Social Meeting at ESCC on 5th December

Our regular society meeting on the 5th of December was a social event hosted at our regular venue, Eastbourne Sovereign Saling Club.

This was well attended with a good selection of food and light refreshments being provided. I believe that this was enjoyed by all of the members who attended.

With a big thanks to Steve G8NFZ and Richard 2E0JXU for organizing the food plus hot and soft drinks.

ANNUAL DINNER Friday 20th January 2023

Members may already be aware that our annual dinner is being planned for Friday 20th of January 2023.

As previous events at the Langham Hotel have been well attended and very enjoyable, we intend to use their facilities again on this occasion also. The dinner will be from 1930. It is hoped that most of our members will attend and bring guests if they so desire. There is a booking form available on the pull-down Tab entitled MEMBERS. Blank fields show the choices of food available for selection.

Payment information is shown at the bottom of the form, with bank transfer being the preferred method. The last chance to book and perhaps, pay by cash will be at ESCC on December 5th at our club meeting.

Monthly Meeting 7th November

This occasion will be led by Tim M0THM who will be demonstrating knots used for portable masts etc.

There should be an opportunity for members to try their hands at knot tying, practicing the Clove Hitch and Bowline etc. all very useful knots to know in outdoor and everyday circumstances. The session will be an informal one, with plenty of time for refreshments and to catch up with the latest news from fellow members.

New members are always welcome to pop along and have a talk to members and or committee about what SARS does for amateur radio..

Monthly meeting 3rd October

This evening’s meeting will feature a talk by Tim M0THM on ropes and knots for antenna rigging – hope to see you there!

Sale of Surplus & S/Key Items PHASE 2

The society has a quantity of radio and related items that are now surplus to requirements. All proceeds from these sales will go directly to SARS funds. The purpose of these sales are to provide additional capital which will be used to finance new materials and equipment for use at our Beachy Head Radio Site. This facility is currently being improved, in order to be more useful and attractive to all of our members. Those wishing to operate at a well equipped site for Contests, Training, Nets or just regular Amateur Radio communications will enjoy a great site with very low RF noise.

All listed items are surplus and or old equipment that has been tested only to the extent indicated. It is all offered for sale without further guarantee. Old electrical and electronic items may develop faults at any time due to component failure or gradually operating causes, some items may need to be repaired or serviced but are all priced accordingly. Mains powered items have PASSED PAT tests at the time of inspection. It is however, recommended that these are carefully examined by a qualified person before use.

LIST of Items for SALE Remaining Items for sale to members only.

YAESU FT-707 HF Transceiver 10W version. £98.00

Rx appears OK 0.36uV for 12dB SINAD on USB at 14.320 MHz, Tx 7.7W (single tone modulation). frequency +145 Hz at above frequency. USB Tx O/P 12.7 W at 3.700 MHz, 13.3W at 28.70 MHz AM, 1.43 W USB.

This is a great radio for any member who wants to get on HF. With 10W o/p it is especially suitable for foundation lincencees.

c/w non OEM Hand Mic and Power Lead. With photocopy of Instructions & Manual in document wallets.


TRIO TR-751E ALL Mode 2m Transceiver c/w Manual £ 40.00

FM Tx appears OK 25.1W @ 145.50 MHz Rx SQ Opens at >0.92uV emf and AF O/P OK, but no noise or change of threshold on adjusting Squelch Control. USB Tx appears OK but no SSB Audio O/P, probably due to Squelch problem. Supplied c/w Mic (Up/Down Keys) DC Power lead and Instruction Manual with circuits.

TR-751E Serial No.7110242

ICOM IC-3200E 2m + 70cm FM Transceiver SPARES or REPAIR Reduced to Clear £ 20.00

UHF Tx and Rx appears OK, VHF Rx Ok but RF power output very low c/w DC Power lead. NO Microphone.


MALDEN Electronics HS-320 Digital Counter LED SPARES or REPAIR Free to first taker.

REEL of RG58C/U 50 OHM Co-Axial Cable. RS Components 388-338 Approx 98 metres ? £25.00

Tinned Copper Stranded, On original reel AS NEW with clear polythene wrapping. (New price >£150)

YAESU FT-77 HF Transceiver Good Used Condition, c/w Manual SPARES/REPAIR Only £60.00

No rubber covering on tuning knob. Powers Up and receives with good sensitivity but frequency display is unstable varying by perhaps +/- 2kHz or so. Frequency also needs adjustment by about 4-20kHz depending upon band. Sensitivity is sometimes intermittent, perhaps Band Pass relay contacts) Tx not tested at this time due to no mic.

FT-77 Serial No.Missing

YAESU FF-501 Dx. (52 OHM) Low Low Filter Fair Condition. Untested. £6.00

Traveler DC 120

ADONIS AM-503 Compressor Microphone Fair Used condition. 8 Pin Plug Untested £15.00

More items may be added, please check this listing regularly for. updates. SARS members will now receive 25% discount on all of the final sale prices.

Buyers are welcome to inspect goods before purchase for which any sale will be final.

Payment by CASH Only at time of collecting purchased items.

Prices too high? Make us a sensible offer!

For more information and to purchase items, please use the contact form. Members can message me by using the Forum thread. Barry G8DXU

From Larkspur to Clansman: Part 4

This instalment continues the series with a look at vehicle harness systems and Rebroadcast operation in more detail.

Clansman Fixed Harness System

The harness has the following prime functions: –

  1. PTT control and Audio path to selected radios for access to radio nets.
  2. Intercommunications between vehicle crewmembers and remote operators.
  3. Control of rebroadcast facilities.
  4. Connection of accessories, Loudspeakers, Data Terminals, Encryption etc.

Harness systems are not a new development and have certainly existed since the Wireless Sets No.19 introduced in 1941.

Control Unit No.16 capable of interconnecting two Wireless Sets No.19 plus WS38 AFV circa WWII (Note Rubber Snatch Connector for Headset)
Larkspur Operators Unit (Plessey MkIV Connectors) (Larkspur did not use snatch connectors!)

The harness and general control system has been gradually refined since these times with the Larkspur harness (c1955) representing a major step forward. The vastly superior connectors (Plessey MkIV) employed, together with Waterproof enclosures being just two of the improvements.

Principally the main aim of the harness is to facilitate intercommunications and operation of the radio sets from several different positions. In an armoured fighting vehicle (AFV) the Driver, Crew and Commander would each have access to a box linked on the radio.

In the noisy environment of an AFV it is essential that the vehicle commander can pass orders to those under his or her command. Also each crewmember must be able to talk back to the commander and others using the Intercom. Headsets with noise cancelling features are used in particularly noisy situations.

Each vehicle is fitted with harness boxes according to operational requirements and the

level of system control required or attributed to a particular location. Live access to radio nets depend upon the switch settings of the various boxes serving each harness location.

Principal settings being “I” Intercom “A” Radio system (Perhaps VHF) or “B” radio system (Perhaps HF). There is usually a momentary switch position labelled “C” Call, which injects a tone over the Intercom to attract attention. This is especially useful for remote operation where operators are nearby, but not continuously monitoring.

Ultimately access to the radio system via the harness or remote control is set at the radios

to which the harness is connected. Vehicle radios such as the RT321 and RT353 have a switch labelled REMOTE. When this is in the LOCAL position, only the local operator can key the transmitter with the PTT and speak over the air. Access to the radio from harness positions is blocked whilst under local control. However the intercom between crew positions continues to function independent of radio settings.

The RT353 also has a provision for Automatic Rebroadcast labelled “AUTO” this is used when two or more VHF sets are interconnected via the appropriate control box.

Harness systems vary from as little as one or two boxes in a lightweight vehicle to many on the larger armoured vehicles. The IB2 or IB3 units are the starting point for most installations where only two or three radios require interconnection.

Interconnecting Box 2

Interconnecting Box-2 Radio

For simple installations where there are only two main radios the IB2 box is probably the most effective method of control and interconnection. The IB2 allows the operator to access two sets from one control position and select either to monitor radio traffic.

The term “access” is used here rather than control. Settings such as frequency cannot be altered, either over the harness or remotely.

Rebroadcast between sets can be A-B or B-A as required. When working HF to VHF nets the local operator takes manual control, as the HF sets do not have automatic rebroadcast.

When two VHF sets are linked via the IB2 and their Remote Switches set to “AUTO “ incoming signals with the NATO 150Hz tone will trigger the transmit on the rebroadcast radio as selected on the IB2.

The local operator has the option to select break-in on either the A or B-side of the relay as desired but otherwise can leave the net unattended.

The IB2 unit contains active circuitry and accordingly requires a separate power cable from a fused outlet on the vehicles DC radio power distribution. Connections from the IB2 to radios A & B are made via 7 way control cables one to each set.

The main harness system boxes are linked together by 12 way connectors. This often takes the form of a Daisy Chain from one box to the next. On larger installations the boxes can be linked in a Ring Main, which increases the integrity of the connections.

If one section of the ring was damaged there is a good chance that continuity would be preserved by the other part and normal operation maintained.

In a typical small installation the only other box required might be a Loudspeaker amplifier. The 12w socket on the Amplifier Loudspeaker would be connected to the IB2 and the loudspeaker either connected to the 4mm “Banana Plug” terminals or 7 pin Audio plug as appropriate.

Amplifier AF Loudspeaker
7 Way Radio & 12 Way Harness sockets on IB2

Clansman Power Supplies

An important part of the Clansman system is the provision and distribution of battery power. Each piece of equipment is either provided with its own fused dc supply or powered from a common fused circuit. Following normal good practice the distribution fuses are principally intended to protect the connecting cables.

3-Way Power Distribution
Single-Way Power Box for GS Installations etc.

Units such as the IB2, Amplifier AF & DCCU also have fuses fitted that protect the individual units.

In FFR vehicles the radio system voltage is 24V provided from batteries that are separate from the vehicles electrics. GS vehicles usually have a 12V battery, which is common to vehicle and any radios fitted. In both cases these supplies are connected to a Fuse and Distribution unit. These have between one to fourteen outputs depending upon installation requirements. Simple GS installations may only have one fused output with a typical small installation having three. Larger installations will usually employ one or more 14-way units. These have eight standard 2-pin Clansman power outlets plus, four others and a pair of special Thorn 50 Amp sockets for powering an Amplifier RF 250W. When installed together with Tuner RF 250W this converts the RT321 to the High Power (300W pep) VRC322.

14 Way Power Distribution Unit
Widney Aish Mains 14/28V DC PSU

When Clansman radios are used as base stations it is often more convenient to operate these from a generator or AC mains supply. The AC Adaptor NSN 6130-99-362-6981 manufactured by Widney Aish in Poole Dorset provides 14/28V at about eight amps & is suitable for the lower powered radios. This will power the RT320, RT351, RT352 via DCCU and the RT321 directly. The RT353 may also be supplied but not on high power, which requires around 10 Amps. If the RT353 Tx power is switched to 15W or less there is no problem. The correct unit for supplying the RT353 & VRC322 station is PSU 50A, which is to be described later in this series of articles.

In the next instalment we look at the internal construction of Clansman sets with some general notes and a few pointers about repairs and the test equipment required.



Copyright 19.01.2014

From Larkspur to Clansman: Part 3

Following on from Larkspur to Clansman part 2, we continue with a look at some of
the accessories used with manpack sets, and Rebroadcast operation.

Accessories common to most Clansman sets

The compatibility of audio accessories between the various Clansman radios is an important part of the system. The following items can be used with all of the radios already mentioned in the text: namely RT350, RT351/2, RT320, RT321, and RT353.

Clansman Handset General Purpose (NSN 5965-99-620-5669)

The lightweight handset made by Racal Acoustics is probably the most common and popular accessory. The handset uses a simple noise cancelling dynamic microphone that produces very good communications quality speech. This is reasonably well sealed against the ingress of dust and water with micro-switches in both the audio and PTT lines. Earpieces are the well-proven rocking armature type, being a smaller version of the ones used with Larkspur. These handsets were perhaps not quite as robust as they could have been, with the clothing clip often being torn off and the edges of the rear cover broken which compromises sealing. There were two types of cord, coiled and straight, many surplus handsets having faulty leads. Fortunately these have plug-in connections and are easily changed.

Handset General Purpose

Handset Remote Control (NSN 5820-99-620-5670)

These are the same as the lightweight handset but with the addition of two press terminals to connect the two-wire DON10 cable. These handsets also incorporate a package that regulates the currents required for correct remote control of PTT and receive functions.
This handset cannot be used with the RT350, which does not have remote control.
The picture also shows Pouch Handset (NSN 5820-99-620-8031) often used to carry the
“Officers” handset, permitting operation and monitoring via the second socket.

Handset Remote Control & Pouch

Infantry & “B” Vehicle Headgear (NSN 5965-99-620-8320)

Again designed by Racal Acoustics for the Clansman range of manpack and “B” vehicle radio sets. This is generally the standard headgear for portable operation, lightweight vehicles and base station use. This headset is very comfortable with excellent receive audio quality. The boom microphone employs the same cartridge as that of the handset. The right hand (satellite) earshell is detachable, leaving its circumaural earpad in position to stabilize the assembly. Thus allowing ambient sounds to be freely heard if desired. All of the Clansman headgear assemblies have a snatch plug that will detach from the Pressel switch box or commanders box if pulled sharply. This allows soldiers to exit from vehicles in an emergency without having to first unscrew plugs or remove helmets and headsets.

Infantry Headset

Noise excluding headset (Sonovalve II)

Another RACAL acoustics product designed to provide hearing protection and communication where the user is required to wear standard steel helmets. Noise excluding earshells incorporate the Racal acoustic valve, which can be opened to permit the passage of airborne sounds but retain protection against explosive noises. Typical applications include soft-top military vehicles, command posts and gun sites etc. As noise excluding headsets go, these are relatively comfortable for extended periods of use.

Noise Excluding Headset

Switch Electrical (Pressel Box) (NSN 9565-99-763-7915)

The Switch Electrical is necessary when headgear assemblies are used and provides a method of keying the transmitter. The seven-pin plug lead connects to the radio or harness box, with the headset snatch-plug connecting to the socket. The Pressel Box is fitted with a switch that allows the microphone audio to be made permanently live, providing constant intercom facilities. When Headsets are used with the Commanders Personal Unit (CPU) the pressel box is not necessary as CPUs have their own PTT switch. Pressel boxes have a 1.5 metre lead with later versions being supplied with a coiled six-way cord. The units are fitted with a clothing clip.

Switch Electrical (Pressel Box)

Audio Extension Lead (NSN 5820-99-117-6142)

Used mainly with the RT350, which does not have remote facilities so that the operator can locate up to ten metres away from the radio. The set can also be placed in an elevated position, such as a wall, building or tree.

Audio Extension Lead


The Ground-Spike Antenna (GSA) is normally used with the RT350 and RT351 or 352 allowing the operator to locate in a safer position up to six meters from the antenna. The GSA consists of a mounting base containing a loading coil and spike for insertion in the ground. The aerial covers between 30-76MHz depending upon the number of rods used. The GSA kits normally contain five 25 inch or in the later issue kits, ten 13 inch rods.

PRC350 with GSA deployed in background
GSA Base Inductor & Spike


The Elevation Kit Ground Spike Antenna allows the GSA to be mounted at the top of the 5.4 metre Clansman mast, tree or other elevated structure. The Inductor RF (Coaxial) is inserted in the coaxial cable from the GSA base together with one of three different lengths of matching section, chosen according to frequency band being worked.

The choice of band being usedNo. of Short Rods (13”)No. of Long Rods (26”)
30-53MHzCoax 17-104
52-71MHzCoax 25-73
70-76MHzCoax 34-52

The shorter rods allow more accurate tuning, found by practical trials or by using an SWR meter. The main disadvantage of the EKGSA being that a change of frequency band requires it to be lowered for alterations to the number rods and matching cables.

Elevation Kit Ground Spike Antenna (EKGSA)


Automatic rebroadcast was mentioned in Part 1 with details on the RT353. In fact all of the VHF sets transmit the standard NATO tone centred on 150Hz. This tone is necessary to allow interworking with the radios used by other NATO forces, such as the SEM25, and is required to open the tone controlled squelch.

When enabled on the receiving set, the tone triggers the rebroadcast facility. In civilian terms such tones are now known as CTCSS (Continuously Tone Coded Signalling System) but are sent at a much lower deviation than that used with Clansman. The level normally being about 10% (+/-300Hz) of system deviation. Clansman uses a level of around 25% of main deviation (1.6KHz). This relatively high level tone is filtered out in the receiver and is only faintly heard by the operator. For amateur purposes the tone is not required and may be found to annoy some of those using receivers that do not have good filtering of the audio pass band (300-3400Hz). The tone from Clansman radios can be reduced or turned off, the method depending upon the particular set, exact details will follow at a later date if enough readers express an interest.

Simple Re-broadcast using the RT351

Connecting together a pair of PRC351 or 352 sets provides one of the simplest and useful applications of rebroadcast. This is easy to set up and just requires the two radios to be linked together by a pair of wires to the remote terminals.

The sets can be a few meters apart or separated by a DON10 cable of up to 3km length. This allows either one or both sets to be located on high ground. There is also the advantage that the transmitter can be located remotely and away from the operator making the position less vulnerable to radio direction finding.

The next installment continues by looking at the harness system and power supplies for vehicle radios.

Barry G8DXU

Copyright 18.12.2013

Festival Of Transport (Hellingly)

This excellent Steam, Agricultural, Commercial and Military Vehicle show will be running over the Bank Holiday Weekend from 27th-29th of August. It is located at Broad Farm near Hellingly and has many Trade stands, static exhibits plus on-site Catering, Refreshments and a Fun Fair.

Whilst again, not an official entry from the society, several members will be exhibiting their Commercial and Military Vehicles. There will be early Series One Land Rovers from 2E0JXU and M0JAO with a working Larkspur, Station Radio C12 from 1955. The Defender 110 Tithonus FFR from G8DXU a full compliment of Clansman radio equipment and a separate static display of Manpacks, as used in the Falklands conflict 40 years ago.

We will probably also display some radio equipment from the WWII era.

Callsign GB2FT has been obtained for working demonstrations of the radio equipment. Please see Calendar for further details. At 1400 (Local) on Saturday and Sunday we will put out calls on the following frequencies. 1976 kHz AM, 28.320 MHz USB and 51.70 MHz FM,

Rural Past Times (RPT) TN31 6JG

Whilst not an official SARS entry, several members will be exhibiting vehicles and equipment at this show.

In previous years, RPT ran at the Pestalozzi village, until its closure. And after two years, has now moved to a new site at Monkings Farm, Horns Cross. This mainly agricultural show also features, Commercial and Military displays plus many trade stalls, Bar and entertainments.

Our own Richard 2E0EOX is the organizer for the military exhibits and will be displaying his FV432 being an excellent example of these Tracked Armored vehicles. This is fitted with working Clansman radio equipment. Barry G8DXU and Andy 2E0GNE will be exhibiting a Defender 110 Tithonus FFR, which is fully fitted with Clansman radio kit VRC353, VRC321 / 322. There will be a separate display of Clansman manpack sets PRC320, PRC349, PRC350, PRC351 as used in the Falklands conflict 40 years ago.

We have call GB2RP which will be used during the show for working demonstrations. Some of the frequencies used being 1976 kHz AM/LSB and USB, 28.320 MHz USB and 51.70 FM. Listen out around 1400 (local) on Saturday and Sunday.

Meeting at ESSC Monday 1st August

We are very pleased to announce that there will be a presentation at our meeting by Rael Paster M0RTP on

Magnetic Loop Antennas.

Real has much experience in the design and construction of these aerials which are physically small when compared to more conventional systems. When used for transmitting the voltages and circulating currents can be high, which poses an interesting set of considerations. Construction requires some plumbing skills and the use of special capacitors such as vacuum variable types.

Doors open 1930 local time for 2000 start . Tea, Coffee and biscuits will be available as usual.