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Author Topic: USB or LSB on CW?  (Read 21132 times)
KB2VWQ
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Posts: 15




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« on: August 10, 2011, 09:34:05 PM »

I am new to CW and I am a little confused what sideband injection should I use on CW (USB or LSB)?
I read that the USB is the standard for CW. Do I have to change sidebands above/below 30 meters like in SSB?

Thank you, 73

Tom
WT2NY

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K6LO
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Posts: 226




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« Reply #1 on: August 10, 2011, 10:12:23 PM »

No you can use USB. If you are using a general coverage receiver with a BFO, choose whichever one results in the least interference.

73,

Luke
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W8JI
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« Reply #2 on: August 11, 2011, 05:00:08 AM »

I am new to CW and I am a little confused what sideband injection should I use on CW (USB or LSB)?
I read that the USB is the standard for CW. Do I have to change sidebands above/below 30 meters like in SSB?

Thank you, 73

Tom
WT2NY



Unlike SSB, it makes no difference at all on CW what you use. The only difference is if the filter is wide and interference from other signals bothers you. For transmitting, there is no difference at all ever.

This is because CW is a single frequency off and on (amplitude modulated) carrier.
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W8JX
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« Reply #3 on: August 11, 2011, 06:12:28 AM »


Unlike SSB, it makes no difference at all on CW what you use. The only difference is if the filter is wide and interference from other signals bothers you. For transmitting, there is no difference at all ever.

This is because CW is a single frequency off and on (amplitude modulated) carrier.

Actually is does make a difference in what  your displayed frequency is on rig. USB has long been the default in radio when in CW mode. If you have a schedule with someone and use LSB to tune them you will be about a couple KC of frequency because of USB default.
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K9IUQ
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Posts: 1695




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« Reply #4 on: August 11, 2011, 08:50:56 AM »

Unlike SSB, it makes no difference at all on CW what you use.

Ah but it does. Here is why. I use FLDigi as a tuning aid on CW. I have a Kenwood TS-590s. In CW mode when I tune a signal, if I tune up the signal goes down (left) on the waterfall.  Also as I tune up the tone of the signal goes down.

This is the exact opposite of what I want. So I use CW-R, R=reverse. This makes the cw signal on the waterfall to go up (right) when I tune up and the tone goes up too. Exactly what I want.

So for me at least it does make a difference whether I use CW or CW-R.

As you point out it can make a difference with close QRM also.


Stan K9IUQ



« Last Edit: August 11, 2011, 08:54:30 AM by K9IUQ » Logged
K9IUQ
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Posts: 1695




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« Reply #5 on: August 11, 2011, 09:03:12 AM »

Actually is does make a difference in what  your displayed frequency is on rig.

If you have a schedule with someone and use LSB to tune them you will be about a couple KC of frequency because of USB default.


Not True.

Nope, it does not, at least it does not on my rig and I just tested it.

I just put my TS-590s in the dummy load at 18.072 on CW mode.
I put my IC-7000 on 18.072 to receive what the TS-590s sends.

I then switched between CW mode and CW-R mode while transmitting. There is NO difference whatsoever in freq or tone pitch on the IC-7000. CW and CW-R sound exactly the same without moving the IC-7000 vfo at all.

When switching between CW and CW-R the TS-590s does NOT change the VFO frequency.

So obviously the Kenwood is compensating for the sideband switch.

If you have 2 radios, try this test yourself..

Stan K9IUQ



« Last Edit: August 11, 2011, 09:06:54 AM by K9IUQ » Logged
PA0BLAH
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Posts: 0




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« Reply #6 on: August 11, 2011, 09:51:07 AM »

The question is perfectly valid.

In the old days, that is the time you had to build your transmitter and receiver all by yourself from spare parts and junk and swap, and you had to learn CW in order to  use the transmitter legally; the situation was:

The transmitter transmit at f0 and hence the tx scale had to be  at f0.

The receiver has to have a beatnote, in order to decode the CW when the beatnote was zero the scale gives the frequency of the zero beat note. That was in the middle of the received band (=IF filter), the place of the carrier in case an AM station was received.

When you put your receiver on 800 Hz beatnote the rx scale was hence 800 Hz lower OR higher than the received station his frequency. Dont't talk me abt variable beat oscillators because it was a generating 1V1, and nowadays the oscillator of the product detector.

Now SSB was going to be used around 1955 in order to decrease the dB gap somewhat between CW and phone.

The suppressed carrier was on one end of the IF filter, not in the middle anymore, in case USB at the lower side and in  LSB at the upperside.

Actually just outside the band because what is passed is 300 thru 2800 Hz sideband.

So when you want to put CW through that filter you can do that by producing CW as an audio tone and modulate it SSB, with the low yield of a "linear" a pure shame.  3dB is wasted. Not much unless you buy it as linear. That's a lot $/dB
a pure shame, but buying a set of Japanese origin and not building your own stuff is a much more greater shame,

When you put that 1000 Hz tone in the audio channel of the rig is is 1 kHz lower or higher than the suppressed carrier in ether and that ought to be the value on the frequency scale. But an SSB transmitter uses as scale the suppressed carrier.

When you listen to a station and you hear it LSB or USB on the same audio pitch 1 kHz, then you transmit zero beat.

Anybody that understands this congrats, the complicating factor may be that the Japanese factory, in order to prevent you transmitting out of band, and blaming them for that mistake, (scale just above 3500 kHz and transmitting CW LSB) corrects the scale such that your transmitted frequency is equal to the scale value.

So take a frequency counter, build one yourself when you don't have one, and measure your transmitted frequency in the CW mode with LSB and USB and you know your whereabouts.
« Last Edit: August 11, 2011, 09:59:48 AM by PA0BLAH » Logged
W8JX
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Posts: 5675




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« Reply #7 on: August 11, 2011, 11:32:19 AM »


I then switched between CW mode and CW-R mode while transmitting. There is NO difference whatsoever in freq or tone pitch on the IC-7000. CW and CW-R sound exactly the same without moving the IC-7000 vfo at all.


I am not wrong.

CW rev offsets frequency so you can shift bandpass/BFO injection but not loose signal. That is what CW REV is designed to do Stan.  If you had simply selected USB/CW to LSB you would have seen shift.
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K9IUQ
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Posts: 1695




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« Reply #8 on: August 11, 2011, 01:06:28 PM »


I am not wrong.

CW rev offsets frequency so you can shift bandpass/BFO injection but not loose signal. That is what CW REV is designed to do Stan.  If you had simply selected USB/CW to LSB you would have seen shift.

Yes, I am well aware you "think" you are never wrong. My radio does not have the modes CW/USB CW/LSB. As I noted in my previous post it has modes CW and CW-R which does reverse sidebands.

I can not think of a recent radio I have owned that has a mode called CW/USB CW/LSB. They all have CW and CW-R which is the same as CW/USB CW/LSB.

Here is a quote from my Icom manual:
"CW-R (CW Reverse) mode uses the opposite side
band

If you have a schedule with someone and use LSB to tune them you will be about a couple KC of frequency because of USB default.

I really have to wonder why if you had a CW schedule with someone that you would use USB or LSB to tune them in instead of CW or CW-R?

Do you actually do CW? Then you would know that your TS-480s has CW and CW-R.

I am well aware what switching between modes LSB and USB while trying to copy a CW signal will do to the frequency readout.We hams however do not use modes LSB or USB to transmit CW. We do not usually copy CW in modes USB or LSB.

We use either mode CW or CW-R.

Stan K9IUQ
« Last Edit: August 11, 2011, 01:28:27 PM by K9IUQ » Logged
W8JX
Member

Posts: 5675




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« Reply #9 on: August 11, 2011, 03:05:47 PM »


I am not wrong.

CW rev offsets frequency so you can shift bandpass/BFO injection but not loose signal. That is what CW REV is designed to do Stan.  If you had simply selected USB/CW to LSB you would have seen shift.

Yes, I am well aware you "think" you are never wrong. My radio does not have the modes CW/USB CW/LSB. As I noted in my previous post it has modes CW and CW-R which does reverse sidebands.

I can not think of a recent radio I have owned that has a mode called CW/USB CW/LSB. They all have CW and CW-R which is the same as CW/USB CW/LSB.

Here is a quote from my Icom manual:
"CW-R (CW Reverse) mode uses the opposite side
band

If you have a schedule with someone and use LSB to tune them you will be about a couple KC of frequency because of USB default.

I really have to wonder why if you had a CW schedule with someone that you would use USB or LSB to tune them in instead of CW or CW-R?

Do you actually do CW? Then you would know that your TS-480s has CW and CW-R.

I am well aware what switching between modes LSB and USB while trying to copy a CW signal will do to the frequency readout.We hams however do not use modes LSB or USB to transmit CW. We do not usually copy CW in modes USB or LSB.

We use either mode CW or CW-R.

Stan K9IUQ


Stan you are a trip. You play with a few buttons and you are in radio heaven without even understanding how and why button works. Again the question was about USB/LSB BFO injection for CW. And again, CW REV AUTOMATICALLY shifts bandpass and frequency to keep signal centered! Somehow in your limited understanding you are now convinced than USB or LSB has no effect on the tuned CW frequency as radio sees it because CW REV button masks it.   CW rev was created/implemented in modern radios to help you place strong interference in a different place in band pass relative to signal you are copying. 

As far as knowing /doing CW, I got my Novice in summer 1969 and early 1970 I had worked all states on CW. I am also a "old" 20 wpm Extra though these days I do not work much CW anymore but still know it and can send it too without a electronic keyer too on a straight key or bug.   Also while my 570, which I have owned for over 12 years now, also supports CW REV too I never used it even though I was still active in CW when I got it. This is because I have always been a very big fan of narrow CW xtal filters in rigs that support them. Never tried to work CW on a rig without one. My current  830 (that I got new) 570 (got new) and 480 (used) all have narrow CW filters in them. Even my first TS-140 that I got about 23 years ago and used for 11 years before selling it to get my 570 had a optional narrow filter in it that I installed in it.
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N2EY
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Posts: 3877




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« Reply #10 on: August 11, 2011, 03:13:52 PM »

It depends entirely on the rig and how it is set up.

What rig are you using?

First off, CW operation is done in CW mode, not SSB. A CW filter is a very good investment.

If a rig is properly set up, and a station properly tuned in, you can switch from CW-N to CW-R and back without retuning or seeing a change of the displayed frequency.

The main reasons to use CW-N vs. CW-R are:

1) In some situations, switching helps deal with QRM. For example, if you set the received tone to 700 Hz and there's another station that gives a 1200 Hz tone, switching to the other setting will put the interfering station at 200 Hz. Depending on your ears and the filter, dealing with one situation may be easier than the other.

2) Some folks prefer to have the rig set up so that, as they turn the main tuning knob higher in frequency, the tone of a received CW signal goes higher. Others prefer the opposite.

73 de Jim, N2EY
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K9IUQ
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Posts: 1695




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« Reply #11 on: August 11, 2011, 06:22:30 PM »


First off, CW operation is done in CW mode, not SSB.

73 de Jim, N2EY

We hams however do not use modes LSB or USB to transmit CW. We do not usually copy CW in modes USB or LSB.

We use either mode CW or CW-R.



W8JX does not seem to understand this and wants us to send CW in CW/USB or CW/LSB

Stan K9IUQ
« Last Edit: August 11, 2011, 06:31:01 PM by K9IUQ » Logged
K9IUQ
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Posts: 1695




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« Reply #12 on: August 11, 2011, 06:26:16 PM »

Stan you are a trip. You play with a few buttons and you are in radio heaven without even understanding how and why button works.

Like many others here on eham I give up trying to talk/listen to you and "your know it all" BS.

I do not work much CW anymore

That says it all..

Stan K9IUQ
« Last Edit: August 11, 2011, 06:38:13 PM by K9IUQ » Logged
W8JX
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Posts: 5675




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« Reply #13 on: August 12, 2011, 06:14:08 AM »

Stan you are a trip. You play with a few buttons and you are in radio heaven without even understanding how and why button works.

Like many others here on eham I give up trying to talk/listen to you and "your know it all" BS.

I do not work much CW anymore

That says it all..

Stan K9IUQ


Stan, knock your self out. I tell you how it ACTUALLY works not how you think it works........
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PA0BLAH
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Posts: 0




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« Reply #14 on: August 12, 2011, 07:05:01 AM »

Yes,

That grumpiness is  originated by the fact that ham radio is degraded to operation of Japanese products. So I regret but I have to conclude that I direct this message to a club of appliance operators.

Now I see, that is written here that a Japanese product, that you buy with easy (printed by government) borrowed money because you are not able to design and build something yourself and still you want to be "proud" of your transmitting equipment, which in fact make Japanese engineers proud,  but we are too stupid to recognise such a thing or we are closing our ears and eyes for that, aren't we?

Let we say that your transmitter keeps the same tx-frequency when you switch form CW to CW reverse. That is measured in this thread, and also reasonable to expect.

Then you switch over to "receive" Your BFO has then to be 600 Hz or what sidetone you desire, to be off the same receiving frequency as the transmit frequency was. Because it is reasonable to suppose that you receive at just the frequency that you were transmitting and that you are not able to copy Morse Code at zero beat.

When that Rx frequency should be just in the middle of your Rx pass band filter, and by switchting from CW to CW rev it would be kept in the middle, you should not have any advantage of suppressing QRM. It should be the same at  CW and CWR

However the difference CW CWR is in receiving maximal when your received CW signal is  close to the filter cutoff. In that case you hear 2, 5 kHz QRM above OR (CWr) 2,5 kHz BELOW the received frequency.

On Rx CW you hear by tuning HIGHER a beat of increasing frequency and by tuning lower than zero beat nothing.

On CWr you hear an increasing frequency beat by tuning lower, and nothing by tuning higher than  zero beat.

Just my dollarcent.

Bob

« Last Edit: August 12, 2011, 07:14:42 AM by PA0BLAH » Logged
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