Light It Up!

Electric lights are everywhere. So much so, we tend to take them for granted. Electric lights have come a long way from the their early start in 1802. Light bulbs, and now Light Emitting Diodes (LED’s) are in almost every appliance on the market, including coffee makers, and radios.

Truthfully, I am unable to determine the first radio to incorporate an electric light within the chassis. I strongly suspect that the inclusion of an electric light was based upon an observation that vacuum tubes (or thermionic valves, as they were once called) have a tendency to glow when power is applied to them. I have read it both ways as to which inspired which, bulb or tube. I really don’t know. What I do know is that at least in 1934, possibly even before then, radios were incorporating electric lights as a part of the overall design.

What purpose does a light bulb serve in a radio? On a purely functional level, they serve no real function. Light bulbs don’t do a thing to make a radio work right. In fact, I have never observed a radio to not work, even if the light bulb is dead. It would seem that the light merely is an aesthetic device, meant to light up the tuning dial or band spread meter, though it is helpful if you must operate in an otherwise dark room, or closet.

So, what happens when a light bulb dies? Truthfully, that is when things get tricky. In our modern age, incandescent bulbs are becoming increasingly difficult to find. If you happen to own a vintage/antique rig, and it requires light bulbs for the tuning dial, you might find yourself at a severe disadvantage, and unable to find a suitable direct replacement. This is a situation that I am certain to find myself in eventually, as I happen to own a 1934 Patterson PR-10 Allwave Receiver.

I admit, some hardware and electronic stores do carry some type of specialty light bulbs, but they are few, far between, and often quite expensive. However, if you are willing to pay the price for it, and it is there, it is most certainly worth it to buy something that is almost guaranteed to work. However, if it doesn’t exist, or your budget is quite tight, you might be up the proverbial creek. Or are you?

At the beginning of this article, I mentioned LED’s. Now I am well aware that these modern devices are not the greatest choice of replacement for the older style screw in incandescent bulbs that our older rigs came with, but they can be made to work. However, a few basics need to be understood about how an LED works.

To start with, the voltage of rating of an LED is about 2.6 VDC, and it must be forward biased. This means that, unlike an incandescent bulb, there is a definite direction of current flow. This also means that you can simply solder in an LED and expect it to just work. The simple truth of the matter is that your antique radio may be providing far more voltage, or amperage, than a typical LED can handle.

That leads to next concern, voltage and amperage. An incandescent light bulb can talk more current than an LED can. Thus, it would be wise to take a volt/ohm meter and test the connectors of where the light bulb goes to determine how much voltage and resistance are present at the point in which the light bulb connects. Some bulbs feed directly off the 117 VAC power supply, and make an LED completely unsuitable for use as a replacement for an incandescent bulb. Even if the voltage is direct current, you still need to discern which point leads to ground and which is live, thus a schematic diagram of the radio in question might prove helpful.

This leads to the next question, if direct current is on the circuit for the bulb, how do we connect an LED? I would hope that you haven’t thrown away that burned out bulb yet, and I would also hope you wrote down everything you can about it, in hopes of finding a proper bulb. That being said, break the bulb.

WHAT?

Yes, break it. You will need to base of the bulb to solder in a resistor to reduce current to the LED and the LED itself. The resistor will have to be soldered inline with the input side of the LED, which should be well marked. The LED output should be soldered to the part of the base that leads to ground. As early model radios varied in terms of bulb voltage from brand to brand, and model to model, I can not give proper specifications regarding how much resistance will be needed to provide enough voltage for the LED without providing too much. Sorry, even I have limitations. After that, you can simply screw the bulb base in and push the resistor off to the side to keep it from obstructing the light from the LED.

I will be honest, this is NOT ideal. However, as is the main principle of Mechanical Ham, it is functional. It does what it needs to, and without getting overly complicated. However, I can not promise that this will work with every radio made. I have encountered quite a few radios, including old general coverage receivers, in which it is impractical, if not impossible to replace the original light bulbs. Such radio are not useless, but they are more difficult to tune if not in an otherwise well lit room.

Yes, light bulbs are virtually everywhere, and that includes in our radios. However, if that light should burn out, it doesn’t mean our radio is gone. Either we can find a way to replace the bulb, incorporate an alternative to the burned out light bulb, or do without it.

Me?

Honestly, even knowing what I’d have to do to put an LED in to replace a light bulb that is no longer manufactured, I think I’d rather just go without the light. The way I see it, if the radio works properly, and I’m in an already well lit room, there is no need to replace something that doesn’t really provide anything extra.

If you really need that light, do what you can, if possible. If you can do without it, think twice before doing anything. You may save yourself some time and headache, and you might even find that proper bulb at a ham flea market. No sense damaging a classic radio unnecessarily.

73, AE7XQ.

QRP? QRO? QRM!

In amateur radio, we use Q-codes to signify certain terms. The primary use of these codes is when operating with Morse Code. Simply put, Q-codes help to reduce the number of characters needed to hold a conversation, also known as a QSO.

Recently, in a post on Facebook, there was a discussion about low power versus high power operation. In all honesty, there were some pretty intense feelings regarding both sides of this rather absurd argument. Yes, I called this argument absurd. Why? We will get to that soon enough, but a definition of terms is in order first:

QRM – Are you being interfered with? I am being interfered with!

QRO – Shall I increase power? Increase power.

QRP – Shall I decrease power? Decrease power.

Of themselves, these terms are reasonably innocent. However, what they technically mean, and how they have come to be understood, that is a whole different issue. However, that is the issue being looked at.

QRP is the term that has become associated with the idea of operating at low power output levels. Depending on mode, and whom you talk to, that can vary from below 10 watts peak envelope power, to nothing above five watts peaks envelope power (PEP). Then there are those operators who work one watt or less.

QRO is generally associated with those ham radio operators who use high power levels. Just what is considered high power varies from ham to ham. Some think of high power as anything above 50 watts PEP. Others will insist upon high power being 100 watts PEP, or more. Then there are those hams who refuse to operate at anything less than 1000 watts PEP, and will even avoid bands in which such power levels are forbidden by the FCC, or the band plan.

What is the rule, according to the FCC, regarding power output? According to FCC rules 97.313, regarding transmitter power, it states in paragraph A, “An amateur station must use the minimum transmitter power necessary to carry out the desired communications.”

For the QRP operator, this rule poses no concern, as the QRP operator is already using so little power, that QRM is virtually impossible. However, for the QRO operator, there might be a few concerns, especially when it comes to the issue of QRM.

I have often heard it said, and I think it true, that it doesn’t matter how fancy your rig, or how powerful your amplifier (legal limit on those is 1.5 kW PEP), if your antenna isn’t good, it just won’t matter. I have also heard it said that if they can hear your, but you can’t hear them, then you are using too much power. Seriously, just because you can crank out a full 1.5kW to “bust through” a pileup doesn’t mean that you should. Nor you use an amplifier just to check into the local rag-chew net, as you might be drowning out the signal of another ham, who doesn’t have amplifier, and may even be a newly licensed Technician.

In all honesty, if you are pushing out so much power than you can be heard on the other side of the planet, yet you are only attempting to work a station that is only a couple of hundred miles away, you should probably turn down the power. It is really inconsiderate to operate at power levels so high that stations you can’t hear are forced to hear you. In fact, you could inadvertently violate a radio silence regulation held by a member nation of the ITU. Certainly it might not be your intent, but the result is just the same.

I can’t say that I have  a definitive answer to this. However, if you absolutely have to run more than 500 watts on any band, no matter how good the band conditions, you are seriously running a risk of causing QRP. Truthfully, I have found that with a good antenna, between 25 and 50 watts is usually sufficient. However, I have to leave it to the reader to decide for themselves. Just bear in mind that the more power used for contacting a given entity, the greater the risk of interfering with another station.

Get the Ticket

Amateur radio is full of many broad concepts and ideas. However, none of them matter without one small thing. That is the license. It doesn’t matter if it is a Technician Class, General Class, or Extra Class, you need an amateur radio license to seriously get started.

To that end, I will say, as this is the first post of Mechanical Ham, the license is the foundation of everything else. This also means that there will frequent postings regarding licensing and why some questions are what they are. This will even include older questions that are no longer part of the question pool, yet may have some relevance in our otherwise overly modern world.

As getting the license is the foundation of all else, it is good to practice in advance of the actual test. I like to recommend AA9PW.com for practice tests, and LCWO (Learn CW Online) for Morse Code. I also tend to recommend the Gordon West WB6NOA books for studying, as he goes through the entire question pool, analyzing the questions and their possible answers, explaining exactly why one particular answer is right, and the others are wrong. This is how I got my Technician, General, and Extra Class license.

What are you waiting for? An invitation? This is it. Get started. Get the Ticket, and open the world.