Second Page of Questions and Answers 

Q I am looking at various cables in my junk box... .what shall I use for my audio gear? 

A. NONE! You are using professional audio equipment in an RF enriched environment! This requires some planned cabling to avoid ground loops and rfi in the audio signal. I refer you to the “Short Primer On RF/RFI Grounding Techniques” report elsewhere in this website.

I strongly suggest you avoid using any of the Radio shack pre-made black audio cables in their plastic bags. Their if shielding is very poor and if you use any of them, you’ll get frustrated trying to hunt down where rfi is entering your audio. I know this from experience! If you must use Radio Shack for your source of wire let me recommend the following: 278-777 four conductor double shielded cable 30 feet per package, 42-2493 computer speaker cable 16 feet, 42-2492 computer speaker cable 8 foot. The computer cables above have dual shielding. I also recommend using a shielded AC power cord when possible Radio Shack part# 61-2860. Be sure to verify you have the “shielded” cable since often the inventory is placed wrong! Also this power cord has the appropriate NEMA connector to fit AC powered ham and audio devices.

Aside from using double-shielded cables you really need to establish a cabling protocol for your shack. This means establishing a standard cable color code so later when you trouble shoot you will always know that red is tip or pin 2 of the XLR connector etc. You then should use when possible XLR connectors for audio, you’ll have better results in the long run. 

Other cable options are “STARQUAD” This is a generic name and is offered by: Belden, Canare, Gepco, and Mogami. Bob Heil also offers an interesting audio cable called “Heil Wire” He will sell it on 20’ lengths.

Q. We can't easily get the type of audio transformer you show in the description of the Muft Box, here in this country. Will you get one for me and send it?

A. I am not in the business or position to get these transformers, but I can tell you were you can. Go to QRZ.com and search on W2IHY, yes the same one who makes the IHY audio equalizer. He can provide you with the transformers and just about any part you need to build the box or maybe a kit to do it all yourself. 

Q. I have an Icom 746 and want to use it to produce great sounding audio like what I hear on 14.178. What secret filters or menus or both do I need to make this radio sound like the audio I hear.

A. The Icom 746 seems to be quite popular especially in Europe. As far as I know there are no filters or secret menus that will in themselves make you sound like the hams on 14.178. To modify this radio in any way internally is probably counterproductive. The radio can sound quite good in it's present somewhat narrow band-pass. You can put any of the Pro audio boxes like an EQ in front of it and with a little work it will play quite well. But, if real high quality HI-FI audio is what you are after, you would be better off in my opinion getting a different radio with a wider band-pass like the Kenwood TS870.

Q. Why do I need a foam windscreen, and what does a foam windscreen do? My mic says it has a built in pop shield, what does this mean? How do I properly install a windscreen and does it ever need replacement?

A. Foam windscreens are actually not all the same! The foam is transparent to sound pressure waves, BUT acts like a labyrinth for high velocity wind or breath guests. WHAT????? When you speak into the microphone, you send pressure waves to the mic element. If pressure and/or velocity of the signal exceeds the design of the mic you'll get distortion, unwanted sounds, or even permanent damage to the microphone element.

The built in windscreen found in most microphones are designed to protect the diaphragm from high velocity air! You will still present popping, reverse breathing sounds [inhaling], noisy "S & T" sounds. The foam windscreen will attenuate this anomaly. You need to install a foam windscreen. I find the Radio Shack 33-373A foam windscreen works quite well, and is inexpensive at about $3.00. To install the windscreen you should carefully slide it over the microphone, do not force it, you'll have a tight fit. I also suggest you do not butt the foam right up to the microphone screen. There should be at least 1/4" or 1/2" space between them. This is to provide additional protection and helps keep you a specific distance from the mic element. 

You have seen studio shots of performers singing: and in front of them there is a round screen device [called a STOPPIT]. This is another type of windscreen and in addition this keeps the performer a specific distance from the mic element for maximum quality and reduction of the unwanted sounds. 

Foam windscreen do deteriorate over time, and should be replaced oh, maybe every few years. Just as you should change your tooth brush after a cold the same holds true for the foam windscreen. the foam holds those nasty germs!

   Q.  Where can I purchase the mix-31 ferrite split bead and what will  it cost?

A.  You do have various sources for the mix-31 ferrite bead, DX  Engineering, The Radio Works, and Mouser       Electronics to name a few sources. The Mouser electronics part number for the 1/4"
      diameter bead is:  623- 0431164281

      The cost per unit varies on quantity ordered, see page 639 of  their catalog #622. for example the cost each       is $2.18 and quantities of 10-50 is $1.81 and over 50 $1.50.

     I have found the prices at Mouser Electronics the best around. Other sources can charge from $2.50 to              $3.18 each and no quantity price breaks.

     Refer to the specific vendor for other sizes of mix-31 split beads that they offer. Again Mouser electronics          has the greater selection.

  Q. I have been listening to various groups chatting about ... let’s call it fidelity SSB. I am not sure what all that means? I hear Hams talking about 0-3k, 80-3k, 100-3.1k, 100-4.k, and some way out to 6k. I also hear folks complaining, “you’re too wide!” “You’re splattering all over the band’s etc. I have a mid priced rig with no internal modifications and I have no clue what the hubbub is all about. Also, what is the proper bandwidth for the so called ‘ fidelity SSB”??? For that matter what is the proper bandwidth for DX audio”???? 

 A.  Now don’t get angry about my answer, I m trying to keep it in the viewpoint of a typical Amateur Radio       station. Let me first answer your questions with another group of questions: What is the correct rf power output level we should use for rag chewing, DX, or contesting? What radio is the correct one for use when rag chewing, DX, and contesting? Finally, what antenna is the appropriate one to use for rag chewing, DX, and contesting? Do you notice a similarity to your original questions? 

The FCC states in extremely broad terms [which is done on purpose] use the minimal whatever to accomplish your communication, also use good engineering practices. Then in the same breath experimentation and trying different things is encouraged throughout the Ham Community. 

As you tune across the bands you II experience a myriad of operating techniques form those that WOW YOU to those that actually hurt your ears, are annoying, and fatiguing. You as the individual in charge and licensed to operate your station has to make some decisions as to what you want your station to present to those listening. Ah, another trite analogy. You drive through the neighborhood and look at the fronts of many homes, some are gorgeous, some look like early slum, and others look like a war zone or just plain. Just as our front yards represent our personality so does what we broadcast over Ham Radio. To make matters even more obscure is what is nice for one person is the opposite of another. 

Now, I’ll address your questions: 

1. DX audio in the purest definition is a very compressed stringent sound. It is void of almost all low frequencies and is designed to pierce through a pile up. The most typical example of a DX audio sound is with a HElL HC-4 mic element into a radio with the compressor [speech processor] full open. Of course, this is the extreme and there are variations to the concept. 

2. Fidelity SSB audio in the most basic of descriptions is audio without excessive compression [speech processor, and a wider range of audio frequencies being transmitted. In other words, the lows, mids, and highs of conversational audio not typically heard in a DX type audio signal. Fidelity SSB audio is more pleasing to the ears, less fatiguing, and stuff you have heard and read before. Again, there is no set standard for Fidelity SSB audio. The range can go from 0-6khz and still be legal HUH? Yep, go listen to the AM Ham Stations they are 6khz wide with a carrier and are perfectly legal. Sideband came into the picture to eliminate the unwanted sideband and carrier to improve band use and operating. For some reason many folks are stuck in the position that SSB audio has to be without character and style and must all sound like a DX audio station. Thus the introduction of a sideband signal with personality. The audio is limited to the specifications of the radio being used. The newer high end rigs now even include transmit AND receive equalizers, so you can adjust the audio to your comfort zone, as with any good stereo radio. 

The bandwidth used for fidelity audio is limited to the transmitter design and filters, either analog or DSP. The same holds true for the receiver, that’s how come you sometimes can’t hear what’s occurring when you hear someone say I’m boosting this 6db and your rig is essentially deaf. I’ll go out on a limb here and say the majority of Hams involved in this mode try to stay within a self-defined bandwidth of [approximately] 0-4k. Actually many of the rigs can hear 6k but only transmit up to 3.2k [+ 1-]. It’s truly difficult to give anything specific because of the many radios in use. The new TEN-TEC ORION, for example will transmit audio up to 3.9k! There are those that are indeed pushing the limits and go to 6k but they are the minority and not the norm! 

3. Splatter: This is another very technical topic and I have limited space here. I suggest you visit John’s NU9N website www.nu9n.com and read his section on “apologetics” Remember, most audio guys use top of the line equipment and have strong signals. Even a DX station with all knobs to the right will splatter! Another observation is when any rig has their noise blanker on there is a phenomenon that occurs and you hear more so called splatter. Simply, if you’re receiving within the transmitter’s bandpass your radio may demodulate the signal in addition to the one you want. The majority of radios used in fidelity SSB are not modified internally and meet the FCC’s acceptance! You will also experience “splatter” when tuned 1khz away from a strong DX station too.  

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