[Skimmertalk] Skimmer and aggregator question(s)

W3OA w3oa at roadrunner.com
Fri May 11 06:38:39 PDT 2012

  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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