Hey, this new forum look is far easier to read...I like it.
ESSB, enhanced SSB generally refers to HF operators as it involves heavy modifications of rigs and many times quite a bit of money in added audio gear.
The basic principle is to get a wider and fuller fidelity signal. Done well it can approach AM, though being SSB it won't have all that bandwidth to use.
A nutshell explanation would be.
1) Widen the passband of the transmit. With many radios allowing 2.2Khz that is a narrow window of frequency response. ESSB tends to start at 2.8Khz up through 3KHz. This allows you a wider frequency spectrum of audio to transmit. With 3kHz, you could theoretically pass 300Hz to 3300Hz or shift that higher or lower with carrier offset in the rig.
Lower lows and higher highs than standard SSB. This gives you more fullness and generally a more natural sounding signal.
2) Widen the passband of the receive. Depending on the rig, you may not be able to actually receive and as a result, hear the wider signals that the first stage of modification can enable.
Your receive has to capture the full width of an incoming signal or it won't be able to process the full information that is transmitted.
3) Managing the dynamics of your signal. Using compressors applied properly you will enhance the power output on SSB. Basically trimming down the peaks to meet the average level makes your signal more punchy and efficient.
Broadcast audio, which this whole exercise imitates, is fully optimized through layers of compression and dynamics handling.
4) EQ and managing the tonal characteristics of the audio. When you widen your passband and possibly set your carrier offset to favor more lows, you can introduce muddiness into your signal making it harder to understand. Using EQ properly, you can then clean up the response of your mic and rig to match your own voice properties.
There are a lot of myths about EQ and microphones out there. The bottom line truth is, you need to be set up for YOU. Each operator's voice and manner of speaking will vary widely, so one man's setup won't necessarily work for the next guy.
As you introduce a compressor, it can put emphasis on unwanted spectral ranges, the low midrange in the area of 500Hz or so as one example. This can make your audio sound flat and boxy. An EQ is critical to balance these 'hot spots' in your audio...if applied correctly.
One quick piece of advice from a former sound engineer. An EQ of any quality, should never be used to boost frequencies.
One should always use an EQ to remove unwanted frequencies. This way you don't introduce distortion to the signal. If a signal sounds like it needs more lows, the other way to look at it is, that the signal probably has too much of a mid-range element. If you simply attenuate the mid-range, the lows in effect will come up. As you remove with an EQ, you will then need to boost the gain up a bit after the EQ in the chain, as you are removing signal level.
5) Effects processing. This is a sticky subject. Though not illegal to use some reverb and delay in the amateur service, I personally don't like to hear high levels of it. You definitely don't want the CB type 'echo' sound, but if you understand studio quality reverb and delay setup, you can get a pro-audio quality to your signal.
Think along the lines of the local Z100 pop station where the guys have the booming reverb on their audio. The trouble here is, what you think you are transmitting many times will have much more effect on the receiving side. It is critical to have actual over the air monitoring of your signal to get the levels correct. The ideal here is that the effects wouldn't be immediately noticed unless they were disabled.
The basic chain is
microphone to a studio mixer
Inserted effects processors, reverb/delay.
compressor inline with the mic audio chain after effects
EQ after the compressor...or before...it's a bit of a battle of opinion here.
mixer output into an impedance transformer to match the rig's audio input.
Or alternately, feed the line level out directly into the balanced modulator circuit in the radio itself....this takes some know-how though and you are essentially bypassing all the rig's built in protections to keep your signal clean.
This was only a nutshell explanation if you can believe that...poke around on google for ESSB for more in-depth explanations of the mods involved.
The Kenwood 850/870/940/950 are pretty commonly modified for this use.
Ten-Tec Jupiter radios can pass 3k as stock as can a few newer high-end Yaesu rigs.
The old boat-anchor rigs are also easily modified for this use.
One last bit, if you modify a rig for ESSB by changing filters in it, it will generally be pretty awful for more difficult use like DX chasing or contesting. You are opening the rig up, defeating some of the efficiency and selectivity the filters are actually set up for.
