Clean signals, FSK and AFSK RTTY

 

    The question of FSK vs AFSK RTTY continues to be discussed.  Each has its pros and cons, which have been touched on elsewhere.  The main question for the moment is: what's the cleanest signal we can achieve?  It's important to consider signal quality for a number of reasons. 

    For one, it is a requirement of our licensing to use the least power necessary to make the contact.  As RTTY is primarily a contesting mode now, stations are often using significant power.  As signals degrade, noise, harmonics and splatter affect operators trying to use adjacent frequencies.  This is unsportsmanlike. Finally, a cleaner signal means whatever power we radiate is concentrated into the mark and space frequencies that make up the transmission.  If we concentrate our power, our effective signal strength is better. 

    So how do you know if your signal is OK? One way is to use dedicated spectrum analyzers.  When I wondered about the quality of FSK from my Icom 7300, I contacted Adam Farson (SK) for advice. He did some testing, and declared it was within spec.  Those results are at the end of his very thorough Icom 7300 test report. 

    Most of us don't have access to dedicated spectrum analyzers.  But many modern rigs have excellent spectrum displays.  If a friend can listen, they can give real time feedback about the signal.  Following are some examples.

    In this case, the radio being tested is an Elecraft K3, running remotely near Buffalo, via a RemoteRig setup.  An Alpha 9500 amp is running into a beam aimed west toward the receiving station in Chicago.  The receiving station is using an EFHW on 40 and a hexbeam on 20, feeding an Icom 7610. Images were captured from screenshots of WFVIEW.  Anydesk is used for screen sharing.

Aat 500W, FSK RTTY on a fading 20m band looks like this:

Hard to make an assessment with a signal this weak.  So we moved to 40m.

On 40M, at 227W, FSK RTTY looks like this:

There is no splatter and there are no harmonics.  The Elecraft K3 is known for a clean FSK RTTY signal and that's what we see.

From here, we change to AFSK RTTY. We are still on 40M.  AFSK is generated by 2Tone, using DOOK, sent via Writelog.  

Now we see splattering and harmonics.  This is a bad signal! Even turning the mic gain and sound card levels way down, we could not make the signal better.

To fix this required a few steps. Software audio controls were NOT sufficient! Dropping audio levels very low still produced splatter. 

The audio line from the soundcard needed an attenuator.  We have been making these by splicing resistors into audio cables in a T-pad configuration. Crude, but essentially free.  Online calculators will help determine the needed resistors. There are also inexpensive attenuators available for $10-20 but we haven't tried them.

The sound card level was dropped, and the mic gain was dropped.  At this point we had very little power out. From there we slowly adjusted mic gain and audio levels back up until we saw peak power output but maintained a clean signal.  Of note, the level of ALC flickering on the K3 was not an indicator of a clean signal.

We achieved signals like the following. The attenuator is in line, mic gain is at 40, the sound card level is at 20:

At this point, we'd like to know, how sensitive is the signal to sound card levels?  If we have to readjust to very fine degrees, then AFSK is not going to be viable for contesting. Initial testing, though, indicates that there is a good range of audio levels that maintain clean signals.  

Here we have raised the sound card level to 60 and we still have a very good signal with no splattering or harmonics.

And the now back down to 20:

Next we will check the signal on multiple bands, keeping audio levels constant.  Good luck and happy contesting,

Ben N9TR and Chuck N8CL

Single USB Cable FSK RTTY for Icom 7300

 I've been very happy with my TinyFSK RTTY interfaces for the Icom 7300. However, recent changes to the station have made them impossible to use without modification. The 7300 can do CAT control or keying, but not simultaneously, because it only generates one serial com port. One solution involves using Eterlogic's VSPE software to allow multiple connections to the single port.  The following is a very well written guide for setting this up with N1MM+ logger software, provided by Gordon Lyman:

Setup Guide for FSK RTTY on an Icom 7300

CW for Beginners: PaddleStick Keyer and the Icom 7300

I've been licensed for a bit over a year now, and have some experience with various bands and modes.  My first radio was a Yaesu handheld, the VX-5R.  This is one durable little radio. It's physical toughness is matched by operating difficulty.  If you don't have a manual... good luck!  Anyhow, the VHF/UHF repeaters around me are pretty active, and are a great way to meet local hams.

I moved up license classes and set up a station with an Icom 7300. I've made a few voice contacts, and used RTTY and FT8.  I've dabbled with PSK31.  But I'd like to get into CW.  I picked up a program or two for learning Morse code to practice learning the characters.  I figured at some point, though, I'd need to send some code, and get on the air.  I needed a paddle to send with, and possibly a keyer.  The 7300 has a built in keyer, but maybe I'd want to be away from it and still send.

There are lots of options for separate paddles and keyers.  I wanted:

• low cost
• combined paddle / keyer
• built in speaker

The PSB2 from K1EL / Hamcrafters seemed to fit the bill.  (It is missing a few features, though: there's no volume control or jack for an external speaker.  Also, it also does not have a computer interface, so you can't use it as a Winkeyer.)

Building the kit

The PaddleStick kit is a pretty straightforward build.   The instructions are clearly written.  The parts are well packaged, and nothing was missing.  My only hiccup was a resistor mixup.  I always check components with a multimeter or capacitor tester before soldering. Still I got confused and mistook a 470 ohm resistor for a 47 ohm resistor because I didn't read the multimeter carefully.  (The color bands are nearly identical, and impossible for me to decipher even with a magnifier.)  Still, the kit went together in about an hour and worked without a hitch. 

Using the Keyer

I'm a complete amateur at this, so I was happy to turn the thing on and hear it make tones.  

• The potentiometer turns the unit on and adjusts speed.  There's a neat setting to store your preferred speed. If you turn it on, but keep the pot all the way counterclockwise, it recalls that speed.
• There is no sidetone volume control or headphone jack. I find the sidetone pleasant and the volume perfect.  It's right about 600 Hz, which I like. It's easy to disable the sidetone.
• I was confused about rig interfacing.  The schematic says the red RCA jack is "key" and the white RCA jack is "PTT." The Icom 7300 has a stereo key jack.  Where should the "key" and "PTT" lines go?  I'm interested in using the PaddleStick in two ways:

1. Use the PaddleStick as paddle and external keyer
1. Set the Icom 7300 to breakin mode and straight key.  Use the settings on the PaddleStick for your keying preference such as speed.  The red jack controls rig keying.
2. Use the PaddleStick as an external paddle only; the 7300 keyer is used.
1. Again, Icom 7300 is in breakin mode, but select Paddle instead of Straight Key.  When the PaddleStick is in paddle mode, the red jack is the left paddle and the white jack is the right paddle.  

To interface with the 7300, I chopped a stereo RCA patch cable in half, tied the grounds together, and then wired the three resulting leads to the 1/4" plug that came with my Icom.  Here's the diagram from the Icom manual:

A few programming hints:

• Hold down the left-most button to enter command mode.  The keyer responds with "r" for ready.
• Turn the sidetone off or on with "a" for audio.  So enter command mode, then send "a" and the keyer should respond with "a" to acknowledge the command was entered.
• Hold down the right-most button and then tap the left-most button to enter tuning mode.  This will "key down" your rig, for tuning.  Press either paddle to exit.
• "s" followed by a two digit number set the default speed.  So "s" "1" "3" would set default WPM to 13.  Select the default keyer speed by turning the pot all the way counterclockwise.
• "x" enters extended command mode. 
• "x" "o" "p" sets the unit to pass through mode
•  "x" then "s" will save current configuration to EEPROM.

Update: 

Overall, I like the kit and the keyer for practice sending.  For on-air work, I had some issues with RFI.  It's also nice to be able to adjust the feel of the paddle.  I've since been mostly using a dual paddle key, with the internal keyer of the 7300.

Pork Belly Burnt Ends

I've been cooking pork belly for a few years now and the "perfect" bite eludes me.  It is tender, flavorful, and has crisp edges.  I've tried smoking bellies, cooked small pieces in a crock pot, cooked them sous vide, finished with a cast iron saute... they're OK, but not what I want.  The best I've found so far is Malcom Reed's "Pork Belly Burnt Ends."  It's a pretty brilliant recipe, actually.

There are 3 steps to this recipe:
1. Season and smoke
2. Steam and tenderize
3. Caramelize

Each step takes roughly 2 hours, so plan for about 6 hours of cooking.  There's no real urgency to the first two steps, but you need to keep an eye on step 3.  So here goes:

1. Season and smoke: Take a pork belly and cube it into portions a bit bigger than what you plan to end with.  Fat will render and you'll lose water, so the pieces will shrink.  Season all over, not too heavy, with a decent rub.  I like Dizzy Pig IPA for this.  Smoke at 250 for about two hours. The pork fat will start to render, and you should get a bit of browning.

This is 20 pounds of pork belly, on three levels, ready to go on a multilevel indirect setup in a large Egg.  The spider with a stone is the heat deflector; adjustable rig with two grids above that, and finally a rig extender on top of that. The spider isn't shown here - it's already in the egg and pretty much lives there. Awesome setup, from Ceramic Grill Store.  You could use the plate setter with the grid above just as easily.  As for smoke, apple or cherry wood are great for this cook.

This gets about 2 hours of smoke, until the outside gets a nice brown color:

2. Steam and tenderize.  The next step is to use steam to render fat and tenderize.  You could leave these on the egg and cook them down indirect, but it takes longer and generates a huge amount of rendered fat.  Instead, take all those pieces and throw them in a foil pan, and cover tightly with aluminum foil.  Get the egg up to 300.  Or do it in the oven.  Let them steam a few hours.  You'll end up with a lot of rendered fat in the bottom of the foil pan.  Drain this off.

3. Caramelize.  Remove the aluminum foil.  Add a few good handfuls of brown sugar and about half a stick of butter.  You'll also need a few good shakes of worcestershire sauce and Tabasco sauce. Drizzle all over with honey.  Cook and stir every 20 minutes.  If there's too much watery liquid in the pan, drain it off.  Add more brown sugar liberally as needed.  Give it a taste now and then.  Finally, add kosher salt to taste. I find these can take a lot of flavor, so adjust as you go and add whatever it needs.  You can add more rub if you want, as well.

Malcolm Reed adds a glaze at the end.  I don't think it's needed because you're building it with the brown sugar, salt, worcestershire and Tabasco anyhow.

Enjoy!

TinyFSK and WinWarbler

WinWarbler is favored by many digital ops for DXing and casual operating.  The following describes setting up TinyFSK for RTTY.

After starting WinWarbler, WW for short, go to config, and in the External Modem tab choose TinyFSK and the COM port for your TinyFSK.  Enter the serial port settings for your TinyFSK: 9600 / 8 / 1 / none.  In the RTTY section, make sure the "enabled" option is checked. Select the appropriate mode for your transceiver for FSK.

For PTT nothing needs to be selected:  Tiny provides PTT. 

In the RTTY tab you will see MMTTY setup.  If you go to that and check on Options,  note that no COM port is entered.  If 2Tone is enabled, note that as with N1MM+ the TX mode will be set to AFSK, which avoids COM port conflicts.  2Tone is not the transmit engine in WW.

The main WW panel should look like this:  RTTY receive and transmit (tinyfsk) is showing.

Note in the green panel, the TinyFSK information is all listed: version, speed, and mark polarity.

N8CL with KD9IWX

Makin' Bacon

The "Two Eggs" of the blog title refer to my two Big Green Eggs.  Technically, one is a large, and one is a small.  Both are great cookers.  I fire one up probably 4 evenings a week when the weather is nice - and once a week when the weather isn't.

One of my favorite things to make is homemade bacon.  It's simple and delicious.  I use a couple of different techniques; I'll cover a bit about the dry cure here and review some of the smoking techniques.

Curing bacon requires 4 ingredients: pork belly, salt, sugar, and nitrite. Ruhlmann's basic cure is:

• 450 g salt
• 225 g sugar
• 50g pink salt, aka Prague powder #1.  

Note that the pink salt is NOT Himalayan pink salt, and it is NOT Prague powder #2.  (Also note that there is no bacon without nitrite.  The "uncured" bacon you see in the grocery store was made with nitrites, possibly from celery. Since the exact amount is unknown, it can't be called "cured.")

Back to the bacon.  Get yourself a pork belly.  Costco sells them, your meat counter can order them. Slice it into pieces that will fit into gallon Ziploc bags.  Add cure: a 5% by weight ratio of cure to meat is plenty.  Seal the bags and place in the fridge. 

Once a day, turn the pieces over and redistribute the fluid that's coming out.  Curing takes about 7 days for an inch or so of thickness.  Give them a rinse at the end of the week.

At the end of the week, slice a piece or two off the end. Fry it up.  Notice how it turns red, just like real bacon!  The nitrite gives it the color and snappy taste and To me, this cure will usually turn out too salty.  Feel free to soak the slabs in cold water. Change the water every few hours and the salt should settle down after a few changes.

(Food with salt content over 2% typically tastes too salty. A great alternative to this dry cure method is called the equilibrium cure.  With an equilibrium cure, the exact amount of salt, sugar and nitrite in the final product can be controlled.)

At this point you could be done.  But you could also smoke the bacon. Cold smoking is not recommended, as the temperatures will typically be in the "danger zone" of 40-140 degrees. You may say, "but the bacon is cured, and I'm applying smoke, what could go wrong?"  The answer is that I don't know and I'm not going to encourage you to find out.

So, most people opt for hot smoking.  Build a small fire in the egg and add your favorite smoking wood.  Fruit woods like apple and cherry are great choices.  Set up the egg for indirect cooking and smoke the meat until the internal temperature of the bacon is 150-160 degrees.  Fry it up as usual but keep an eye on it: it's partially cooked already.

Since I mentioned not doing something dangerous, now is where I advise do as I say, not as I do. I figure if food is kept safe at temps below 40 degrees, why not smoke at that temperature?  I freeze the slabs of bacon until I'm ready for smoking.  Then, the small egg gets started with a small fire.  Very little smoking wood is needed - a chunk or two is fine.  Three, here, had plenty left over after a few hours of smoke. The platesetter is needed to deflect the heat.  

The top of the small egg is connected to the intake of the large egg with standard flexible drier hose. Blue painters tape holds it all in place.  

The cold slabs of bacon go into the large.  Most of the heat should be confined to the small egg and any that gets out will be dissipated by the drier hose. Without the platesetter inside the small, you may melt the first few inches of drier hose.  Ask me how I know....

Here's some slabs of bacon on an Adjustable Rig.  Definitely not necessary to have an AR, but it does let you load lots of stuff into the egg all at once.  Great product.

A few hours of smoke should be plenty.  I like to vacuum seal the slabs at this point and throw them back in the freezer. This lets the smoke distribute and mellow.

Slicing the bacon is done by hand, with a long slicing knife.  I use a standard 12" Victorinox with a fibrox handle.  If you are lucky enough to have a capable motorized slicer, I am jealous.  Sometimes your local butcher may slice for you, in exchange for your continued support.

This is sliced hot smoked bacon:

And this is sliced cold smoked bacon:

Finally, a one-egg way to do the smoking.  This is a styrofoam cooler, with trays for bacon slabs.  I held up the trays with long metal skewers.  I did this in the summertime, and kept the inside cool(ish) with ice.

If you're interested in bacon, and charcuterie in general, check out Ruhlman and Polcyn's book for a good intro.

Programming a TinyFSK with the Arduino IDE

Getting K0SM's software copied over to an Arduino Nano is fairly straight forward, but there are a few important steps to follow. Note that the "genuine" Nano is no longer sold, so you must use a clone; the original chip set used an FT232 FTDI chip, and many clones are sold with that chip. Some, however, have a CH340 chip, and that requires downloading and installing drivers to the Arduino Drivers folder. It is easier just to check the specs and go with an FT232 chip. Nano clones are also sold with and without header pins. I prefer those with header pins in the package but not soldered to the board. That way you can mount the Nano any way you want.

First, download the Arduino IDE:

You have a choice: I suggest using the old version 1.0.6. The newest version does not recognize some Nano clones. So far 1.0.6 has worked with several for me. A blank sketch looks like this:

Then Google K0SM's Tiny site: http://www.frontiernet.net/~aflowers/tinyfsk/. Near the bottom of his posting is the link to the source code: copy the entire code, and paste it into a blank Arduino sketch.

Go to your Control Panel----Device Manager-----Ports (COM and LPT)---and watch what port comes up when you plug your Nano USB cable into the computer. Back in the Arduino IDE, under the Tools tab, be sure that port is entered in Ports and Nano is entered in the Board menu.


Now under the Sketch tab click Verify/Compile, and if all is well, the sketch will fly through and verify. A Timer1 error code indicates that an updated Timer1 needs to be copied and pasted into the Arduino folder:

Finally, Click File.....upload....and the Nano will be a TinyFSK!