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Update: An engineer is on the way today to fix problem in West Southampton

We have lost our Video camera and Weather feed thanks to a fault on internet provider network which occurred at 1101AM on Monday 28th of December, which affected the Millbrook, Maybush and Shirley areas of Southampton.

While the fault in the network has been cleared, it has the effect of this has knocked out our connection to the internet. This fault is a variation on a theme on around 50% of the reason's as to why we lose connection, some of the faults are to do with the linking equipment, all of this as such is is all out of our control. Due to the COVID restrictions We can't go to our site to make our standby alternative arrangements work - frustratingly.

Unfortunately as this is late December, and many are on leave, We seem to have little hope of any any improvement and a return to service of the weather station or a viewable camera until Monday the 4th or later on in the week. However We are pleased to say our internet free link to GB7PO works fine, and this is the reason why we dont use the internet for this link!



Storm Bella raced across much of England last night dropping 10mm of rain upon Southampton, and bringing around 4 hours of light rain and high speed winds including multi high speed gust, the highest being 72.5MPH as measured by the on site weather station, "Isouth 502" accessible through our website, at 01:29 this morning, and a later 70MPH gust at 04:19 this morning.

Southampton seems to have come through the storm more or less unscathed and our aerials stand proudly at around 170ft above the ground, just as they did yesterday! Therefore We thank the aerial install teams for their good & hard work and look forward to next year and its storms with interest!




Following Saturdays visit, Andy G4MYS went to site again after the internet failure at around 1150 to investigate, were pleased to say hey lads thats was not us! - all was well at our end!

One job done.
Next was to check that the "MT suck out filter" had been put in to the GB3SU receiver line to rid GB3SU of QRM from GB7MT,...which it had, Let off me the hock at least I can find a receiver cable first time, which can be helpful!! We experimented with the filter in the aerial feeder cable too, which was also found to make no difference. We ask why does the filter not suck out the signal? and We don't know, off site testing of the Filter is next to do, to establish that it is on the correct frequencies I.E.:- MT tx frequency of 439.6625MHz, which it passes, and a 30db suck out notch on the SU rx freq of 434.8Mhz. There are other things we can do like shoving MT up at Millbrook Towers but that's a bit drastic!

While on site we had a complaint of GB7MT :- motorboating ( tx signal going on and off in rapid sequence ), as a result, We have put GB7MT on to the unused GB7IV aerial ( see the picky on which aerial is which ) where the interference is much reduced, although this aerial has more gain this is lost in the extra feeder length, thus the MT signal may be slightly lower. We will have a think about this to once again maximise the repeaters performance in the new year.

GB7IV: We had what we thought was two sets of filters, one set has proved to be on 222MHz which is not very useful in the UK, the other set is on 145MHz, has around a 3db insert loss thus losing around half its power and halving the input signal. Thus its with a local radio "dealer" who is trying to perfect its performance. Once we have a set of working duplexers, then GB7IV ( VHF ) can go on air, in its different forms:
D star & Fusion, we wait with interest!



We give our many thanks to the many who came on air for the privilege 0f helping to test the TAIT T 8110 VHF high band mobiles, on air as GB3SH. We mention in particular Les G0FAJ for persisting with low power tests on GB3SH ( Taits ) and in particular Mick G6ASJ whom We really messed around, with the RF level tests and John 2E0ZBE for bringing up MT to check for the jamming experiments with GB3SU!.

We wedged GB3SH TAITs as they are in a 2U case, in below the existing SH,and above GB7MT, which allowed for easy RF and DC connections....
The GB3SH tests were amazing, - the unit works better then expected, remaining stable even on 25 Watts of RF with no extra heatsink, We measured only 35*C on the heatsink fins after some time of operating at ( more then ) full power. Many stations commented on the better sounding sound quality which was very pleasing, We noted no desencing, which the incumbent SH seems to suffer from slightly.
So We will carry on with casing up the unit and integrate the logic and try again.

As For GB3SU, We put the MT suck out filter in line and expected the MT blocking to stop dead, which It did not, - Time was getting on, and it was getting both dark and colder, It is still in circuit while we have a think as to what is wrong, while the popular thought is that I put the filter in the Tx line, rather then the Rx!, As SU is boxed up, and in the rack, and difficult to see which N plug is which, SU needs to be removed from the rack as there is no evidence that the cooling fan is running, and that needs a look at sooner rather then later.

We give our grateful thanks to the many stations who worked all three repeaters today, Well repeat the experiment another day, before letting it lose with its logic built by David M0XIX, and we will tell you more about it's sound and use later on.
The weather on the day was amazing with bright blue sky and a good sun changing to less then 1/2mile viability, heavy rain, a thunderstorm to the south of us,and hail coming in, and a rush of wind that shifted materials around on the floor and lifting them aloft, at that stage I was glad to be in wedged between the repeater rack and a wall trying to couple SU to its filters! While We are totally safe at on that floor level as there is a ceiling, and the roof is above, and 5ft high walls to keep us safe, but the wind is a little worrying! and that was only a 50MPH gust!

Andy G8UVS



As your likely aware were building another GB3SH from a pair of TAIT T8110 ex PMR Mobiles, like GB3SU, they are in a 19" rack tray, but before we go any further, Well air test them this afternoon, (19/12/20) this is to

* ensure they will settle on to the duplexer and aerial and behave

* see if the weird QRM gets into it!

* find any other annoying site / related problems

* find out about it on air behaviour.

Alan G8IPG and Andy G8UVS will be on site, and the best way of helping will be to work each other please, our presence will be noted by the on site SH going off ! We hope to be ready for Test QSOs by around 1400L this afternoon!

As its in default "Tait" Mode the repeater has only has a Bleat, after overs like SU, but at least you will hear it!. At this stage We have not fitted Dave's Logic as this is test only, ( the remote shut down is not yet wired in! ) We will remove it from site later in the afternoon so the back panel can be dressed see attached picky as to progress

We will take the opportunity, of fitting the GB7MT filter to GB3SU rx line so hopefully MT will no jam SU
So if your about, please give it a go !

15/12/2020 WORKSHOP NEWS

The committee is pleased to advise to us all that We are in the process of building a complete 145MHz repeater, and a brand new 433MHz repeater.

Alan G8IPG has obtained two Tait TM 8110 Mobiles, and programmed them to be the repeater Transmit and Receive modules.

David M0XIX has built the Logic based on a "PIC" chip, PIC micro-controllers ( Programmable Interface Controllers), are electronic circuits that can be programmed to carry out a vast range of tasks. They can be programmed to be timers, which is really our function, or to control a production line and much more. They are found in most electronic devices such as alarm systems, computer control systems, phones, washing machines, Dish Washers, Cars, and almost any electronic device.
For David this has involved designing the programming of the chip, to drive the repeater logic the way We want as users.

Andy G4MYS has obtained the 19" rack-tray and is doing the metal bashing, and parts dressing.

This project will give us a complete swoop out-able VHF repeater.
This repeater will allow us to get the currently on-air RF Technology "Eclipse" unit out, and make the spare receivers and transmitter proven working clones.

With the aid of twin fans, and a leaf out of Yaesu's book, air will be drawn in through a slot in the front panel, through the radio's own heatsink fins, and exhausted out the back of the rack, allowing us to carry on at full licensed power.

Additionally We were indeed fortunate to inherit from SMC a brand new old stock 1U, UHF, RF Technology UHF Repeater, usable in the Amateur Band, without modification. Alan G8IPG has had to spend much time trying to work out why it would not repeat, this unit, with another gift from SMC a Zetron "Model 38A" Repeater Controller, once again: New - Old stock,.. which is very similar to the Unit which drives the Currently On air GB3SH, Alan too has had to fathom out how to Programme this Controller and of course make the leads to do so! This UHF repeater likewise will be a complete working swoop out unit.

Thus both these complete units, means that a failure with our FM repeaters, is not followed by a panic! trying to get it back on air or another on the air! We just swoop them over!



We're pleased to say the repeater sited weather Camera & station on site " ISOUTH 502 " is back, having returned at around 1609L today 10th December 20. The fault was " a "router" in the Maybush area which had locked up, or had lost connection.
As to why this may of happened , we dont know,... We understand this is rare, however we do know Southampton had a spat of short power fails yesterday, also suffering an exploding sub station!!

Andy G4MYS



Both our camera and the weather station are off air due to a common to both internet related fault, which is not under our control. From previous experience, they could be off air for up to 10 days while new equipment is sought by the provider, so keep checking back!

Unfortunately with COVID making access difficult, it is not possible to provide a viable alternative RF path for the internet link at this time.

There are other Private weather stations out there, and they can be accessed at" WEATHER UNDERGROUND" also , "Southamptonweather" also provides an excellent information site.

Andy FABO the wx station and camera operators



This weeks on site works was to return GB3SH to our normal single aerial working, and reinsert our own Receiver band pass filter. We put GB3SH onto twin aerial working experimentally to see if the repeater would work better in this configuration, unfortunately as you may well of heard it did not. Listeners were treated to an annoying sucking noise from time to time, in particular when the repeater was pinged ( many have got in to this bad habit of not giving a callsign ) Thus We have to reverted to the design configuration of single aerial operation as the duplexers are intended to do.

The exact cause of the RF feedback is not known, by us, apart from that for installation two aerial working was the trigger, as all 5 filters were still in circuit. Were sorry We cant explain it. But We do know is: put it back and it will behave --works.

GB3SH should now behave as intended.

There has been some comments about the age of the kit on air, the best description would be newish old stock, these units were first made available in 1994, 26 years ago, however this unit came in to our hands brand new, in the boxes in 2010, and was out of use for 8 years while we were off air.

Thus GB3SH is around 3 years old in working terms, and so far we have not used either of the spare transmitters receivers or PSU, So don't worry GB3SH in its Eclipe from R F Technology is good for many years.

As a repeater group we need quality equipment which has a lifetime exceeding 20 years, with few faults or internal problems, ( This especially applies now that commercial kit is digital not FM,)

Thus We use TAIT & RF Technology Repeater equipment, also the Procomm filters and the 4 stack aerials - that we use on SU & MT. The only replaceable kit we use is the (VHF
/UHF ) aerials which are built to hammy standards for use at 10 / 15 M above the ground, not 60M up in the open sky! These hammy aerials are are simply not man enough, due to the materials used, therefore, to ensure good service from them we replace before they break, at around 24 months! and that's after We have re-engineered them internally to last that long! ( this will be the subject of a separate article )

Other work on site done was tidying of the remote shutdown wiring, and this took both SH & MT off air for around 90 minutes and reconfiguring the UPS machine.

At this stage We don't know why the weather station is off air, its likely to be an off site problem which we have no control off. IE an internet problem.



Today Alan & Andy had another go at seeing what could be done to stop the QRM, and you will note it has reduced by 99%, unfortunately not by our direct actions!

So today with the correct coupler to hand we tried:

TWIN Twin aerial working: with the aerial combining parts were removed, and The Transmitter of GB3SH connected to one aerial, and the receiver using a different identical aerial!
This disconnects the direct RF path from the transmitter to the receiver,... and had no effect on the QRM what so ever! ( as expected )
For the record the transmitting aerial is above the GB7MT aerial, and the receiving aerial is above the GB3SU aerial.

However because we can, we have left the system on Twin aerial working, for the experiment, and so far, the system seems happy, basically We want to know how we can configure the system in different ways to get it to work!

Fit another bandpass filter: We have been very kindly lent a bandpass filter from DCI in Canada, to fit in our receiver line to see if that can help,
and were sorry to report it made no difference at all! We're very thankful to its owner for the loan, This filter is in circuit now.

We tried another Transmitter, however due to the levels of signal it was not possible to determine if the transmitter we were using was causing problems or not, and we also tried the signal generator to see if twin aerial working caused any problems and think not.

At this stage we have not got round to trying another repeater, as this would find out if the problem was being generated in our transmitter or receiver, and is a test we need to do when the QRM returns!!

It was at this time that the Engineer from the interfering transmitters arrived, and we changed the system dipole aerial, we noted a crack in the balum assembly, the that systems dipole, but in all fairness one needs to inspect internally inside the balum assembly box. To see if the resin had been cracked or damaged, so far we have not done this ! And the interference continued - So its not their aerial!!

He has now put his system on to a higher aerial, to see what gives and if that is workable, and this is how the systems function at this time. Which leaves several questions and may give answers.

However it is known for every 30 foot of horizontal separation the same difference in attenuation is found in 1 foot vertically ! As his aerial is now good 10 feet above ours, this is like shifting our aerial 300 feet horizontally away!



Our repeater station based Undergroundweather station " Isouth 502 " is back (on air). The fault was a 48Volt POE power unit failure, elsewhere in Southampton. A workaround is currently in operation while correct parts are sought, and this should keep us going for the foreseeable future.

Check it out and enjoy!



The on site weather station "Isouth 502" is off due to a failure in the Internet system, which is beyond our control, the actual fault location is unknown at this stage, however, I'm told the fault will be investigated on Monday 5th October.

That does not mean to say service will return on Monday as replacement equipment may be required, and need to be obtained, Its a shame it goes out during interesting weather conditions, but rest assured its not us ! and the service will come back soonest.



There has been a blocking of GB3SU by GB7MT for some time now, causing a desencing of the GB3SU receiver, unfortunately this blocking has extended over more time by the COVID Crisis. We had hoped further separation of the GB3SU & GB7MT aerials and coaxial feeders which were side by side would cure the problem. This has not been the case, So We have ordered a most suitable filter from Procom which is fitted in the GB3SU receiver coaxial cable, just behind the receiver, this will put an 80db null on the GB7MT frequency, and a pass filter on the 434.800 SU receive frequency. The effect of this filter will remove the MT signal plus give a narrow bandpass for the SU signals. The filter, a Procom BPBR 70/3-5/7 is expected to be with us and fitted, by mid November, and is brand new new and aligned to our frequencies.
We thank Alan G8IPG for finding this very suitable filter for us. We are getting the filter at "mates rates" with no mark up, and we thanks our "mates" for this kindness, the cost is £189:00


These tests were being made in an attempt to learn how the QRM is electrically made, and where is mixed. For the record: We do know where its coming from, We know the frequencies in use, and how the frequencies mix to produce another signal on our input.

In summery it needs "offending transmitter 1" and " offending Transmitter 2 " which use one common aerial,.. on what is known as a " circulator " ( Simplistic explanation: can be thought of as a roundabout for RF - most of what goes in only comes out of one exit, the other stuff ends up in dummy loads ) plus GB3 SH transmitter in to our aerial ( of course ) to play up, this explains why sometimes the QRM is rather short, does not do it for some time or belches on for some time.
Thus we are trying to see if the problem is with our equipment, or elsewhere, the following experiments were tried:

* Try another aerial, further away from the existing aerials.
We put the GB3SH aerial we took down last Monday, and fitted it on a Speaker stand on the roof for the duration of the test as far away from the aerial which the Two transmitters are connected too.
This increased the separation from around 15 Feet / 5M to around 75 feet / 24M apart, it was hoped this would show if close fitting of the aerials was the cause. John 2E0ZBE & Mic G6ASJ tested this for us and the noise carried on unabated!

* try two aerial working -
As we have two fitted VHF ( /UHF ) colinears ( for GB3 SH & GB3IV ) this is an easy trick for us to try, This was tested by Peter M1PVF apart from making the receiver deaf this test proved nothing!

* Try the repeater in to a dummy load, see if the QRM comes down the aerial coaxial feeder
John 2E0ZBE reported hearing the CWID, with a dummy load connected to the aerial port of the duplexers, but we experienced no QRM despite hearing both " offending transmitters" , on our monitor receivers, and keying our tx up.
From this We conclude the signal comes down our feeder cable.

* Try working SH on batteries & disconnect SH from the AC & AC Earth grounding
looking at: is it coming from the earth bonding - No difference the QRM continued unabated.

* Try disconnecting SU & MT from both power and their aerials
is it mixing inside the other repeaters?
No - No difference

So this brings us round to next weeks experiments These will be done on a windless dry day as we need access to the roof again, please bear in mind while we do this GB3SH may be unavailable which will include going off air mid-sentence while we test! Work includes fitting a different transmitter module, and trying a different make of GB3SH, and other stuff.

We thank Alan G8IPG, Andy G4MYS, and especially: John 2E0ZBE, Mick G6ASJ and Peter M1PVF for trafficking GB3SH for us while we used their test QSOs to help us hunt down the problems.


Another Problem Overcome

We have fitted a mains power fail alarm. One of the problems we have is the RCB socket which we get our power from. These are designed to be "Fail safe" in the event of loss of supply, as a result they are prone to tripping out under brown out conditions ( a momentary loss of supply or dip in supply voltage ) and remaining off, leaving us powered by our back up batteries and the UPS machine, with no knowledge of the power trip out!

The machine which we have fitted monitors the mains voltage, and room temperature, and advises the team of a mains fail, encouraging a visit to site to reset the RCB!,... this is sent out by text avoiding the problems of the Internet. This of course only advises of a power supply fail, another reporting unit will be fitted soon, and this unit will advise of mains fail, and or power supply fail, this will be broadcast on GB3SH as a pipping noise, during overs and CWID which we will all be able to hear!


We have now finished fitting all our aerials, for our repeaters,each now has its own aerial. We have arranged it so that the UHF 4 stack TETRA type aerials is also a mast for the two VHF(/UHF ) colinears.

Much work and expense has been spent on this installation, the new aerials + new coaxial cable, T&K brackets and their rawl bolts, 6 shelly mast clamps, all in around £1300 has been spent, to try and get the best we can from the system's installed.

With Reference to the full aerial picky, there is other systems on site, of course, and a redundant 220Mhz Band 3 comms system aerial array, from the early 1990s, now disused, as Band 3 is part of the Digital DRAB Broadcasting band, that is the tall guyed 4 stack array centre of the roof, with the coax hanging off the guy lines!.

Thus three white stick colinears are to do with us. The lowest white stick is the old GB3SH aerial, which John 2E0ZBE can be seen removing form the top of " the link to GB7PO stubmast", in picky 2. So the two 4 stack arrays support two colinears and these are the aerials We are using, The 4 stacks are Jaybeam commercial aerials for the 430 / 440 MHz band, with a lifespan of over 30 years..

The colinears are modified Dimond X-200, these are of course standard build hammy aerials, from Nevada Radio, which have been modified and upgraded to enable them to withstand the extra movement that being fitted at 160 feet ( 48.76M ) above the ground brings. The elements of these types of aerials are typically simply crimped together, or screwed together. They are upgraded by soldering the crimps, or screw joins up, to ensure continuous low resistance connection between the sections. We use the Dimond X 200 as they have N sockets, and have two pipe support holes unlike the GP 6 from Comet which is fitted with a SO239 socket, these also need soldering up internally to ensure long life expectancy. It is my opinion however, that the internals of the GP6 are of a higher quality. We will do a post-Mortum on the old colinear next week, and will give you a photographic report, of what damage 18 months service with GB3SH and wind-speeds up to 96MPH can bring!

Five of us worked upon the install on last Monday the Wx was kind and at times during the afternoon our weather speed logger was not moving, temperatures reached 24.4*C on that roof where we were, according to our on site weather station "ISouth 502", A lift on 70cm was somewhat "off putting" to our installers who could not resist responding to General calls on PMR446 channel 8, French stations in Normandy being worked on PMR 446 Handhelds, also one of the local hams who had gone up Beacon hill, near Warnford, and a G4 on the Island, there seemed to be more hams on channel 8 then there were on 433.5MHz!. So aside from chasing DX on on PMR446, We did install one stub mast with the 4 stack for GB7MT and a new Colinear for GB3SH, so go play and let us know on air, on Facebook, or email GB3SHSU with your reception reports! We give our thanks to our install team of the day: SWL Andy, Andy G4MYS, Alan G8IPG, John 2E0ZBE, Nigel G7POC

Click Images Below


Antenna Layout

John Old SH Removal

New MT / SH

MT / PO Link

Weather Station

Andy & Alan
New SH Checks

Fixing MT / SH

PO Link & SH MT

Old SH Dismantle Weather Data

Should the fine weather continue to next weekend, then our engineers will be on site Monday 28th September to find out more about the interference which is on GB3SH most weekday mornings.

These tests will result in short off periods, low power output, and different ( test ) aerials being used, and weak test carriers for periods of time, resulting in a noisy output. This work will not start until 0930, users and members will be requested to let us get on with the work, and NOT put signals of their own though during the tests, the date for your diary is MONDAY 28 September, ONLY if the weather is good! Our other repeaters GB3SU & GB7MT are unaffected by the QRM and will operate as normal, and will may be able to field comments though SU
15/09/2020 ENGINEERING

If the exceptionally fine weather continues, then on Monday 21st September 2020 engineering work will be done on site to enable GB7MT to be changed from its temporary aerial to its main aerial, MT as such wont be off air too long, really only long enough to remove the RF cable and fit another, and this will be sometime during the afternoon.

To allow this to happen, a lot of hard work in the direct sun has to be done and GB3SH will also have to go off air for a few hours, from around 1030 AM +/_ 30mins, GB3SH will also receive a new aerial, in part due to wind damage, which may well explain some of the annoying clicking heard during high winds, in recent months

Thus you are asked please, to note the signal levels of the repeaters SH & MT on Sunday, certainly before Monday, and again after the new aerials are energised say late Monday afternoon, and let us know the difference, this can be done on Facebook, in the comments and on the Internet:

The change may take some time as mechanical work has to be done, and the aerials and connections need to be mechanically secure and waterproof!. During this work GB3SU will be ready for use and not taken off air, as its on a different stub mast.


GB7MT will be off air for around 30 minutes sometime on Tuesday 1st September, while DC power metering is fitted.

We are fitting the meters as the repeaters no obvious or small "Tx" indicators, as is common these days with most amateur radios equipment.

We are also keen to know the current draw and voltage of the DC lines to the individual repeaters.
The DC meters will of course show the repeater current drawn, which will yield a lot of information.
Click picture to expand

27/08/2020 QRM logging - Help is needed:

With regard to the interference to GB3SH, we need stations who can let us know if they hear data signals on +/_ 2KHz of our input frequency of 145.0625MHz.

This is one experiment where all of us can help out, be it our regular users, those who monitor our traffic, and listeners,...who live within 10 miles of Junction 8 of the M27.

*You will need to listen, but with preference carefully Monitor our input that is: 145.0625MHz, you will need to have the CTCSS or Tone off, and squelch as low as it will go before the squelch breaks, with preference you will be using an outdoor aerial, a vertical or vertical beam for the monitoring, beams or quads need to be aimed at the repeater station which is at Hightown Southampton, near to Junction 8 of the M27.

* We are listening for digital noises, ( only digital noises - on this occasion ) these sound like a harsh buzz or rasping noise, this traffic is somewhat intermittent, but is enough to cause annoyance to the repeater, it does not happen all the time, It seems more prone to occur from 08:30 to 10:00 weekdays, the interference is momentary; lasting form less then a second to up to four or five seconds at a time.

* Purpose of the test is to establish firstly if a ("mixing") fault or problem is causing the accidental transmission on our input, from the transmitter(s) involved, We are also trying to work out how bad the problem is by asking stations in a 10 mile radios to report their finding to us, and we for our part will report back to you on our web site and Facebook pages our findings.

We Would like to know:
1 if you can hear it,
2 or if you cant hear it , this is useful too,
3 and your station approx. location,
a detailed log is not required,
4 all this data can be sent to us by e-mail to

Note you will-not hear the QRM on the repeater output unless there is a QSO in progress! it is the input we are asking you to monitor please

24/08/2020 QRM LATEST GB3SH

We are pleased to say we know what is causing the on going morning QRM on GB3 SH, and even better where its coming from, and it's frequencies.
As a result of cooperation from the equipment's service company manager, Peter G6GFA, to whom we say a great many of thanks, tests have already been made to prove the source, that was done last Sunday evening, the problem being is its very, close in distance from our aerial.
Indeed this equipment cased us grief when We first put SH on air, and We were able to reduce interference from it by using an AFL built, 145Mhz tuned band pass filter, in the receiver positioned in the coaxial cable.

This filter allows the 2M band signals through with very little loss, and gives attenuation outside our band in the order of some 60db. However only half the other system was in use, last week the second transmitter of that system was reintroduced, after some time not being on site, this second transmitter is only 300Khz from the first in frequency, all be it around 170MHz.

We also know it only happens when both transmitters operate at the same time, much of the time these two are not transmitting simultaneously, and during that time we receive no problems.

We know a receiver filter almost kills it, so there are further tests to be done, and one of the simplest is to put another filter in, but this time in the transmitter coaxial cable.
Thus on Wednesday afternoon GB3SH will be off for a while, while its TX filter is put in circuit, for the technically minded its an AFL band pass filter, with an insert loss of around 1db measured at our TX frequency, and on the interfering transmitters frequency it has an attenuation of some 84.3db.

Why a TX line filter?
Of course We accept that GB3SH transmits on 145.6625MHz.. Why should we be interested in a deep null on 169MHz? The reason for this is one of the possible faults causing the interference is a mixing process where the others transmitters power gets into our transmitter and "mixes" causing the interfering signal, but giving those transmitters a notch of 92bd, We will prove one way or another that is / not the cause. Need less to say it will be in for a few days as We monitor the effects and decide how to progress forward. One unwanted effect of this is a slight loss of power, where does the lost power go? into heating up the filter ! is the correct answer. We are pleased to borrow this filter from one of our members, and thank him, purchasing one would be in the £600 mark!

23/08/2020 MAINTENANCE Monday 24th August 10:00 - 14:00 (Update 11:45 Work Completed G4MYS on site)

All Of our repeaters will be subject to service interruption on Monday 24th August, GB7MT & GB3SH in particular may be off for several hours late Monday Morning, this is to correct a wiring fault which left GB7MT off air after a "brown Out", a low voltage AC event last week. It is hoped all will be well by 1400 Local.

19/08/2020 GB7MT

GB7MT Went off air between 1200 & 2100 hours Tuesday 18 August 20, due to the RCB socket, which supply's the AC to our repeater station dropping out, as there had been a momentary drop of the AC supply.

We have off course battery back up, however a wiring connection error meant that MT is only connected to the AC power supply! and not its rack back up battery as well, resulting in MT going off air.

The RCB was reset at 1014 Wednesday morning, Having located a miss-wire to the DC supply buss, this will be corrected so MT can Join SH on the back up battery soonest, this will mean a de-rack of-the equipment to do a simple soldering job!

The battery had been happy to supply SH since the AC fail.! Co-sited GB3SU was also on air from its own battery power.

For the technically minded we have over 380Amps hours of battery back up for the repeaters alone, with an additional UPS machine power linking, and AC equipment.

We will endeavor to fit a "pipper" to give an audible indication of AC failure soonest as well!
18/08/2020 QRM on GB3SH

We have a heavy buzzing, at the end of overs sometimes. The effect of this is to slightly deafen the GB3SH receiver, fortunately the CTCSS receiver filter cuts out the QRM very quickly.

It is digital signals, likely coming from a co-sited communications system, We are fortunate in as much as we know who runs this system, and have already spoken to the manger who runs what we thinks is the system responsible. We hope to be on our way to resolve the problem week starting 24 August.
Thus there is no need to fill in QRM reports on this one, - as we know all about it! In the mean time GB3SU is doing very well a simple QSY to UHF should get you away from the QRM



The South Hampshire Repeater Group take QRM to our repeaters quite seriously. We have now set up a very quick and simple reporting submission form.

We are asking our users to report any interference either input or output that has interfered with their use of the repeater.

The QRM maybe legal or an illegal source but we have to document this over a period of time to make a full submission to OFCOM

Thank you for your help in making and improving our repeaters

Click Here For The On Line Form You can also e-mail any reports that you may have collated to Andy G4MYS

22/07/2020 QRM INVESTIGATION (70cm)

The QRM see picky QRM 1 which is the display of a spectrum analiser, it displays from just below 434.5MHz to just above 436.5Mhz, it shows the pairs pulses which make up the QRM, as the Horizontal bars the red line up the middle is the input to GB3IW, We can see from this the deviation on the input signal on IW and the wide deviation signal of the QRM.

So We know:
* its data,
* Is on from around 0830 to 1230 each Monday / Thursday, only.
* It is vertical, the horizontal signal is way down in signal strength, more work will be done on measuring that tomorrow
* its across the 70cm Band, of interest,
is its not so close to our outputs, as if they are deliberately not running near our outputs!

there are several pairs which appear and disappear in an order, you can see overlapping signals to the right of the vertical red line, the lower display is called a waterfall, and this displays a moving display from now back in time over around 30 seconds, the top display shows how powerful in relative terms the signals on any given frequency.

* The strongest at the repeater site comes from the north
From the roof of the repeater site we can detect many signals and directions, we attempted to locate the strongest which comes from the North. We looked for this signal in the Winchester area, and it is so strong the receiver could hear it without an aerial, Ive never known that receiver do that before, we were in open country no where near any mast! So we know
*its not running low power

It can, and does jam at the same time:
GB3SU Thornhill, Southampton
GB3IW Hills above Ventnor IOW
GB3AW Ashmansworth Andover

We are interested in suggested hot areas spots far we have:
Southampton western docks although we know who operates kit in the docks and they suggest this is a false lead.
Woolstone area
HMDY Portsmouth

After the One from the north has been tracked down, We'd like another to go find!
Please feed us with information , like signal strength + direction

At this time all of this bring up more questions:
The purpose of all this QRM?,
who's running it?
also why only weekday mornings?
wheres it coming from?.

Answer some of these questions and we may get to work this QRM out! and get it dealt with!
As to why have we not heard it before? simply as we had an inefficient aerial that could not hear it!
Put up a proper aerial like a 4 stack and we inherit QRM!

Can I help?- yes get out and df your local strong signal please and let us know what you find! photograph what you find! or feed us information!

Click to Download Analyser Video HERE
QRM 1 (Click to Make Bigger)

15/07/2020 GB3SU / GB7MT ANTENNA UPGRADE (Update 23rd July)

Aerial Improvement programme started.
We have started on our aerial improvement programme, delayed of course by the needs of controlling COVID, the first pair was GB3SU and GB7IV, who's aerial is carrying GB7MT signal. The costs of getting on air, and resultant depletion of funds, and interference had resulted in the previous temporary "get you going" system, which saw SU using a low dipole which was screened to the south East.

SU is on a 4 stack "TETRA" style commercially use intended, Jaybeam aerial, these are rated for 155 MPH winds., we for our part have installed the aerial system to a high mechanical standard, as you can see from the photographs using three SMC mast clamps rather then two, adding brass washers on the plates to spread the load, thick wall 2" commercial grade aluminum tube has been used, the feeder has been cable tied up the 4 stack for the VHF operations of GB7IV. The aerial connections are protected by insulation tape, encapsulated with "Denso" tape which is used by commercial riggers and Gas fitters, to prevent rusting of gas fittings on steel pipework, as it is 100% effective, for decades! Its a corrosion preventive tape can be described as a gauze in a green snotty, slimy muck, which sticks by the nature of the "muck" to everything, esp hands. It can be brought from Ebay, for £7 for 10M, and unlike the inferior self-melting tape does not have a short shelf life!

The SU aerial is giving a good account for itself and we really welcome reports good and bad, it seems that from reports so far that its been a win, win, win situation.

GB7MT is on the IV aerial, until its 4 stack is fitted next month, this install will take much more effort from our installers, and will take two days to achieve as a new feeder has to be drawn through, The colinear for SH will need beefing up first, and tested, thus that too will gain from being at full working height.

Having partly achieved a good aerial system for SU, we are frustrated by unexpected interference issues of pulsing noises which seems only to occur in the working week from around 0900 to 1200 ish, and is only noticeable when someone is transmitting, ( on the input ) We would like further information on this QRM. As to where it is, please, and DF information please - for instance can you hear it? on the input?... bearing in mind to hear it there needs to be someone else transmitting you can also hear! The reason for this is its wide band and really one needs a wide band ( FM broadcast style ) filter to hear it!! We are actively encouraging as part of the self learning part of our hobby the tracking down of this QRM..using low cost home built aerials such as the HB9CV.

We have been asked: is it the on site weather station ( ISOUTH 502 ) which is on 868Mhz? The answer is no, as Andy G4MYS, and G7POC, have exactly the same type of wx stations, while they do pulse, its only about once a minute, our QRM is around 90 pulses a minute, and we would of sussed that some time ago,- its not a problem!

Is it the traffic lights was another? We don't know yet! However it only seems to operate when its needed viz 0930 till 1230 weekdays!

Email to many thanks

We give our thanks not just to the three lads involved in the fitting of the aerials, but also to all the working members who by their actions like sales at rallys, and selling donated equipment, to which we also say a big thanks to our kind donors, We have got the funds together to purchase over £1000.00 worth of new aerials and feeders to make this project as good as we can get it.

SH & MT will receive their new aerials soonest COVID restrictions , the weather allow as of mid July this looks like mid August! Around the 14th !

Andy G4MYS



We have been invited to play on a usually switched off UHF repeater on SUNDAY 5th JULY, 10:00 - 17:00. Possibly to 19:00 if required.
This is a very well sited repeater to the west of Winchester, high up on a mast! - for doing range testing of the repeater site. You are invited to join in using handhelds, mobile and base stations.

RX 438.400MHZ (NO TONE). TX 430.800MHZ (NO TONE) that is to say neither CTCSS or 1750Hz tone burst is needed to get in!
Of course running 71.9Hz wont hurt, its simply not needed!

Programme up your radio before you go, as the splits are non standard : Note RX on 438.400Mhz and TX on 430.800 a minus (-) shift of 7.6Mhz is used!

We have particular interest in:
Romsey, and surrounds,... the A338 Ringwood to Salisbury.... parts of the New Forest in particular along the A31, if you want to wander of the main roads on a hand held please do so, call in and let us know the national grid reference

In particular we'd like you to think about where your going before hand, and work out your national grid squares.

( They start SU in Hampshire area or SZ for the Island ) at the places you intend to call in from!

We'd also like you to log your journey with us in advance to try and ensure we don't all go to the same place! You can do that by contacting

Ideally we would like you to pull over and specifically work the operator station callsign ++++++ at the specific points you have identified.

If your having trouble with the National grid system you can chat to myself Andy G4MYS on our repeaters SH SH MT repeaters about it, as I was with the Ordnance Survey for a number of years, and am very familiar with national grid reference system! or

There is a website called Grid reference finder on which you can get a National grid reference to to either 6 or ten digits

Andy group Chairman.


Our Weather station "ISouth502" is back on air after the problems were fixed today, Mon 15th July, we are pleased to say and Thank those involved, one of whom is also a ham for their hard work and diligence in sorting out what was a complex fault,
So go enjoy: You can look it up directly as "ISouth 502"

go via "Undergroundweather" and follow the on screen instructions, which is hard work,
or go via our opening screen on GB3SH.CO.UK tab "WEATHER"




Both Broadcastifty our live radio audio stream service to the internet, and the On site weather station "Isouth 502" which is available on Weatherunderground, have been out of order for a while due to different faults which are nothing to do with us!
Broadcasfifty have been having trouble with their computers and hand over systems in the USA, they should now be running as usual, and you are invited to also inform us of problems at

The problem with "Isouth 502", the weather station is very different in nature, being down to the route between our repeater internet switch and the outside world. We are informed that this should be in order by mid next week, and look forward to seeing the data once again.


The GB7MT wx station is off air due to failure in telecomms equipment which is beyond our control. We understand from the engineers who run the comms system that It will be fixed in the week ending 12 June.

The Wx station itself, is still gathering information, and is sending that data via a UHF link to its base station, which talks to a USB hub, there should be no need for intervention to recommence the data stream. The station is privately funded by members of the committee, for the sole purpose of monitoring wind speeds on site, for assessing potential wind damage to the aerials,.. so far the highest speed experienced was 96MPH last November, which is excellent news for white stick colinears as -- were still on air!

Our thanks go out to those involved in sorting out the problem, which has proved interesting to say the least!

After COVID 19 is over we plan to add a camera to the station, looking at the horizon, for weather observation purposes, which will make it significantly more interesting.


17/04/2020 Get on the air to care – RSGB launches national campaign in partnership with the NHS

Communications Manager | April 17, 2020

Watch The Video Click Here

The Radio Society of Great Britain, working in partnership with the NHS, has launched a new campaign called “Get on the air to care” to support the emotional health and wellbeing of 75,000 licensed UK radio amateurs – just some of the 3,000,000 worldwide.

Paul Devlin, NHS England Emergency Care Improvement Support Team and RSGB District Representative, says: “Now, more than ever, we need to optimise all modes of communication to help reduce loneliness and isolation within communities. Amateur radio provides a wonderful, unprecedented opportunity to help make this a reality”.

World Amateur Radio Day on Saturday 18 April celebrates this innovative, global community. Whilst amateur radio evolves continually to include technologies which are at the forefront of modern radio communications, radio amateurs can “Get on the air to care” with a simple handheld device.

Steve Thomas, M1ACB, General Manager of the RSGB explains: “Please help to increase amateur radio activity through club and repeater group nets, chatting with your friends or just by calling CQ. If you’d like to show your support for the NHS at the same time, Ofcom is happy for radio amateurs to add “/NHS” to the end of their call signs.”

GB1NHS, the UK’s National Health Service radio communications station will be on the air as part of this campaign so listen out for it!

Our new “Get on the air to care” web page at
includes our launch video so do take a look.

As you get involved in “Get on the air to care” by being more active on the radio, please share your photos, video clips and news with us via and also on social media using the hashtag #GOTA2C


Were are sorry to announce GB3SH is of air due to a fault in the receiver, due to the Covid 19 were not in the position to do anything about it for some time, we do have another receiver of course but still we cant fit it! As this is a rx based problem the TX and logic sound fine and hopefully the CWID will keep you and me company for many weeks, meanwhile service is normal on SU & MT.

Andy G4MYS


We have noticed that the cwid on GB3SU is very LOUD, were sorry about that! as a quick work around set your CTCSS in decode also and you will not notice the CWID
Need less to say there is nothing were going to do about it for the time being - as its a fault in the audio generation of the pips & CWID which is likely to be a dodgy skeleton pot in the G3RKL mk1 logic board which is around 23 years old! which means the CWID & pips may totally misbehave: it may go loud or soft or anywhere in between before we get the chance to repair it.

Andy G4MYS

13/03/2020 As you may know we are hoping to be out this year with our sales table raising much needed funds to keep our repeaters on air.

We were due to be set up in April at Kempton Park but as you will read this has been postponed.


With the current situation of what is now called a pandemic break-out of the Coronavirus COVID-19, it is with great regret that we have to announce that it has been decided to postpone the Kempton Rally that was due to be held on Sunday 19th April 2020. We have been able to secure a date for the postponed rally of Sunday 15th November 2020.

After a lot of thought we considered it would be prudent to do so due to health considerations. It has been postponed on the grounds that it is advisable to avoid and keep away from gatherings or events where there is an increased possibility of contracting or spreading the virus regardless of appropriate measures being taken. As you will be aware we have lots of people attending who are advancing in age and may not be in the best of health, added to which the event is normally very crowded and there is no way of avoiding close contact.

If you have booked already and payment has been made, we will hold the money over for the next event. Please keep the paperwork that you will have already received.

By November we hope that it will be business as usual.

Sorry for the inconvenience caused, we hope you will understand and continue to support us.

Paul Berkeley
Radio Fairs


Technical Update

The groups technical team has been working on getting a set of duplexers working for GB7IV, the greatest problem here is the new cost of such units new which is around £2,500. Second hand units have there own problems as we have found which includes theft of parts, parts not being suitable on the ham band, and stowage corrosion, which can be in the base and internally on second hand kit.

In order to get just 4 filters going we have brought a number of "cans" and made the very critical length cables after a lot of careful research, and have selected the best pairs to work with. We have checked them, and need to do further work on the caverty jump cables lengths.

More alignment and testing will happen in the next two weeks, after that On air testing will happen, with the D-star repeater before its moved to the repeater site. And then even more testing will have to happen to settle down two VHF repeaters very close together. Affer all that the D-star repeater machine wont be internet connected as we are still trying to understand the Centross operating system.

We understand some of you are asking about a Fusion repeater, the simple answer is The IV group has a D Star repeater, We may be able to borrow a fusion repeater to play with, but at over £1000 if you want us to run one on VHF, then hands will have to go into pockets! Let us know its for the "fusion fund" then we will know if these are serious "wants" or just someone else can pay for it, and ill use it requests.

It has to noted that most of the funding comes from a small percentage of our user base, and the efforts of the committee at rallys ....

23/02/2020 AGM
Southampton Amateur Radio Club Meeting WEDNESDAY 18th March 2020

The Southampton Amateur Radio Club meet at The Peartree Inn Southampton on the 3rd Wednesday of every month.

We The South Hampshire Repeater Group are also there for any questions and to report progress.

You can also get information on the Radio Amateur courses for those starting and those who wish to progress.

New and old members always welcome. Good to see some of the old members coming back and returning to the airways.

WEDNESDAY Evening: 18th March at the Peartree Inn, Woolston, SO19 7GZ

19:00 for 19:30 : large car park, no worries parking!

Drink policy: we purchase our own they sell soft drinks / Coffee, water and booze! however they don't do meals.

20/02/2020 Radio Caroline Support Group Meeting : All members are welcome to come along to this meeting Wednesday March 25th : Click Image

Southampton Amateur Radio Club Meeting WEDNESDAY 19th February 2020
The Southampton Amateur Radio Club meet at The Peartree Inn Southampton on the 3rd Wednesday of every month.

We The South Hampshire Repeater Group are also there for any questions and to report progress.

You can also get information on the Radio Amateur courses for those starting and those who wish to progress.

New and old members always welcome. Good to see some of the old members coming back and returning to the airways.

WEDNESDAY Evening: 19thFebruary at the Peartree Inn, Woolston, SO19 7GZ

19:00 for 19:30 : large car park, no worries parking!

Drink policy: we purchase our own they sell soft drinks / Coffee, water and booze! however they don't do meals.


The new four stack antenn system being tested in Chandlers Ford. There is also a picture of the monitoring antennas that we installed for the web monitoring stream on line very soon.

Instalation of the four stack to the MT SU site will be soon whern the weather improves.

The Engineers insist on warm no wind and plenty of hot soup!


11/01/2020 We will have our new commercial grade aerial for GB7MT on show off this coming Wednesday at the Southampton Amateur Radio club meet at the Peartree Pub in Woolston for all to examine and admire!

Its a Brand new aerial from "Jaybeam wireless", A 4 stack "tetra" style dipole array aerial nearly 10 feet high! rated to withstand 160MPH winds and handle 200 watts of power, We will also With a the new aerial for GB3SH as well !

We'll also have an FT 100M the Yaesu Fusion mobile used to work GB7MT for your interest.

Bring your cameras!

The next meeting is at The Peartree Inn
Wednesday 15th January 7:30pm SO19 5GZ