Dummy Load Refurbishment

At a recent surplus sale at my local radio club (Cambridge & District Amateur Radio Club) I bought a dummy load for £5, getting it on the bench the resistance at the PL259 socket measured 88 ohms.

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I also knew that the internal cooling fan was  U/S, so I stripped everything out of the case, ready for cleaning and reassembly.

The tubular resistors have an copper shim inside the aluminium clamping brackets, all parts were cleaned and degreased and put back together, on the rear heat sink I used heat transfer paste, and after replacing the internal fan, installed a cheap thermostatically controlled switch which I got from ebay, the temperature sensor is bonded to the rear resistor clamp .

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The temperature selection is set by dip switches on the PCB, I set the fan to operate when the temperature is greater than 35c, power to the PCB is via a fused 2.5mm DC socket.

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After reassembly the resistance dropped the 46 ohms and the fan kicks in when tested.

My homemade paint tin dummy load works great but the mineral oil is ‘wicking’ up the cables and finding its way to freedom, this one will mean the paint tin being relegated to the shed.

iPhone 6 WiFi Connectivity Issues and HG633 Router Solved

I have recently upgraded my Broadband package and this came with a HG633 router, blog on this is here: Router Upgrade, a day or so after installation Apple updated my daughters iPhone 6 after this update the phone kept dropping in and out of WiFi connectivity.

A the router was new and my Samsung Galaxy worked fine as did the i tablet mini, so it pointed to her phone.

Cutting a long story short including swapping the phone for a new one, the problem seems to stem from the fact that the HG633 has two WiFi frequencies available (5GHz and 2.4GHz), both being ON by default and sharing the same SSID, this makes the iPhone 6 very unhappy.

The problem of frequent disconnects and reconnects was solved by entering the router setup and renaming the WiFi SSID’s so that each frequency had a unique identification, based on the signal strength is the frequency you ‘pair’ with, this has cured the problem.

Hope this helps bring peace and harmony back into the homestead.

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Apple update (Feb 16) causes frequent WiFi connection issues with HG633.

 

Router & RAM Upgrade

I have had Fibre to the Home for a while at 38Mb download speeds, Talktalk my ISP offered 76Mb download speeds for a small increase in costs, the engineer called today (27 Jan 16) to check my actual speeds which were well below that quoted and installed a new HG633 router.

The problem of reduced speed performance is Openreach’s as its infrastructure, so I’ll have to wait and see, the current download speed is 56Mb so still not too shabby for here.

Manuals  for the Huawei HG 533 can be found here, the actual HG633 manual I haven’t managed to track down yet.

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At the same time of the Broadband upgrade, I decided to increase the RAM in my Weather PC from 8Gb to 32Gb as it was regularly running at 7Gb used, the PC is a Dell Precision T490 and uses Server RAM modules which cost a total of £60 from ebay.

Davis Vantage Pro2 Fan Change

I check and clean my weather station twice a year, just before Christmas I noticed the  FARS (Fan Aspirated Radiation Shieldfan which draws air past the external temperature and humidity sensor had stopped working, (write up from a previous blog on how I installed it is here –FARS Link).

As an interim measure I increased the voltage to the fan from 1.7v to 2.8v, which kept the motor working for a few more weeks before it finally wouldn’t kick into life.

In February 2014 I had bought 5 spare motors (minimum order but cheap as chips) from Jameco.com, so today I decided the weather wasn’t going to catch me out  and I made a start on replacing the fan.

Disassembly of the unit is very easy, removing the Rain Bucket exposes three cross head screws which hold the FARS in place, whilst holding the base of the FARS, undo each of the screws until you have the weight of the FARS in your hand, slowly lowering your hand the weight of the unit will be held by the interconnecting wires to the ISS.

The power to the fan is via a small plug and once removed, the fan assembly slides out of the shield as one unit.

The fan is held onto the motor by an interference fit, pulling on the fan will remove it from the motors shaft.

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The motor is held in the fan body by silicon, I used a craft drill with a tapered bit to remove this.

2016-01-23 09.41.35It didn’t take too long to get the motor out, the next job was to tidy the fan body socket and de-solder the old fan motor wires.

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New motor from Jameco compared to the one removed just in case I had ordered the wrong one!

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The motor needs packing to center it in the fan body, jerryg on the WXForum gave his solution of using insulating tape to build the diameter and this works really well, I made it so the motor was a snug, but not tight fit (as the motor uses brushes to make electrical contact to the rotating commutator, the motor will inevitably fail and need replacement).

The motor has three holes at the shaft end of the body which in the the original motor had been taped over, so I did the same, pushing the motor in the body I used a few dabs of silicon to hold it in place and pushed on the, the last part of this job was to solder wires on making sure the red wire went to the terminal marked with a + sign!

Once connections are made, a cable tie holds the wires neatly to fan body.

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While everything was apart, I checked the voltage regulator to the fan to make sure everything was ok, this is a Velleman unit with 24vAC in and I have removed the potentiometer and replaced it with a fixed value resistor giving a stable output of 2.8v DC.

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After a washing  down with soapy water the tipping bucket, Stevenson screen and rain bucket, everything was put back together, the total time taken was about an hour, now I know what I need to do, this could be done in under 30 minutes.

If you prefer to simply change the complete fan unit (Davis 7758), this can be bought from Weatherspares  in the UK who offer exceptional customer service.

Just got to see how long this motor lasts, once all the motors I’ve bought are gone, I’ll put a PC fan motor in and monitor the output to generate an alarm, I have made a a circuit based on this site, but I need to play a bit more to get it to work properly.

Link to original FARS blog..

Chatteris Weather Page Updates

Over the festive break, I’ve taken the opportunity to tweak my weather web pages and add a few features:-

  1.   Meteotemplate

This is a new style dashboard accessible from the menu bar of Chatteris Weather, if you prefer this template, save it as a favorite.

Jachym, the author of the script is continually adding new functionality and wherever possible I will adjust my site to incorporate his hard work.

2.   International Space Station (ISS)

I have always had a link to the ISS, but now Maj Tim is orbiting, I thought it would be fitting to have a bespoke page showing the live camera stream and graphical overlay of where the ISS is in real time.

3.   Live Webcam

I have recently fitted a Hikvision IP webcam which is streaming live video 24/7. I’m working on the time lapse feature and this will follow shortly.

4.  Supercounter

I have had revolver map on my site for a while as well as a whos-online script and PHP Web Stat, Supercounter was very easy to set up and implement, site statistics are available from the above link, what is of interest is that the majority of refers have come from webcam sites.

5.  Page Header Image

New design which will change to reflect either a reason to celebrate, when not a special header, a new standard image will be used with a change of title from Chatteris Weather to Chatteris Weather Station.

6.  Status Page

Added a screen grab image of the Weather Display program which drives Chatteris Weather, looking at the image you can see at a glance the overall conditions which are updated every 5 minutes.

Construction of More Blitzortung Lightning Detectors

I offer my help to the Blitzortung Forum members who find soldering is not for them, especially the tiny components; the  boards below are:

Top Left –  Blitzortung Controller with pre made daughter board plugged in

Top-Right – Amplifier which interfaces the antennas (not shown) to the controller

Bottom Left – E-Field Amplifier connects to controller

Bottom Right – E-Field Pre Amplifier  connects to E-Field Amplifier

SAM_5587 (Medium)The owner of the boards (Julian – Bremen, Germany) had kindly put all the parts in uniquely identifiable bags which certainly saved me time usually spent in sorting out the components.

In total I spent about 9 hours building up the boards and installing the firmware in the daughter board, hopefully that will be another one on the Blitzortung network.

General Web Site Maintenance

Decided to do a little bit of autumn maintenance of the weather web site:

  • Added London Underground service status to the Trains page
  • Added a link to Solent Harbor radio to replace the broken audio media player
  • Repaired the link to Talking Chatteris Weather on the web front page
  • Changed the time lapse video feed to mp.4 format and configured a JW Player in an iframe to show this
  • Rationalized some of the menu to make navigation easier
  • White listed my ip address in ZBlocker after I locked myself out of the site 🙁
  • Added  more Chatteris related community interest links and checked existing ones, adjusting to newer links where needed
  • Changed some of the upload times to the correct value in the page text

If you find any broken links, please use the Contact Form to let me know.

 

CCTV Pan & Tilt Head Interfaced to Orbitron and Ham Radio Deluxe

I have blogged  previously  about using a CCTV head as a platform for ham radio antennas and have made a manual controller to do this.

I already have an Easy Rotor Control for my rotator but thought I would experiment with a dual control ERC-M unit in linking it to a Pan & Tilt head I was given.

I bought the ERC-M, two Rotorcards and enclosure with matrix positioning display and front controls for this project. The parts came as a kit and took a few hours to put together, a with a previous kit from ERC, the instructions were excellent and the unit operated first time on power up.

The Pan & Tilt head I have is 24vDC, but will work on 12vDC, once the connections were made to the Rotorcard relays, the next step was to calibrate to positional potentiometers which are part of the head and allow presets to be selected. (Note – the positional pots need a 5v to 15v supply across them, this can be taken from the Rotorcard but as no take off terminals are fitted this board, I fed the pots directly from the power supply)

The kit comes with a CD containing all drivers, manuals and instructions plus a calibration program and operating program, I opted for a USB version of the ERC-M, I needed to point to the USB driver location on the CD during the installation of the ERC-M, after installation, checking in device manager confirmed the controller was using Com Port 6.

Setting the calibration program to the correct com port number allowed me to first calibrate the Pan or Azimuth, once this was done after following the on screen instruction I calibrate the Tilt or Elevation, this needs a bearing to be entered when the platform is at the top position or 90 degrees to ground, once this is done, calibration is as the Azimuth by following the on screen instructions.

The calibration software can be closed and the operational software opened to test functionality of the head, clicking on the compass rose will take the head to that position.

I use Ham Radio Deluxe but the garage PC where I do my building has no radio related software, so I downloaded Orbitron satellite tracking software.

As the Orbitron does not have a physical connection to the ERC-M, the program Pstrotator was also downloaded as the interface as this will connect to Com Port 6 and drive the controller, the internal data exchange between Orbitron and Pstrotator is via DDE, this additional file needs to be downloaded from the Orbitron site.

Pstrotator was only used to test concept and I used the demo version which is time limited.

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I entered positional settings in Orbitron and clicked on DDE connect (a pop up will say if you need to download this if you haven’t already), if all I well, the positional data details of the satellite you selected will show in a small splash screen.

Opening Pstrotator, enter setting for the Com Port, type of head (Az & EL) and controller (ERC-D), close and then reopen the program, click on ‘track’ and the head will follow the trajectory of the satellite when in range.

A really cool feature of Pstrotator is the ability to take a feed from  a local WeatherUnderground feeding weather station (Chatteris Weather), when high winds are detected, the antenna will automatically turn to the wind reducing mast windage loading.

This use of a CCTV head to position tracking antennas is certainly a lot cheaper than buying a bespoke unit,  CCTV heads are made for external use and have decent torque, jut check if you get one that they are 24vDC and have the pots for presets, these come up all the time on Ebay for about £50, so all in you can have a quality tracking system for about £200.

I will mount the Rotorcards in a small enclosure and move everything next to the rig and interface with Ham Radio Deluxe, I have tested the tracking element with my existing Azimuth rotator, so I don’t envisage any issues with the ERC-M, the next job is to save up for some 8 core cable from the Rotorcards to the head!

General information and status updates.

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