[pskmail] Re: pskmail on other mode

  • From: John Douyere <vk2eta@xxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Fri, 28 Aug 2009 09:13:46 +1000


Thank you for the information. It is a good reference and is my source of
information when I experiment with digital modes in Fldigi.

Are you active in PSKmail?

Best regards,

John (VK2ETA)

On Fri, Aug 28, 2009 at 8:10 AM, Adrian Engele <aa5uk@xxxxxxxxx> wrote:

> Hi John,
> Just reading all the PSKMail BB messages and just saw yours. Interesting
> analysis for sure.
> I was wondering if you had seen the following analysis of the various modes
> on the flidigi site: http://www.w1hkj.com/FldigiHelp/Modes/index.htm
> Just thought I would pass it along in case you haven't.
> 73,
> Adrian
> Chicago, IL
> ------------------------------
> *From:* John Douyere <vk2eta@xxxxxxxxx>
> *To:* pskmail@xxxxxxxxxxxxx
> *Sent:* Thursday, August 27, 2009 4:57:57 PM
> *Subject:* [pskmail] Re: pskmail on other mode
> Hi Greg,
> Here in VK we have long distances and not many people in between, so mobile
> coverage is quickly fading off when we get away from the cities.
> So I have done a number of experiments in HF NVIS and VHF and although it
> is not "PSKmail" per say it works quite well with other modes (some better
> than others).
> Here is a summary of my experience:
> - in VHF and UHF I did some comparisons between SSB and FM. Although FM
> needs a higher signal to noise ratio than SSB to work for voice, some
> digital modes give almost the same performance in SSB and FM: I have tried
> successfully THOR, MFSK but not DominoEX for a strange reason.
> One issue with SSB on VHF and worse in UHF is that for staying within the
> acquisition range of the server (typically 20 to 40Hz), the accuracy of the
> VFO would need to be much higher than what is available currently. My FT857
> and 817 give at best +/-1PPM but at 145MHZ I would need 0.27PPM of
> stability.
> So most modes like PSK, and the slow MFSK ones are difficult to tune using
> SSB at VHF as it is easy to be 100 or 150Hz out despite having the right
> dial frequency.
> This is where FM wins, because tuning is not so important. So what you
> loose in sensitivity (a little only with the right modes), you gain in ease
> of tuning. The only modes I had success with on VHF/SSB was THOR because of
> it's tolerance to mis-tuning.
> Using FM, I could barely hear the signal in the noise (no squelch), but the
> decoding was good. In only one case did THOR perform better on SSB than on
> FM.
> - In HF, as Rein (or Per I am not sure) has confirmed by tests, some other
> modes are much more sensitive than PSK250 or 125. They also survive much
> better the multipath distorsion of NVIS and lightning strikes noise in the
> low frequencies (typically 80 and 40M).
> My best experiences have been using MFSK and THOR. I had poor results with
> DominoEX which is strange since it is a close cousin of THOR. I also had
> poor results with the MT modes because I believe of the interaction between
> fldigi and PSKMail (the control characters are not consistently passed
> through in my experience).
> I haven't tried Olivia much but it should work also.
> So my best vote so far based on my experience: THOR8 for robustness (but it
> is slow), otherwise THOR22 is a good compromise. For speed MFSK64 is really
> good but 1K bandwidth, and MFSK16 or 22 a good compromise between robustness
> and bandwidth.
> In my experience in marginal conditions THOR22 and MFSK32 will beat PSK
> hands down. You can try one of these two with the current settings in the
> servers.
> Note that if you want to use the slower modes like THOR8 or MFSK16 some
> adjustments to the timings of the server are necessary. In fact I have
> compiled a series of small changes that are required for the server to
> accept these slow modes.
> I can now successfully have a position report or a connected session with
> THOR8. I get a very very robust link. I can send you the code if you want to
> experiment.
> Sorry for the long response, but I find that subject interesting.
> Hope this helps,
> Regards,
>  John (VK2ETA)
> On Fri, Aug 28, 2009 at 5:11 AM, Greg <kb1ncj@xxxxxxxxx> wrote:
>> Would pskmail function on MT63 2k on vhf, uhf? It wouldn't be "psk"mail,
>> but was wanting to experiment...   -Greg
> start: 0000-00-00 end: 0000-00-00

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