Noise Cancelling Speaker

After reading reviews and watching YouTube videos, I decided to buy a BHI noise cancelling speaker from Radioworld ltd – Link to Information.
I opted for this version as it has a small footprint and is very adaptable, for example if I choose to put a rig in a vehicle, transferring it is a very simple matter of unplugging the audio 3.5mm jack from the transceiver and 12v power lead, the other plus was that it has a 3.5mm mono headphone jack which cuts the speaker when plugged in, meaning the feed to the headphones benefits from the noise cancelling. (see warning)

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The unit works really well and reduces interference and in some cases completely eliminates it enabling me to hear stations which I couldn’t otherwise.

The speaker has a number of controls:

Power Off/ Audio Bypass, with this ON the unit is a powered amplifier with the volume being adjusted but a control on the top of the speaker (Note – as a powered speaker it is susceptible to picking up the polling of any mobile phones near to the unit which can be very annoying), with the power on, but the noise cancellation OFF, a RED led will be lit on the front of the unit.

Turning noise cancellation ON is done by a slide switch on the top of the unit, the LED will change to green when in this mode, a multi-position rotary switch on the rear of the unit adjusts the level of filtering, you know when you have too much noise cancellation as the speech sounds like they are underwater!

I’m very please with the unit and it works well, two things I have found is that the filtering initially introduces latency during tuning until the noise cancelling stabilizes, this only takes a few moments but gives the impression that you are not on frequency with the tendency therefore to tune past the spot frequency in use, the other issue is that any roger bleep, radio confirmation or CW tone is not caught by the noise cancelling circuit and will break through the unit at an Warning – incredibly loud volume, be aware of this if you are wearing headphones (as I found out!!).

New Blitzortung Power Supply

Due to my previous blogs about a dodgy power supply unit (PSU) used for Chatteris Weathers Blitzortung lightning detector, I ordered a low electrical noise PSU off ebay.com, I ordered the 5v PSU on the 5th January, I received a mail confirming dispatch on the 7th January and on the 10th January it arrived from Hong Kong!

I plugged the unit in the detected signal quality is excellent, the PSU was quite expensive, but well worth the money as the performance of the unit is considerable better than before.
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Spot the spelling mistake 🙂

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5v USB at 1A and an output of 8.5v which I have used to power thermostat controlling the temperature in the small equipment room.

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TeraDak unit next to my NAS.

TeraDak PSU
Although ‘smoothing’ is on, the trace is considerably better than anything before it.

signal2
Lightning detection trace, picked up from Scotland, so not that far away.

CCTV Pan/Tilt Controller – Part 2

This is Part 2 from this previous thread, the remaining parts have arrived so I could complete the circuit which (hopefully) will give a relatively accurate positional indication, the circuit uses two LM3914 (one for Pan the other Tilt) with a potential divider signal being derived from the potentiometers (Pots) within the Pan/Tilt head, I have mounted the reference resistors slightly proud of the Veroboard as I’m not convinced that the values are correct, so I will be able to modify these from the top of the Veroboard.

Pan_tilt Leds
Circuit diagram of positional indication for the Pan element, for Tilt I have used three LEDs and so the wires from each LED will go to the appropriate leg of the IC which has the correct voltage when aligned to the correct position, a mod to make is to convert the mode of the LM3914, so instead of a ‘spot’ led indication used as in the direction indication, where each LED follows each other and then fades out, the tilt will show the LEDs staying on as the platform transitions from zero degrees to ninety degrees.

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Veroboard showing resistors raised for ease of modification should it be needed as the accuracy of the Pan/Tilt pots has not yet been confirmed.

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The Veroboard has been temporarily secured using a cable tie, this arrangement will be replaced with something more permanent when the unit has been proved in service.

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Connector block with two sets of three wires for the Pan/Tilt positional feedback Pots, followed by the Pan and Tilt motor drives and at the end, the brake release feed.

The supply is 24vDC which is reduced and regulated to 12v via board on the right, this is fully adjustable and will be used to tweak the voltages to make allowances for any external cabling voltage drops that are incurred at installation.

Lightning Analysis Reinstated

I have tweaked and restored the lightning analysis pages records_summary.php with the websites menubar link taking you to the records summary page, at the base of this page is a number of further links which drill into the details, (at the time of writing no new events have been generated since 2014).

The base program is called ‘Discharge’, a link to download this is on each lightning analysis page displayed.

PayPal Button

Chatteris Weather is a non-for-profit community interest site, a number of users have asked how can they contribute to the sites running costs which I really appreciate, in response to that I have placed a discrete ‘Donate’ button at the base of the web sites left hand menubar, clicking will take you the secure PayPal area where an amount of your choosing can be entered.




 

Weather Station Equipment & Software

Thought I’d do a quick blog on the equipment and software in use at Chatteris Weather as I have made some changes recently.

The PC is a Hewlett Packard HPd530 tower unit, the original 360Gb hard drive has been supplemented with an additional 1Tb drive, this is used to store the mirror of the main C:drive and web site backups – this in turn is backed up to a NAS (network Attached Storage) and another hard drive in a removable caddy all just in case, wish we could predict a failure in advance!

crystal_ball_LG

The PC has 4Mb RAM and a Pentium 4 – 2.66GHz CPU, the operating system is XP Professional, Service Pack 3, this PC cost £80 (Ebay).

All powered elements relating to the weather station are on UPS backed power including the router.

The weather station is a Davis Vantage Pro2, with the following sensors:

      Wind Speed

 

      Wind Direction

 

      External Temperature

 

      Humidity

 

      Rain

 

      Solar

 

    Ultra Violet

Additional sensors, not part of the Davis Vantage Pro2, are fitted to detect lightning, these are the Boltek LD-250 and a community project – Blitzortung.

The Davis Vantage Pro2 is hardwired to a LCD display, this display also outputs the data via a USB port to the Weather PC, Weather Display software process this data and presents it in graphical and tabular form, this program is extremely comprehensive in functionality.

To allow an image to be included on the weather site, I have used a Canon digital camera operated by SebecTec software, should the software detect that the camera is ‘frozen’, a USB relay will operate, resetting power to the camera and causing the program to restart.

I use Startwatch to automatically start in sequence the following programs, (I use this over the System Scheduler as it displays CPU and memory usage, this application is left open on my desktop as the colour indicators next to each program show me instantly what is working well and what isn’t):

      Nexstorm – This is the local graphical interface to the Boltek LD-250 lightning detector.

 

      StormVue NGX Data Server – This is used for the remote web interface display.

 

      SebecTec – Camera software.

 

      Weather Display – Main program.

 

      WXSIMATE – Data collector for weather simulator and local forecasting software.

 

      WXSIM – Local weather simulator software

 

    WASP2 – Launches Nexstorm images to the web site and to the StrikeStar network.

Programs which start with the PC are:

      TSentry – Lightning Alert e-mail addon to Nexstorm.

 

      StrikeStarEU – Sends data to the StrikeStar network from Nexstorm.

 

    System Scheduler (Professional) – Executes programs.

Scheduled Programms – these are controlled by the System Scheduler –

      Discharge – Lightning analysis software displaying output on web site.

 

      Autolearn – This WXSIM addon works in conjunction with WRET Data Retreval software and causes adaptive changes to the WXSIM forecast based on analysis of history files.

 

      WXCompare – The scheduler runs the sequence of logging scripts in order that WXCompare functions.

 

    Acronic – Every Sunday an automated backup is taken.

Software used to administer Chatteris Weather is:

      Filezilla – Data transfer.

 

      Notepad++ – Editing.

 

      TeamViewer – Remote access for diagnostics or restarts.

 

      WDL Configurator – This is the programming package for Weather Display Live which is used on the site.

 

    CCleaner – File and registry cleaner.

I haven’t mentioned Blitzortung as the controller has a built in web server allowing me to access it via a web browser, no local software is required.

What I’m finding is that the PC is slightly under-powered in terms of performance, both the Weather Display and WXSIM forecast programs are quite resource hungry, the former especially when creating hourly and daily movie files and the later when it is generating a forecast, due to lack of processor power I had to move the creation of the Twitter feed to the half hour as their was just too much going on the hour and subsequently Twitter data did not get published.

2014-12-27 21.42.25 (Medium)The lower screen has Weather Display showing, the Weather PC is the taller of the two, you may just be able to make out the removable Hard Drive caddy on top of the smaller PC, I use this to backup each of the PC’s.

Dramatic Difference with Lightning Detection Signal

After finding the radio interference problem caused by a plug in power supply unit, (link to Thread), this also caused power quality issues to the Blitzortung lightning detector to which it was powering, here we have a before and after traces of background noise:

blitz badPulses caused the automatic gain to be reduced, effecting the detection range.

blitz goodConsiderable improvement of signal quality.

detectionLightning detection trace, this trace was captured during the storm activity in the image below.

station

The green squares indicate stations online, the grey squares are stations that are currently offline.

Electrical Interference – The hunt with my mate Billy.

I have had a problem of a really strong pulsating radio interference signal lifting my noise floor, the strongest signal were at 350Mhz, 521.5Mhz, 924.7 Mhz, 990.3Mhz, 1.802Mhz, 145.537Mhz and 145.000Mhz detected by my trusty AM radio, Billy.

SAM_5244 (Large)Billy the Fish with a broken gill.

Preliminary investigations walking around the house and outside pointed to it being the neighbours solar panels as when I got near to his garage where the inverter is located, Billy went nuts, it was as though it was radiating out everywhere, putting Billy over my buried radials in lawn amplified this signal up, even putting the radio near the earthed outside tap picked the interference up.

As I was convinced the interference was from outside of my house, the only way to prove this was to turn the power OFF to the house, so with Billy in hand, I turned the power OFF expecting the radio to go quiet, but it didn’t!

Looking around in the garage, where I turned the power off, for a source of the noise, I saw the UPS for the PC was ON, turning this OFF the noise reduced, but still did not stop, walking around with Billy the interference was still very evident.

Went inside the house and heard two other UPS bleeping, the first one is in a room directly above the garage and as soon as I turned this OFF the majority of the noise stopped.

SAM_5251 (Large)

The next visit was to a room off my home office where my network kit is installed, the main UPS is fitted there, turning this off and the radio went dead quiet, so much for my theory of blaming the neighbours solar panels!!

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So now to start turning things back on, with all the breakers off, I turned the main power switch ON, and the radio stayed quite, turning the breakers ON one by one, I didn’t get very far until the radio kicked off again.

First breaker causing a problem was the garage sockets, turning the switches on the sockets OFF in turn, I came to one which stopped the noise when turned off, it was a 12v switched mode power supply for a camera causing the interference.

The next breaker to cause me a problem was the one to the house sockets, switching this ON, yet again caused the radio to detect interference, back into the house with Billy, the hunt was on!

It turned out to be right under my nose in the office, it was the Blitzortung lightning detection controllers power supply unit.

SAM_5243 (Large)

I will investigate sourcing a low noise 5v DC linear PSU as well as making improvements to the controllers earthing as I don’t want to disable the unit.

I do have background hum from the power supplies feeding the Netgear switches and other small load items, but it’s nowhere near as bad as it was and I know what’s causing it, which is good, total elimination is the optimal solution, but proberbly unrealistic, so bit by bit I’ll chip away and get the noise floor as low as I can.

General information and status updates.