs


1/1 CHOKES/LINE ISOLATORS:

Mini & Medium format 1/1 chokes, in line isolators, noise killers (in some cases), BNC or SO239 or “N” type, 25/50/100/250/400/1000 watt pep, all PTFE coax wound cores using Ni/Zn or Mn versions for different solutions. NO IRON POWDER CORES USED.

SPECIAL 1000Watt 1/1 CHOKE/LINE ISOLATOR:

A top quality 1/1 unit with the RIGHT core and the RIGHT high quality coaxial cable. Using the FAIR-RITE FT240-31 Mn core #2631803802 wound with PTFE semi-rigid RG402 coax which uses a solid braid and it does not get better than this. Tested on air with 1kw key down CW. The basic unit is fitted with certified PTFE sockets not cheap Chinese half plastic versions, “N” types are optional. Superb returned RF attenuation from 2 > 50MHz (approx 35db) and also good for noise reduction on the feedline where applicable. Resin potted for stability in UV protected lapped lid enclosure with internal rubber seal and suitable for indoor or outdoor use. Also optional RG142 double screened silver plated PTFE coax available, see further down page.

FT240-31 Mn core below with RG142 double silver plated screened PTFE coax

PTFE SO239 sockets, resin potted and the finest quality and price.


TRUE GUANELLA CURRENT BALUNS

PLEASE NOTE THAT THE FOLLOWING 2/1: 2.5/1 AND 4/1 MINI GUANELLA CURRENT VERSIONS WILL NO LONGER BE AVAILABLE WHEN STOCKS RUN OUT AS OUR CUSTOM MADE CORES ARE VERY LOW IN QUANTITY AND ANY FURTHER ORDERS WOULD HAVE TO BE A MINIMUM OF 500 UNITS WHICH IS NOT VIABLE: SO, WHEN THEY ARE GONE THEY ARE GONE!


2/1 UNITS: LIMITED STOCKS

2/1 MINI GUANELLA CURRENT VERSIONS:

REMEMBER: IF A 2/1 IS BUILT ON A SINGLE CORE IT IS A “VOLTAGE” UNIT AND NOT A CURRENT UNIT

A unique GUANELLA dual side by side cores (Ni/Zn/F14 special mix, custom made cores for optimum return loss) current balun. 50 > 100 ohms and designed from our superb range of GUANELLA baluns built to a very high standard. This unit is probably the only correct version ever manufactured, it uses the 2 cores to feed the lines correctly and does NOT use a single core for the 2 lines and then another core for a 1/1 unit (VOLTAGE UNITS). Depending on power requirements up to 6 cores are used along with up to 6 inter-woven windings which produces a good RL when terminated at 100 ohms over 2 to 30MHz (1.2 > 1.5 vswr). Housed in a poly uv enclosure and resin potted, 2 stainless steel line/mount supports are fitted. Suitable for Doublets, OSCD, and Delta Loop antennas as a direct connection to the lines/loop. Available with BNC or SO239 socket. 

The 2/1 Guanella Current Unit 


2.5/1 UNITS: LIMITED STOCKS

2.5/1 MINI GUANELLA CURRENT VERSIONS:

REMEMBER: IF A 2.5/1 IS BUILT ON A SINGLE CORE IT IS A “VOLTAGE” UNIT AND NOT A CURRENT UNIT

A unique GUANELLA dual side by side cores (Ni/Zn/F14 special mix custom made cores for optimum return loss) current balun. 52 > 125 ohms and designed from our superb range of GUANELLA baluns (unbal coax to bal lines/loop) built to a very high standard. This unit is POSSIBLY the only correct version ever manufactured and was down scaled from the 200 ohm Guanella version, it uses the 2 cores to feed the lines correctly and does NOT use a single core for the 2 lines and then another core for a 1/1 unit (VOLTAGE UNITS). Depending on power requirements up to 6 cores are used along with up to 6 inter-woven windings which produces a good RL when terminated at 125 ohms over 2 to 30MHz (under 1.2 vswr sweep terminated test @ 125 ohms). Housed in a poly uv protected enclosure (Grey or Black) and resin potted, 2 stainless steel line/mount supports are fitted. Suitable for Doublets, OSCD, and Delta Loop antennas as a direct connection to the lines. Available with BNC or SO239 socket.

The 100 watt pep version uses dual cores wound with 4 PTFE wires feeding current where it should be.

A superb sweep matched at 52 > 125 ohms

Below: Lockable line terminations fitted.

Below: Multi hole mounting BNC Versions of the 2.5/1 Guanella current Balun

Square loop BNC version below fitted with stainless steel mounting on the top of the unit for line strain relief

Below: SO239 versions resin potted


2.5/1 GUANELLA CURRENT 400w PEP VERSION:

REMEMBER: IF A 2.5/1 IS BUILT ON A SINGLE CORE IT IS A “VOLTAGE” UNIT AND NOT A CURRENT UNIT

A unique GUANELLA double stack side by side cores (4 x Ni/Zn/F14 special mix custom made cores for optimum return loss) current balun. 52 > 125 ohms and designed from our superb range of GUANELLA baluns (unbal coax to bal lines/loop) built to a very high standard. This unit is POSSIBLY the only correct version ever manufactured and was down scaled from the 200 ohm Minns multi-core Guanella current version, it uses 4 cores to feed the lines correctly and does NOT use a single core for the 2 lines and then another core for a 1/1 unit (VOLTAGE UNITS). 4 cores are used along with 4 inter-woven windings which produces a good Return Loss value when terminated at 125 ohms over 3 to 30MHz (1.2/1). Housed in a Hammond ABS uv protected black or grey uv enclosure and resin potted, 2 stainless steel line/side mount supports are fitted plus a top mounting loop. PTFE SO239 socket. Lockable line connectors. Suitable for Doublets, OSCD, and Delta Loop/Square Loop antennas with a direct connection to the lines.

400w pep ICAS 4 core 2.5/1                 

Terminated 125 ohm sweep               

4 core resin potted true current balun. Option of no SO239 but fittings for balance feeder to differential tuner.

In other words balanced feeder in and balanced feeder out.

4 x stainless steel strain reliefs for lines, mounting and coaxial cable.

Internal view of 4 custom made Ni/Zn/F14 cores with 4 interwoven PTFE windings TRUE Guanella 2.5/1 400w

2 Marine A4 stainless steel line strain reliefs, plus one for top mounting and one for coax cable.

Resin potted, condensation vent, lockable line connections and certified PTFE SO239 socket


4/1 UNITS:

VOLTAGE: CURRENT: UN/UN:

4/1 MINI VOLTAGE VERSIONS:

Mini 4/1 Baluns 2 > 30MHz RL = 30db, Ni/Zn/F14 custom made core wound with PTFE wire in PTFE sleeve, top commercial grade, 100 watt pep (400w versions made to order but larger enclosure), resin potted. Guaranteed the best available, BNC/SO239/”N” type skts.

4/1 MINI VOLTAGE UN/UN VERSIONS:

Mini 4/1 un/un units 2 > 30MHz RL = -30db, Ni/Zn/F14 custom made core wound with PTFE wire in PTFE sleeve, top commercial grade, PTFE SO239 or BNC socket, 125 watt pep (400w versions made to order but larger enclosure), resin potted, counterpoise/ground post fitted. Guaranteed the best available.

4/1 un/un superb 200 ohm terminated sweep offering -30db RL @ 2 > 30MHz, guaranteed the best commercial unit on the market

RL value: 30db over 2 to 30MHz centered on 15MHz +/- 15MHz

CONTACT

CLICK THE WORD “CONTACT” ABOVE


4/1 GUANELLA CURRENT VERSIONS: LIMITED STOCKS

4/1 MINI GUANELLA CURRENT

REMEMBER: IF A 4/1 IS BUILT ON A SINGLE CORE IT IS A “VOLTAGE” UNIT AND NOT A CURRENT UNIT

A unique GUANELLA 2 side by side cores (Ni/Zn/F14 custom made special mix cores) current balun. 50 > 200 ohms and designed from our superb range of GUANELLA baluns (unbal coax to bal lines/loop) built to a very high standard. This unit is THE REAL WAY to build the current balun, it uses the 2 cores to feed the lines correctly and does NOT use a single core for the 2 lines and then another core for a 1/1 unit (VOLTAGE UNIT). Depending on power requirements up to 6 cores are used along with up to 6 inter-woven windings which produces a good RL over 2 to 30MHz. Housed in a poly uv enclosure and resin potted, 2 stainless steel line/mount supports are fitted. Suitable for Doublets, OSCD, and Delta Loop antennas as a direct connection to the lines/loop. Available with BNC, SO239 or “N” type sockets. 

BELOW: HIGHER POWER VERSIONS 50 > 200 OHMS

Top commercial quality 4/1 Guanella current baluns. Multi-core, up to 6 cores used depending on power requirements, TRUE current units not fake single core versions, UV/IP protected enclosure, Marine M4 quality stainless steel line support rings, also provided for mounting and coax cable support. Dual special custom made Ni/Zn/F14 cores wound with silver plated PTFE wire. Genuine PTFE SO239 socket, resin potted with condensation vent. Dual ceramic insulators for lines fitted with solder tags and wing nuts. Superb sweep of 2 > 30MHz. Various power ratings for 100/125/250/400/1000 watts pep ICAS, optional tunable chokes on each line output to give a perfect balance (see further down this page). High power versions terminated 200 ohm sweep 0 > 30MHz: 15MHz @ RL 38db = (VSWR 1.03/1). Ideal for loops, Doublets and OSCD antennas. Compare this quality and price to the MFJ versions.

Which one would you buy?

Left: MFJ-911 300w ?? FT140-43 x 2 100w: Special RF Comms cores 2 x Ni/ZN/F14 250w: or 4 core 400w

RF Comms builds sweep below: The “TRUE” Guanella current balun

Return loss = 38db terminated at 200 ohms as pictured below using custom made cores and silver plated PTFE wire

The return loss on this unit is just superb: The REAL solution for Doublets, loops and OSCD antennas

400w pep version quad cores and dual windings: ceramic insulators: resin potted:

1 and 1.5 kw multi core commercial 4/1 Guanella current baluns also available in 2 core and 4 core FT240 format

True Guanella Current baluns, get the current to the antenna! and not the voltage

4 Stack “N” type 4/1 True Guanella Current balun above & below

Professional commercial results


9/1 VOLTAGE UN/UN UNITS:

Mini 9/1 un/un units 2 > 30MHz, Custom made Ni/Zn/F14 core PTFE wire wound, top quality, counterpoise connector fitted, BNC or SO239 sockets, non resin or resin potted, weatherproofed, cases are black or grey, main line and counterpoise ss strain reliefs, 100w versions, superb Rhombic terminators or just use as a multiband antenna (ATU required).

High power 9/1 VOLTAGE un/un units, Mil spec PTFE silver plated wire wound on a large Amidon core, lockable insulators pos/neg, PTFE SO239, 400w pep ICAS, marine stainless line support eyes plus mounting plus coax (ATU required), the best quality available.


49/1 UN/UN MULTI-BAND ANTENNA UNITS:

RESONANT END FED ANTENNAS

NO TUNER REQUIRED

FOR AMATEUR RADIO USERS

LOTS OF SPECIAL OFFERS

THE PERFECT SOLUTION FOR QRP (LOW POWER)

OPERATION & UP TO 1KW.

4 resonant (Bands 7/14/21/28MHz) frequencies from one piece of wire or use a half-wave length of wire for a spot frequency

between 2 and 30MHz

SUPER LOW COST AND SIMPLE TO INSTALL

READ THE PDF BELOW! CLICK THE LINK

The-End-Fed-Half-Wave-Antenna

Note the comments of recommendations

(G Whip Antennas G4ICD designers of the first LC resonant HWEFD in 2007 and read the reports in Eham )

KEY POINTS

1) DO NOT USE 1/1 CHOKES AT THE ANTENNA FEEDPOINT: WHY? Because ALL un/un units whether it be 4/1, 6/1, 5/1, 9/1 49/1 etc have the last winding connected to the earth of the RF socket, so the coax braid is used as the hidden counterpoise. If you experience RF in the shack then fit a quality 1/1 line isolator at the radio feed-point. Type “31” mix wound with RG142 is the best solution, but even at 400w I have never seen RF return problems.

2: For 7/14/21/28MHz we suggest 12 > 15 mtrs of coax and 20 mtrs of line, for 3.5/7/14/21/28MHz we suggest 20 mtrs of coax and 40 mtrs of line, remember that the unit is an un/un and if you change the feeder/coax the antenna resonance may move as this is an unbalanced antenna.

49/1 EFHW UN/UN 1KW UNITS:

Low profile 1000 watt pep ICAS unit using Genuine Amidon (Fair-rite) dual FT240-43 cores, 30kv 100pf 5% capacitor not 3kv like most units available, double bus grounded PFTE SO239 or “N” type socket, 3 x Marine M4 stainless steel rings for mounting (left), line support (right) and coax strain relief (front), and of course resin potted in a quality Weiss UV enclosure with rubber gasket lid and condensation vent. Under half the price of the MFJ unit and REAL quality!!! OPTION EXTRAS of GROUND POST EARTHING BOLT and ceramic insulator 

EMAIL G4ICD@BTINTERNET.COM


DUAL CORE 1KW SPECIAL BUILD WITH 4 SUPPORTS (A4 MARINE) AND GROUND/COUNTERPOISE EARTHING

1KW CHOKE

1000 Watts PEP (ICAS), Amidon FT240-31 Mn core (the best) wound with PTFE Semi-rigid Coax,

fitted with dual PTFE SO239 sockets, this is the best you can get!


49/1 400 watt single core version below.

Fitted with Genuine Amidon Fair-rite FT240-43 single core with either 14 SWG or Mil grade quality silver plated PTFE wire and 30kv 100pf 5% +/- quality capacitor.

CRAZY PRICE WHILST STOCKS LAST

see picture below

CONTACT

The 49/1 un/un: NO TUNER REQUIRED: A superb single frequency or multi-band unit, A RESONANT End Fed Halfwave antenna un/un offering harmonics from the base frequency, just add your wire, ideal for small gardens, low or high power units available, used by commercial HF users Worldwide with staggering in Country results. Our test unit has been demonstrated many times to Commercial and Amateur visitors showing just how good these units can perform as they offer RESONANCE. With just 10 watts of ssb (Icom IC-705 and TX 599) over 12000 kms has been worked on the higher bands via F2 (21/28MHz) subject to Solar conditions (A & K Index figures). Reunion Island and other islands in the Indian Ocean are worked on a regular basis from here in the UK and that is 8000 kms on 28MHz. Our units are resin potted and UV protected, 100w versions use custom made cores (Ni/Zn/F14) that offers a VERY low insertion loss of 0.3db, this is achieved by using a special core mix of Ni/Zn/F14 material and our special resin which changes the L/C ratio just enough to offer that little more return loss (RL vs VSWR), 2 units measured back to back = 0.6 db on certified calibrated equipment, available in BNC/SO239 or “N” type sockets. 50/100/200 and 400/1000 (dual core) watts pep versions.

A superb resonant antenna sweep and you can get 6 bands out of it

EMAIL FOR COLLECTION DETAILS

CONTACT

CLICK THE WORD “CONTACT” ABOVE


50MHz RESONANT END FED

Designed by G4ICD many years ago for VHF commercial applications (30 > 75MHz) this version is a “banded” L/C half-wave matching unit with no insertion loss, no core is used due to losses. It provides a superb match with just a Half-wave radiator made of kevlar or a telescopic antenna. Small footprint for qrp (100watt) or larger versions for high power (250 watt) it is the ideal solution to get on the band and work lots of exotic dx on VHF especially during the Summer months of Sporadic “E”.

Super match/sweep: 26/5/2023: Wkd 18 Eu Countries on ssb in 2023 (“ES” opening):

UPDATE 2024: Working mega amounts of dx in Eu/US/SA and Africa during late May/early June via “ES” and TEP linked openings, even working Aurora in April/May.

Below: 50 or 70MHz portable 1/2 wave resonant end fed (no cores used just a perfect LC match)

5Mtr Telescopic antenna set for 50 MHz (2.9 mtrs) or 70MHz (2 mtrs)

CONTACT

CLICK THE WORD “CONTACT” ABOVE FOR UK SALES


SV4401A HVNA

A FEW FREE UNITS SUBJECT TO CONDITIONS

We have been supplied with 5 of these units from a Telecomms giant to compliment our IR drone surveys for antenna Network problems, all are new but 3 have broken on/off switches and need repairing (I have now replaced the switches), after contacting the survey teams they are not required to be returned. One will be kept and registered with RFCOMMS the other ones are being offered FREE but with conditions. They will have to be registered to the user and remain the property of the Telecomms organisation and the user may have to meet the survey team on site in Hampshire at some point to do a sweep of the antenna system and then email the plot back to the controller of operations. The units are simple to operate, enter a start frequency (ie 2 MHz) and enter the stop frequency (3GHz?), press “RUN”, job done. Save the plot to the internal SD card and then email it to the info provided with the analyser.

The items are top class, they are not toys, they call it a handheld but it is mega big, 2 hands needed to hold it, the full colour HD screen is incredible even in bright sunlight, brand new and updated to 100 db dynamic range (S21), internal 6.7 amp USB rechargeable/replaceable battery pack. 0 > 4.4 GHz, kit is 3 kgs in weight, a mega large 7″ colour touch screen and does all forms of antenna measurements, coax loss, feeder checks, all S11 & S21 data measurements including low/high pass filter design, rf transformer sweeps, return loss and VSWR etc. In built RF & sweep generator etc etc. Email RFCOMMS to go on the list. Priority will be given to local knowledgeable operators of this type of equipment. It can be used for home RF research work. Cased with calibration kit, “N” type adaptors and large format printed instruction manual. Size is 190mm x 130mm x 30mm @ 1.9 Kg (3kg kit case and leads etc) and includes 8Gig SD card:

THESE ARE NEW UNITS:

UPDATE 11/4/2024:

2 UNITS NOW RESERVED AND SUPPLIED 6/4/2024:

2 MORE ALLOCATED AND SUPPLIED (BROKEN ON/OFF SWITCHES BUT REPLACED THEM) 10/4/2024:

TRYING TO GET ANOTHER BATCH OF “SERVICE REQUIRED UNITS” IE BROKEN ON/OFF SWITCHES WHICH ARE EASY TO REPAIR: 2 PEOPLE ON THE LIST 16/4/2024:

Superb Hi-res HD colour screen: Smith Charts, Feeder loss, Filter design, Cavities,

Harmonics, VSWR, return loss, anything to do with antennas and tuned ccts

The new 100db dynamic VNA lab standard instrument

The SV4401A Vs the Mini 1300

The “Monster” 4401A compared to a Rig-Expert AA 230 Zoom

Handheld?? You need 2 hands to hold this superb instrument

The new 6 GHz 7″ touchscreen version



VISUAL VSWR METER FREE

WITH PURCHASES OVER £100 COLLECTION ONLY

OR FREE

50MHz 250W RESONANT END FED ANTENNA WORTH £40

VISUAL VSWR METER FREE

WITH PURCHASES OVER £100 COLLECTION ONLY

OR FREE

50MHz 250W RESONANT END FED ANTENNA WORTH £40

CONTACT


ICOM/ELECRAFT/XEIGU KIT CASE £42

NOW SOLD

CONTACT