Re: Curious minds want to know ... why no SSB?


Gary DeBock
 

Hi Neil, Kevin and Others,
 
Kevin's detailed explanation concerning the unsuitability of SSB in "consumer-grade" Ultralight radios is quite profound, and reflects the original thinking of John Bryant in setting up the ULR group classification system in early 2008. John solicited ideas from the leaders of the movement at that time (including Kevin, who by the way is the originator of the "Ultralight Radio" moniker), and we all agreed that SSB capability would create an unfair advantage in chasing DX on pocket radios (although at that time, nothing like the G6 existed).
 
DSP capability was discussed by the Definitions Committee (plus John and me) when the first PL-300WT models came out, and we reached a quick consensus that this was a positive change for ULR's, and something that would not create an unfair advantage. The fact that many barefoot ULR DXers continue to prefer traditional models like the SRF-T615 and the E100 confirms that thinking. We had a DSP-related discussion about the multiple filters (which were not originally allowed), and decided to allow them. 
 
As for large external antennas, Neil, the "barefoot" award class rules these out, and would be the perfect competitive forum for those ULR-DXers not enthused with tinkering, monster loops, and similar fanaticism. The "unlimited" ULR award class was essentially set up by two incurable antenna fanatics-- John B. and me. We took great pleasure in trying to outdo each other, and really didn't care how big the antennas became (as long as we were rolling in the TP's at Grayland). Seriously, though, the ULR "Unlimited Class" has really been a boon for antenna experimentation of all types, and if you assess the current AM-DXing community for centers of technical enthusiasm and innovation, you will find that our booming ULR group is right at the top of the list. The combination of relatively cheap receivers and supremely innovative DXers has created this unique situation, a definite tribute to John, Kevin and the other founding fathers.
 
73, Gary DeBock (in Puyallup, WA)  
 
 

In a message dated 8/10/2010 10:53:18 A.M. Pacific Daylight Time, satya@... writes:
 

Hi Neil:

Thanks for your question! I'll put in my two cents.

In general, one of the attractions of Ultralights is that one can take a small consumer-grade, AM-only receiver (as opposed to one built with a DX hobbyist in mind) and still pull in an incredible amount of DX. With the limitation of AM-only, additional skill and luck is required, which is part of the fun and challenge. With SSB or synch, one has the ability to inject/augment the carrier (which enhances the ability to hear a weak or fading station), and more importantly to select an individual sideband, which is a tremendous advantage in tough DX situations. SSB also allows the detection of split-frequency heterodynes, another big advantage when listening for trans-oceanic signals. If one did not want this artificial handicap, then one would use a communications receiver, but for me part of the fun and challenge is to see what can be received using minimal equipment, analogous to crystal set builders who voluntarily place even bigger obstacles in front of themselves. The U LR definitions were crafted with this general principle in mind.

Some receivers now have DSP filtering, but are still exclusively AM receivers without the ability to isolate an individual sideband. As with all AM radios, they can favor one sideband to some degree, but it falls well short of what a synch or SSB-equipped receiver can do. For example, synch and SSB on my Sony 7600GR, even with its ho-hum filtering, make it a better DX rig IMHO than the Tecsun PL-380. Truth be told, the DSP filters on the newer radios don't have particularly good skirt selectivity, compared to even cheap filters found in analog sets, much less the DSP filters on a Perseus SDR: as such, the consumer-grade DSP filtering is something of a trade-off. Also, since DSP is the apparent wave of the future for even cheap consumer-grade receivers, disqualifying DSP sets would eventually rule out buying any new Ultralights(!).

If a small radio had an RF gain control or a pre-amp, being able to boost or cut the RF signal wouldn't, in my experience, provide the same sort of advantage as SSB or synch, and would not be a disqualifier. I am not aware of these controls being in a small, under-$100 set - my guess is that it would cost too much to implement - so it may not ever be an issue. As you say, large external antennas do indeed offer a big advantage, which is why we differentiate between "barefoot" class and "unlimited" class for reception records and contests. Putting new filters and ferrites into off-the-shelf receivers also propels one into the unlimited class. Even with these augmentations, as monstrous as they may be at times, one still has the limitation of processing the signal on a cheap little AM-only receiver.

For me, who like others had lost a degree of enthusiasm for DXing with a communications receiver, Ultralight DXing offered (and continues to offer) a much-appreciated shot in the DX arm for interest and enthusiasm.

Thanks - Kevin S
Bainbridge Island, WA

--- In ultralightdx@..., "neilkj6fba" wrote:
>
> The definition of "Ultralight" radios seemingly excludes radios with SSB
> or sync capabilities since they would have an unfair advantage.
> However, radios with DSP are readily accepted. Does not a DSP radio
> have an advantage of over radios? How about small sized radios with RF
> gain controls or pre-amps? What makes synchronous detection so
> disqualifying?
>
> Does not a LARGE external antenna give an advantage over a "barefoot"
> radio? Is a radio using a 6 foot square directional loop still
> "consumer grade?" Sure doesn't fit in my pocket!
>
> I can certainly understand the goal of keep low cost as a factor in
> ranking a radio as ultralight and also the importance of size. But
> aren't both of these factors stretched substantially when large antennas
> are used to create "records of achievement" or internal modifications
> far beyond the ability of consumers?
>
> I realize that there are criteria for the awards program that divide
> into Barefoot and Unlimited.
>

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