CW with a Kenwood TS590SG

[N1IA]

Hello:

First let me say this is an AWESOME piece of software. I have a question: is there a place where I can set the received CW to exactly match my Kenwood TS590SG? I see I can change the filtering of course. But can't see where I can change the CW tones to match what I am receiving in the 590SG. I have tried CW normal and CW reverse. On USB, they match exactly.

Any help appreciated.

Scott N1IA

[Max]

Scott, it's down to the way you set up the filters in CW mode. In CW mode, SDRC (in SDR mode) will be netted on to the received signal when the CW signal you are receiving is exactly centred in the CW filter width. It's maybe not immediately obvious, but what this means it is that you must set the CW Filter centre frequencies (all of them) in CW to your preferred audio pitch. So changing the CW filter centre frequency results in a different received tone (with signal exactly centred). I don't use an external radio, but I have all of my CW filters set with a centre frequency of 700Hz. That means when any CW signal is bang on centre of the filter width, the tone will be 700Hz. To adjust the centre frequency of the CW filters, just press the three little dots top left of the filter panel then select each filter in turn and edit the centre frequency.

So the corollary is true. If you want the CW tone frequency to match the TS-590 you will need to play with setting the CW centre frequency for all the CW filters in SDRC until the tone frequency matches the external rig.

All of the above assumes you are using the TS-590 in "parallel antenna" mode, i.e. the same antenna is split to feed both the SDR and the TS-590. If you are using the TS-590 to feed its IF to the SDR, then it may be that you also need to enter offsets in the mode offset box in the External Radio Settings to make sure that when you sync the 590 that this results in the CW signal that you have tuned in the 590 results in SDRC being tuned bang-centre of the CW filter. To get to these settings you press the tiny question mark at the top right hand side of the External Radio panel in the RX DSP section.

There is no adjustment for mode offset if you are using the radio in "Parallel Antenna" mode, but then you would only use the first technique I mentioned above. If using "IF Mode" then you would need to have the filters set in CW for your usual preferred tone anyway (as per above), then if there's any discrepancy when sync'd to the TS-590, use the "Offset" to bring it back correct.

Hope this helps a little.

Max

[N1IA]

Yes it does. I have been playing with the filters and see what you mean. Thanks for the help!

[pklein]

This thread was very helpful--thanks! I’m setting up SDRC and an Airspy HF+ to use as my HF receiver, with my ICOM 7300 as the transmitter, linked as an additional radio via Omni-Rig. I've run into a wrinkle on CW.

A useful CW trick is to offset the signal from the center of the filter. That way, the perceived pitch center of the noise is different from the pitch of the CW note. This helps the brain separate the signal from the noise. Sometimes it’s better than just narrowing the filter with the defined buttons. In ancient days, when superhets roamed the earth, we used IF shift or passband tuning to accomplish this. Easy.

I thought I could use SDRC’s "filter hi and low" controls to do the same thing. But no. The CW filters shift the pitch of the CW note (apparently, to keep it centered in the passband) as I adjust the high and low limits of the filter. Which also means that I am no longer "zero beat" with the HF transceiver.

The defined filter buttons are fine. I’ve set their center frequency and the 7300’s CW pitch to my preferred 650 Hz. And on SSB, I can use the filter hi/low controls like a PBT control. But CW behaves differently. Is there a way to change or work around this? Thanks!

73 de Peter, KD7MW

[Max]

I thought I could use SDRC’s "filter hi and low" controls to do the same thing. But no. The CW filters shift the pitch of the CW note (apparently, to keep it centered in the passband) as I adjust the high and low limits of the filter. Which also means that I am no longer "zero beat" with the HF transceiver.

73 de Peter, KD7MW

Not sure what you mean by "no longer zero-beat with the HF transceiver"? For CW work, the carrier frequency is always zero beat with the TX surely. When you change the hi/low settings for the CW filter, this only defines the offset of the filter centre from the carrier frequency, and hence the preferred tone frequency. The carrier frequency will always be synced with the external radio carrier frequency I would think? I can't test this as I don't have an external radio, but that's how I always understood it should work and not sure how it could be any different?

Are you using the SDR to listen to the IF output of the 590, or is it in "parallel receiver" so both 590 and SDR attached direct to the antenna? Reason I ask is that if using IF mode there are additional offsets to trim for each mode if necessary in the External Radio dialogue. Obviously not available in the parallel rigs "shared antenna" mode.

73

Max

[jdow]

He essentially wants the center of the filter offset from the CW received tone and still have the frequency shown as the actual CW carrier frequency received and that he will transmit. I can think of how Simon could implement it. I've never played with this myself. CW is painful with my level of dyslexia. I have to count dits and dahs. I made it to 30 WPM on ship to shore transmissions. But it was quite exhausting. So I eschew the joys of CW.

{^_^}

[Max]

He essentially wants the center of the filter offset from the CW received tone and still have the frequency shown as the actual CW carrier frequency received and that he will transmit.
{^_^}

Yes, I understand he wants to offset the peak frequency of the noise to be different from the CW tone. Firstly, I don't think it can be done with the options available in SDRC, but I was querying the issue of not being "netted" because as far as I can see, the frequency displayed for the carrier will always be correct and also "netted" with the external radio.

Max

[pklein]

I'm "netting" the HF+ and the 7300 using "External Radio." Both connect to the antenna with an SRD Switch (or they will when the switch arrives--right now I'm just testing things without transmitting). When I tune in a CW signal, the pitch of the signal is the same on both receivers. But when I use the "Filter Hi" adjustment to raise or lower the filter's ceiling, the pitches heard by each receiver diverge. The farther I adjust the filter ceiling away from the filter's nominal setting, the greater the difference between the two pitches.

[Max]

I'm "netting" the HF+ and the 7300 using "External Radio." Both connect to the antenna with an SRD Switch (or they will when the switch arrives--right now I'm just testing things without transmitting). When I tune in a CW signal, the pitch of the signal is the same on both receivers. But when I use the "Filter Hi" adjustment to raise or lower the filter's ceiling, the pitches heard by each receiver diverge. The farther I adjust the filter ceiling away from the filter's nominal setting, the greater the difference between the two pitches.

Yes, that is expected behaviour. If you only adjust HI without adjusting LOW then by definition you are adjusting the filter centre frequency and hence the tone heard. In order to hear the same pitch in both receivers you need to decide what is your preferred RX tone frequency (presumably from the 7300) and make sure that the Centre frequency in the filter always matches that.

Easiest thing is in SDRC, set up a series of filters to your preferred widths and then go through each one and set the centre frequency to be the same preferred pitch frequency for every filter. After that you will never need to adjust it again.

Max

[jdow]

The idea, Max, is to separate "filter center" from "CW tone". That way the "tone" of the background noise can be jiggered to be slightly different from the "CW tone." So two things must be defined, in essence, that are now one. There must be a CW tone frequency definition and a IF filter center frequency. (Define the IF filter as center frequency and bandwidth to make it easier to control. But that's simply a simultaneous command to move both the low edge and high edge X Hz higher or lower in frequency.) For what it is worth I'd like to see this sort of adjustability with SSB filters. I did this a lot on SSB with my ProII. My remote control tool worked CF/BW rather than LE/HE.

{^_^}