Excessive Single Side Band Transmission, also know as ESSB or eSSB.

There seems to be an increase in the transmit bandwidth range for SSB communications, which traditionally operates within a narrow-band of approximately 3 kHz. Now if we go with a 3 khz “Voice channel” for Single Side Band (SSB) then the Transmitted Bandwidth, let's call it the TxBW, should fit into the range 0-3000 kHz.

However, I’ve noticed more and more operators use a TxBW of 4 kHz or more. This is often referred to as Extended Single Side Band (ESSB) which I have seen to extend in some instances even to 5 kHz and more. The claim to fame is HiFi Audio.

Now Amateur Radio is an experimental hobby, so this, on the surface, shouldn’t irk anyone, shouldn’t it? However, I frequently encounter ESSB operators on 20 and 40m talking to operators who have not modified their station for ESSB communications, i.e. a station with a TxBW 5 kHz to a station with a 3 kHz Receiver Bandwidth, lets call that RxBW.

So what seems to be the issue?

Let's say a QSO is conducted on 14.229 MHz, one operator uses a TxBW of 2.9 khz and the other uses a TxBW of 2.4 kHz. Signal are good with about S7 both ways. Since this is conducted using the Upper Side Band and, if we apply a Voice Channel spectrum of 3 kHz the used frequency spectrum for that QSO is from 14.229 – 14.231 MHz (not quite but let's stick with 3 kHz). Stations operating on 14.232 MHz should not have any issues operating. However, let's assume one of the operators is operating at a TxBW of 5 kHz. This situation would infringe stations operating on 14.232 MHz quite badly. Another example would be if a DX station is calling on 14.232 MHz and I would like to work that station. However, I will be unable to do so due to the excessive TxBW of the ESSB operator (14.229 - 14.234 MHz). 

Anyone see an issue here? Well, I do! However, the question is does the ESSB operator see the issue? From my experience most ESSB operators do not.

So why use 5 kHz TxBW whilst conducting DX contacts. Aren't we trying to share the limited frequency spectrum between all Amateurs? There is certainly NO benefit to the station receiving the ESSB station. 

Frequency spectrum during “openings” are crowded and transmitting with a 5 kHz TxBW during these opening does not show any courteousey towards other spectrum users.

The above shows an Australian Operators transmission with a TxBW of  5 kHz and the DX station using a  less than 3 kHz “Voice Channel”. I will assume that the DX stations RxBW would not be more than it's TxBW.

NOTE: I’m referring to the TxBW and not the Intermodulation Products (IM) or “splatter”, e.g. the light blue “hair or whiskers” on either side of the signal, which are obvious related but are not discussed here.

This is even more frustrating on the 40m Band, as there are more an more local stations operating with a TxBW of greater than 4 kHz. 

Now Amateur Radio is an experimental hobby and experimenting with a TxBW > 3 kHz does fall under this category. So, yes I believe in experimenting but this is not experimenting, this is not understanding the implication of excessive TxBW. And believe me I’m all for experimenting. However, I am quite happy with a 2.4 kHz well balanced audio TxBW which would influence the use of an appropriate RxBW.

Additionally I believe that these operator would not know how much "real" power they are transmitting. If we talk about 400W PEP, then the average output power would be rather LOW.

NOTE: I also observed that these type of operators seem to drop their TxBW to 3 kHz during Contests!?!  Yet they seem to believe that during crowded DX sessions it is OK to use 5 kHz or more TxBW. Isn't that a bit hypocritical?

Since Amateur Radio is a self regulating hobby it might be about time to add a frequency spectrum for those inclined to use ESSB. I believe this has been done for certain other modulation schemes (AM/FM/DIGITAL).

ICOM IC-7610 S-Meter Tracking

Having been checking the S-Meter for my prefered software solutions  (SDR) I thought it might be a good time to also (re)check the S-Meter in my ICOM IC-7610. The setup is the same as for the previous two checks. Below is the result of my checks for my IC-7610. A quick graph of how well my ICOM IC-7610 S-Meter is tracking using the proverbial 6dB steps (6dB/S-Unit).

Setup:

• Signal generator: XG3
• Level: -34.8dBm @ 13.8V
• Att: HP-355C & HP-355D (38dB for approx. -73dBm level)
• Frequency: 14.175MHz

Result:

CLICK on the GRAPH for a better view.

The graph shows a pretty linear S-Meter for the IC-7610 up to S5 however, it is at 3dB steps. It is not following the 6dB/S-Value IRAU Standard. The above graph has been produce with the PreAmp off. 

It is interesting though, that the Attenuator (ATT) values are in 6 dB (6/12/18 dB) steps, which would indicate that ICOM is familiar with the 6 dB scaling value for S-Meters.

Not only would it be nice to have a 6dB per S-Point scale it would also be nice to have S-Value compensation when using the additional Pre-amplifiers. 

Maybe a firmware/software update?  It is afterall a Software Defined Radio. I would hesitate a guess that it would not be that difficult to implement this kind of behaviour. It has been shown that Amatuer coders can make this possible, even accommodating different receiver gain settings, i.e. compensating for attenuation or amplification. 

Here is a note from ICOM's S-Meter blurb for the IC-R8600!

Absolute Value of RSSI (Received Signal Strength Indicator)

The IC-R8600 shows S-meter, dBμ, dBμ (emf) and dBm meter types in the RSSI. The dBμ, dBμ (emf) and dBm meter has a high ±3dB accuracy* (between 0.5–1100MHz) that can be used for measuring signal strength level.

Why can't we have 6dB S-meter steps and have the same display functionality as the IC-R8600 in our IC-7610, why ICOM?

Adjusting the S-Meter for HDSDR

Since ICOM has released Firmware v.1.42 for the IC-7610 the I&Q port is working again. This opened up the possibility to use HDSDR (Sampling rate of 1.92MHz with an effective Bandwidth of 1.66MHz) again. Since I still had the S-Meter check setup "set up" from the "Adjusting the S-Meter in Thetis"  I decided to check and adjust, if need be, the HDSDR/IC-7610 combo.

The setup is basically the same as for Thetis, except the SDR in this case is an IC-7610.

Setup:

• Signal generator: XG3
• Level: -34.8dBm @ 13.8V
• Att: HP-355C & HP-355D (38dB for approx. -73dBm level)

In HDSDR under Options [F7] we find Calibration Setting. This opens the HDSDR Calibration Panel.

Selecting the S-Meter Calibration tab:

The current configuration seems to correspond to an S-Meter reading of S9 +10dB on HDSDR:

and an S9 on the ICOM without the Pre-Amp engaged.

So next we add -73dBm to the Correct Level [dBm] field and press the [Calculate] button.

And the result is:

reducing attenuation by 6dB we get:

and, as expected, adding 6dB we see:

So in a Software Defined Radio (SDR) application written by Amateur's we do get the proverbial 6dB per S-Unit. 

Adjusting the S-Meter in Thetis

After about five (5) years I resurrected my ANAN 100D again. Trying a few versions, including a development version, I settled on Thetis v2.10.3.5 x64 u2. Seems to be running fine on my Windows 11 system. Quite a few improvements over the last five years. Going through the Setup/Configuration of the system I stumbled over a Level Cal inside the [Calibration] tab which can be found under the [General] tab. This allows one the ability to "automagically" set the S-Meter to a user provided level, .... sweet ....

I've decided to use my trusty old Elecraft XG3 RF Signal Source which I have checked against a calibrated RF Powermeter. At 20m the output at the -33dBm level measured -34.8dBm @ 13.8V. So using an attenuator with 38dB attenuation  will give me a -72.8dBm level into the ANAN. A short RG58 cable into a MFJ-1700B switch and another 50cm of RG58 should compensate for the missing 0.2dB to make it -73dBm.

Setup:

• Signal generator: XG3
• Level: -34.8dBm @ 13.8V
• Att: HP-355C & HP-355D (38dB)

And this is how it look in real live.

Here is the Thetis setup:

After pressing the Level Cal [Start] button, the system goes and runs an internal calibration routine. A window pops up to inform us about the progress status of the calibration.

Well, the result is quite pleasing. 

And if we add 6dB attenuation we get:

And not to forget if we do subtract 6dB attenuation the result is:

Struth, 6dB steps who would have thought that is a possibility. 

Oh and this is at every SSB Bandwidth we choose. My default is 2K1, however if I choose 2K9 the S-Meter still shows -73dBm. Yikes, it is possible! It is software defined after all.

It would be nice if my IC-7610 would not change the S-Meter reading with the engagement of the Pre-Amp(s).

References:

• A Little History about S-Points
• IARU Standards
• The beginning of the S-Meter revolution
• IARU Technical Recommendation R.1