HELLSCHREIBER

By Bob Wexelbaum, W2ILP

 

March 2006                                             VOL.  79, NO. 3                                                  CIR 120

 
In my digital mode lecture series at GARC the forth mode covered was Hellschreiber. I am again presenting it here.  There are now other digital modes that can be run with the same hardware interface which I may cover in future newsletters. .

 

There were not enough Morse operators to fill military needs during WW II.  The U.S. solved the problem by using RTTY, as well as Morse for military communication.  The Germans also resorted to a teleprinter, but it used an entirely different system.  It was called Hellschreiber.  It was originally invented by Rudolph Hell some time in the 1920s.  The German Army used  Hellschreiber teleprinters to key ordinary CW transmitters, and used ordinary CW receivers to drive dot matrix teleprinters, which printed on strips of paper tape.

Now we are able to use the Hellschreiber concept in a much more modern way.  We can use a personal computer and the same interface to a HF SSB transceiver as was used for RTTY, PSK-31, MFSK-16, etc.  We only need to down load the freeware for Hellschreiber and we will be ready to operate.   The freeware is available from IZ8BLY’s web site:-

Http://xoomer.virgilo.it/aporcino/Hell/index.htm

Hellschreiber differs from all of the other digital modes in that the received signal is not decoded to be an ASCII font in order to be displayed.  Hellschreiber actually sends a strip of a TV like display directly to the computer monitor.  Let us compare Hellschreiber to the old black and white analog TV.  The analog TV signal contains synchronization (synch) pulses and a video signal.  The video signal is Amplitude Modulated (AM) and the amplitude of the signal determines if the spot intensity on a CRT is going to be white, black or a shade of gray.   The TV picture tube (CRT) is scanned at a horizontal rate of 15,750 Hz, and a vertical rate of 60 Hz.  In order to reduce flickering alternate frames are interlaced.

 

HELLSCHREIBER (continued)

 

The TV synch pulses determine when the scan will start both horizontally and vertically for each frame.  By contrast in Hellschreiber there is no gray scale, so that Hellschreiber only needs to transmit black and white.  In fact it only sends black.  Key down is black and key up is white.  This is thus true digital of the simplest form. . According to IZ8BLY the software has the option of providing for gray pixels, but that option is not being utilized at present as all keyboard characters can be shown in only black and white.  The principal of Hellschreiber operation is not unlike Wirephoto or FAX without any gray scale.  When the key is up there is nothing being transmitted so the display either sends white pixels or the blank background noise level.  The noise level might appear gray or white depending on the noise level just as it randomly appears in waterfall displays.  The black key down pulses transmit black digital pixels that are equivalent to the TV video.  The software actually shapes the black pixel pulses somewhat.  It rounds them off a bit just as a key click filter might.  This is done to prevent differentiation (overshoots) of the fast step function that is caused when we send pulses.  An interesting feature of Hellschreiber is that it needs no sync pulses, as it uses no synchronization technique.  The vertical scan frequency is derived from the PC’s clock, as is the horizontal rate at which the strip of signal moves across the screen from left to right.  The system does not require vertical sync because the characters are displayed twice.  What you see is either two lines of the same text or one line and a part of a line above it and the remaining part below it.  Thus there is always at least one complete line that is readable..  The resolution of the characters received is determined by a 7 by 7 matrix of pixels.  This enables viewing of all keyboard characters, both capitals and small case.  Again the software can optionally work with matrixes of other dimensions…but the 7 by 7 matrix is what is presently being used. The characters appear smooth and solid, except when greatly enlarged.  When the display is projected on a large screen for demonstrations, it is possible to see the pixel resolution as steps on curved character parts.  If the characters appear slanted the cause would be that the transmitted vertical scan rate is not the same as the receiving PC’s vertical scan rate.  This can be adjusted for  by using software adjustment, but it is seldom required, as PC clocks are normally sufficiently accurate.  Hellschreiber messages can be read in a high noise level in spite of the fact that the signal is close to the noise.  This is because we read using whole word recognition and we can recognize familiar words even when some pixels are missing.  Our eyes and brains do the recognition job when we receive Hellschreiber messages and not a computer sound card’s decoder/encoder.  There are 49 pixels per character.  150 Characters (30 words) are transmitted per minute. Each pixel pulse is 8.164 ms long.  What I described thus far is called Feld Hell.   There are other versions of Hellschreiber.  There are various multi-tone versions, frequency shift and FM versions.  Normally hams will use Feld Hell when calling CQ and may change mode after contact is established.  Feld-Hell has a BW of 300-350 Hz.  FM-Hell’s BW is only 150 Hz

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HELLSCHREIBER (continued)

 

Hellschreiber is less popular than other digital modes.  I don’t know why this is so because it works well for DX contacts and there are lots of DX stations using it.  It can be used legally in any part of the CW portions of all ham bands but it is most popular on 20 Meters between 14.065 and 14.080 MHz.   Serious Hellschreiber users join a reflector and find out when and where activity is to occur.  There are also Hellschreiber Activity Days (HADS) when hams that use Hellschreiber are encouraged to go on the air.  These occur at the end of every other month.  Be sure to check with others before transmitting, as the CW and other digital mode specialists are very touchy about seeing Hellschreiber signals where they don’t want them to belong..  It has recently become a turf war for sub bands and it is hoped that the FCC rules will clear up sub band problems by defining signals by their required bandwidths rather than their mode.   Standardizing to only a few modes would seem any easy solution but this does not lend itself to encouraging experimentation.  The FCC rules require that any codes used must be made available at no cost.  This is why there is always some freeware.  There is also software that must be paid for for the same modes, but I have been told that the costly software is no better than the freeware for the modes I have described.

Computers keep getting faster and thus lend themselves to schemes that were previously impossible.  You might say that this is an evolution toward what is now being called nano technology.  It may now be science fiction but some scientists believe that the only limit to small increments will occur as we approach the size of subatomic particles.

Hellschreiber served its purpose during WWII and it can still be used as effectively as Morse CW.  It is really a very high speed CW mode and mathematically it retains the same advantages as CW, except for its benefit of human recognition by anyone who can read text but is not trained to copy Morse.   Wire photo and facsimile (FAX) were developed to fit the needs of newspaper correspondents who needed to send still pictures along with their reports.

 Early home computers were fast enough to generate the 8.164 ms Hell pixel pulses.  Modern computers can shape or generate the HF radio frequency carrier that exists during the pixel pulse time. The computers of the future will do what might seem impossible now.  Hellschreiber is important if it only serves as an introduction to the whole subject of still picture generation and leads to the study of moving picture generation.    In the future we will discuss SSTV, which is a method for sending still pictures by amateur radio on HF.   We can then follow by discussing Amateur Television (ATV), which uses the same standards as commercial analog TV on UHF ham frequencies. Then we can get to the topic of scan conversion techniques that have been used for radar displays.  There were once large analog scan converters that used TV cameras to view radar CRT displays.  They were large and difficult to adjust.  They were replaced by digital scan conversion that is now used.  Displays no longer depend on the decay of CRT phosphors (persistence) as digital video can be retained as long as desired in random access digital memories (RAMs). Digital storage led to the development of digital memory storage oscilloscopes.  These same techniques now make HDTV possible..

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PRESIDENT’S PAGE

BY

KE2LJ

 

            There's not much in the way of new things to report to report. We had a group of people working on a pre-proposal effort to do an upgrade to the venerable B52 bomber. But apparently the Government cancelled that effort, and the work came to a rapid halt. There were probably 100 Engineers that will be let go if they don’t find other assignments in Bethpage. So far, the Winter in NY has been OK. Only a couple of snowfalls, and I think they are all done. It’s almost time to put my snow plowing tractor away in the shed till summer. A few weeks ago, we went to west palm beach for the week, and stayed in our little condo. This place was worth about $20K when I got it, and now they are selling for around $90K. The prices in palm beach county continue to rise as the baby boomers look for retirement properties there. But, I wasn’t on vacation, I had to work all week. That’s why none of my Florida friends got any visits or phone calls from me. I travel with my laptop and I was glued to that baby for up to 10 hours a day till Friday night. After that I got to spend some time with my XYL, but we headed home Sunday. I use that same laptop at work, at home, and on travel. I only turn it off when it’s in the case. That means that it’s only powered off for a few hours a week. I put it on when I get home from work, and turn it off when I head  to the office. At home, I have a cable modem with optonline’s high speed Internet service. It’s really good. I added a wireless router, and a wireless card to my laptop. So I can sit in my easy chair and be working when I need to. But when I go to Florida, things are usually a little different. Since I am only there a few weeks a year, I won’t pay for high speed Internet service, and I have to resort to telephone modem dial-up speeds. That is always slow, because the phone lines are old and noisy, and I never get a good connection. But last month, I tried my wireless card anyway, and sure enough, it picked up 2 or 3 wireless networks nearby. It seems that some of my fellow condo dwellers also have wireless routers, but they didn’t follow all the instructions. They didn’t enable security on their routers, and assign a password. I merely connected to one of those networks and was on the Internet, live, and fast! After that I connected to our work network, and things looked exactly the same as they do when I’m in my office in Plant 1. We are beginning to see widespread deployment of wireless Internet, now called “wi-fi” by the media. Many cities like Philly and San Francisco are working towards a plan to give free Internet access to all of their citizens. That’s a really good thing. And by the way; I got my wireless router and card really cheap at a sale in Staples. The $49 item came with an in-store immediate rebate of $45. So I paid $4 and took it home! Not too bad. So keep an eye on those circulars you get on Sunday. When one of these really good sales comes up, the goods sell out quickly, and you need to get up here around 9 AM Monday if you want to score. Good Luck.  -Pat KE2LJ

CQ DE WA2LQO MARCH 2005

GRUMMAN AMATEUR RADIO CLU

MINUTES OF GENERAL MEETING -2/15/2006

Karen KC2OPX

The meeting was called to order at 5:45 PM by Pat.

 

TREASURERS REPORT – Ed, WB2EAV          REPEATERS – Gordon, KB2UB

Finances continue to be in good shape.                     Nothing new to report.  Bethpage repeater is weak..

                                                                                                                                                                                                                                 

VE REPORT – Bob, W2ILP                                  NET REPORT- Zack, WB2PUE

One applicant passed Technician exam.                   146.745 repeater is very weak

A second applicant upgraded to General.                  145.330 repeater is good.

VEs present were AB2NT, KC2HNN,                      Sunday morning 40-Meter net was good.

W2ILP and W2QUV.  This was the first

VE session held at Briarcliffe College.                                         

                                                                                                            

NEW BUSINESS:

Ed Hare, ARRL Lab Manager, will be lecturing on the ills of BPL in Greenlawn on March 14th.             (Unfortunately the time conflicts with our March VE session).  This lecture is being presented by the             EMC section of the IEEE.   We have learned that LIPA is going to test BPL in Commack and             Hauppauge. This meeting was rescheduled for April 4th.  See notice elsewhere in this newsletter.

 

PROGRAM:

A presentation was given by Tom Carruba, KA2D who is our ARRL Emergency Coordinator.  He spoke             about the role of the Amateur Radio Emergency Service (ARES).  ARES supports training programs,      and coordinates members who are active in meetings, drills, and marathons.  It is important to join so as          to get on a membership list and be available if and when needed in an emergency of any kind.  While            ARES members are not to be first responders, they may be called when and if needed to coordinate with   other communication services.

 

The meeting was adjoined at 6:45 PM.

 

GARC NETS:

40 Meters: 7.289 MHz at 7:30 AM EST Sundays.

20 Meters: The 20 Meter WAG net has been cancelled because of inactivity.

2 Meters (via repeaters): 146.745 MHz  (-.600)at 8:30 PM EST Thursdays.

                                           145.330 MHz (- .600) at 9:00 PM EST Thursdays.

[Tone for both repeaters is 136.5 Hz]         (ARES/RACES) Mondays

                                                                                                    

MEETINGS

General Meetings of the GARC are held on the third Wednesday of each month, starting at 5:30 PM.   The meetings are usually held at the Underwriters Lab, 1285 Walt Whitman Road,  Melville, NY.  Driving directions and maps can be obtained from http://www.mapquest.com   It is suggested that the GARC Web Site be checked to be certain of meeting location, which may change after this newsletter is distributed. Board meetings are held eight days before the General Meeting and GARC members are invited. to attend, but please call Pat Masterson, KE2LJ, at 516-346-7125 to confirm place and time of meeting.

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GARC WEB SITE

The web site of the GARC can be found at http://www.qsl.net/wa2lqo/     Webmaster is Pat Masterson KE2LJ.  Pictures of GARC activities, archives of newsletters, roster of members, and other information about the GARC may be found there.

                                                                                                                                                                                                                                                                                                                                                                                                                

Internet Link of the Month for Internerds

 

The internet link for this month is:- http://www.xs4all.nl/~nl9222/software.htm

 

This link provides an index of software for most ham digital modes as well as for some other ham related functions.  This index covers both DOS and/or Windows operating systems in PCs.  There may be another index elsewhere for the Mac users.  You might ask why there is still old DOS software around when most new computers go directly to Windows.  Many of us have old computers that use DOS and want to dedicate them to our ham station, where they may be adequate and permit us to free up our new PC with Windows XP for our other home computer needs.  The link is called Amateur Radio Visual Software.  Notice that Dimension 4, which was previously explained in this column, is also included on this Index.  I would suggest that you use the software that I suggested for each digital mode, unless you are using a different operating system.  Ham Radio is a hobby that is designed to promote some experimentation.  This includes seeing for yourself what software is best for you.  Be sure you know how to delete software if you don’t like it, but feel free to try whatever works best for you. 

 

ED HARE WILL SPEAK ABOUT BPL ON LONG ISLAND

 

Ed Hare, ARRL Lab Manager was scheduled to speak at an IEEE – EMC Society meeting on March 14th.  Due to circumstances the meeting had to be rescheduled for Tuesday, April 4, 2006.  This is good because the original time conflicted with the GARC VE session.  Broad band over Power Lines (BPL) is now a serious issue on Long Island as a BPL system is going to be tested in the Commack-Hauppauge area.

The meeting will be at 6 PM.  Pizza will be served.  You need not be a member of the IEEE to attend this meeting.  Only U.S. citizenship is required, but you must register for the meeting by calling Sandy Mazzola at 631-262-8376.  The meeting will be held at BAE Systems in Greenlawn.

 

 

PUZZLE

Here is another cryptogram.  This is a short “expert” one, so I’ll give you a hint.  It also applies to cryptogram printers.

 

 

M   XZTG   EMJ   INQCVCT   TCTQAGLVJB    FNG   M   KVIXQVJG.   –ZIEMQ   RVUPT--

 

Solution to February’s cryptogram:

WHY SHOULD WE BUY PRESCRIPTION DRUG INSURANCE FROM COMPANIES THAT LIMIT THE BRANDS OF DRUGS WE CAN GET?   WE DON”T BUY AUTO INSURANCE THAT LIMITSD THE BRANDS OF CARS THAT CAN HIT US.    –BOB WEX--

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GARC VE SESSIONS

 

We are continuing to proctor exams for all classes of ham licenses on the second Tuesday of each month starting at 5:00 PM.

 

The present exams are:

Element 1: 5 WPM CW,

Element 2: Technician

Element 3: General   

Element 4: Amateur Extra Class.

 

The fee for 2006 is $14 for all exams taken at one sitting. 

 

Applicants for upgrades should bring a photocopy of their license and their FRN number.

 

New, first time applicants should be aware that their Social Security number will be required on their application form.  All applicants should bring driver’s license or other picture ID.

 

Until further notice, VE exams will be at Briarcliffe College

Room: Islip #5

Bethpage, NY

Briarcliffe in Bethpage is located in a building that was formerly part of the Grumman complex.

 

All applicants should contact W2ILP to preregister if possible, but walk-ins may still be accepted.

 

For any information e-mail: -

[email protected] or phone: -

(631) 499-2214

 

Study material information is available at the http://www.arrl.org or the http://www.w5yi.org web site.

All VECs use the same Q & A pools.

Since the beginning of the VE program the GARC has provided opportunities to take ham exams monthly, during all twelve months of every year.

 

Bob Wexelbaum, W2ILP

and the Grumman VE team.

                                   

 

CQ de WA2LQO

March 2006

 VOL.  79,  NO.  3

 

EDITOR

Bob Wexelbaum  W2ILP

(631) 499-2214

[email protected]

 

CONTRIBUTING WRITERS

PAT MASTERSON, KE2LJ

And all the members of GARC (we hope!)

 

CQ de WA2LQO is published monthly by the Grumman Amateur Radio Club for its members and friends. Send articles and amateur equipment advertisements to:

KE2LJ or W2ILP

 

ELECTRONIC SUBMISSIONS

If you want to submit articles or amateur equipment ads via e-mail do the following:

1. For submission direct to editor call him at above number to set up a transfer.

2. For e-mail transfer:

Internet Address

[email protected]

 

 
EDITORIAL

 

 Our February VE session at Briarcliffe College went well.  We plan to have all future sessions at Briarcliffe. 

 

The FCC has not stated when the CW exams will be eliminated, although they had stated that they planned to entirely eliminate the CW requirement.

A 5 wpm CW exam remains required for a General Class license until further notice.  It was expected that the FCC would announce the CW elimination at the Dayton HamVention, but the latest news is that this will not happen.

 

A new Technician class question pool is now available at the W5YI.org web site.  The exam seems to be at least as difficult as the previous exam, if not more so, since it covers more material.  There is a petition to create an easier entry exam, but no action has been taken on it.  It might take the form of recreating a Novice class but without a CW exam.

 

The new Technician exams will not be given until July 2006.

 

VY 73,

 

W2ILP (I License People)…with the help of the VE team, a VEC and the FCC.

 

GRUMMAN AMATEUR RADIO CLUB OFFICERS FOR 2005

 

President                Pat Masterson              KE2LJ            V01-01    516-346-7125

Vice President       Gordon Sammis            KB2UB          Retiree     631-666-7463

Secretary               Karen Cefalo                KC2OPX                        
Treasurer               Ed Gellender                  WB2EAV        X02-14   516-575-0013

1Yr Board Member    Zack Zilavy            WB2PUE        Retiree     631-667-4628
1YrBoard Member     Dave Ledo              AB2EF

1Yr Board Member    Bob Christen          W2FPF           

2Yr Board Member    Bob Wexelbaum     W2ILP         Retiree     631-499-2214

2Yr Board Member    Jack Cotterell         WA2PYK       Retiree     516-249-0979

Trustee WA2LQO        Ray Schubnel        W2DKM      Retiree

 

STANDING COMMITTEE CHAIRMEN

 

Meeting Programs       Contact a Board Member

FCC Exam Coord.      Bob Wexelbaum     W2ILP                          631-499-2214

 

 

GRUMMAN AMATEUR RADIO CLUB OFFICERS FOR 1997

 

President                        Pat Masterson          KE2LJ           B38-111        346-6316

Vice President               Gordon Sammis       KB2UB         C63-005        575-1846

Secretary                       Peter Rapelje            N2PYV          Retiree           676-0694

Treasurer                       Phil  Simonetti          N2ZED          K10-14          346-8124 

2Yr Board Member     Paul Chalson            WA2FOF       A16-043        224-8153

2Yr Board Member     Howard Liebman    W2QUV         Retiree           433-7487

2Yr Board Member     Martin Miller            NN2C             Retiree           423-8153

1Yr Board Member     Zak Zilavy                WB2PUE       Retiree           667-4628

1Yr Board Member     Hank Niemczyk      W2ZZE          Retiree           796-3212

Trustee WA2LQO        Ray Schubnel           W2DKM       C31-005        575-5036

 

STANDING COMMITTEE CHAIRMEN

 

Meeting Programs       Contact a Board Member

FCC Exam Coord.      Bob Wexelbaum     W2ILP                                   499-2214

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

 


GRUMMAN AMATEUR RADIO CLUB

Sixty Years 1944 -2004

P.O. Box 0644

Bethpage, NY 11714-0644

 

 

 

                                                                                                        FIRST CLASS

                                                                           DO  NOT DELAY

                          TECHNICAL BITS                

 

We have been talking about HF radio receivers here.  Receivers were normally store bought but transmitters were usually home brewed before Single Sideband became popular.  Many hams started as SWLs, using general coverage short wave receivers that became part of their first ham radio set up when they got licensed.   A new license meant getting the parts together to build a transmitter or buying a transmitter from another ham.  There were few transmitters on the market and most were expensive.    CW transmitters were relatively easy to build and the needed parts were available in catalogs or for New Yorkers on Cortlandt Street.   The cost of the parts depended on how much power you could afford to run.  The limit was 1 kWatt plate input power.  This determined the DC power supply requirements and the selection of the final RF amplifier tube or tubes.  The transmitter started out with an oscillator that was either crystal controlled or a variable frequency oscillator.  The oscillator stage was followed by stages that amplified the RF and/or multiplied its frequency.  The amplifier stage or stages were called buffers.  Up until that point receiving tubes could be used, as low power was involved but if you wanted to get more than 40 watts or so of output RF your final RF   power tube or tubes were tubes designed for transmitters. These included beam power pentodes such as the 807, and went up to large air cooled tetrodes and triodes.  Tubes could be used in parallel or in push-pull to increase their power capabilities.  For CW transmitters tubes could be operated as class C amplifiers.  This meant biasing them so that they only amplified part of the RF sine wave.  This made them very power efficient but allowed them to generate unwanted harmonics.