Many missed the 76th anniversary of the D-Day landings in Normandy last year. These were substantially cancelled due to the pandemic. It looks like the 77th anniversary is going to be commemorated by a number of organisations, groups, societies and individuals.
SARS has secured special event call GB2SF (Sword Force) and hopes to participate in various radio nets over this weekend to mark the occasion. More information will be provided as our plans for the weekend are developed. Members can access the Forum thread to register their interest and ideas, which will be most welcome.
An announcement from the EHVS indicates that this years show will be held over the Bank Holiday weekend of 28th to 30th of August. More details should be available in May following clarification of the rules for Step 3 from our government. SARS members who are interested in attending with displays or helping with our Special Event Radio Station are requested to keep an eye on our Forum for further information.
Radio Amateurs, Boat owners, professional and other users of Radio Communications equipment running over 10W RF Power are to be affected by licence changes proposed to come into effect on the 18th of May.
Ofcom are proposing to implement the ICNIRP recommendations on the levels of Radio Frequency (Non-Ionizing) radiation. Strict limits may be introduced that restrict the levels of RF radiation from amateur and other installations.
Users (Licencees) will be required to ensure that their transmitters comply with the limits set for “Public exposure” to radio frequency emissions. These emissions being for frequencies above 10MHz. This could have a serious impact on the way radio amateurs deploy and use their apparatus. Also on many small boats where marine VHF transceivers are connected to a normal 1/2 Wave end fed aerial (3dBi) and on high power 25W separation needs to be over 2 metres. Mobile installations operated by radio amateurs in a public place will have to comply with the new limits.
It is however noted that the above refers to exposure of the “Public” to Electromagnetic Fields. The limits do not apply to the Licencee, Operator or Installer of the equipment.
Now that our government has published a road map out of the current lock-down your society is actively planning future activities.
We hope that, once again we can establish entries in forthcoming HF and VHF contests. This obviously depends upon the restrictions in place at the time and social distancing etc will be required for another couple of months or so.
Hopefully most restrictions will have been lifted by the time of the Low Power contests in July/August. Members are invited to participate in discussions on our Forum regarding future events.
It is with great regret that the society hears that John (Jack) Vaughan G3DQY become a Silent Key on the 5th of February at the Conquest Hospital.
John was a long standing and Honorary member of the society, having been our chairman in past years. He was manager of our Hailsham shack for several decades and a very keen and expert CW operator. John will be sadly missed by his colleagues in the society.
We extend our sincere condolences to his friends and family.
Iris Martin G6ZNO had been a long standing member of SARS serving as Secretary for many years. She had many interests being a keen electronic organ player and winemaker.
Her pleasant and lively personality will be greatly missed at society meetings and by all of the membership that knew her. The committee extend their sincere condolences to her family and husband Peter G6GVM.
SARS house magazine “AirTime” for 2021 is normally published on or before the last day of each month. This is available to members only and can be be viewed or downloaded from the Members area of this site.
Following a decision at our AGM in March, this magazine will now be edited by committee. Members are invited to send in articles and news that they would like to see included. Please contact the editorial team on the email displayed in current issues of AirTime.
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.2b 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” (R2) 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!
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.
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.