Friday, August 16, 2019

Radio GaGa eQSLs from earlier this month

Here are a couple eQSL from RadioGaGa!

This one was a test of **3 WATTS** AM and USB combined modes...

And this one from a stronger DSB/USB test

Monday, August 12, 2019

Antennas in the Burbs

This will be a dynamic post as I will seek ideas on how to place antennas in the little chunk o' suburbia I call home.

This is the yard... Let the hair yanking begin!

DESCRIPTION OF WHAT THIS IS - Straight up is approx 3 to 6 degrees west of true north. It is a total of approx. 165' deep and 70' wide. The teal boxes with aqua outlines are the house and garage, respectively.

The green lines are the chain link fences dividing the yards. The left fence is about 80' and the right maybe 90'. They're probably like 36" high except the north, which has 6' wooden picket fence sections on the opposite yard maybe 3/4ths of the width. The fences do not enter the front yard on either side.

There is a medium-sized Maple (35' tall maybe)  in the SW part of the "parkway". The white blob in the rear-center is a Tea Tree and the blobs to the left are Rose of Sharon shrubs. There is actually a third one north of those under the drop, but I covered it with grass when I edited the pic to remove the large willow trees we had cut down this summer.

The power/utility  drop is the RED LINE. It dissects the yard diagonally from about 40' in the center to the far northeast corner. Utility/power lines run above the north end of the property. A real PITA!

One thing... our electrical service needs to be updated as it's still old 60 Amp service. I wonder if I could get them to take it underground instead of a drop when that is done?  I don't mind running over/under data lines, but power drops, no way! But the drop severely limits my options, to say the least.

I do not have a tower or mast right now. I really need one, but flat wallets speak loudly! But I have a UHF corner reflector I need to put up since our local PBS affiliate sold the license to the FCC last year... for a measly $18M.. probably all spent already on Yachts and such for the old dumbfucks who run Central Michigan University's media wing. A local standalone AM just sold for more than that a month or two back! So, now I need a TV antenna. I do have some mast pipe but nothing I can use for taller than maybe 20'.

Fun Weekend on 43 Meters!

ION radio QSL from this weekend's listening...

Sunday, August 11, 2019

WREC QSL received

Just received a QSL from Radio Free East Coast, WREC operator PJ Sparx. Thank you for the show!

Radio Broadcast Audio Processing... Part Four -The Gear Itself

"But I don't HAVE all this stuff and can't afford to get it, Boogie! What can I do??"

There is no set answer. If you look for gear on eBay, take care not to overpay. You can find decent broadcast gear that will do the job fairly reasonable. However, the used equipment comes with a hidden cost of likely needing alignment or parts replaced, especially vintage gear. You can also use basic studio/live sound gear by Behringer, Alesis, Peavey, etc, which will do the job, but requires a bit of tweaking to sound good, They generally do not sound as good as broadcast gear. But you can often find good deals on used gear on Craigslist or even Fakebook Markeplace if you look long enough.

There is another option I must mention, and that is COMPUTER DSP PROCESSORS. I *love* StereoTool. It's very powerful, and older *FREE* versions will run on very old windoze systems. I keep a couple older  PC's on the shelf with pretty much nothing but ST installed on them.  In particular, I like version *5.02*. It'll run fine on Windoze 2000 and XP on a gig of RAM and single-core processor. It does all I need and has no nag saying "this station is processed using Stereo Tool..." every so often. Newer versions took some of the stuff I use and added it to the "registered" pay version, thus the nags in the audio. The downside??? LATENCY in the output audio... Granted, for AM/SSB situations, you can reduce the lag considerably because you do not need stereo nor much over about 10kHz anyway. There are many other DSP available as well, even Orban makes one I believe.

I've used just about every kind of processing there is, from Winamp plug ins to homebrewed circuits to Orban Optimods. They all basically do the same thing. I ran an AM station with a Behringer stereo compressor, using left channel as the AGC, through a Radio Shack EQ, and then through the right channel as a peak limiter. It sounded quite nice, actually. If you try this, just make sure that STEREO LINK is disabled so each channel can operate independently as far as ratios and time constants are concerned. The point is to make the gear work for you, not the other way around! If you follow my suggestions in these posts, especially starting with setting up your mixer first, you should be able to get your station to sound nice both locally AND far away. You get no bonus marks for spending the most money on your gear, just a flatter wallet!

As time permits, I will post about different gear you can use on your stations, and different tricks and tweaks to optimize your audio.

One more thought... If you are going to transmit, PLEASE set up a free email (I use for reception reports and requests and PLEASE, *PLEASE* QSL your listeners. By doing this, you can get feedback from your listeners about how your station sounds in the wild, and your listeners get something to show for their efforts!!!

Good luck in the ether and I hope to catch your station soon on my radio!

Radio Broadcast Audio Processing... Part Three - Tweaking your Airsound

Okay... thus far we have our mixer set up so that we have reasonable control over all of our sources, and our processing set up so the levels are controlled and stable no matter what the mixer is doing. However, once on the air the sound may be too bassy, too shrill, distorted highs or other issues. This step is probably the most subjective of them all, because what sounds great to you locally may not in fact sound so good "in the wild'. Or, you may absolutely HATE how it sounds locally, but it sounds awesome far away. But, we shall continue nevertheless.

Once the audio reaches the transmitter input, there are many things to consider. Matching your audio output to your transmitter's input may happen in several different ways, from microphones taped to headphones to a full-out balanced line input. Or maybe you've bypassed your transmitter's microphone input altogether. It isn't that important but you should be aware that sometimes there are better ways to get your audio transmitted and you should always investigate that further with regards to your rig. You should also learn and know your transmitter's input stage as some have virtually no processing while others have built-in peak limiters, EQ and filters, which will all matter a LOT.

One thing that *really* makes a big difference at this stage is EQUALIZATION. The old tone control on steroids. This beast is the golden tweak for any transmitter. With equalization, you can cure a range of airsound issues from popping bass, screechy voice and scratchy highs.

This is a Behringer Equalizer. A *decent* piece of gear, not total crap and not "high-end" either, but it will do the job. A lot of people, especially in broadcasting, *hate* Behringer gear, mainly because they do have kinda weak power supplies. I will not go into that here...

This unit has two channels, for stereo use. Unless you are transmitting a stereo signal, all you would need is one channel. The large section on the unit are your tone controls. To the left is the gain structure settings, input/output metering and a peak limiter.  The thing I do like about this particular EQ is that it includes a PEAK LIMITER after the equalizer stage. Unless you are only boosting a little bit (1 - 2 dB), you should ALWAYS have a peak limiter after an EQ.

Starting out, you want to adjust the OUTPUT control almost all the way down. Adjust the INPUT control until your processed audio reads around 0dB. Adjust the LIMITER THRESHOLD until the gain reduction lights one or two LEDs. You don't want excessive limiting at this point, just enough to keep peaks controlled. Any more will lead to squashing or pumping.

Let's look at that left section a second... There are LOW and HIGH CUT filters. You should set these to roll off any frequencies your transmitter will not pass. So, if your transmitter has a filter which cuts everything over 5kHz, there's no real reason to push that in there as all it will do is cause problems, like distortion. Same with the low end... if your TX doesn't pass anything below 150Hz, cut it. The lucky operator has a TX with no filtering and passes audio as high as you can put into it. Most Ham transmitters in the last 30 years or so probably have some kind of filters. Some also have limiters or clippers. If so, reduce your peak limiter after the EQ so it barely flickers, or disable it altogether. Also, do not run your input too hard or the built-in limiter will grind your nice audio to a pulp.

Set your processed audio level to the transmitter so you are not exceeding 100% modulation or running your TX internal processing too hard.

Saturday, August 10, 2019

Radio Broadcast Audio Processing... Part Two - Processing Your Audio

Oh yeah... some may need to smoke a fatty to digest the following information. It can get deep.

In it's basic form, audio processing performs one task... to keep your audio constant and clean. That doesn't sound too bad, does it? Well, it really isn't, but it surely can get that way!

The basic audio processing you need it a PEAK LIMITER to keep those audio peaks out of the mixer that exceed 100% from going over into the transmitter. For AM, you can use something called "asymmetrical processing" to let your positive go over 100% while keeping NEGATIVE peaks from exceeding 99%. A little crazy indeed. However, not all AM transmitters can even do these peaks past +100%, so we will address that entire headache in a future post. SSB, FM, TV, digital modes and basic AM transmitters WILL NOT and SHOULD NOT do asymmetrical modulation. It's mainly for commercial AM broadcasters, but some hams embrace it as well (Hi TimTron!!).

What the peak limiter does is "ATTACK" these peaks quickly and RELEASE them just as quickly when they're over. The limiter attacks when a peak is above a certain THRESHOLD, Usually set to 0dB/100%. Anything above that is limited, what's below is not. How drastically peaks attacked is what is called the COMPRESSION RATIO. Typically, not always though, a 4dB rise above THRESHOLD point results in ONE dB rise in the output, and this is known as a *4 to 1* (4:1) COMPRESSION RATIO.  When this limiting is occuring, how much is called GAIN REDUCTION.

This, in it's basic form, keeps you from overmodulating your transmitter on loud peaks. That is ALL it's meant to do. Because of it's really fast ATTACK and RELEASE times, pushing more into the peak limiter will literally mash the life out of your audio, making it sound super squashed in the receiver.

We've determined that you need to protect your transmitter from peaks in excess of +100%. The peak limiter does that. It should never be used to push up your quieter passages because it's basically a  hand grinder for audio signals. So then, how do we keep the levels into the limiter from dropping below threshold or really squashing the life out of your audio? Simple...


Yes, works just like AGC in shortwave radios, just on your audio chain. An AGC is basically the same as a limiter circuit EXCEPT that it attacks and releases the peaks MUCH SLOWER... so it more or less pulls loud audio down and pushes soft audio up... just like a radio's AGC does to the signal.

"Well, why can't I just rely on the radio's AGC to level my signal??" Good question, and I have the answer! The AGC in the radio is also got all the noise between your antenna and the radio's antenna to deal with. If your signal is weak and the AGC in the radio is pulling up hard, it pulls up all the static and noise floor into your audio. That simple.

And in the same vein, you do not want your AGC in your audio chain to pull all kinds of hiss, buzz from RF, ground loop hum, feedback from the mic, etc, when the level drops past a certain point. When your faders are all set all the way down, you do not want any noise pulling up. To do so just plain sounds bad. All you're accomplishing by pinning your agc is pushing more noise to the listener's ears than they already have to deal with. JUST DON'T DO IT!!!

Now then... if you have an AGC and a limiter after your mixing console, you want your hottest signal to push it down just enough to not push the peak limiter too hard. I never recommend over 8dB of gain reduction on limiting, and the same on AGC.

So, we're at the AGC stage again... it can be just a simple unit like an old CBS Audimax, which compresses everything alike, or it can have multiple bands for bass, midrange and presence/highs. The advantage to these multiband units is, they do not cause PUMPING or HOLE-PUNCHING in your audio. What is that??? Well, imagine a moog organ note that's -10dB on your mixer... then, add a drum track at +2 dB over that. What is going to happen if ran really hard, is the bass drum will kick in, punch into gain reduction, but release so slow that the moog note is knocked practically to nothing and then slowly pulls up just in time to get mauled by the next bass beat. It gives a really choppy, "up-and-down in the wrong places" sound output. Think early 1970's AM radio. A song is ending, a loud jingle hits, song fading just disappears into the jingle, then the next song's notes slowly pull up from the big hole they were kicked into.

This doesn't happen (theoretically) when using a multiband compressor/AGC, because each band is narrow and is controlled without affecting the gain reduction on bands to either side of it. Unless, your AGC unit is running too hard, then all bets on sound quality are off.

So, the AGC and Peak Limiter now provide your transmitter a controlled, safe level. However, that does not mean all is hunky-dorey yet.

Your audio may sound too bassy, muffled, "stale" or even lifeless on the receiving end. Your midrange may be too hot, giving you a "tin can" response, your highs like saying "S" or cymbal crashes (called SIBILANCE, FWIW) may be turning into static of their own. While the flat processed audio may sound splendid on your studio speakers, all hell can break loose when it is fed to a transmitter input. And usually does!

How you approach this part of the quagmire will be covered in the next part, "Adjusting Your Station's Airsound. But I have to eat before I faceplant!!!