12 volt TO3 5 Amp regulator ie 78H12K. Failing that a TO-220 or TO-3P could be used. Wanted by G0PIA. You may have noticed he has also advertised for one in the July RadCom.
If you think we look a bit of a ‘rum bunch’ please forgive us, (it was a long session). You will pleased to learn we are now all chipper and looking forward to meeting you at the Club one Wednesday evening. Foundation Exam training is now becoming almost a continuous event. Whilst some Clubs make a charge for training we tend not to. We trust that anyone fairly local will become a regular Club member anyway.
Training at the Havering Amateur Radio Club was previously a little ‘up and down’. Nowadays however everyone is pulling together nicely to give 100% to the trainees. Here is Steve G8PMU overseeing Michael M3DOV getting to grips with resistor colour codes, coax plugs and mains plugs. Refreshing to see our trainees know “without being taught” how to check a mains plug for all the correct ratings, fuse, and wire lengths.
Having got both Mick M6IFQ and Ken M6LRJ through the exam we are now doing the practical exercises with some more new members, one of whom (Petre) is about ready to sit the Foundation Exam. UPDATE Guess what! He has just sat the exam and passed, well done Marian.
Watch this space to read of more happy souls.
And another completed, rather an interesting story too. Our student was ready to sit the exam, only one problem – no exam papers. This was when people were murdered on Westminster Bridge and the ‘keeper of the papers’ was held safe in the Houses of Parliament. Unable to leave for hours he was unable to attend the exam and bring the papers. Fortunately the exam was reset for a few days later. Again we got worried. The exam was due to start at 5pm. Three of us were expecting the student to arrive in good time but 5pm had come and gone! He finally arrived 10 minutes late having been held up on a long train journey. Since the exam had to be finished by 6pm it was a bit of a toss-up with regards explaining rules or just getting on with it. No worries however, being a bright spark he completed the paper in half an hour and passed, phew!
Well done to Ken (above) who has just passed the intermediate exam. There were about 45 questions if I remember correctly and Ken only got a couple wrong. I’m not surprised really as there were some awkward ones which would have had me pondering for quite a while too, and probably ticking the wrong box. Well done to Bill our latest exam entrant. Early on in the marking we got worried but after a few ‘bad starts’ the sheet became a clean sweep thereafter.
Just a quick write up of Mountnessing Windmill until I get time to write it up better. Another great day out for the Havering ARC. Making some contact with some rare mills and a few old ones. Quite a few Dutch mills in the log and quite few German stations in the log to. Shame to see the mill in disrepair at the moment so we hope our small donation went some way to getting it fixed up. Also thanks to Karl, Essex County Council and the friends of the Mountnessing windmill for making us feel welcome.
Steve G8PMU making a few on his ex-military equipment. A great day for experimenters. Also worked the usual 160m club top band net.
Who? What? When……is that the great man Oliver G3TPJ operating. Oh yes… we had a really great experience with Oliver operating. Oliver bringing his own form of wit to the windmill (we were in stitches with Oliver’s jokes). Also in the shot is John 2E0WJI John Dale.
Didn’t go through the night on this one as many of us had other commitments but a great success. Thanks to the guys who helped make it happen.
Weather, some love the word, some loath it, the truth is we have to suffer it….whatever the weather…..get it..? Having a clear prediction on the weather can be god send, if your nipping to the shops or taking a holiday, the weather is of paramount importance. It gives us fine food and crops, its replenishes the grass and washes away dirt, it brings the rain we need to live, so why are so many so clueless about “weather”.
Our very own Alan Paul G3RJI or www.upminsterweather.co.uk fame gives us an amazing in depth analysis of weather and his world renowned weather station. During the talk we had great pleasure in learning why heat is often cooling…..”what”, yes heat can cool us if managed correctly. Call me a hypocrite but its all true and how we manage humidity is key to just that effect. Alans talk spoke in depth on receiving weather data in the early days of NOAA and 136mhz geo-orbiting satellites to geo-stationary satellites of today. Alan now points his equipment to Eutelsat 10a and with snazzy programs to decode weather data from MSG or Meteo Sat 2nd Generation the ordinary amateur weather guy or gal can now be a professional in his or her own right, giving rise to a new breed of reliable weather forecast. Alan has featured in many publications and has been prominent in the Romford Recorder for quite a while. Even using his weather station to send detailed weather via his APRS setup for the rest of Essex and beyond to appreciate.
Unfortunately predicting the weather and rendering images from space is costly. I personally tried to get into lightening reporting and using TTA or time to arrival synced to a GPS receiver that received the pulse from a strike and converted the energy from a ferrite type antenna into highly accurate strike data. Something that I did not ever get around to actually doing….baaahh! This is where dedicated weather predictors like Alan Paul step in and take up the rains (not a typo…a pun). Yes Alan has equipment to actually detect and report strikes…..genius (he says in an Italian accent).
My turnstile antenna still sits on the side of the house, not really receiving much these days unfortunately, however its testament to a fad I once had with the weather. Now days most of the weather is received directly over the internet or grabbed off websites. A shame really however time waits for no person. I still tune in to Northwoods weather broadcasts on 4610khz from time to time and run FLDigi on my Ubuntu PC just for fun, however I rarely get a chance due to work commitments. Looking at the images we managed to take at the talk we can see boards of stills of Infra-red and Colour images received via satellite to via the Internet.
Now days people use one wire techniques and Raspberry Pi’s or Arduino to grab weather data and send it over the Internet for analysis, however just having a DHT22 or worse a DHT11 sensor can lead to big swings in accurate weather reporting and unless your equipment is kept calibrated its unfortunately a hindrance to other dedicated weather predictors. You will see APRS is awash with bad data and corrupt information. So if your thinking about getting into weather on the cheap, keep your information in house as there seems to be a glut of dodgy info flashing around. If you want to get into APRS on the cheap for receiving weather data then you can download AFSK1200 for Windows and use your soundcard to receive APRS on 144.800mhz FM (along with other data of course). As your not transmitting you won’t need a 1:1 transformer to isolate the RF from your PC but remember to remove the cable from your PC to Radio when transmitting.
Lastly, Alan took us through his various features that he uses to get accurate weather information, including a Solar sensor, UV sensor and rain gauge. naturally every station needs a thermometer and Alan goes the extra mile with relative humidity sensing equipment, called a Whirling Pschycrometer which is one of the most reliable instruments, not requiring any batteries, and only taking around 15-20 seconds to obtain a reading. It is like a football rattle and is simply a holder with two thermometers, one of which has its bulb end exposed to the air and the other end covered with gauze which is kept wet via a small inbuilt container topped up with water prior to use. The unit is spun around for 15 – 20 seconds and the two thermometer readings are taken. Both thermometers will read differently with the wet one reading lower by just a few degrees. The wet thermometer gives a lower reading because when it is spun around some of the water on the gauze evaporates which cools the thermometer down. Just how much water evaporates depends on the RH at the time. If the RH is high then less water will evaporate and if it is low, then more will evaporate. Its a tad confusing but seeing it demonstrated helps and this is all plotted in a large book containing graphs called a Pschycrometric chart book.
In the current world or climate change, and weather diversity, then we all should be concerned about the weather….right. Then we should thank our lucky stars we have dedicated weather predicting gurus like Alan Paul G3RJI to keep an eye on what’s hot and not….Oh! no not more puns.
More information and live weather data can be found here on Alan’s website.
Final word. During the demonstration, Alan’s rain catcher was damaged and we never like to see our guest speakers go away upset. As this equipment came from the USA it naturally cost quite a bit. If you have a rain gauge or catcher that you would like to sell or donate then please contact the website here email@example.com. In the meantime I will search the web for a replacement. Remember Alan puts weather data into the public domain for free, his services are free so in between running a full time business he also gives up his valuable time to give us delightful weather data. The Davis Rain Collector.
best 73 de Spence M0STO
Another brilliant talk by Steve G8PMU, giving the members an insight into DMR. OK Love it Loath it….its here and its probably going to stay. My Personal thoughts….is it a phone, is it a radio….its…both. If DMR promises not to call time on analogue radio equipment and were not going to lose spectrum like analogue television….fine I am for it. I love to build little projects, Frog CW Morse transmitter being the quickest so far that actually transmits/receives. I really doubt analogue radio will go kaput in my lifetime and I really think that the spectrum DMR uses is secure for years and years to come….right……who’s with me on that? hams are getting more spectrum, don’t you know. 70.5 to 71.5mhz, 146 to 147mhz, 60 meter, 472khz and more to come. We are lucky and DMR won’t force the world digital soon, so were clear on that. And back to the talk. Steve started showing us that the Digital spectrum is already quite thick with modes that won’t talk to each other…..its branding, its competition and its who has the bigger antenna all over again, except the modes are having the whole VHS – betamax and HD Video or Blu-ray….errrr….DMR or D-Star or Fusion…there, I said it. Each have qualities but it has already become clear that D-Star is in third place with drop outs, deaf repeaters, overly expensive equipment and a substandard protocol that works when it wants. Fusion coming in next with its quirky microphones that take pictures (and 30 minutes to transmit lo-res images…. that’s so uncool), cheap repeaters and again overly expensive equipment. The clear winner here is DMR… why? I hear you say. The security services use them, the radio is not propriety, there cheap, compatible, repeaters link and distribute seamlessly (roaming is unbelievable), shared bandwidth, brilliant power consumption (better than 50% duty cycle as far as I can tell). the list goes on. As DMR uses TDMA it keeps the bandwidth to just 6.25khz per channel (25khz on FM wideband). So the benefits are clear. Steve also talks about how roaming gives a nice bridge of repeater function and range responding equipment. You drive around chatting away and the RSSI drops to a level when your radio simply seeks out the next strongest repeater in that talk group and your off again. No need to fumble with switches or knobs while you drive around and no need to lose the contact.
When I started out in radio i was unsure why a repeater could only talk locally. OK it was considerably further than simplex at the same power levels but I wanted to see more. I was convinced repeaters could talk to each other by changing the output frequency opening up each other with special DTMF tones and to chat to the next nearest repeater….that way a QSO with Scotland was via say….5 or so repeaters…..I was wrong, but the concept was in my head…for years hoping that one day it would happen. No it never did but today we have a solution, Internet linking repeaters that take our voices turn them into bleeps and send them over the Internet for the other repeater to take the bleeps, turn them back into audio and then back into a good old fashioned QSO.. well kind of. So the basics are explained. Now we have websites to look at the RSSI of the transmission (repeaters only) and the users BER or bit error ratio which is neatly converted to a loss percentage. My job requires me fiddling about with CER,BER,MER and more error ratios on a daily basis and I can tell you its no fun when you either have a signal or nowt when the BER etc drops below a certain threshold. Fortunately for DMR that threshold is pretty low and from observations the BER is actually VBER and the audio drops quality as the error ratio declines before your really out of range all together. Other digital radios will drop out way before DMR it seems and the recovery is equally as poor.
Our American cousins across the pond are lucky enough to have DMR 900mhz available and the majority of security services are 900mhz which is great for the second hand radio market, but not so good if there is no ham band to cater for it. In the UK, the frequency of choice and early adopters seem to have hugged and embraced the 70cm band and a good flow of professional and not so professional radios are appearing on the market every day. Sadly 145mhz DMR is not so popular and neither are the radios. Again, at the time of writing, there are no dual band DMR radios that I know of but i feel those clever Chinese will dream up the “Bish Bosh look at my wad” type gizmo’s that will cater for both bands and aimed at amateurs and those who want entry to that band on the cheap, much like Beofengs have captured the top of spurri din makers list. Having a radio do the splits (a bit like Rebel Wilson in the BT Advert) will surely get people rushing out or buying like mad from that well known auction site to get into DMR.
Firstly!!, you do have to register to A) get access to some repeaters that Internet link and B) convert your callsign into a number. DMR works by sending your number encoded along with the transmission for the other user to see and then use the code plug that was previously uploaded to the radio to then display your name and the other stations name. Similar to a DNS server, but for radios. Cool I hear you cry. Hhhhmmm if you want to use your friends radio…you get some strange reports and/or ignored totally by people thinking your a pirate? However programming your callsign as a loaner or lender is pretty simple. The code plugs are updated quite frequently and generally only worth updating when a major update is about. Adding user numbers and names manually helps a lot as you don’t lose your mind when looking through the repeater list you memorised (new code plugs tend to jumble things up on every new update, much to the annoyance of this ham and followed by a fist bashing desk session, so keep a backup ofthe old code plug before you overwrite it).
So code plug in hand, radio battery full…what next. Well programming a code plug is straight forward, entering the detail manually …not so. Your number is your radios ID, you enter your callsign only as a power on message normally. DMR does not see callsigns unless your text messaging other uses. just be weary that calling someone private over a repeater is as good as encryption and you will get banned from the repeater and possibly need to re-register for a new Radio ID. You have been warned. Most of the code plug is as simple as 1,2,3 but do read the readme files with most of the programming software. Time outs, analogue busy repeater lockout etc will catch out some out. If a repeater is busy it will inhibit your transmit. So the other party has to stop talking and the repeater shut down before you can talk….a pain in the neck if the other party keeps asking “are you still there” and not letting the repeater close down. Not all radio do but some have this function as default and standard.
So DMR….. in a nutshell. most of this blog is off the back of Steve G8PMU’s talk and a little further reading with my opinion mixed in. Also keep an eye on TOT rek-ey too. if TOT is set and TOT re-key is too, it will inhibit another PTT in the set period. You time out after 60 seconds and a 30 second re-key is set, your probably going to love that like the proverbial hole in the head. (a good place for an idiom don’t you think).
Here are a few useful sites and please comment. many thanks as ever t Steve G8PMU and thanks for those who attended the talk.
http://www.cc-3.net/monitor.php?filter=uk a handy RSSi monitor (currently not working)
http://www.codeplugcentral.co.uk/ (the latest code plugs will appear here)
http://live.ham-dmr.net/ (Europe wide DMR monitor)
http://www.dmr-marc.net/ (Check your callsign is registered)
http://www.dmruk.net/ (DMR MARC’s UK variant)
http://register.ham-digital.net (Register your Callsign for an ID)
http://norcaldmr.org/listen-now/ (Great concept, needs Chrome Browser though)