AM Modulation Feeltech FY6600

I needed an AM modulated signal for something I am dicking about with. Selecting the AM wave type with a 7Mhz carrier produced a 50Mhz singal. I am not sure what is going on there, but I think it might be the DAC aliasing. So after RTFM and coming to the conclusion it was as  good as toilet paper, IE something to wipe your arse with, I did the old Jazz hands routine and searched on google for the answer.

The answer was actually quite simple, set channel 2 to the modulation width you would like, in this case i think I went 20Khz, set channel one to the carrier frequency and the hit the modulation button, select the modulation type and Bob is your uncle.

 

This is the 20Khz signal 100% modulated.

And this is the view on the spectrum analyzer, it kind of sorta looks like an AM signal yeah? I probably should have reduced the carrier power level and increased the modulated signal level to make it look more legit, but hey, i was excited enough to get this far and was over the whole fix it till its broken work cycle that I employ. Anyway, I now know what I am doing, and probably need another signal source to try demodulating AM signals, something to use as the LO as I am tying up both outputs on the function gen.

Onwards and upwards.

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MC3361 Mixer IC

What can I say, I like to trawl through parts catalogues and find somewhat obscure parts or ultra cheep parts to play with. So, when i found the MC3361, which is an FM Cordless phone IC, I thought why not. It costs 25 cents in one offs, and has some conversion gain and I assume its a gilbert cell in there, so its way cheaper than an SA612 and others.

LO in is on pin one, you can also add an xtal here for the LO. RF in is on pin 16 and the IF out is on pin 3. Now i did not try and match the impedance’s which are around 1800 ohms, i just fed in 50 ohms from my function generator into the LO and RF ports and then attached the spectrum analyzer to the IF port.

Other than some DC blocking caps and a 50 ohm termination resistor on the input there is not much to add to this. And as you can see from the plot below from the spectrum analyzer its working doubley balanced. RF in is suppressed and the sum and difference are the dominate signals. RF in was 7Mhz and the LO was 1Mhz for the sum and difference of 6 and 8mhz IF frequencies.

Is it as good as other mixers? I don’t know, but it works and its cheap, so i think its worth a go. Oh and it also has an FM de-modulator, AF amp and a op-amp for filtering in there also. I am yet to play with the other bits, i just setup the board for mixing only and well, mixing works.

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RF In The Ham Shack

I have had this intermittent problem with RF in the shack. Mainly this was on 20m where when transmitting some digital mode like FT8, the software would crash and the computer would send random serial commands to the radio and just mess things up. Mostly this was on 20m, but also on 15m the wireless mouse would stop working while in transmit. So i had some RF issue happening and by chance I worked out what it was.

Now, for work i spend a good part of my time on a motorcycle out delivering and I like to listen to the radio, podcasts and even ebooks using software that reads the text to me, while i work. I use these cheep arse bluetooth headsets to pipe the audio into my ears from my phone.

It turns out, when i have these plugged in and charging, they are acting as antenna and RF is then being fed into the mouse and keyboard dongle and computer VIA USB and then out the USB to serial cable for the radio’s cat control. Who would have thought that something as simple as USB charging would be the cause of all my problems.

Solution was simple, unplug the bluetooth headsets and everything is tickety boo. Oh and the reason why I have 2 of these, the battery only last 4 hours and 2 means I can work all day and keep the sounds coming. 🙂

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A Typical Day In Australia

Just a typical day in Australia where there is something trying to kill you. I am pretty sure this big bastard was an eastern brown snake, probably the most deadly snake in Australia, which is a land of deadly snakes. Brown snakes are aggressive and will stand up and attack anything that pisses them off including cars. I was far enough away from this guy to not be a threat, I took my photo, the snake crossed the road and I rode away. Lucky i was riding on the footpath, if i did not see him and rode to close, it might have struck me.

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HackRF and SdrAngel PTT

One of the annoying things about the HackRF is that its only 1/2 duplex. It could be a receiver or a transmitter but never both at the same time as a transceiver. Not anymore. SDRangel now has a new feature, the PTT button that automatically switches from RX to TX and back again. To use it is very easy. Setup your source device, then setup your sink device, click the play button and then when you hit the PTT button you will switch from RX to TX like a pro,

I have been playing with this new feature this morning using a 2m handheld and the HackRF and having QSO’s with myself at the milliwatt level LOL. The received audio in SDRangel sounds rather rubbish, i am sure I have some setting wrong somewhere, but it sounds thin and at times distorted. The transmitted audio does sound a little better.

As far as software goes, its good to see the developers of this continue to improve and expand it. There are also a lot of new demodulation types as well since I last updated it.

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Echolink On Linux

Sometime ago, i wrote a bit of a guide on how to install echolink on linux, what packages you needed to install and what not and how to compile and install it. Its one of the posts on here that gets a lot of comments, usually questions as to why its not working for them or upgrading their OS broke everything because of static linking.

Anyway, as it turns out someone has taken over maintaining the project, they have made the few minor changed that were needed to make it compile on modern flavors of linux and they have made packages available for it.

So its now just a simple matter to install it on any debian based distro using aptitude.

And that is all you have to do.

 

 

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Linux And Me

Linux, hmmm, you watch the fan bois come out in force to defend their god over this post. But linux is like a case of the drizzling shits, and endless stream of watery faeces that stick to everything, stink to high heaven and will eventually kill you.

I am not a neanderthal, or and Luddite, I have been using unix and linux on and off for just about forever. But i am at a point in life where I do not want to screw around with things. I want my tools to not require me to fight them to get any work done. When i grab a hammer i do not get out a saw and an plane and some sandpaper to make a fucking hammer, It needs to be ready just to hit shit.

So if its not working out of the box, if i have to fight it, diagnose 100 problems just to get a system that does everything i need, then I do not want to use it. This is the story so far. Oh I should mention, I am writing this post in linux, I have everything just about sorted out other than 1 piece of software that I do not really want to change because I like how it works and it does everything that i need. More on that later.

So i started out with Mint, I used to use mint as my daily driver when I was coding for online games. Back when I had simpler needs and all i really needed was a programming IDE, browser and email to be happy. It was what I went to initially, i know my way around it, it looks good and its what I have installed on the wifes computer. But for whatever reason, it would lock up every couple of days on my computer. No idea why, just random lockups. So it was out.

Next was Manjaro, Oh i liked this distro, its look and feel was good, it was responsive and fast, but it had a bug with fonts-config and I had no idea how to fix it and could not find any explanation on how to either. Its a shame really, but if I cannot run certain software on a distro, then its out nano vna saver is important here, i am a home brewer after all.

Then i gave MX a try, this might have actually been an ok distro, but out of the box the package manager was using an out of date repository and by the time i worked out what was happening, the install was fucked up. Wine would not install wine32, kind of needed for the older 32bit windows software that there are no linux version of, and something as simple as installing Kdenlive in a KDE desktop borked because of broken dependencies. Its shit like that, which really turn people off. I did not bother reinstalling and trying again after than. It was dead to me.

So i thought i would go old school with Opensuse, it had the KDE missing icons bug, not hard to fix, but in a modern bleeding edge distro you would think that they would fix it so that it uses the non broken theme and icons. But the thing that killed this for me, I could not get it to work with my wifi printer. Most others discover the printer add the cups driver and bang its working. Nope, it could not even discover it.

And now we have gone back full circle. I am running Kubuntu, yeah canonicle are something I like to avoid, but here we are, everything is running and all i have left now that I do not have a suitable replacement for is Ham Radio Deluxe. Not that I am doing a whole lot of operating at the moment, one antenna is down, the other one is putting RF in the shack and I have not been bothered to fix either of them as Im probably moving within the next few months and need to take it all down. So for that, i will dual boot with windows just for logging and for using DM870 for digital modes.

Yeah i know about fldigi and the suit of software that goes along with it, but its like looking at the 1850’s, if they made the thing look sleek and modern it might be a suitable alternative, but as it looks now, yeah i just cannot bring myself to use it. That, and when i tried it in windows it never worked for me, even with the sound settings flat out it never had enough gain and the rig control was meh as well. Never did work out what its problem was, HRD worked and never gave me a problem, so i just ponied up and bought it.

Anyway, that is my story, Linux is pain in the arse and a piece of shit that is still not ready for the main game, but, i think i will be able to make things work for now. All this because windows broke the bloody MTP driver for my phone and tablet. And if you are a linux fan boi and I have touched you on the frequency because I spoke ill of your god, don’t bother commenting, you are not going to change my mind that linux is turds on fire. If its perfect for you, that is great. Not everyone is you.

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