New Callsign

Congratulations to David Taft on passing his Foundation exam. David took the remotely invigilated exam and now has the callsign M7BDP, assistance with training being provided by Tim M0THM.

Clansman VRC353 RT353 How to remove NATO 150Hz Tone

The Clansman VRC353 vehicular or Fixed station Transceiver covers 30-75.975Mhz with an output power of circa 50W. This radio can be used for re-broadcast when associated with the RB2 or similar harness interface. NATO radios have an embedded 150Hz tone similar to CTCSS which triggers the re-broadcast function. In Clansman equipment this tone is filtered out so that the operator is not aware of its presence.

When set to Narrow, the main deviation is about 6kHz which is acceptable for amateur 4m or 6m frequencies with 25kHz channel separation. However the Tone deviation is set at about 1.6kHz which is much higher than the normal 10-20% of system deviation. Amateurs using Clansman or most converted PMR sets will enjoy filtering of frequencies below 300Hz. Others will hear an, perhaps annoying 150Hz buzz!

Fortunately turning off the tone produced by the VRC353 is a relatively easy process. The Silica Gell Dessicator at the rear of the outer case should be unscrewed first. This releases any difference in air pressure between the internal hermetically sealed case and local atmosphere. Next remove the four Hex bolts in each of the front corners of the case. Now release the Hex bolt between the two cooling fans.

Using the handle on the front of the transceiver gently pull the body out of the case. Be careful as the outer case and main unit are both quite heavy. Once withdrawn, lay the unit on a protective and ideally, grounded static conductive matting as pictured below.

On the lower left hand side of the radio (viewed from the front) is found a group of four control boards. Printed Electronic Circuits (PEC’s) These boards number from the bottom and it is No.2 that contains the Transmitter Deviation controls. There is a plate retaining the PECs held in place by two fasteners. It is not necessary to remove this plate or any board.

Adjustments should be made through the slot in the plate where each Multi-Turn Potentiometer is readily accessible. These controls are labelled A, D & T from left to right.

“A” adjusts the Main or Analogue deviation. “D” adjusts the Data Deviation and “T” the Tone deviation. Do not touch the Analogue of Data deviation controls unless you have access to a good deviation meter and audio signal source!

General view of the RT353 Transceiver internal assemblies and Control PECs approx bottom centre.

The transceiver should be tested before and after adjustments to ensure that it is functioning correctly. Please do not carry out any adjustments unless you are competent with working on such complex equipment. Also bear in mind that these radios are were first produced in 1977 and suffer from the usual component ageing, making their future reliability increasingly uncertain. Repairs require special to type test equipment that may not be available to most radio amateurs.

However properly maintained VRC353s are generally quite reliable and capable of some very good performance when used on FM (Narrow) in the Four and Six metre amateur bands.

Location of preset potentiometers for adjustment of Main and Tone deviation

Above photograph shows details to locate the Deviation adjustments. The three presets are visible through the slot in the Control Board cover. Tone level is by the right hand control labelled “T”

When reassembling the unit and replacing the outer case ensure that this is done in dry warm conditions. Apply a smear of general purpose grease around the front panel “O” ring seal, then replace and tighten the Hex bolts. Lastly the perforated aluminium tube containing the dessicant should be unscrewed from its retaining window. Dry this in an Oven at around 100 degrees C before reassembly and return it to its original position in the case.

The note regarding Beryllium Oxide refers to the Transmitter Output valve and is only a hazard to health if damaged or tampered with.

Barry G8DXU Copyright 25.10.20

SSB nets on 144.325MHz, 28.320MHz & 1976kHz

There was a very good response to our Net on Saturday the 7th November from 1400. Twelve stations called in on Two Metres SSB, with a good number of these later migrating to 10m and 160m. Net control was by SARS G1KAR/P from our Beachy Head site. Please see the Forum thread on this website for more info and to leave your comments.

With many thanks to all of the stations that participated and contributed to making these Nets an enjoyable success.

Post Lock-down Freedom Camp at Beachy Head 10-11th July

Having endured some sixteen or so weeks of the lock-down the gradual return to normality started from the 6th of July was very welcome news. Radio amateurs have been fortunate to be able to continue with their hobby, keeping in contact with their fellows over the air waves aided by the connectivity of the internet for those without access to space for aerials.

Southdown A.R.S. are incredibly fortunate to have a radio site at Beachy Head where we can pursue our radio interests away from the radio noise and interference caused by Broadband and electrical equipment. And on a hill at an altitude of 480 feet near open fields with some great views!

Wishing to enjoy these facilities as soon as possible a small group of members planned a radio camp at the site. With numbers being strictly limited to six attendees outside family groups. The event was posted on our Forum and Calendar awaiting responses on first come first served basis.

Initially there were responses from three members wishing to attend both Friday and Saturday, with apologies from some who were already attending other functions. We were planning to continue our members cumulative contest from 1630-1830 Friday with the added bonus of the IARU HF contest running over the weekend. This gave plenty of opportunity for radio operating on HF for those wishing to participate.

Andy 2E0GNE and Tim M0THM were first to arrive at the site with Barry G8DXU slightly delayed collecting provisions and diesel for the site generator, which was running very low.

Ancient and modern! Station Radio C12 from 1955 and ICOM IC-7300 SDR Transceiver used for IARU contest..

We pitched our tents, with the usual difficulty securing even substantial, tent pegs in the hard ground and beach substrate. The aerial to be used in the contest was a 20m Dipole, deployed from the main Tennamast. We also ran a 100 foot long wire for the Station Radio C12 to the 8m mast on G8DXUs Land Rover Defender FFR. The Larkspur Station Radio C12 was brought along just in case there might be members who wanted a contact on Top Band, but this did not happen during this event. However it did reveal a couple of faults, such as dirty ATU relay contacts and intermittent lamp connections. Plus a loose ground connection on the Plessey MkIV plug of the control harness, making the PTT intermittent. These problems have all now been rectified in readiness for VMARS Dynamotor Day on the 29th of August.

Our members contest started at 1630 local time on 14.055MHz when it was hoped that we may be able to make contact with Dick SV0RPE in Crete. However after a couple of CQ calls, no members were heard using CW so we switched to USB

Andy 2E0GNE and Tim M0THM firing up the wood burning Barbecue on Saturday evening.
Sunset at BHRS looking North West towards Firle Beacon

Our first contact with a club member was actually on the 15 metre band with Steve G8NFZ

An additional bonus to the great radio propagation, members using Beachy Head are often treated to some spectacular sunsets.
At the end of the event all equipment has to be stowed away in readiness for the next occasion.

Our next major event would be the 2 metre and 70cm Low Power contest running over the weekend of 1st 2nd August respectively. This is a 25 Watt maximum power event and on this occasion must be for single operators only.

There was the added bonus that during the same weekend the European HF contest is also running. We made an entry in this event in order to keep a couple of members occupied whilst G8DXU operated in the main VHF event.

Overall the weekend of 10-11th July was very enjoyable, with the few members attending making the most of the opportunity to get out into the open air and do some radio operating.

Flemming Christensen G4MJC S/K

It is with regret that the society has learnt that Flemming who was an early member of SARS become a silent key some weeks ago..

Flemming G4MJC had great enthusiasm for VHF and particularly 6m where he was often heard during contests. He will be sadly missed by his fellow amateurs. Our condolences go out to his family.

Ian G7HFS…….PA3IKH in Zeeland SATURDAY 15th August

Several SARS members made contact with Ian whilst he was in Holland at West Kapelle on Top band (160m) using 1976kHz USB. Contact was also established from Beachy Head on (60m) 5363kHz USB by G8DXU and G1KAR/P with Andy 2E0GNE operating.

Anthony G4UPY was also on net, together with Chris G3XFE in Heathfield. Thanks go out to all stations for their co-operation and especially to Ian for making the effort to include SARS members in these interesting inter-European propagation experiments.

Some Sad News G8CVV SK

Previously a long standing member of SARS, Barry Chuter G8CVV became a Silent Key on Sunday 26th of July. Barry had moved from Eastbourne to Minehead about two years ago to be closer to his family.

He had a special interest in VHF and was renown for his knowledge and expertise in High Voltage generation and research into lightening. The title page on this site shows one of Barry’s demonstrations of a small Tesla coil discharge!

Barry was a Staff Sargent in the local TA in which he served from the 1970s until retirement. Barry developed the “Chuter Box” to facilitate voice communications over the MODs Triffid / Ptarmigan radio system. He was also a Technical Officer working in the local Eastbourne “C” Submarine Repeater station.

He will be sadly missed by members of the society, together with his friends in the TA and British Telecom.

Icom IC-7300 Basic Operating

Over the course of two lectures in February 2020, club member Steve Sims G8NFZ presented a series on operating the IC-7300 HF transceiver for the benefit of club members. He has now compiled these slides into a video series, which can be found embedded below. Our thanks to Steve for his extensive work on this series and for taking the time to edit & record these videos so that all can benefit. The YouTube playlist can be found here.

Part 1

Part 2

Part 3

Part 4

Part 5

Part 6

Part 7

Members Contests / Competition

Results appear in the October edition of AirTime

Future meetings postponed due to COVID-19

After careful consideration and in light of the fact that a significant proportion of our membership is particularly vulnerable to COVID-19, the Committee has taken the decision to indefinitely postpone all future monthly meetings as well as meetings at the Cafe Continental on Wednesdays, until further notice. Meetings at the club shacks will continue with attendance at the discretion of members.

We hope to be able to reinstate future meeting dates as soon as possible, but in the meantime a special club net is planned, with the following details:

Every Wednesday 14:00 hrs, 70cm GB3ZX (Butts Brow) repeater
Output: 430.825 Mhz
Input: 438.425 MHz (+7.6 MHz)
Input tone: 88.5 Hz

Please see our calendar for details of scaled-down events, camps and activities, these are generally limited to six members. On-Air meetings and contests are still open to all members.