[VHFcontesting] [VHF] Re: The meaning of coherence [was: [WSVHF] [VHF] VUAC Seeks Input]

Les Rayburn les at highnoonfilm.com
Sat Dec 5 13:45:09 PST 2009


I've sent a recommendation to my VUAC rep requesting that they eliminate the 
phrase "coherent" and leave the definition requiring one stage of electronic 
detection. (AKA, it has to be radio)

Earning VUCC via light is no picnic, and despite the "ease" of making those 
four grid contacts via laser during a contest, it's only rarely done.

Zack's other point was also one of my arguments to the VUAC. From the 
experiments done in Europe and folks like Clint Turner here in the US, it's 
clear that LED's arrays are superior to lasers for optical transmission 
through the atmosphere, assuming that DX is your goal. The current rule 
actually hinders the use of the state of the art optical communications 
systems, so I think it needs to be changed.

I do agree that it's a minor point of concern to only a few.

Ramsey sells a laser kit that can be used for 4 grid QSO's out to at least 
5-10Km, and with modification is capable of that fifth grid for VUCC from 
the right locations. Whole shooting match for a pair of those is under $200 
bucks. For contest, it's one of the least expensive bands you can add to 
your rover set up.


Les Rayburn, N1LF
121 Mayfair Park
Maylene, AL 35114

From: "Zack Widup" <w9sz.zack at gmail.com>
Sent: Saturday, December 05, 2009 3:36 PM
To: <VHFcontesting at contesting.com>
Cc: "Stanford VHF email Remailer" <VHF at w6yx.stanford.edu>; 
<wsvhf at mailman.qth.net>
Subject: [VHF] Re: [VHFcontesting] The meaning of coherence [was: [WSVHF] 
[VHF] VUAC  Seeks Input]

> I feel people are missing the point. We are talking about amateur radio.
> Amateur RADIO. Of course you can copy Morse code sent by a flashlight with
> your eyes, but does this relate to RADIO?
> You cannot copy Morse code or SSB or any other mode on any other amateur
> radio frequencies by directly observing the RF with your eyes and ears.
> Microwave equipment can get pretty complex. You can use a phase-locked LO,
> preamps, power amps, whatever ... but it's the equipment that is 
> generating
> the final message you see or hear. I see observing a flashlight sending
> Morse code as analogous to being able to see a 2304 MHz RF signal directly
> with my eyes.
> Light communication can also be done in the realm of amateur radio. You 
> just
> have to figure out how to modulate and demodulate it. Using a flashlight
> modulated by a speaker cone as you described may get you 4 grid squares if
> you're grid corner circling but that fifth grid is going to be very
> difficult to get for VUCC with a flashlight.
> I have no doubt that it can be done with lasers and LED's. I would LOVE to
> make a light QSO over a 90 mile path via cloud scatter. I believe it's 
> been
> done before. LED's are preferable to lasers for propagation through a
> turbulent medium (the atmosphere) so I think that is the purpose of the 
> request. Possibly to admit LED's along with lasers.
> Has anyone actually sent a recommendation to their VUAC rep yet?
> 73, Zack W9SZ
> On Fri, Dec 4, 2009 at 6:28 PM, George Sintchak/WA2VNV 
> <wa2vnv at optonline.net
>> wrote:
>> My $.02 thoughts (coherent or not).
>> Laser or LED, coherent or not? Which mode gets the message completed for 
>> a
>> valid contact? Does it really matter?  A non-coherent flashlight emitter
>> aimed at an electronically amplified voice modulated reflective speaker
>> cone
>> which can be seem from a 1km distance thru a telescope with a
>> photomultiplier amplifier and eye piece photo diode detector connected
>> to....... Please read on....
>> Most of us will use our sense of hearing to decode a message using voice 
>> or
>> CW tones as long as "electronic detection", "electronic amplification" is
>> used somewhere in the (receiver?) link. Now, try this if you are deaf -
>> just
>> put in some earplugs and see how many contest contacts you can make.
>> No problem, you say, do it visually, RTTY, text video, blinking LED,
>> etc..... Visual is OK - we use our eyes - to see/read the message info 
>> and
>> make the contact. (Yes, I know there are some that can decode RTTY in 
>> their
>> head by sound.) We just decode the message with our "eyes" instead of our
>> "ears". Computer (assisted ?) detection (WSJT, PSK31, etc) is OK too. 
>> Some
>> deaf/blind "feel" the speaker cone to decode the CW message, even if QLF
>> (look it up).
>> We can use any of our "senses" to make a valid contact exchange.  Does it
>> really make a difference whether it's coherent or not? Auditory, Visual,
>> Tactile ? The point I wish to make is you still have to make a valid
>> contact
>> exchange. My reasoning along these lines is that if we (hams) are to
>> provide
>> emergency communications (backup or otherwise), encourage 
>> experimentation,
>> and increase contest activity, we should use whatever it takes to get the
>> message (contact) completed.  Viz. The crew in a dark, disabled submarine
>> on
>> the ocean bottom using a hammer on the hull and the ship using
>> sophisticated
>> sonar doing a search couldn't care less if it's coherent or not. Also
>> remember (1968) the U.S.S. Pueblo captured ship, when commander Bucher
>> blinked this eyes using Morse code to send secret pleas for help during 
>> his
>> video filmed confession - a pretty amazing feat that the North Korean
>> captors didn't figure out.  We got the message!
>> I realize that the current discussion is about the coherence of the 
>> emitter
>> and the method(s) of detection/distance, but let's not forget the bigger
>> picture of what the contest and the communication "art" is all about if 
>> we
>> want to encourage more experimentation and activity to that end. The more
>> complicated or restrictive the rules become, the more discouraged will
>> "throw in the towel" and leave. Regardless of the "mode" you still have 
>> to
>> make the valid contact exchange. Please make it easy/simple.
>> If you read this far, thanks for patience.
>> Best 73's
>> George, WA2VNV, FN30kv
>> SLOP, 50-1296
>> ----- Original Message -----
>> From: "Fred Lass" <felasstic at yahoo.com>
>> To: "Stanford VHF email Remailer" <VHF at w6yx.stanford.edu>; "Ev Tupis"
>> <w2ev at yahoo.com>
>> Cc: <wsvhf at mailman.qth.net>; "Vhfcontesting Remailer"
>> <VHFcontesting at contesting.com>
>>  Sent: Thursday, December 03, 2009 8:19 PM
>> Subject: Re: [VHFcontesting] The meaning of coherence [was: [WSVHF] [VHF]
>> VUAC Seeks Input]
>> Hi Ev,
>> I'll volunteer an answer based on my own observations.
>> The intent of the rule in the first place was to eliminate QSOs with a
>> flashlight and eyes.
>> The term coherence has been questioned over the use of monochromatic LEDs
>> instead of lasers.
>> All contestants should operate with the same interpretation of the rules.
>> There is no right or wrong answer and responses that are not focused (pun
>> intended) are fine.
>> 73, Fred K2TR (Hudson Division VUAC)
>> --- On Thu, 12/3/09, Ev Tupis <w2ev at yahoo.com> wrote:
>> From: Ev Tupis <w2ev at yahoo.com>
>> Subject: [VHFcontesting] The meaning of coherence [was: [WSVHF] [VHF] 
>> Seeks Input]
>> To: "Stanford VHF email Remailer" <VHF at w6yx.stanford.edu>
>> Cc: wsvhf at mailman.qth.net, "Vhfcontesting Remailer"
>> <VHFcontesting at contesting.com>
>> Date: Thursday, December 3, 2009, 5:31 AM
>> As this thread becomes more incoherant (many of us don't belong to all of
>> the lists cc'd, so our replies will be missed)...I keyed in on the actual
>> request, "to determine if the rule should be modified to make it clearer 
>> as
>> to the meaning of coherence."
>> Dear VUCC,
>> You have the advantage. We don't know...
>> ... the intent of the rule's presence in the first place.
>> ... the what way(s) in which the meaning of the term being misunderstood
>> ... what problems this causes for you.
>> As a result, our commentary is "all over the board". Could you clarify
>> these
>> three points?
>> Ev, W2EV
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