Throughout the radio hobby, establishing and maintaining a record keeping system is an important facet of active participation.  Regardless of which segment of the electromagnetic spectrum the listening enthusiast chooses to pursue, keeping track of what, where and who was heard is important.  This allows the hobbyist to set and meet goals as well as document what exactly was heard.  Many listening enthusiasts use strictly written records while some use a combination of written records and some form of audio archive.  With the increasing difficulties in obtaining written QSL’s, many DX’ers are taking the position that a clear recording of a broadcast with a station ID confirms that a given target was heard.  The purpose of this article is to help those who make audio recordings of what they hear utilize the latest technology to capture their audio.

In the past 20 years, cassette recording of radio programming was the format of choice.  The medium is small, easy to handle and portable.  Recording equipment could be purchased at reasonable pricing which was capable of making very faithful recordings.  Technological improvements produced reliable, portable equipment which was equally useful at home or it could be taken into the field on DX’peditions allowing the DX’er to return with exciting clips of audio from rare stations.

For all its convenience, tape recording has its shortcomings.  Audio recorded on cassette tapes tend to be “hissy” even when Dolby? noise reduction was used.  The low, 1-7/8 IPS speed allowed for quick tape saturation when a signal faded up suddenly resulting in distortion or sometimes inaudible passages in the recording.   Finally, indexing or keeping track of what was actually on a tape is cumbersome at best.  Written notes must be kept against tape index counter readings.  If the notes become lost or accuracy during an active listening session is compromised, the usefulness of the recorded audio is academic at best.

Time and technology have presented several new formats of audio recording.   Digital Audio Tape (DAT), writeable CD and Minidisc? (MD) are but a few.  Because of the unique capabilities offered to the radio hobbyist, this article will focus on integrating the Minidisc format into your listening hobby.  Also, we’ll look at a few Minidisc models to illustrate the various useful features the medium offers.

The recordable Minidisc is a reusable medium whose appearance is approximately that of a standard 3-1/2” computer floppy disk.  However, the MD is smaller at about 2/3 the size of the size of the floppy.  The discs are offered by the major magnetic media manufacturers such as Maxell, TDK, Sony, etc.   As of this writing, a pack of 4 Maxell Gold MiniDiscs sells for $7.99 with a free case offer on the Internet at Planet MiniDisc:

That’s about 600 minutes of mono record time representing the equivalent of 6.6 - 90 minute cassettes.

Through its digital ATRAC coding system, a single Minidisc is capable faithfully recording an exact digital copy of up to 74 minutes of stereo audio on as many as 254 separate tracks or individual cuts.  On hardware so equipped, the recording time is approximately doubled when program material is recorded in mono.

An important feature for the hobbyist, a Minidisc can hold up to 1,700 characters of user programmable text, numbers and characters that are used to label each track or selection recorded.

The MD disk itself is written and read with a low power laser thus, typical specifications are about the same as a CD.  Frequency response is 20-20,000 cps +- .3db, undetectable wow and flutter, signal-to-noise ratio in excess of 100db, etc….  Audio can be input and output from most Minidisc equipment in a variety of methods.  This includes conventional line level audio connected VIA RCA plugs.  For the musical purest with compatible equipment, some machines offer direct digital input VIA a single coaxial input or, in the case of the more upscale equipment, the digital signal is opto-coupled from the audio source VIA a single fiber-optic cable.  The radio hobbyist will  most likely to use the RCA inputs to couple line level audio from their receiver to the recorder.

Minidisc recorders are available from most of the major Japanese electronics manufacturers.  There are home units about the size of a CD player, which run off the commercial power mains.  Some manufacturers also offer portable models whose footprint is no bigger than 2 credit cards yet are full featured and can operate for many hours on various types of batteries.   Sony seems to offer the broadest line of home recorder/players and there are several excellent brands of portable and even car units (players) on the market as well.

As the hobbyist begins to read the product literature from the various models to choose one which best suits his or her need, they can be quickly overwhelmed by the many  product features recording in the digital realm offers.

A good way to start the selection process of an MD unit is by visiting the Minidisc Community page on the Internet.  Its available at:

Here, you can learn about the various features such as editing modes, track indexing and synchro-recording offered by the MD format.   What is easy about selecting a Minidisc recorder for hobby use is to identify a few features Important to the DX’er then use that criteria to help make a hardware choice.

Perhaps one of the more unique characteristics of the format is the ability to add user chosen titling information to each recorded track.  As the selection is played back, the titling information appears back on the players main display in one or more lines usually by scrolling.   The titling information is entered as the initial recording is being made or during a later edit.

Where I recording a 25M reception of All India Radio, a basic entry might consist of the following which the recorder would encode as data onto the disc which would display as the audio is played back:

AIR Bangalore  11.620 mHz  2142 UTC  08/19/00

With this 45 character note scrolling across the screen of the player, there is little doubt as to what the program material is being played back.  I noted the station name,  frequency and that the recording was started at 2142 UTC (more on time labeling later).  The date was August 19, 2000.

A more detailed description for the same logging might read:

AIR Bangalore  11.620 mHz  2142 UTC  08/19/00.  Note ID by OM @ 0:18.0

In the case of the detailed description of my AIR logging (68 characters), some additional detail was added to indicate that at 18 minutes into the recording, there was an ID by a male announcer.   You may title each selection if you wish and what is written and its format is completely your choice.

Because the Minidisc recording system works in real time, most hardware offers several modes of accounting for both playing and recording time.  Time into track, length of track, time remaining on disc are but a few of the time display modes.  On a personal note, I always label my recordings as to exactly what time they start.  I can then refer to the time into track to correlate the occurrence of a recorded event with the actual time at a later date.

The titling feature is key and can be a very powerful aid to the radio hobbyist.

Because of the potential power of titling, pay particular attention to whether a particular piece of hardware, be it a home or portable unit, offers the ability to title tracks.  Nearly as important as the feature allowing the machines to title a track is how the user must go about adding the text.  Most home and all portable units allow the text to be entered VIA multi-function keys or controls on the front panel.  Some home units allow the text to be additionally entered VIA a remote control.

I particularly like a feature offered by both the Sony MDS JB-930 (Street price: $319 US) and the soon to appear MDS JB-940 which allows a standard computer keyboard to be plugged right into the front of the machine.  All text entry, including upper and lower case alphabet, numbers and punctuation can be conveniently typed in from that keyboard.  Additionally, some functions of the machine can also be controlled by entries VIA the keyboard in addition to the usual front panel and included remote controls. Additional information about Sony MD Products may be obtained at their www site .

Hardware equipped with the mono recording feature (sometimes called “extended play”) is becoming increasingly difficult to locate but is important feature for the hobbyist.   There was some controversy concerning high frequency loss caused by the algorithm used to digitally encode and thus enable monaural recording.   The frequencies were the loss occurred were well beyond the range needed by the hobbyist yet, some manufacturers may be by-passing the issue by simply deleting the feature on newer machines.  Indeed the Sony MDS JB-940, which will replace the MDS JB-930, does not list monaural recording as a product feature.  That issue can be reviewed at the Minidisc Community www site.

If you cannot locate a home player with monaural recording, there is an easy work around albeit with the loss of the double record time advantage.  Simply combining the right and left RCA inputs with a simple “Y” adapter from your local Radio Shack works fine.

Home recorder/players range in price from $159 to over $700US.

Portable players offer many of the same features but in a much smaller package.  All of the MD format advantages, including the excellent specifications, apply to portables.   The footprint of the typical portable is tiny and approximates 2 credit cards laid side by side or, about 3-1/8” W X ¾” thick X 3-1/2” D (78.8 X 18.8 X 86.8mm).  The players are just slightly larger than the actual MiniDisc.

Battery life for a typical new technology portable is excellent.  One machine quotes 34 hours of playback or 13 hours of recording time on just 3 “AA” cells.  Newer machines even offer latest technology, rechargeable Lithium Ion cells which have excellent capacity but none of the charge “memory” issues associated with conventional NiCad’s.

Interestingly, most of the portable machines are so small, standard “AA” cells will not fit in the case and must be located in a separate battery case.  Some players come equipped with a specially sized rechargeable battery that will fit inside the case making a neat, easily portable package great for DX’peditions.

Due to their size, portables have a few additional issues including the ones mentioned for home units to be aware of.  Some portables do not offer manual input gain controls.  Instead, an audio ALC circuit is employed which while sophisticated, may not be able to properly ride gain on something like a static crash.

Because of their small dimensional size, the controls are likewise small.   This can cause operations such as titling and editing to be a bit challenging.  However, when faced with the choice of using a cassette or a portable MD,  the MD wins hands down every time.

Like portable CD’s, MiniDisc players are very rugged.  Many use an anti-skip design which “remembers” a certain number of seconds of previously played material but on an ongoing basis.  Should a shock occur and the data feed from the disc interrupted, the player will digitally reconstruct the audio from the previously memorized audio data.  Know that like all home electronics, getting a MiniDisc player wet is its death-knell.  The lead in the solder used in the assembly of the circuits will begin to corrode and the process is not repairable or reversible.

Finally, make sure the model of choice offers a Line Level Input.   It is this input which connects to the line level audio output of your receiver.  Pass up units which offer only a microphone or digital input.

A couple of portable models which offer the features used by the hobbyist are the Aiwa AM-C80 

 
Sharp MD-MS722. 

Both offer titling and mono-recording.  I choose the Aiwa model as the US model features an included “Car Kit” which enables the unit to play through my car stereo VIA a special cassette configured as an input device.  A cigarette lighter plug, regulated to the appropriate voltage, is also part of the “Car Kit.”

Portable recorder/players range in price from $100US all the way to $1,300 for the Marantz PMD-650.

Watch the sales but be very careful about Internet purchases.  Many of the US based divisions of Japanese manufacturers will not honor warranty coverage on products generally bought over the Internet unless it is
through an “Authorized Internet Dealer.”

Here are a few examples:

Crutchfield at:
http://www.crutchfield.com

J & R Music World:
http://www.jandr.com