[RTTY] RTTY Skimmer

Thu Mar 24 12:21:44 EDT 2016

I am a RTTY DXer not a RTTY contester, but I have spent a lot of time developing software that seeks to understand the "meaning" of digital mode QSOs.  Two observations:

1. Expecting the RTTY community to quickly change its behavior en masse is unrealistic. Encouraging constructive changes is still a good idea, but takes time. Software must reliably interpret current practices.

2. In the example

QSL 73 AB1CD CQ CD1AB CD1AB

the application should know that AB1CD has been making QSOs on this frequency. Thus it should not identify CD1AB as the CQer.

In my experience, such problems can generally be overcome by asking the question "what additional context must be extracted and retained to enable reliable disambiguation?" This does create the problem of deciding when to abandon acquired context, e.g. how long after AB1CD was last heard on that frequency do we conclude that AB1CD has QSY'd or lost propagation?

    73,

           Dave, 8P9RY

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Don AA5AU
Sent: Thursday, March 24, 2016 11:53 AM
To: V Sidarau; rtty at contesting.com
Subject: Re: [RTTY] RTTY Skimmer

Good points except that RTTY contesters have been adding CQ at the end of their CQ messages for many years now and it's more the norm now than not. I wouldn't be against adding QRZ at the end instead of CQ. The point is that someone tuning across a signal sees someone callsign once or twice and you don't know if that station is calling someone or calling CQ. By placing CQ (or QRZ) at the end, you know right away what's going and no need to wait and continue listening (time wasted).
Since Alex has weighed in that adding an extra space at the end does will not significantly impact the error rate, the question is now...
Does adding QRZ instead of CQ at the end of a message reduce the error rate?
Don AA5AU

      From: V Sidarau <vs_otw at rogers.com>
 To: rtty at contesting.com
 Sent: Thursday, March 24, 2016 8:32 AM
 Subject: Re: [RTTY] RTTY Skimmer

Don,

Let me respectfully disagree with your positive statement regarding the trailing CQ.
1. The "CQ call" exists for several decades now. It used to have a strict, clear and logic sequence, CQ [General call, Listen to me, I am ready to communicate with everybody] DE [My identification follows] AB1CD [actual call-sign] PSE K [Please go ahead with calling me]. The trailing CQ breaks the sequence. I for one, if I see or hear a CQ, I expect a call-sign to follow. If no call-sign follows, I feel confused.
You can say, my reading is just emotional, who cares about "proper"
sequence, and the trailing CQ does already have its own well established history. All correct,

BUT

2. It is perfectly clear by now that trailing CQ calls for problems, at least with RTTY skimmers. If AB1CD finishes a QSO and CD1AB calls him, the string like QSL 73 AB1CD CQ CD1AB CD1AB most probably will end up with CD1AB spotted by a skimmer as a CQer. It is a problem, and it will remain a problem as long as the trailing CQ is around. 

To make the long story short.

My QSL-QRZ button is programmed as
QSL TU VE3IAE QRZ
and I never have anybody else spotted on my run frequency. 

OK, QRZ is 1 character longer than CQ (big deal) but your CQ frequency remains your CQ frequency.

73,

Vlad VE3IAE

--

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Don Hill AA5AU
Sent: Wednesday, March 23, 2016 10:21 PM
To: rtty at contesting.com
Subject: Re: [RTTY] RTTY Skimmer

We've heard some good things in this thread. We heard from, I think it was Dave K6LL, who believes the RTTY skimmer spots are getting better. And we've heard from Pete, N4ZR, saying that by using "aggressive" validation, we get better spot accuracy with only a small reduction in the number of spots.
This all seems good but we need all RTTY skimmer ops to use this aggressive setting.

I shied away from using RTTY skimmer spots after trying to use them on a couple of occasions last year only to get slowed down by chasing spots of S&P stations instead of run stations. I am going to try using skimmer spots again during EA RTTY next weekend to see what improvements have been made. I do realize the potential upside of RTTY skimmer spots.

I do have one question. I understand that one of the biggest issues is that RTTY contesters place "CQ" at the end of their CQ message (and it's for good reason). Most of us use a single space at the end of that message. Would it help if everyone who places CQ at the end of their CQ message, used two spaces instead of one after that trailing "CQ"? If so, I'll start doing that and advocate that others do it as well. Would it make a difference? Would we get less S&P stations being spotted by RTTY skimmer?

73, Don AA5AU

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Pete Smith N4ZR
Sent: Wednesday, March 23, 2016 5:45 AM
To: rtty at contesting.com
Subject: Re: [RTTY] RTTY Skimmer

Thanks for calling this out, Ian.  I checked, and discovered that DF4UE is running "minimal" validation.  I'm sure this is an oversight on his part, and have just sent an e-mail to him suggesting he adopt the recommended RBN standards of "normal" validation on CW and "aggressive" 
on RTTY. Recent tests confirmed that "aggressive" validation on RTTY results in usefully better spot accuracy with only a small reduction in the raw number of spots.

73, Pete N4ZR
Download the new N1MM Logger+ at
<http://N1MM.hamdocs.com>. Check
out the Reverse Beacon Network at
<http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 3/23/2016 4:28 AM, Ian White wrote:
> K6LL wrote:
>> In my experience, the VE3NEA RTTY Skimmers are much improved lately 
>> on spotting stations that are actually calling CQ.  I always connect 
>> to a CC-Cluster node, using CC-user Software, which seamlessly feeds 
>> N1MM Logger.  I think the CC Clusters do some filtering to validate 
>> spots from multiple skimmers.  My usual nodes are VE7CC-1 or AE5E-2.
>>
>> RTTY Skimmers have definitely come of age in the past 12 months.
>> Many thanks to all those who are feeding the RBN, both CW and RTTY!
> The quality of RTTY skimmer spots does continue to improve, but there 
> is still a significant 'leakage' of spots for stations that are 
> replying to a CQ.
>
> Although "CQ" can appear at both the beginning and end of a text 
> string, it still should not be too difficult to parse an ambiguous 
> fragment like "GM3W CQ K6LL". One of the two spaces in that string 
> will be a genuine, synchronous RTTY <space> character; but the other 
> will just be an asynchronous gap between two different stations.
>
> And above all: if there is any doubt, the skimmer should *not* spot! 
> It isn't a race between different skimmers, and there's sure to be 
> another CQ coming along shortly.
>
> Another problem last weekend was that one specific skimmer (DF4UE-#) 
> was spotting consistently incorrect callsigns.
>
>
> 73 from Ian GM3SEK (@GM3W)
>
>
>> -----Original Message-----
>> From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Dave 
>> Hachadorian
>> Sent: 22 March 2016 23:03
>> To: reflector RTTY
>> Subject: Re: [RTTY] RTTY Skimmer
>>
>> In my experience, the VE3NEA RTTY Skimmers are much improved lately 
>> on spotting stations that are actually calling CQ.  I always connect 
>> to a CC-Cluster node, using CC-user Software, which seamlessly feeds 
>> N1MM Logger.  I think the CC Clusters do some filtering to validate 
>> spots from multiple skimmers.  My usual nodes are VE7CC-1 or AE5E-2.
>>
>> RTTY Skimmers have definitely come of age in the past 12 months.
>> Many thanks to all those who are feeding the RBN, both CW and RTTY!
>>
>> Dave Hachadorian, K6LL
>> Yuma, AZ
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From:  pcooper
>> Sent: Tuesday, March 22, 2016 10:31 AM
>> To: Al Kozakiewicz
>> Cc: rtty at contesting.com
>> Subject: Re: [RTTY] RTTY Skimmer
>>
>> Al AB2ZY and the group,
>>
>> I have local access to a skimmer cluster as well as a normal cluster.
>> Both run simultaneously here in the shack 24/7. Looking at the 
>> skimmer cluster, I repeatedly see spots for stations that are 
>> responding to a CQ call, rather than calling CQ themselves.
>>
>> I have tried using the skimmer cluster in a contest, and that simply 
>> clogs up the bandmap with loads of spots that aren't calling CQ.
>> I know the skimmer clusters are supposed to be intelligent and only 
>> spots calls who are sending CQ, but I see far more spots for those 
>> that aren't.
>>
>> Where cluster access is allowed in a contest, I will use the normal 
>> cluster, as I mostly use it to gauge whether another band is open, or 
>> worth trying. If there is some juicy DX spotted, I may well try for 
>> them, depending on the situation, but generally, if that juicy DX has 
>> just been spotted, it's usually pointless trying, as loads of others 
>> will already be there.
>> This was evident during the BARTG contest at the weekend, as I came 
>> across FP/KV1J calling CQ on 20m, so I tried to get in, but he had a 
>> mini pile-up going. I did try a couple of times more, but then he got 
>> spotted, and I gave up, as it just got silly, with callers shouting 
>> over each other and the exchange in progress.
>> Happily came across him again later, and got in first shout. It was 
>> similar with HP3/VY2SS.
>>
>> That's just my own view of things.....
>>
>> 73 de Phil GU0SUP
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