[600MRG] How Much Better Today?

[Norm Into]

Frank,

An interesting proposal. I think I remember the article in the AWA and also
recall speculation that some of the experiments were receiving HF
signals-considering the wide band width of the receiving apparatus.

 

The IEEE literature and other sources have widely documented all kinds of
propagation info.

 

One should be able to measure the characteristics of all the apparatus now
in museums.

 

Good luck on an interesting challenge.

 

            73,      Norm K8NI

 

From: Frank Lotito [mailto:k3dz at live.com] 
Sent: Friday, July 03, 2015 9:06 AM
To: 600 / 630 Meter Group
Cc: wb8yyy at yahoo.com; tedvas at wvbr.com
Subject: How Much Better Today?

 

 

I would like to propose an academic exercise that is beyond my present
capabilities, unless I want to risk a cerebral incident.  Maybe one or more
of the readers can "quantitatively" demonstrate that indeed in the last 90
to 100 years significant progress has been made in "2-way communication" at
wavelengths "greater than 600 meters."  The exercise: Can long path (greater
than 500 miles) communications be reliably accomplished between today's
"amateurs and Part 5 licensees, with their ERP and typical antenna
constraints" in comparison to long path communications from 90 to 100 years
ago as practiced by radio services of that era, be they amateur, government,
military and commercial radio-telegraph?  This could be done by constructing
a "model" of all the key factors (blocks) in the transmit / receive
communications path with each block in the model characterized with a
quantitatively determined range of of its transfer function, S sub 21.  

 

I would suggest that initially the analysis exclude QRSs, JT-9 and WSPR
modes. After the "communications path model" is developed, we can then
insert the more advanced communications modes to demonstrate how a poor to
marginal current era station might be elevated to an effective (but
painfully slow w.r.t baud rate) communications station.  The model could be
used by present and future 600 / 630 and 220 meter participants to determine
which updates to their present / proposed station  would get them the best
bang for the buck.   

 

Using a similar approach around some 9 years ago, WB8YYY and WN3F (now
W2VDX) co-authored a 2-part article that appeared in the Antique Wireless
Association's "The AWA Journal", January 2006, pages 26-28, and April 2006,
pages 40-42.  They tried to "quantitatively" demonstrate trans-Atlantic
communications of the initial Marconi transmissions between the (now)
Canadian Maritime provinces and Ireland.  The co-authors attempted to put
performance numbers to items such as antenna efficiency, path loss, detector
sensitivity, information band-width, transmitter power, etc.  Using an
on-line Excel Spread Sheet, the reader could use the authors' performance
numbers, or change one or more performance numbers to see what would happen.
I would assume that the EME amateurs have done similar analysis (plural)
over the years.  

 

For this particular exercise, I would submit we do know with reasonable
reliability reliably the "black box" S-Factor transfer function S sub 21 of
each block of each block (stage) of a modern transmit and receiving 2-way
path.  For 90-100 year old equipment educated guesses may be the best than
can be done for the "communications path model."

 

Last, you may ask why spend the time modeling a 90-100 year old transmit /
receive station.  The old vs new comparison reaffirming the advantages of
using technology to overcome obstacles that could only be breached in the
past with brute force.  The old vs new modeling may also attract to the
ranks of Lowfers the amateur who's interests lie with the historical aspects
of communication, including the plethora of rather simple "hollow-stage
designs," alla pre-WW2 designs.  This past winter we saw an example of a
historical 630 meter CW transmitter built by NO3M / WG2XJM.

 

73 Frank K3DZ / WH2XHA