Mon, 10 Apr 2000 22:17:23 -0400
Larry Kayser wrote:
> Thank you for your thoughtful memo! We are in violent agreement. This said
> I must bring several points to your attention.
> >It would be unfortunate to limit ourselves to just use of these two
> >relatively simple pieces of DSP software which at the end of the day are
> >really just narrowband power detectors in not that narrow a bandwidth.
> The piece from my announcement that mentions these two pieces of software
> was for domestic Canadian consumption. I am dealing with many amateurs here
> who have no exposure or experience with LF and specifically they have no
> experience with LF and using either of the mentioned software packages.
> >I feel there is a lot more to be gained by coherent integration
> Yes, certainly, the work today needs to be rethought and redone enough to
> make optimum of very fine frequency control and specific benefit from the
> knowledge of time to a high degree of accuracy. I have been emailing with
> Bill, VE2IQ on this subject seeking to find out if he feels it is time to
> move to the next level. Our discussions are very preliminary at this point.
> >Use of the VE2IQ software and other slow BPSK modes goes
> >some way towards this, but all suffer badly from the need for clock
> >recovery and tracking. The need to get initial timing information
> >throws away much of the usefulness of this mode.
> Well, it is not now optimum in terms of what can be done today, but we not
> only need to see what can be done today but what the "reach" might be that
> would give us a real push forward.
> >The ultimate solution is to use GPS timing. I know quite a number of
> >operators in the US are now using GPS locked frequency and time sources,
> >and they are begining to make an appearance here.
> Well I am sitting here with an old HP 5248L frequency counter with the guts
> slowing coming out and the Oscillator awaiting the arrival of one of Brooks
> Shera's boards to let my OEM GPS receiver stabilize the HP Oscillator to a
> few parts in 10 to the -11th or so.
> >Having the
> >transition points of the bit intervals known precisely to the
> >microsecond (if the path length is known) leaves the signal recovery
> >task to be merely an integration over whatever time is needed for the
> >bandwidth with no lockup or preamble phase.
> Certainly. I understand the need, I do not have all the skills to pull it
> off alone. But I can promise you that my transmitter here will meet all
> such requirements. I have moved a Sulzer Labs high stability frequency
> standard into my remote HF radio site, from which I will transmit LF signals
> in Westport, and it will hold to a couple of parts in 10 to the -10th as it
> is without further help.
> >TAPR have a range of GPS and frequency locking projects / kits. Who in
> >the US Lowfer community have the DSP hardware, even if not the
> >programming skills, to experiment with these techniques. Ideally, if a
> >Motorola DSP 56002EVM module, GPS receiver and carrier frequency known
> >accurately to milli Hz are availble software can be shared and
> >experiments made with known equipment capabilities.
> Take this as offered, I am in an astonishingly high level of agreement with
> you. My side here is ready, the basics are in place here to develop a
> working system to a new level of accuracy. TAPR, as of a moment ago, do not
> seem to have completed the work with the TAC2 to stabilize an oscillator.
> Brooks Shera's work is available now and I am just waiting for him to let me
> know the final price for the pieces and then he will ship be the bits I need
> here. Please take a look at Brooks's site
> I hope this will be useful to you.
> >Some people are going to spend lots of time/money/effort on antennas and
> >PAs, why not put a similar effort into signal processing as well. So
> >what if it takes 10 hours to send a message, at least it will have been
> >sent from a station that does not have a farm on which to erect huge
> Andy, if we co-ordinated this announcement and your response we could not be
> in a stronger level of agreement.
> Lets identify one thing. The TransAtlantic II effort this coming fall will
> seek to do things with what we have now. We have no time to do more (in my
> opinion), it is pushing us hard to get ready for November. I drove 150
> miles round trip today to interview a chap who used to tune up LF and
> Broadcast Band (ours) antennas. I have a tad more skill in this area
> tonight - and a pile of notes.
> When it comes to the next level, this is were I stand now. My friend Mitch,
> VE3OT is working the issues with me. My station here is already taking
> shape for the next level, I want to be part of this activity very much as it
> is what attracted me to the LF scene in the first place. I have written
> previously to David, G0MRF and to Dave, G3YXM about the use of AD9832,
> AD9835, and AD9850 DDS devices so we could have milliHz control of the DDS.
> David was kind enough to help me solve the exciter problem with one of his
> boards so the situation for November is settled. Just this morning I have
> had an offer from the US to get some boards that will fit the AD9835 device.
> We are trying to see if we can fabricate a board here that will work with
> the device. I have never worked with these thumb nail sized devices, but we
> are going to keep going till we have RX's and TX's that are slaved to GPS
> and we will have them here by this winter when we get back from VO1.
> For a start, until we have something better, I will start with Bill, VE2IQ's
> work. His system has let him hear the TEXAS LowFer beacon at his home north
> of Montreal. His GRAB capability is working here now. In the next few days
> we will start to test this system over some 300 mile path. If there is a
> way to go further, I want to be part of it and will do my best to be ready
> when anyone else is ready.
> My last comment. On February 11th we missed a chance to probably bridge the
> North Atlantic from here to the UK. I am not able to be here in the shack
> during all hours of darkness but I sure would like to work you, computer to
> computer, the next time we have a repeat of February 11th. I have a great
> huge fire bell here in the basement that I would really like to hook up to a
> computer that would go off when your signal is detected over here. Lets do
> I am also sending a copy of this email to Mitch Powell and Bill de Carle,
> please include them in any reply