[Skimmertalk] Skimmer and aggregator question(s)

Fri May 11 06:50:43 PDT 2012

Look for what?

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net

-----Original Message-----
From: W3OA [mailto:w3oa at roadrunner.com] 
Sent: Friday, May 11, 2012 13:39
To: K1TTT; skimmertalk at contesting.com; skimmer at dxwatch.com
Subject: Re: [Skimmertalk] Skimmer and aggregator question(s)

  Good point.

Look at the bottom right corner of Aggregator's Connections tab.

73 - Dick, W3OA

On 5/11/2012 9:24 AM, K1TTT wrote:
> If you use the aggregator feature that lets you connect to it with 
> telnet and you have multiple instances on a machine don't you have to 
> change the port for the telnet connection on some of them?  I don't 
> see how to do that on the latest aggregator.
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
> -----Original Message-----
> From: Pete Smith N4ZR [mailto:n4zr at contesting.com]
> Sent: Friday, May 11, 2012 12:56
> To: skimmertalk at contesting.com
> Cc: skimmer at dxwatch.com
> Subject: Re: [Skimmertalk] Skimmer and aggregator question(s)
> Responses interleaved below, Kaz ...
> 73, Pete N4ZR
> The World Contest Station Database, updated daily at 
> www.conteststations.com The Reverse Beacon Network at 
> http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at 
> telnet.reversebeacon.net, port 7000 and arcluster.reversebeacon.net, 
> port 7000
> On 5/10/2012 6:22 PM, kaz wrote:
>> Hi folks.  First, apologies if this double posts to the list.
>> Finally laid hands on a couple of softrock kits, and I am finally 
>> getting a chance to play with skimmer and SDR.  Way fun.  I expected 
>> the surface mount parts to be difficult when building the first Softrock.
>> Never tried any surface mount project before.  Wrong.  Turns out 
>> reading the numbers to sort out the capacitors was the hard part.
>> Bright lights and magnification, and even my 17yo son had trouble(and 
>> he has 20/13 vision).
>> But enough digression.
>> Bought skimmer license, have skimmer running on 40m and 80m.  40m 
>> calibrated(I think), 80m still pending.
>> Question#1
>> I'm not clear on the relationship between the skimmers and aggregator.
>> If I run a skimmer session for each softrock, do I run aggregator for 
>> each skimmer?
>> My initial expectation was to run the skimmer sessions for each 
>> Softrock, use wintelnetx to put the spots together, and use 
>> aggregator to ship the spots to the RBN from the wintelnetx 
>> window/port used to collect the spots.
>> I found the documents N4ZR has written to be "spot on", but I have 
>> not seen/found any that describe this relationship.  (I probably did 
>> not look hard enough....???..hints appreciated)
> Yes, this approach is fine, in principle.  The thing that is 
> important, from the RBN's perspective, is to keep the association 
> between a given instance of CW Skimmer and the Softrock for a given 
> band.  That way, if we see a calibration error coming up on the 
> Skimmer Details page of the website <http.reversebeacon.net>  you'll 
> be able to associate it with that instance of Skimmer and make the
necessary changes.
> Rather than running WintelnetX, I suggest you do what Tim, KQ8M does.
> Here's a quote from an e-mail I just got from him.
> "Every instance of skimmer has its own Aggregator. There is 3 instance 
> of skimmer and Aggregator running on 2 computers. The other 2 
> computers have 2 instances. What I had learned from Dick, W3UA, was to 
> rename each instance differently [he means to rename the exe file]and 
> use separate directories, of course. You have to do that with Skimmer 
> anyhow. I keep Aggregator in each skimmer's directories. Also, each 
> skimmer uses the same callsign. If you use separate callsigns it comes out
separately on the RBN."
>> Question #2
>> Is it necessary/required to open the port to the skimmer/aggregator 
>> to the world_wide_interwebz?  I would really rather not do that at 
>> this
> point.
> Aggregator does not use a port, so you should be able just to start it 
> and go.
>> Other trivia:
>> With two skimmers running on mostly dead bands, a dual core Pentium D 
>> (Dell Optiplex 745) ticks off about 15-20% CPU when the skimmers are 
>> minimized.  The 80m softrock skimmer is at 48khz on the on-boad 
>> Soundmax.  The 40m softrock skimmer is at 96khz on an ASUS Xonar DG.
>> The Xonar DG seems to be a fantastic value for a sound card. Also 
>> available as PCI-E, Xonar DGX.  Its main limitation over the more 
>> expensive siblings in the Xonar line seems to be its 96khz max sample 
>> rate, vs 192khz for big brother.
> 96 KHz comes pretty cheap - the 192 KHz bandwidth is more of a 
> specialty item.
> When you first crank up your Softrocks it is likely that you will have 
> images on the opposite side of the center frequency from the real signals.
> You need to run the I/Q Balance calibration to get rid of these.  That 
> routine requires strong signals across the entire range, so I've found 
> the easiest way is to turn my radio down very low (RF output) and 
> provide the signals it needs from one end of the range to the other.
> The other thing that helps a lot is to use audio isolation 
> transformers on the two channels.  Without them you will probably see 
> a fairly large noise bump at the center frequency, resulting from hum.  
> The iso transformers will "transform" this into a relatively narrow 
> dead spot, caused by the lower frequency roll-off of the iso 
> transformer.  I used some relatively good Triad isos in order no not 
> have roll-off near the ends of the frequency range, but if you already 
> have some my suggestion would be to try them and see.
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