Old Telegraph key, new use, Help

[paulears]

Please don't take this the wrong way - but surely the entire point of amateur radio is experimentation. Building simple circuits, a bit of soldering practice and a huge amount of BODGE. I've never been particularly good with the electronics theory but knocking up simple circuits should be within the grasp of most 14 year olds in school? None of my first attempts years ago worked. I'd get electrolytic capacitors the wrong way around, or misread the coloured bands on resistors - and loads of times my soldering skills were more about blobs rather than nice flowed joints.

Making PCBs is another skill I never really got to grips with so strip type board, and using a drill to break the tracks made things easier for my head.

If it doesn't work, then it's logic getting it going with simple stuff.

I too view instructions as proof that something is too complicated. If you need instructions the product isn't designed well. My son complained the tin of paint he bought didn't have instructions.

3.5mm connectors with 4 circuits are pretty much the domain of mobile phones - where you need three for stereo, so the mic needs the extra one. This is very basic stuff, that frankly I'm surprised a ham has;t come across before. It's not complicated - if you think about it, it's common sense. A single circuit needs two contacts - so for a mono speaker or mic - two do nicely. If you want speaker AND mic, that takes it up to three, and stereo needs 3 too.


I'm wondering exactly what you're going to do with this? Don't forget that this basic circuit needs you to put the handle into transmit - you will have to establish how it does it. It could be the resistance of the mic being put into circuit with the PTT that switches it, or it could be one of the rings shorts to the sleeve when the PTT is pressed. You are going to have to look inside an external speaker mic to see the wiring.

This could all be a bit pointless, because it occurs to me that the person the other end will have to have the same system to reply. None of my radios, even the ones with key inputs, can send CW on FM without external bodging. The folk that help people learn Morse on 2 or 70 will have already built a gadget like yours, but who else has them?

 

[K7MEM]

K7MEM, that's a fair point about instructions, I didn't notice that the schematic had all of the resistor values and such, but I found them now. Would you recommend trying to make a pcb, or just using a perfboard?

I would recommend just wiring it up on perfboard. Once you get everything working, you can consider going to PCB. But most of my perfboard projects turn out to be the final version. And, as "paulears" pointed out, PCB design is a very different skill set.

However, if you want to experiment with computer based schematic capture and PCB design, you might try Eagle. They offer a full design set for schematic capture and PCB design. The full version costs about $1,000 for a license but they offer a scaled down version for free. The free version works for single page schematics and 4" x 5" double sided PCBs. I find it great for small projects. I don't actually go to PCB, but I use it to document my schematics and to work out possible layouts.

If you continue with your EE education you will get into some very high end CAD (Computer Aided Design) and CAE (Computer Aided Engineering) software. For example, there is software by Cadence and Mentor. A full suite of their tools will set a engineering company back $200,000 to $300,000, for a 2-3 user license. An early understanding of these tool will give you a leg up in the industry.

WA0CBW, Thanks, I was kind of confused because I have seen some 3.5mm jacks with 2, 3, and 4 bands, so I'll have to find one that matches the radio.

You will need to check your manual to see what connector is required. "paulears" and "WA0CBW" explained that pretty well. The 2-band (mono) and 3-band (stereo) jacks have been around for a long time, in 1/8" (3.5mm) and 1/4" (6.35mm) diameters. So they are pretty easy to understand. But the 4-band is relatively new to the mix.

As "paulears" indicated these are common to mobile phones, but they are now also common to laptops and pads. I was looking for a new laptop recently and notices that they no longer use a separate jack for audio in and audio out. All the new computers use the 4-band plug and if you want to separate the audio in/out, you need to build or buy a breakout cable.

At a recent ham fest, I looked for 4-band breakout cables to go with my shiney new HP laptop, but none were available. All I was able to find where the 4-band connectors. So I bought the connectors and will have to make my own cable. And signal information on the connector was not provided with the laptop. The only information provided with the laptop was a single page that said: "Insert the battery, plug it in, and turn it on." Of course, it said that in several languages, to fill the page.

Martin - K7MEM

 

[KK6YBJ]

Please don't take this the wrong way - but surely the entire point of amateur radio is experimentation. Building simple circuits, a bit of soldering practice and a huge amount of BODGE. I've never been particularly good with the electronics theory but knocking up simple circuits should be within the grasp of most 14 year olds in school? None of my first attempts years ago worked. I'd get electrolytic capacitors the wrong way around, or misread the coloured bands on resistors - and loads of times my soldering skills were more about blobs rather than nice flowed joints.

Making PCBs is another skill I never really got to grips with so strip type board, and using a drill to break the tracks made things easier for my head.

If it doesn't work, then it's logic getting it going with simple stuff.

I too view instructions as proof that something is too complicated. If you need instructions the product isn't designed well. My son complained the tin of paint he bought didn't have instructions.

3.5mm connectors with 4 circuits are pretty much the domain of mobile phones - where you need three for stereo, so the mic needs the extra one. This is very basic stuff, that frankly I'm surprised a ham has;t come across before. It's not complicated - if you think about it, it's common sense. A single circuit needs two contacts - so for a mono speaker or mic - two do nicely. If you want speaker AND mic, that takes it up to three, and stereo needs 3 too.


I'm wondering exactly what you're going to do with this? Don't forget that this basic circuit needs you to put the handle into transmit - you will have to establish how it does it. It could be the resistance of the mic being put into circuit with the PTT that switches it, or it could be one of the rings shorts to the sleeve when the PTT is pressed. You are going to have to look inside an external speaker mic to see the wiring.

This could all be a bit pointless, because it occurs to me that the person the other end will have to have the same system to reply. None of my radios, even the ones with key inputs, can send CW on FM without external bodging. The folk that help people learn Morse on 2 or 70 will have already built a gadget like yours, but who else has them?

I am pretty new to amateur radio, I've only had my license about 2 months, and this will be my first build for amateur radio. In many things, I like to get things right the first time around, but maybe I'll just have to get used to experimenting and revising, while hopefully avoiding the magic smoke.

Thanks for the advice, I'll just go for perfboard or a breadboard

Regarding the instructions for the CPO, I wasn't looking for step by step instructions, just a parts list, and maybe a few tips for the assembly like which pins to use on the 3.5mm jacks.

That makes sense now that you say it, but as I said before, I am new to amateur radio and hadn't hear much about it previously. So, thanks for the learning experience, I appreciate your help.

Couldn't I just push the PTT button on the handheld and hold it with one hand while using the other to tap the key? Or would that not work while a mic is plugged into the jack? My radio has a 3.5mm jack for a mic and a 2.5mm jack for headphones, I think both of them have 3 bands based on pictures of speakers and mics I have seen for sale, but I personally, don't have one, so I'm not 100% sure.

Even if there is no one to reply, I will be able to get practice learning CW if I ever buy a rig that supports it.

 

[KK6YBJ]

I would recommend just wiring it up on perfboard. Once you get everything working, you can consider going to PCB. But most of my perfboard projects turn out to be the final version. And, as "paulears" pointed out, PCB design is a very different skill set.

However, if you want to experiment with computer based schematic capture and PCB design, you might try Eagle. They offer a full design set for schematic capture and PCB design. The full version costs about $1,000 for a license but they offer a scaled down version for free. The free version works for single page schematics and 4" x 5" double sided PCBs. I find it great for small projects. I don't actually go to PCB, but I use it to document my schematics and to work out possible layouts.

If you continue with your EE education you will get into some very high end CAD (Computer Aided Design) and CAE (Computer Aided Engineering) software. For example, there is software by Cadence and Mentor. A full suite of their tools will set a engineering company back $200,000 to $300,000, for a 2-3 user license. An early understanding of these tool will give you a leg up in the industry.



You will need to check your manual to see what connector is required. "paulears" and "WA0CBW" explained that pretty well. The 2-band (mono) and 3-band (stereo) jacks have been around for a long time, in 1/8" (3.5mm) and 1/4" (6.35mm) diameters. So they are pretty easy to understand. But the 4-band is relatively new to the mix.

As "paulears" indicated these are common to mobile phones, but they are now also common to laptops and pads. I was looking for a new laptop recently and notices that they no longer use a separate jack for audio in and audio out. All the new computers use the 4-band plug and if you want to separate the audio in/out, you need to build or buy a breakout cable.

At a recent ham fest, I looked for 4-band breakout cables to go with my shiney new HP laptop, but none were available. All I was able to find where the 4-band connectors. So I bought the connectors and will have to make my own cable. And signal information on the connector was not provided with the laptop. The only information provided with the laptop was a single page that said: "Insert the battery, plug it in, and turn it on." Of course, it said that in several languages, to fill the page.

Martin - K7MEM

Thanks for the advice on Eagle, I'll look into the free version.

I am actually in high school right now, but we have an elective called engineering where we have about six units and explore electrical, mechanical, civil, computer, and a couple other types of engineering.

Thanks for the advice on the audio jacks, I'll have to dig up my manual for my radio, but I think it was similar to your laptops instructions, just with less perfect grammar.

 

[paulears]

Personally I'd build the oscillator and not worry about connecting it to the radio. When I was learningm we did send it on FM 2m to the other two people in the group, and I'm certain the results were painful to listen to while we really were awful. If I was doing it on my own, I'd do it in private first.

 

[K7MEM]

I am actually in high school right now, but we have an elective called engineering where we have about six units and explore electrical, mechanical, civil, computer, and a couple other types of engineering.

Well that's great! I'm glad that they are still offering some kind of training in high school.

For 10th to 12th grade (1964-1967) I went to a Vocational and Technical High School in Perth Amboy, NJ, for Electronics. The classes were a little more intense than what was offered in the normal high school. Right from the first day you knew you were on your own. They didn't provide busses for any students and I lived in a different town, about 10 miles away. They expected you to find your way to school every day. Good thing there were public service busses, although they weren't always reliable. I had a very long walk many days (of course it was uphill both ways, in the show). But back then I could do 5-10 miles without thinking about it.

But it was a good school. For half of your day you were in shop. For me that was Electronics shop. The other half was dedicated to the usual high school classes (history, english, math,...). However, they were centered around your chosen field and making your way in the world, after graduation. For example, in English, we learned things like, how to read the help wanted ads, how to fill out a job application, how to present yourself at a job interview, etc.. There were lots of things we needed to know after graduation. But it was the same for all the other subjects. They were directed toward your chosen field and for you to be a success after high school. Electronics wasn't the only choice. they also offered Electrical, Auto Mechanics, Machine Shop, Carpentry, Sheet Metal, Drafting, and Paint.

My graduating class was very small. All of those shops only added up to 67 seniors for graduation.

But, things are very different now. Good luck in the future.

Martin - K7MEM

 

[KK6YBJ]

Personally I'd build the oscillator and not worry about connecting it to the radio. When I was learningm we did send it on FM 2m to the other two people in the group, and I'm certain the results were painful to listen to while we really were awful. If I was doing it on my own, I'd do it in private first.

That's what I was more or less planning on. I was going to practice it with headphones first, and after some practice go onto the repeater and try a conversation or two.

 

[KK6YBJ]

Well that's great! I'm glad that they are still offering some kind of training in high school.

For 10th to 12th grade (1964-1967) I went to a Vocational and Technical High School in Perth Amboy, NJ, for Electronics. The classes were a little more intense than what was offered in the normal high school. Right from the first day you knew you were on your own. They didn't provide busses for any students and I lived in a different town, about 10 miles away. They expected you to find your way to school every day. Good thing there were public service busses, although they weren't always reliable. I had a very long walk many days (of course it was uphill both ways, in the show). But back then I could do 5-10 miles without thinking about it.

But it was a good school. For half of your day you were in shop. For me that was Electronics shop. The other half was dedicated to the usual high school classes (history, english, math,...). However, they were centered around your chosen field and making your way in the world, after graduation. For example, in English, we learned things like, how to read the help wanted ads, how to fill out a job application, how to present yourself at a job interview, etc.. There were lots of things we needed to know after graduation. But it was the same for all the other subjects. They were directed toward your chosen field and for you to be a success after high school. Electronics wasn't the only choice. they also offered Electrical, Auto Mechanics, Machine Shop, Carpentry, Sheet Metal, Drafting, and Paint.

My graduating class was very small. All of those shops only added up to 67 seniors for graduation.

But, things are very different now. Good luck in the future.

Martin - K7MEM

That sounds really cool, I wish that was an option for me, but alas, mine is just an elective for about 30-45 minutes per day. And I've heard that my high school is one of only a dozen or so high schools in California to offer engineering as an elective.

My school is really big, my graduating class will be closer to 500, but there is only about 32 people (from all of the 4 grades) taking the engineering elective. Our school doesn't really provide that much of applicable knowledge, like filling out job applications and such.

 

[paulears]

I was going to practice it with headphones first, and after some practice go onto the repeater and try a conversation or two.

What!

If you go on a repeater in even a small town/city and send CW you will do yourself endless damage. Repeaters are for speaking. Nobody sends CW on a repeater! In fact, it's also pointless, as nobody will have the facility to reply, will they? OK on the out the way channels, or maybe ones set aside for CW - but unless you live somewhere where they have a CW friendly repeater (which I've never heard of) it's going to infuriate people. Many folks leave radios on all day, and having the CW idents every five minutes is very annoying - imagine somebody trying to do it non-stop!

 

[K7MEM]

What!

If you go on a repeater in even a small town/city and send CW you will do yourself endless damage. Repeaters are for speaking. Nobody sends CW on a repeater! In fact, it's also pointless, as nobody will have the facility to reply, will they? OK on the out the way channels, or maybe ones set aside for CW - but unless you live somewhere where they have a CW friendly repeater (which I've never heard of) it's going to infuriate people. Many folks leave radios on all day, and having the CW idents every five minutes is very annoying - imagine somebody trying to do it non-stop!

I agree with "paulears". I would not use a repeater channel for CW of any kind, unless it is specifically allowed by the repeater owner. The repeater owner makes the repeater rules.

But there is plenty of other space (Simplex Channels - no offset) available for general use. Just pick one that isn't commonly used so you don't rile the locals.

Now all of this is going under the assumption that you are using a on/off tone modulating a FM transceiver. The CW-IDs that you hear on repeaters are a similar operation. But if you were doing real CW (on/off carrier), you would have to go down to the bottom end of a band (e.g. 2 meters - 144.0 - 144.1 MHz). I don't think anyone would set their scanner that low in frequency.

Martin - K7MEM

 

[KK6YBJ]

I have emailed the owner of the repeater to ask what the rules are regarding CW on the repeater, and will not attempt to until I receive a reply. I wasn't planning on trying that anyways until after I had learned Morse by practicing "offline", which will likely take a while. The reason that I was planning on using the repeater instead of a simplex channel is that I have heard a few people talking on the repeater, but for the most part it is quiet, and I would have no idea where to find someone sending CW on a simplex channel. The repeater is not frequently used, even for voice; sometimes I leave my radio on almost all day and will hear one or two voice conversations and the repeaters voice identifier every hour on the hour.

 

[paulears]

Amateur radio is full of conventions - most never written down. Common ones like asking for a QSL card through a repeater - cue lots of hand in front of mouth smirks.

You are having to build an oscillator and manually built in the ability to close the PTT - nobody makes such a thing for sale commercially because nobody really wants to do it.

My guess is the repeater keeper will have his mouth drop open, buy hey = he might say yes. I fear though that doing it will NOT be popular. If you don'tt have a modest aerial system that gives you a bit of range, I'd spend my money on that first, or maybe look to the HF bands where a handful of Watts on CW can get you around the world. In the UK, the band plan has CW sections - is this not the case where you are?

 

[jwt873]

I was poking around today on the web and by chance came across an MFJ device that is made specifically for connecting a CW key to a 2 meter radio. So, I thought I'd revisit this thread and post the info here: MFJ Enterprises Inc.

It's kind of pricey, compared to whipping up an oscillator from scratch, but it is an interesting option for 'appliance' operators.

 

[K4EET]

I was poking around today on the web and by chance came across an MFJ device that is made specifically for connecting a CW key to a 2 meter radio. So, I thought I'd revisit this thread and post the info here: MFJ Enterprises Inc.

It's kind of pricey, compared to whipping up an oscillator from scratch, but it is an interesting option for 'appliance' operators.

Interesting that you should find that. Several comments...

1. Download the instruction guide (7 page PDF) here and read it before purchasing this unit.

2. Note that this unit is made for HT (portables) and not a mobile (or base) 2 Meter rig.

3. The connecting cable is a 5 pin DIN to two mini-phone plugs for a speaker-mic connection. The appropriate cable number is as follows:
a) Kenwood MFJ-5026
b) Yaesu/Radio Shack/Icom MFJ-5024
c) Alinco/Standard MFJ-5022

Thanks for posting this unit. Very interesting...

73, Dave K4EET

 

[K4EET]

<snip> It's kind of pricey, compared to whipping up an oscillator from scratch, but it is an interesting option for 'appliance' operators.

One other comment, the MFJ-552 2 Meter CW Interface is partially "pricey" because instead of an acoustic connection (pressing the PTT and holding the mic next to the code oscillator's speaker), this unit is hardwired to an HT's speaker-mic input. It automatically keys the radio when you send code and unkeys the radio when you stop sending. It is also directly connected to the mic input which means that it is NOT an 8 ohm impedance connection from the code oscillator's 8 ohm speaker output. The mic connection is matched to the manufacturer's mic impedance and signal levels unlike the code practice oscillator schematic. Finally, this unit also has a speaker so you can use it as a standalone code practice oscillator and also hear the sidetone when connected to the HT. Pretty cool unit...

73, Dave K4EET

 

[KK6YBJ]

Thanks for the recommendation on the MFJ unit, however, it is pretty expensive, and I was hoping to be able to make the interface myself. If I can't get the CPO to interface with my HT, I will look into making a small radio just for transmitting/ receiving CW.

 

[KK6YBJ]

My guess is the repeater keeper will have his mouth drop open, buy hey = he might say yes. I fear though that doing it will NOT be popular. If you don'tt have a modest aerial system that gives you a bit of range, I'd spend my money on that first, or maybe look to the HF bands where a handful of Watts on CW can get you around the world. In the UK, the band plan has CW sections - is this not the case where you are?

Band Plan CW is allowed in the 2m and 70cm bands, which is what my HT can transmit in. I don't have a base unit yet, as they are pretty expensive, and I am still new to amateur radio and wanted to start with a handheld.

 

[majoco]

Nobody has asked if you know morse code yet - you shouldn't start sending until you can receive at the required rate. You aren't going to get many contacts if your sending is so bad that no-one can understand it.

 

[jwt873]

Band Plan CW is allowed in the 2m and 70cm bands

Connecting an oscillator to an FM radio isn't actually CW.

CW is turning the carrier off and on. There is no modulation either by frequency or amplitude hence the term continuous wave. (CW). It's officially designated 'A1A'.

Sending on/off tones via an FM radio results in a frequency modulated signal. It's usually called 'Modulated CW' and abbreviated (MCW). The official designation is F2A.

CW is allowed pretty well everywhere.. MCW isn't. You would not want to transmit FM MCW below 29.520 Mhz

 

[KK6YBJ]

Nobody has asked if you know morse code yet - you shouldn't start sending until you can receive at the required rate. You aren't going to get many contacts if your sending is so bad that no-one can understand it.

That was the point of the CPO, so I can learn morse first, then plug it in to transmit after I've learned.