sounds, sensors, stones
Ipswich council did a nice job making this rec better for wildlife while keeping the facilities, and it’s a pleasant little oasis of birdlife. The birds are getting up earlier than the Sunday traffic on the ring road, this recording is a lovely piece of avian exuberance and joie de vivre.
Recording started at 5:30 am
RSPB Ipswich Local Group leader Chris Courtney and a group of our surveyors met up today at the Brunswick Road Recreation ground for a press event to celebrate the completion of the survey in 2016. (above pic is Chris (L) with Joe Underwood, Ipswich Parks and Wildlife ranger)
Naturally if you’re in the group being photographed you don’t get to take pics of the group 😉 It was good to meet up and put some names ot the faces of our sparrow surveyors from last year and talk with the rangers, who have improved this rec for wildlife.
The Sparrows of Ipswich 2016 report.
There’s something charming about the few pedestrian level crossings that take footpaths over the railway, reminders that the footpaths were here before the railways.
Network Rail have hated this one on the Fonnereau Way for a while, trying to close it in 2012 and now they are back for another bite of the cherry.
In an attempt to show how lethal these things are, or perhaps how much the pedestrians are in need of a Darwin award they have erected this panjandrum to bark out dire audio warnings about walking into the path of an oncoming train while you are glued to your phone, distracted by children and various other hazards.
I stood by the annunicator tripping the PIR sensor to get the full sequence of announcements this thing barks out at passers-by. (recording edited slightly to shorten dead space)
To be honest, if you don’t pick up that something is amiss when you see this
and hear this
then you’re tired of living and should spend all of your time in your phone, else go collect your Darwin award.
Network Rail is trying to harangue the local landowners into going along with their scheming
The Fonnereau Way has been used for a long time, although it’s been the subject of a fight when someone into horseyculture bought a property in 2009 at the Westerfield terminal, claiming to be all surprised there was a footpath there, trying to block it up and have it stopped on several occasions. Unsuccessfully, it appears. Nevertheless, Network Rail may yet succeed.
The British Museum in London is full of all sorts of oddball items. Some of the things on the ground floor are much more in the line of the cabinet of curiosities than the themed collections upstairs. As you turn to the left after coming through the main entrance there is a Victorian room dedicated to the Enlightenment. Although the cabinet of curiosities approach is frowned on nowadays, it appeals to the randomly curious part of me. It’s home to a small collection of John Dee’s magical items
Here we have John Dee’s obsidian scrying mirror. Obsdian is apparently a natural volcanic glass formed from solidified lava, and can be polished to a smooth dark surface. I didn’t notice from the description, but apparently this comes from Mexico via the Spanish.
It’s the devil’s own job to get a picture of this in the dim light of the Museum, and taking a picture of a black object is never tremendous fun. John Dee entered Cambridge university at 15 and graduated two years later. He taught at various European universities before returning to England when he was 24 to teach navigation and mathematics to captains of the British Navy, playing a key role in the fight against the Spanish Navy.
Astronomy and astrology were linked disciplines at the time. Dee was imprisoned in 1553, allegedly for casting a horoscope for Elizabeth, Queen Mary’s sister and heiress to the throne. It’s easy to see how he got into hot water – the horoscope indicated Mary would die, and Dee was charged with attempting to kill Queen Mary with sorcery. He was released in 1555. Elizabeth became queen in 1558, and Dee’s fate improved.
Instead of scrivening mirrors we have computers and they operate not on unseen angels but on unseen electrons. Because of his failures Dee remains modernity’s dark and forgotten twin. We are able to live in a world that he could conceive of, but one which he could have never invented.
Dee is best known now for his work on occult phenomena and contact with the spirit world, which he began in earnest in 1581. He found this contact hard, so he starting doing this work third-hand, by employing gifted ‘scryers’ – people who could see the spirit world directly. Using scryers enabled Dee to take comprehensive notes. He first worked with one individual, Barnabas Saul, until Saul was burned out from some disturbing encounters, and Dee searched for a replacement to help him.
In 1582 he found him, in the form of the imperfect rascal Edward Kelley. Kelley was a sensitive, but also a charlatan, whose ears had been cropped for forgery, so he was difficult to use as a witness. Dee’s notes indicate that in November their spiritual research encountered the Angel Uriel, who instructed them to create a talisman that would make communication with the spirit world easier. Dee and Kelley constructed these and other magickal tools.
This breakthrough led to Dee using a novel language called Enochian script, and the pair made significant progress, and their fame spread. This led to sponsorship from a Polish noble, who was dazzled by Kelley’s scrying ability when he came to England, and who funded the pair’s attempts to discover how to transmute iron into gold. When the noble’s money ran out, Dee and Kelly were sent to Prague with a letter of introduction to Emperor Rudolph II. This began auspiciously, as Rudolph was also attracted to the possibility of the Philosopher’s Stone, but naturally their experiments always remained on the verge of success without actually delivering.
Dee’s reputation as a wizard caused problems at home in England, where in 1583 a mob attacked his home in Mortlake and destroyed his books and instruments. His fortunes started to decline when the Pope instructed Rudolph to expel Dee and Kelly, and they sought sponsorship for their work from King Stephen of Poland and another noble, Count Rosenberg, who accommodated the pair in his castle.
Kelley’s mischief meant that they parted their ways when he made some unreasonable demands of Dee, who then returned to England in some style in 1589. However, without Kelley he now relied other scryers who were even less reliable than Kelley. Dee held a few more posts before retiring in 1603. Dee died in relative poverty in 1608 – Kelley had perished in 1595 jumping from a window escaping from a Prague penitentiary.
A fascinating diversion into Elizabethan intrigue and mystical inquiry, brought on by a chance visit to the Enlightenment room. A few cabinets down is fellow Cambridge alumnus Stukeley’s romanticised picture of A British Druid in his 1740 book “Stonehenge, A Temple Restor’d to the British Druids”
which is why Druids have been associated with Stonehenge ever since. All part fo what makes the British Museum a wonderfully diverse way to pass a couple of hours in London.
The RSPB Ipswich Local Group surveyed the town’s sparrows last year, and we have the results now in. It’s a little bit better than I had thought – strongholds to the north-west and south-east. It’s tough to compare this with the 2006 survey because that wasn’t controlled-effort, although at first glance they still seem to be losing the fight around the Valley Road area relative to the earlier survey.
tl;dr – to fix the problem throw the Skytec Pro 600 away and buy something better before the Skytec blows your speakers again. Don’t buy Skytec, and if you have it throw it away before it fails on you.
Skytec is cheap rubbish made in China for kids who are wannabe DJs but have little money. This is not quality – I had to repair this amplifier because of a fundamental defect in the engineering design. These are fine for background music, say in a pub. They’ll go reasonably loud in a modest party setting ,say 30 people, but it’s rough, and it’s nasty. You’ll save on the amp and pay in bass drive units if you DJ with this at any scale 😉 And get a limiter if you can, but if you can afford that you won’t be down at the Skytec end of the market.
I made the dumb mistake of buying one of these used from Cash Converters for £30 a while back. I bought it purely on price, I wanted something basic for parties of about 30-50 people. I knew nothing about PA, but I figured a hifi amp wouldn’t cut it for that sort of usage. What I hadn’t anticipated was people shift junk onto the PA market with design defects that were solved in the 1970s. They don’t even need any new parts, just put the Vbe multiplier on the heatsink rather than on the circuit board.
Skytec 600s are sold as 600W and the manual claims 600W output. They are absolutely away with the fairies on that, to the extent they should be done under the Trade Descriptions Act. I guess they hide behind the fact they don’t say RMS power, so they probably mean peak power, though that’s still only 280W. I measured 80V p-p, which is about 28Vrms. Run that into 4Ω and you’ll get V²/R≈200W. Do that for any length of time and it will blow because of the inadequate heatsinking and bad thermal design.
HiFi tower talk glowingly about the MOSFETs
Skytec’s PA-600 gives you the extra power you need with exceptional bass. All sound components are co-ordinated carefully and captivate their longevity. The modern MOSFET transistors and extra large power transformers give great sound and dynamics. The high build quality makes it the ideal amplifier for tours and gigging. For use on stages, for DJs, monitoring, parties and conferences.
but there ain’t no MOSFETs in this, simply a pair of paralleled bipolar junction transistors in the complementary pair output stage, 2SA1941 and 2SC5198. Toshiba described the transistors as suitable for 75W amps, you have two in parallel so 150W tops, okay times two for stereo = 300W. The toroidal transformer isn’t over 600W, I’d guess 200W from the size.
It worked OK for me for a couple of years, but then I let someone use it unsupervised for live music. Which brings me to the first warning
I wasn’t, there, and the result was a blown output stage and blown woofer. It only cost me £11 to service the amp and £50 to change out the woofer, so I am now down £91, and I still have a junk amplifier, though it works now. Now that I know the ghastly horror of the circuit design I am not sure I have the balls to use it again, but at least it works as it was meant to originally 😉
After all, the promotional blurb says this:
The high build quality makes it the ideal amplifier for tours and gigging. For use on stages, for DJs, monitoring, parties and conferences.
so what’s the problems then? Dynamic range – live music has a higher peak to mean ratio than recorded music. You end up pushing the bugger harder, so unless you limit the live source in the mix you’ll clip the output. At least that’s what I assume happened, I wasn’t there when It failed 😉 The Skytec is fine for prerecorded music, but the basic problem is that this amp has zero protection for the speakers or the output stage. Worse still, the VBE multiplier that biases the output stage isn’t thermally coupled to the heatsink on the output stage. Let’s hear it from Rod Elliott why this sucks
Thermal Stability
It can be seen that in the Darlington configuration, there are two emitter-base junctions for each output device. Since each has its own thermal characteristic (a fall of about 2mV per degree C), the combination can be difficult to make thermally stable. In addition, the gain of transistors often increases as they get hotter, thus compounding the problem. The bias ‘servo’, typically a transistor Vbe multiplier, must be mounted on the heatsink to ensure good thermal equilibrium with the output devices, and in some cases can still barely manage to maintain thermal stability.
If stability is not maintained, the amplifier may be subject to thermal runaway, where after a certain output device temperature is reached, the continued fall of Vbe causes even more quiescent current to flow, causing the temperature to rise further, and so on. A point is reached where the power dissipated is so high that the output transistors fail – often with catastrophic results to the remainder of the circuit and/or the attached loudspeakers.
I got to find that out the hard way. I’ve actually managed to do a fair number of parties with this fine, but I was always careful to keep the bouncing LEDs of the output display under control by controlling the master gain.
On a wing and a prayer.
They run a PC case fan 100% of the time onto the main heatsink, sucking air out of the case, inflow is through the front. There’s no margin for error – although I didn’t trace the circuit it’s a complementary pair of paralleled output transistors driven by a driver (effectively making a Darlington output) so you got four VBE drops reducing with temperature at 2mV/deg C, asking for thermal runaway. There’s no fight against that with the VBE multiplier because it’s not thermally coupled. Get the die temp of those output devices hot enough, say 40C above ambient and you have 40*2*2 = 160mV less bias than you started with (the drivers are conveniently mounted on the heatsink to make sure their VBE drops too). This is designed for thermal runaway and the only thing standing between you and a blown output stage is the hope the heatsink and the fan keep the temperature rise down. You can get a little bit of an idea of the architecture from this thread and this PDF of a similar noname PA amp which gives a rough idea of the architecture on the output
Change the 2SA1941 and 2SC5198 transistors 😉 I buzzed these through with a DVM on diode setting and found them all short, traced back to the drivers expecting them to have gone but they were OK, traced back a further stage of BJTs but they were OK too. The 5A fuse saved the other passive components.
It’s quite repair-friendly – unscrew the three screws on the base holding the heatsink, unplug all the connectors after taking a photo to remember where they go back. Lift the PA module out, snip the duff transistor legs to save the PCB while desoldering the pins one at a time.
I powered up the repaired stage on a 30-0-30V bench power supply set to limit at 100mA, I know it’s meant to work off 60-0-60V but I got a signal through and confirmed it wasn’t still duff, before getting it onto the main supply. I also compared the quiescent current (10mA at 30-0-30V) with the good side, which was the same, so I figured the VBE multiplier was still set about right. Easy win for about £11 in parts. In fact one of the old output transistors was still okay, presumably saved by it’s parallel buddy shorting across it, but I’m not chancing it.
I also went round and tightened the output transistors a tad. It’s easy to overdo this, but the still- working side was about finger-tight like the failed side. I wonder if this also led to the early demise. You just can’t risk the transistor die heating up to any great amount with this design.
Having fixed it I started to test it looking for why it blew. I got a couple of 50W 6Ω wirewound resistors. These are sold on Ebay to people doing LED upgrades to their lights, to put in parallel with the LEDs and draw 24W so the automotive CAN bus filament blown detector doesn’t keep going off. I figured 6Ω is a nice compromise between typical 8Ω and 4Ω speaker loads; real speakers present complex loads anyway. It was the cheapest way of getting a power resistor up to the job. I then dunk the resistors in a pan of water.
since I don’t have a heatsink/fan combo up to dissipating 300W. I know electricity and water don’t really mix, but I figure the water isn’t going to shunt my 6 ohms too much. Worth heatshrinking the ends of the resistors though 😉 The reason I used a pan is because the failure mode of these type of power resistors is to violently eject the ceramic slug out the end. So a Pyrex dish or a jam jar isn’t really desirable.
Running both channels full tilt at 130Wpc for two minutes the transistors get up to about 50C at the hottest part of the plastic case. If fairness to the amp I’ve been able to fill a rented Scout hall with music without ever taking it up that high even on peaks, so I ran it for five minutes at 33 watts per channel (~40V p-p). And got the transistor cases up to 110C. The manufacturer’s spec for the junction temperature is 150C peak. If you thrash this like that for a long time I guess the heatsink/case fan combo is hopelessly inadequate, and it blows.
Sadly I battle tested the inadequacy of the design a second time. Five minutes after running the second test, after I had brought the signal down to 0, I was greeted with this, telling me the right hand channel has gone DC, presumably thermal runaway again.
While I know how to repair this, I don’t know how to fix it to make it fit for purpose because of the fact the Vbe multiplier isn’t on the heatsink. It’s probably true that my needs don’t push it that hard, but an amplifier that blows after running a steady 33W for five minutes isn’t something I’m going to risk ever using, so it’s time to scrap it.
Skytec Pro600 – Avoid. Just say no.
Richard and Joanne went along to the one day course run by SoilBioLab at Rushall Farm late last year. Simon, Andrea and Jen from the SoilBioLab team taught us how to take soil samples and qualitatively grade soils and compost & compost tea.
Their approach to qualifying the results is quicker and (in our humble opinion) more applicable to fieldwork than the full Soil Food Web Elaine Ingham method. You can use a cheaper biological microscope, closer to the student microscope end of the scale, rather than the more sophisticated microscope recommended by Elaine Ingham in her video training courses.
We found it a really useful day. In theory we “knew” a lot of this stuff, but there is nothing more useful than spending the day with people who really know their stuff, which the SoilBioLab team most certainly do, and being able to ask dumb questions, which they were unfailingly able to answer.
Soil Biolab also offer more detailed quantitative tests if you send them soil samples by post – they suggest a combination of doing your own analysis along with getting them to do more in depth tests from time to time.
An enormous thank you to Dave Beecher this guest post on his experience of hot composting. Dave has been working alongside Zach Wright who himself learned directly from the mighty Elaine Ingham herself! This post includes a very entertaining video of Dave making his compost pile, an activity the clearly fascinated everyone (including Billy the Dog!) at Caerhys Organic Farm in St Davids, Wales! You can contact Dave on (an image to protect him from spam):
So, my first attempt only got as far as turn 3 and would not heat up after that. It became very wet (liquid running out the bottom) once all the green material started to break down. I didn’t have enough high N and my green material contained a lot of internal water.
Pile shrunk down a lot as I did not compact sufficiently when building the initial pile. Using a flat head shovel every 6-12 inches works well. The second pallet was larger than first allowing for a bigger ring and making the pile look really small. Keep the diameter of the ring the same regardless of pallet size. This will allow better control when turning as you will be able to divide you material up evenly to comply with the turning break down as shown below.
I started again and treated the first attempt as 50% and then added 20% brown, 20% green and 10% high N. This worked a treat and i ended up getting 6 turns in as it was still quiet hot after the 5th.
Temp
I used a 500kg grain bag with pull cord to cover the pile. This worked well as i could open the top and release excess heat and condensation, preventing the top of the pile from getting soggy. I had to turn two days in a row as it was getting very close to 70c. I made sure to air it out well on the second turn and not compact it down at all. This allowed me to keep the temp 55-59C for 3 days.
Water
After the first pile getting to wet i held back a little on the water when making the second pile. The temp was slow to rise only 18C the following morning. I add 7L of water to the top and sides that evening, it reached temp by the next day. I continued to add water when need and based it on visual and squeeze method.
Flies and Midges
When the pile was covered and slightly damp from condensation there were a few hanging around. Once i removed it and allowed it to dry out they disappeared
Mushroom
Got my first 2 mushroom on day 17 loads on day 19, by day 22 they were gone just some pin heads were visible.
Compost Biology
After 1 month i found 5 bacteria feeding nematodes, one predatory, lots of amoeba and one our two fungi spores
After 7 weeks i was getting 30-50 nematodes per slide mainly bacteria and 3-5 predatory, a diverse range of amoeba and fungi development.
The pile is now 10 weeks old, I will be heading back to Wales next week to see how it’s getting on and will let you.
Happy Composting!
Dave
An enormous thank you to Nigel Griffith for this guest post on Farm Scale Composting at Landews Meadow Regenerative Agriculture Center, Challock, Kent in the South East of England. It is full of incredibly helpful, practical advice!
At Landews Meadow one of our main goals is to improve and regenerate our soils.
Our farm is just under 56 acres of very open land on the top of the North Kent Downs, we can see the North Sea from one field and a short walk away and we can see the English channel, so we have a very exposed site. Our soil is a heavy clay with lots of flints in and 8 feet down you hit the chalk downs. The soil gets boggy in winter and bakes hard in the summer and suffers from compaction, wind erosion and water erosion. For the past 30 plus years the fields had been used for set stocking sheep or cut for hay. The previous management system had been spraying nitrogen fertilisers and weed killers on the pasture.
We have implemented systems (swales, keyline ploughing and tree planting) to reduce the run off, increase filtration and water retention and reduce wind burn. Our initial tests on the soil showed that whilst it has a good mineral content but the only soil biology to be found was bacterial. With only bacteria in soil it will become more compacted and more acidic.
For the past 2 years we have been researching and trialling compost and compost teas to find a workable solution to kick starting the life in our soil. As the vast majority of our livestock lives outside 365 days a year we don’t generate lots of soiled bedding so we don’t have vast supplies of materials for making compost.
In April of 2016 we attended a course with Zach Wright of www.livingsoil.net who is one of a very few people certified and approved by Elaine Ingham. Zach describes himself as a Decompiculturalist and has spent most of his adult life making compost. He has refined the process and his course taught us not just how to make quality compost, but how to make quality compost that was full of soil life and how to test it with a microscope.
In this blog I want to share with you the basics of making ‘Biologicaly alive beneficial compost’ and how we apply this to our land. Field trials conducted by Zach and Elaine and trials sponsored by The Duchy of Cornwall are starting to show huge benefits for both pasture and crops when the soil is brought back to life, this soil food web breaks down available matter in the soil, making the the nutrients soluble and available to the plant, so that no artificial fertilsers are required. Once you have re-established this lost biology in your soil all you have to ensure is that you are feeding the soil food web and not damaging it by pouring on chemicals, we feed our microbes with holistically grazed animals (Cattle, chickens and ducks), the cattle trample grass and manure and the chickens scrape and manure as they go providing food for the soil food web.
Tools required
Raw Materials
The main constituent parts of any compost fit in to 3 categories:
The more local diversity you can add the better, you are looking to create environments for a huge variety of microbial life. We do a walk around the farm and find other things to throw in, feathers, mushrooms (No shelf or conch type) and whatever else we can find that will decompose.
We also add ground seaweed meal and crushed up bio char.
The process
Your pile will be impacted by the elements depending on the time of year and its position, if it is exposed to rain and wind you may want to cover it with a tarp or it could get too dry or too wet, we leave ours open for the first few days to get the aeration of the wind but cover it if we are due torrential rain and after 7 days to stop it drying out.
Managing your Pile
Check both the moisture and temperature daily and record them in a table like this:
If your pile is too dry, water it, as soon as your pile is over 70 degrees it needs to be turned.
Work to this turning schedule
| Temperature | Days Before Turn |
| 55 – 59 degrees C | 3 days |
| 60- 65 degrees C | 2 days |
| 66 – 70 degrees C | 1 day |
| Above 70 degrees C | TURN NOW |
The target is to keep the pile between 55 degrees and 70 degrees with a minimum of 5 turns so every part of your pile has spent 3 days at the core. This will kill weed seeds and pathogens but allow your beneficials to grow and speeds up the decomposition of the matter . Lower than 55 degrees and pathogens and seeds can survive, above 70 degrees and you are killing everything.
Interestingly the UK regulations for commercial compost require PAS 100 compost to have been kept at a much higher temperature for much longer periods (understandable when they are cleansing all types of waste in their process) but we want our pile to be a breeding ground for our soil life so it is critical that as soon as you go above 70 degrees to turn it. Every commercial compost I have examined under the microscope is devoid of anything but bacteria.
The Turning Process
Last Tuesday Richard and Joanne headed down to Kent to visit Nigel and Wendy at Landews Meadow Farm who very kindly found some time in their very busy work schedule to show us round. Their farm is a truly impressive place, and I’ve written up a summary of the “non-compost” parts of what we learned on The Oak Tree Farm website here.
Nigel has been working hard to implement Elaine Ingham’s methods on his farm, and the results are visible and impressive. He hasn’t carried out controlled tests as he is keen to have the benefits of the soil improvements everywhere, something we can understand, and have done ourselves with our 2016 tomato polytunnel, but the number of wormcasts on his pasture surface show very clearly that there is a lot of biology in his soil! Like us, his farm has very low rainfall, particularly in summer, though his soil is clay unlike the sandy loam of The Oak Tree.
Nigel went on Zach Wright’s UK course Spring 2016. We were gutted to have missed this, it looked really excellent, but we understand that Dave Beecher has been working closely with Zach and will be running similar courses in the UK soon – when we hear more we’ll keep you posted!
Nigel makes compost in the “hardware cloth” cylinders recommended by both Zach Wright and Elaine Ingham. We’ve found that hardware cloth doesn’t seem to be a British English term, which makes it hard to track down to buy. “Galvanised wire mesh” seems to be similar stuff in the UK. Nigel builds his heaps on pallets covered with woven weed control fabric “mypex” and he wraps a single layer of tarp over and round the heap to keep the heat in.
Nigel’s raw ingredients are
He uses a hose with a finger over the end to spray materials as they are added to the heap (by contrast we have been using a fine spray head). He has had considerable success with this method, managing to match the exacting temperature profile demanded by Elaine Ingham and Zach Wright’s methods, and the resulting material certainly looks excellent.
Landews Meadow Farm is on quite an exposed site (they have a fine wind turbine!) and while the compost area is protected by a hedgerow, it takes a fair bit of incoming weather (the English Channel is visible from the farm on a clear day!) Clearly the use of animal manure slurry is a good way to get compost heaps up to temperature as we found with using poultry manure slurry in our heap 160910. We had struggled to get heaps up to temperature reliably before doing this. He does five compost heap turns, carefully manipulating the material to ensure that all parts get up to heat in the hot centre at some point.
We were particularly interested to hear the simple “Zach Wright” method of making compost extract. We had attempted to mimic this following a phone conversation with Nigel before the visit, but we had made it more complicated than it needed to be! Nigel simply takes a 30l container, adds compost to it (see the photo below for an idea of how much) and then stirs it with a stick for about 30 seconds. Easy!
Once stirred he uses the secret ingredient of a jelly bag (the sort you use to strain fruit to make sweet jelly preserves) to strain the mixture before using it in his tractor mounted sprayer – brilliant! It is just these sorts of practical details we wanted to learn – it had never occurred to me to use a jelly bag (though I have one in the loft somewhere!) He then dilutes it into about 200l of water. Apparently Zach Wright dilutes further saying that one hardware cloth/galvanised wire mesh heap can be used to treat 200 acres!
Once again, a huge thank you to Nigel and Wendy for welcoming us to their beautiful, innovative and productive farm!
