HL2 and 630M band

[Glenn]

Hi

My shiny new HL2 & N2ADR filter just arrived this week and is working
A-OK with Quisk!  Is there any reason the HL2 would not work OK on
472khz or even 137khz with an outboard LPF for the respective bands? 
Would I just set no filters in the filter tab of the Quisk radio filter
config?

TIA and 73

Glenn VE9GJ

[Steve Drury]

Hi Glenn,

I had the HL2 hooked up to the speccy so without checking the
specifications I took 3 plots of TX output - drive was set for 5W
(37dBm) on 3.7MHz (Drive of 222 on SparkSDR).

Answer is yes, 0.5dB increase on 472kHz and 0.7dB decrease on 137kHz;
2nd harmonic is low so easy to filter unwanted products.

I know RX is good at LF as have been listening to broadcast stations.
Hope this helps?

Steve G6ALU

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[Matthew]

Glen,

See here for a discussion about LF/VLF.

Crucially, the rx transformer doesn't have a great response down this low in frequency. Claudio offers a suggestion for a better core in the link above, and there is a footprint on the HL2 PCB to take this. However, I'm sure you will have already noticed, this doesn't stop LF reception and MW/LW broadcast stations still come through.

If you are transmitting on these bands, I suspect you will almost certainly be using a PA to make up for antenna inefficiency? You can easily bypass the filters to do this, or use low power out (RF1) depending on your amp specification.

73 Matthew M5EVT.

[Glenn]

Hi Matthew
Thanks for the link. I hadn't found it in my searches using 630m or 472khz. Never thought to try 500khz!
I currently use my TS-590SG with a tx transverter with about 20 watts. I have just received LPF and driver boards from Ken K5DNL to build a 630m PA that will be capable of 200w. Now that I have my new HL2 I realized I could use it for 630m and that would free up the Kenwood for orher jobs. I may just use the K5DNL 200w LPF directly on the output of the HL2 until I get the 630m PA built.

73
Glenn VE9GJ

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[Heikki Ahola]

Hi Group,

When studying the options to work on MF bands like 630m, I noticed that high efficiency Class-E amps are being used. Those seem to require input frequency of 2x or 4x of the final output as they perform frequency division in their operation. In WSJT-X and its new FST4 etc modes this has been taken in account in the settings. I wonder if any of the SDR software available for HL2 has this option, which, however, is not just a display issue but also the filters etc. have to be adjusted accordingly.

73 de Heikki (OH2LZI)

[Christian Veith]

Hi Heikki,

It's definitely possible in SDR Console to define ne Transmit/Receive offsets. In your case you would just set a tx offset and SDR console will transmit with the higher frequency when dialed to the desired frequency. Filters are selected from the real tx Freq.

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[Heikki Ahola]

Hi,

Strictly speaking, it is not an offset (plus/minus) I am referring to but a division/multiplication. In real life this may not be of any importance (human brains are very flexible !) but in  e.g. Softrock-type rigs this type of conversion is essential. This reminds me of QUISK which appears to be applicable with Softrock also, maybe it is already there ...

73 de Heikki (OH2LZI)

torstai 12. marraskuuta 2020 7.38.46 UTC Christian Veith kirjoitti:

Hi Heikki,

It's definitely possible in SDR Console to define ne Transmit/Receive offsets. In your case you would just set a tx offset and SDR console will transmit with the higher frequency when dialed to the desired frequency. Filters are selected from the real tx Freq.

Heikki Ahola <heikk...@gmail.com> schrieb am Do., 12. Nov. 2020, 07:15:

Hi Group,

When studying the options to work on MF bands like 630m, I noticed that high efficiency Class-E amps are being used. Those seem to require input frequency of 2x or 4x of the final output as they perform frequency division in their operation. In WSJT-X and its new FST4 etc modes this has been taken in account in the settings. I wonder if any of the SDR software available for HL2 has this option, which, however, is not just a display issue but also the filters etc. have to be adjusted accordingly.

73 de Heikki (OH2LZI)

lauantai 7. marraskuuta 2020 0.42.21 UTC Glenn kirjoitti:

Hi

My shiny new HL2 & N2ADR filter just arrived this week and is working
A-OK with Quisk!  Is there any reason the HL2 would not work OK on
472khz or even 137khz with an outboard LPF for the respective bands? 
Would I just set no filters in the filter tab of the Quisk radio filter
config?

TIA and 73

Glenn VE9GJ

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[James Ahlstrom]

Hello Heikki and Group,

On Thursday, November 12, 2020 at 1:15:16 AM UTC-5 Heikki Ahola wrote:

When studying the options to work on MF bands like 630m, I noticed that high efficiency Class-E amps are being used. Those seem to require input frequency of 2x or 4x of the final output as they perform frequency division in their operation..

To do that with Quisk, you would use a custom hardware file and just multiply the frequency sent to the hardware by two or four. This is a one line change, but does require some Python knowledge. The rest of Quisk would operate as before. Different filters could be set as usual.

Jim

N2ADR 

[Alan Hopper]

Hi Heikki,

that is interesting, currently Spark only has an offset but it is easy to add a multiplier at the same point, I shall add it to the list.

73 Alan M0NNB

[Alan Hopper]

Hi Heikki,

just a thought, I think most software has a frequency calibaration setting, it may not expect big numbers like x2 or x4 but might work, I'll have a look at Spark.

73 Alan M0NNB

[Kristofer Danner]

FWIW, I just now changed to the BN73-2402 transformer suggested by Claudio here: https://groups.google.com/g/hermes-lite/c/fQtf4mi88IE/m/3Maaxfc1AQAJ

I can hear WWVB down on 60khz and several NDBs REALLY good now. Looking forward to some overnight WSPR/FST4W spotting, seems the results will certainly be improved!

[Steve Haynal]

Hi,

Thanks for testing that mod out and reporting your result. It is helpful to know about.

73,

Steve

kf7o

[Kristofer Danner]

Only a few call signs spotted on 2200m which I guess is not too surprising. Last night on 630m I got 14 unique calls which is way better than I have seen in the past and I know my antenna which is only a 40m long wire is far from optimal plus a LPF would certainly help as well. That K5DNL guy, I spot him at least every 10 minutes. I need to get one of those amps he makes and put together some kind of 630m antenna to get in on this action.