Wednesday, May 30, 2018

A LED Replacement Light For Your Soldering Iron



A Communicator Reprise: January 2012





One of handiest tools for the Ham Shack workbench is a Weller soldering gun.   It’s a 100 and 140 watt gun in a good old Bakelite case. This year it’s celebrating its 40th year on the work bench.  The thing  has been dropped so many times, it’s a miracle the gun still works, but thanks to several tubes of 5-minute epoxy and some crazy glue, it’s still in fine working condition.


But recently the little incandescent pilot lamp/tip illuminator burnt out and I just couldn’t find the right replacement bulb… a 2.0 volt bulb with a focusing lens at the end, something you used to be able to find in a common flashlight… a common flashlight 40 years ago. So while hunting in my parts bin, I came across a white light LED and decided to update the old gun with a modern light source.

So I removed the bulb from it’s screw base, found the right current-limiting resistor for 20ma at 2 volts and proceeded to assemble my new LED spot light.
There are a few things to ponder… the gun supplies 2v AC, your LED is a diode, so it’s going to work on one half the cycle, which translates into less light output…
Also the junction breakdown voltage is rather low on a LED, so if one were to use  higher AC voltages, it would most likely “expire” rather quickly.  But it’s only 2 volts, so I wasn’t worried.  You could put a 1N4007 in series on the other lead to help the LED deal with reverse voltages, but only if you were working with higher than 6-9 VAC.

So to hold things in place, I potted the resistor in epoxy putty, which set in 3 minutes and then soldered the LED to it.  I only had a ½ watt resistor, larger than I needed but it fit nicely in the screw base.  So if I wanted a 20mA current draw, that would be R = E / I = 2/.02 = 100 ohms and I just happened to have a 100 ohm resistor in my parts cabinet.  P (in watts) = E x I = 2 x .02 = .04 watts or 40 mW of heat dissipation so a ½ watt resistor wasn’t necessary, but it was the only size I have in stock and size wasn’t an issue.


A few minutes later I had a modern light source in an antique tool… but would it work?  But of course… for ½ the cycles per second -- so the light from it wasn’t as bright as I was hoping, but good enough to shed a bit of illumination on what was being soldered and certainly adequate for a pilot light to verify the gun was on.   OK for younger eyes, but this old buzzard needs a few more candle power!  Why didn’t I put a tiny bridge rectifier on the power leads to feed the LED with better DC?  Cause it was only a 2 volt tap off the coil inside the gun.. and for every diode you insert, you lose 0.7 of a volt.   Why did I need this in the first place you ask?  Well the tips of my fingers and tongue hadn’t recovered from my earlier attempts to see if the soldering tip was getting hot!  





Sunday, May 27, 2018

Marine Mobile...



A Communicator Reprise: January 2012


Most countries' amateur radio licenses allow licensed operators to install and use radio transmission equipment while at sea. Such operation is known as maritime mobile amateur radio. In most cases the operator's call sign needs to be extended by adding the suffix '/MM' when transmitting at sea.

There are some special considerations when installing and using amateur radio transmitters and receivers afloat. These include power supply, RF ground, antenna design and EMC (Electromagnetic compatibility) with other electronic equipment aboard.

For MF and HF use, the most common antenna design is to add two RF insulators into the backstay of the mast and feed it from the transceiver using a sintered bronze ground plate, bolted to the outside of the hull, well under the waterline, as a ground. On metal hulled boats the ground plate can be dispensed with, and the whole hull used for this purpose. In this case, the thickness of any paint layer is entirely negligible at RF. On a yacht with twin backstays, if insulators are placed in both of them and they are fed from the masthead, they may be usable as an 'inverted vee' avoiding the need to feed the antenna against ground. Either format will require the use of an ATU (Antenna Tuning Unit) to achieve resonance for the HF frequency in use, as the physical length of the antenna will almost invariably be incorrect at the frequency of choice. A few twin-masted sailing vessels have the space to erect a "Tee" antenna or an inverted "L" between masts. These antenna configurations are more common on merchant ships.

For VHF and UHF operation, one option is to mount a small yagi antenna to a pole 1–2 m (3–6 ft) long and haul this to the masthead using a flag halyard. If the halyard is correctly knotted to the middle and bottom of the pole, it is easy enough to make the antenna project above the clutter at the masthead into clear air. The problem is in rotating it - it usually needs to be lowered and re-raised to alter the direction of its beam. For the safety of masthead fittings and lights it is better if these yagis are light in weight and made largely of, for example, plastic tubes supporting internal wire conductors. Operating in this way is best reserved for when in harbour or at anchor, to avoid interfering with the operation of the boat. Repeated loss of signal due to rolling and pitching would make it impractical for useful communication at sea anyway.

For FM operation on the 2m band, the masthead vertical whip that is normally installed for marine VHF operation will provide good omni-directional, vertically polarized signals. The frequency of operation around 145 MHz is close enough to the antenna's design frequency of 156 MHz that most amateur transceivers will not need an ATU and will not suffer unduly from a poor (high) SWR.


Grounding

For a single-ended HF antenna, a good electrical ground connection is essential. It is also necessary from the points of view of safety and EMC considerations on any radio transmitter installation on a boat or ship. As mentioned above, metal-hulled vessels have a natural advantage in that, especially at HF and lower frequencies, the hull can be considered to be in contact with the water, as the insulating properties of the paint layer against the water is a capacitance that presents very little electrical impedance to the RF currents. For fibreglass and wooden hulls and HF transmission, the usual solution is to attach a sintered bronze plate to the outside of the hull for RF ground. The construction of a sintered bronze plate is porous to water so that although the plate may be only a square foot or two and an inch thick, the actual surface area of metal in electrical contact with the water is very many times that.

Once a good connection to the sea water has been established, it is necessary to make a good RF connection from the transceiver and/or the ATU to the grounding system. While it might seem that a good, thick wire is all that is needed, for large RF currents it is usually recommended that copper grounding tape is used. This is not because thick wires will not be able to support the currents involved, but because it is more likely that RF currents will remain flowing along something that has a wide surface area without re-transmitting themselves along the way due to skin effect. The key pathway from the ATU of a single-ended antenna system to the ground plate, or the hull ground-point, should be as short and as straight as possible. This should be considered from the start when deciding where to mount the various components within the hull. There is not much that the installer can do about the losses in, and the efficiencies of, the transceiver, the ATU, the antenna or its feed, but extra effort put into the efficiency of the ground paths will pay much bigger dividends, in terms of radiated power and freedom from EMC problems later, than any other single aspect of the installation. The salty sea makes an exceptionally good ground plane, and effort put into achieving a good connection to it will be handsomely repaid.


Going on a cruise?

You will first need the permission of the cruise ship company itself to even have an Amateur Radio transmitter in your possession while on board (whether in use or not).  So your first step is to make sure you have written authorization to have your radio with you.
Next, besides the company itself you will need to have permission of the ship's captain in order to use the radio.  Do not assume you can simply throw up a vertical outside of your stateroom and operate!

Once you have authorization to operate ship board, you still have to worry about reciprocal operating privileges with the country where your ship is, including territorial waters.

Canadian and US licensees need no special permit or authorization other than their own Industry Canada or FCC license and they stay within Canadian, US or International waters.  When an FCC licensed amateur is operating an amateur rig aboard a US-registered vessel in international waters, he or she must follow Part 97 of the FCC rules, particularly Section 97.11. 

If the ship is of foreign registry, you must obtain a reciprocal operating authorization from the country of registry in addition to being in compliance with Section 97.11. When amateurs enter the territorial waters of a country, they fall under their communications jurisdiction. This means that they must obtain the required reciprocal operating authorization. There are three such authorizations: CEPT which applies to most European countries and certain overseas territories; IARP which applies to certain countries in the America's; Reciprocal Permit which is available from most countries, but application must be made to the country and a fee paid.

In Canada, these permits may be obtained from Radio Amateurs of Canada (RAC) for a modest fee.






Friday, May 25, 2018

Contest Preparation Training

A Communicator Reprise: December 2011


Totally excellent fun!

Contesting is as close as you will get to conditions operating in an emergency. If you can effectively contest, you can pass emergency traffic. Therefore, this article is republished with an eye to the annual June Field Day. The contest training tips are valid and can be applied at the Surrey Amateur Radio Operational Training Centre (OTC). There are several Elmers within our group who would happily provide this training.

TRAINING PREPARATION

This event took an amazing amount of work to prepare for, but I believe we pulled it off very well and we're very happy with the results.  The next one will be a lot easier. John VA7XB, did a lot of agricultural work so that the seed of the idea of members turning out for operator training would fall on receptive ground.  How much fertilizer did he use?  I'm not going to go there.
Fred VE7IO opened his station for our use and revamped it to make it possible for the use of 2 radios at the same time. This required getting rid of all the junk on his office desk. Installed radios for the second op position. Added an 80m dipole up 100 ft to enhance the station low-band long distance (DX) capability. Totally changed his antenna switching system so that any antenna could be accessed by either op position and generated an op schedule.
Jim VE7FO, prepped and delivered a training session on logging SSB contacts on N1MM which included materials such that the trainees could practice at home - no radio required - before attending the actual operating event. Designed the new VE7IO antenna switching system.  Developed a Briefing Package and the plan for mentoring ops in the fine art of Search & Pounce and Running. 
This doesn't sound like much but it took us many full-time days. VE7IO and VE7FO shared the mentoring duties during the event.


THE PLAN

The purpose of the classroom style logging training was to enable trainees to get in some logging practice ahead of time so that they could more quickly develop the confidence to operate in Run Mode. The plan for the event itself was for the mentor to:-

  • Take the trainee through the Briefing Package.
  • Listen to actual contest QSOs taking place on the radio when going through the Running and S&P procedures.
  • Start the trainee making a few S&P contacts.
  • Just to get comfortable while the practice done at home kicks in.
  • Mentor to make a couple first.
  • Then get the trainee into Run mode.
  • Mentor to make a couple first.
  • The Mentor to provide reassurance and guidance as required.

RUNNING

A step-by-step guide to making contacts in Run Mode. Arranged in such a way as to make what the op needs to say at each step in the QSO very prominent while still providing basic info as to what's going on and how to log the QSO.


SEARCHING & POUNCING

Same idea as the Running info. I messed-up! Now what?
It's quite easy to make an error when entering the log info.  If you catch it as you make it it's easy to fix.  The further you are through the QSO the harder it gets. This section shows how to deal with each case. Things the op needs to do before actually operating.

  • Band map
  • Intro to packet cluster spots.
  • What it shows the op.
  • How to rapidly go to the frequency of a spotted station in order to work him.
  • How to use the spot colours to determine which ones to work first.
  • Phonetic Alphabets

Yes, that's plural.  The ISO (I think) standard phonetic alphabet pretty much sucks when signals are weak and interference is strong.  Three alternative lists are provided along with the standard.  However, it is recommended to only use the alternatives when the standard alphabet doesn't work.  (Don't want the EMCOMM folks to get into bad habits.)

  • Contest Rules

A copy of the official rules.

  • Antenna Switching Diagram

This shouldn't have been in the package as the ops are required to ask the Station Manager for permission to change antennas and it is the Station Manager's responsibility to change the switches to suit if he agrees that it would be a good thing to do.


WHAT ACTUALLY HAPPENED


LOGGING PRACTICE AT HOME

I meant to ask each one at the start of the event whether or not they had been able to but I forgot.  In any event, it looked to me as if most either didn't get the opportunity to do it or the practice methodology I proposed didn't work nearly as well as I thought it would.  I would be interested in hearing from anyone who did get some practice time in how much time they put into it and whether or not it helped.


THE EVENT

All my planning was based on the idea that I would mentor Friday evening and Saturday from 6 am until 5 pm, when I would go home, and Sunday from 9 am to the end and that VE7IO would mentor during the remaining time.
Well, I totally overlooked the fact that, because we had two op positions, we could have two ops starting at the same time.  Sure enough, right at the beginning of the event (1700L Friday) we had two ops show up on schedule and I hadn't put any thought into how I should deal with this.  I tried several approaches but only recall trying to have one log while the other operated.

So, a rather rough start and I apologize to the two who had to suffer through this.  Still, as I recall, once they got going on their own op positions things got better for them.  They did very well at working some pretty exotic DX.  Between them they worked Israel, China, Gambia, Madeira Islands, the Azores, Cape Verde, Philippines, South Cook Islands, Korea, Japan, Northern Mariana Islands, Guam, Aruba, Curacao, European Russia, Asiatic Russia, Kazakhstan, Antigua & Barbuda, Australia, Indonesia, Ascension Is, New Zealand, East Malaysia, Portugal, Germany, Spain, Ireland, France, Scotland, Italy, US Virgin Islands and Namibia.  Not bad for 5 hours of op time.
After that I only had one op to deal with at a time and things went much more smoothly.
Two of our ops who were to occupy the time from 9 am to the end at 5 pm were unfortunately unable to make it and I ended up with no one to mentor from noon to the end.

I thought I'd use the time to create some .wav files of the CQ, Exchange and Thank You messages.  N1MM can be set up to play these files at the appropriate times when you hit Enter.  This greatly reduces the strain on the op's voice.  Due to my unfamiliarity with the Micro-Ham interface between the computer and radio I was unable to get this to work so Fred and I spent the rest of the time discussing how things went and what we might change for the next time.


OBSERVATIONS

I was a little disappointed that very few ops actually got into Run mode.  After all, that was the point of the training session.  Still, I think everybody enjoyed the experience so I'm hoping they'll all be back for the next one (and most of them ready to get into Run mode after the first half hour or so).  The high bands were in terrific shape.  Best I've heard them in many years.

We tried to publish our score very frequently to the Getscores web site so that members could follow our progress.  Unfortunately, the site crashed 2 minutes after the start of the contest and stayed that way.  We didn't make my goal of 1,000 QSOs.  I'm sure we would have if we'd been able to get most people into Run mode.


HOW DID WE DO?


QSOs

We made 526 QSOs. This translates into 1259 QSO points.


MULTIPLIERS


  • We contacted 138 countries (you can count a country once for every band you work it on - our unique country total was 73)
  • We contacted 98 CQ Zones
  • Total multipliers = 236

SCORE

1259 QSO points X 236 Multipliers = 297,124

WHAT CHANGES WOULD I MAKE?

Very few. Some tweaking of the Briefing Package. More emphasis on getting ops into Run Mode. Don't schedule 2 newbies for the same time slot unless 2 mentors are available.

~ Jim Smith, VE7FO



Wednesday, May 16, 2018

Fraser River Freshet Emergency Activation


SEPAR Members Respond

The Fraser River is experiencing one of the largest flows in recorded history. Warm temperatures are accelerating the snow melt in the interior of the province. This could result in a once per hundred year flood. 


On Sunday May 13, Tuesday May 15 and Wednesday May 16, the Surrey Emergency Program - Amateur Radio (SEPAR) was activated by the Emergency Coordinator for the City of Surrey. We had a good turnout and I'd like to thank everyone that helped out at this activation.







We had a really good showing and Surrey Fire Service & the Surrey Emergency Program are happy with the help we provided. Also, a thanks to SARC for the use of the repeater.

This is a great example of how valuable SEPAR, as an integral part of the Surrey Emergency Program, can be. Other parts of Canada and the United States have the ARES program and those Amateur operators, while invaluable are not usually tied to the City, and are therefore not asked to volunteer for an activation that is not primarily communication oriented. SEPAR while we would like to have a communications component, is still available to the City, and BC (as City and Emergency Management BC volunteers). 

Personally I would like the City to continue to make use of us in times of need.

While this was not primarily a communications activation, we did find a way to make use of our ability to communicate by radio. Several times I was asked to confirm an issue from the command trailer and I was able to do that much faster than those that only used cell phones.  The times I did have an issue communicating, I could have resolved it without a cell phone call, had I remembered that we had designated a couple of simplex frequencies.

Below is a link to the BC River Forcast Centre for information about warnings, advisories and evacuation due to the freshet and flooding in British Columbia.
http://bcrfc.env.gov.bc.ca/warnings/index.htm




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