eHam

eHam Forums => CW => Topic started by: KK4MRN on March 03, 2013, 05:34:07 PM



Title: CW pileup and transceivers
Post by: KK4MRN on March 03, 2013, 05:34:07 PM
I got a ham radio the other day.  The transceiver is only for UHF/VHF.  Only people I heard or made contacts were on FM repeaters.

My radio has a receiver that can receiver SSB and CW.

Tonight, I was listening on 40 meters around the CW calling frequency of 7.030 MHz after stringing up some hookup wire on the celing from one side to the other.  Now, I can pick up CW very well. 

I will here one person sending CW, then a bunch of people sending CW.   Is this a pile up of people trying to respond to some long distance person (DX I think is the correct terminology)?  How do you handle these situations?

The CW is too fast for me now.  If it was 1 WPM, I probably could copy it.  LOL.   But, I am still learning...

I do plan on buying or building a CW transceiver once I think I'll able to communicate.  What do you think would be good for a newbie?

Even though I see CW in the band plans, it seems like the HF bands is where I am hearing the CW transmissions.


Title: RE: CW pileup and transceivers
Post by: NO2A on March 03, 2013, 07:29:02 PM
If you listen to 40m,try above 7100,especially around 7115. You`ll hear slower cw in that part of the band. I`ve worked quite a few stations looking for slower speeds in that portion of the band. It`s fun,and I`m glad to see that portion of the band being used. To answer your question about the activity on 7030,yes that sounds like a dx pileup. Though the dx can be anywhere in the cw band,you`ll hear much of it below 7025. Listen around sunset,you`ll hear plenty of European dx in that area.


Title: RE: CW pileup and transceivers
Post by: M0LEP on March 04, 2013, 01:44:52 AM
Tonight, I was listening on 40 meters around the CW calling frequency of 7.030 MHz after stringing up some hookup wire on the celing from one side to the other.  Now, I can pick up CW very well.

There is no specific "calling frequency" in the HF bands for most modes (though one or two like SSTV do tend to stick to particular frequencies). Mostly you'll find callers spread about parts of the bands. A handy tool to help track CW callers down is http://www.reversebeacon.net , which also handily reports the speeds at which the callers are calling.

...and yes, that was very likely a pile-up of sorts. If you're lucky you can hear both sides of the conversation. Sometimes you only hear the big stations, so there are gaps of apparent silence while the faint DX station you can't hear is transmiting...


Title: RE: CW pileup and transceivers
Post by: KB4QAA on March 04, 2013, 09:55:53 AM
One word:  Filters

Most CW ops will have at least one filter, typically 250khz, 300khz, or 500khz.

I'm a 500khz man, but for really crowded conditions even that isn't narrow enough.  It does come in handy for some digital ops as well.

There is no 'CW calling frequency", however some of the CW clubs have designated certain frequencies to assist their members.

If conditions are too crowded, spin the dial.  If the other op is too fast, ask him to QRS.  Don't be afraid  to send a slow CQ, as there are many considerate operators who will gladly change to meet your speed.  Still, it pays push yourself at times, and hang in a QSO even if you miss letters, since you can usually understand the gist, and it will improve your copy speed.

See you on the air!  bill


Title: RE: CW pileup and transceivers
Post by: K3TN on March 07, 2013, 03:31:09 AM
Try tuning to 7.0475 at 8PM EST on a Tuesday or Thursday evening, and  you will hear W1AW sending slow speed code practice. No pileup, strong signal, steady code - great to get a feel for copying CW.

You can find the full W1AW operating scheduled here (http://www.arrl.org/w1aw-operating-schedule).

73 John K3TN


Title: RE: CW pileup and transceivers
Post by: PA0BLAH on March 07, 2013, 11:51:38 AM


Most CW ops will have at least one filter, typically 250khz, 300khz, or 500khz.

I'm a 500khz man,

Those filters don't add whatever you expect, because the bandwidth of the IF is at most 5 kHz.


Title: RE: CW pileup and transceivers
Post by: AA4PB on March 07, 2013, 12:37:17 PM
"Those filters don't add whatever you expect, because the bandwidth of the IF is at most 5 kHz."

If you install a 250Hz filter then the bandwidth of the IF is only 250Hz. You get a lot less interferrence with a 250Hz bandwidth then you do with a 5kHz bandwidth. Filters can make a huge difference.



Title: RE: CW pileup and transceivers
Post by: PA0BLAH on March 07, 2013, 12:59:22 PM
I agree, but he was not talking about a 250 Hz filter ,but about  filters much wider then his IF bandwidth.


Title: RE: CW pileup and transceivers
Post by: AA4PB on March 07, 2013, 04:17:28 PM
I didn't notice that he typed kHz in lieu of Hz - a typo I presume.


Title: RE: CW pileup and transceivers
Post by: WB3CQM on March 07, 2013, 07:06:05 PM
"Those filters don't add whatever you expect, because the bandwidth of the IF is at most 5 kHz."

If you install a 250Hz filter then the bandwidth of the IF is only 250Hz. You get a lot less interferrence with a 250Hz bandwidth then you do with a 5kHz bandwidth. Filters can make a huge difference.



The filter can be a good thing you should hear less interference  and then again it can work against you. Is my 2 cents.

In chasing DX and listening into a pile up I use 1.1khz wide filter and at times wider. To wide can work against you, like I am talking 2-3khz wide.

But without any question it does give the mind a work out having wider filter in. Again I almost NEVER use a narrow filter listening into pile ups. Reason, I can tune a pile up faster , I can hear a 5nn on the edge and tune faster to that freq. I can hear deeper in the layers of stations . Hands down , I almost NEVER tune a pile up narrower  than 1.1khz wide filter. But maybe 1000's of pile ups makes this possible. I can track a dx working stations up and down faster and more easy with wider filter. I do not sit on same freq and call. I track to same freq of last station worked or try and get ahead. IF I can here ?Of course this is not 100% possible to hear every station worked.  

When do I use 600 400 250 hz or less filter ? When listening only to the DX station if need be. Mostly I hardly go less than 600 wide and most of time am still using 1.1 khz wide filter.  

But maybe next pile up I break all those rules ? Who knows. But each to their own and  your style of operating.


I am not disagreeing with any one . Just explaining what works for me.

73 and See you in the pile ups.

JIM


Title: RE: CW pileup and transceivers
Post by: PA0BLAH on March 08, 2013, 04:20:12 AM
JIM

Your story confirms the known fact that the human mind works like a one octave wide audio filter.

You still can copy a CW signal with or without filter in case of QRM when you concentrate on the pitch, with or without small filter. Lower pitch makes it easier.

However in rag chewing is is less tiring and easier to use a small filter when there is nearby QRM. it also makes the signal to noise ratio better, which is also less tiring for (temporary in QSB) weak signals.
Of course I suppose your AVC is not pumping the receiver gain in the rhythm of the QRM station.

So the conclusion may be that small filters are for rag chewers and the wider ones for the pileup visitors.

Bob


Title: RE: CW pileup and transceivers
Post by: AK4YH on March 08, 2013, 01:20:48 PM
Quote
I do plan on buying or building a CW transceiver once I think I'll able to communicate.  What do you think would be good for a newbie?

Hello,

If you can solder, I would highly suggest a kit, like an Elecraft KX1 or Weber Tri-Bander.

http://www.elecraft.com/KX1/KX1.htm (http://www.elecraft.com/KX1/KX1.htm)

http://qrpkits.com/tribander.html (http://qrpkits.com/tribander.html)

You get a lot for your money with these kits, especially the Elecraft, which with additional modules will do 80/40/30/20m and has an optional automatic tuner. The Tri-bander does cost much less and has three bands of your choice. I Built an Elecraft K1 and it is a great little rig. Building these rig isn't difficult, if you can follow directions step-by-step.

If I was to buy an already built one, I'd probably go with a Ten-Tec, made in China QRP radio:
http://www.tentec.com/products/Sale-Price%21%21-Two-Band-CW-QRP-Transceiver-%252d-40-%252d-20-Meters.html (http://www.tentec.com/products/Sale-Price%21%21-Two-Band-CW-QRP-Transceiver-%252d-40-%252d-20-Meters.html)
On sale for $188 right now!

If you want SSB as well, you might want to look into the MFJ-94xx line... But once you get into CW, you probably won't use SSB much anymore...

Gil.