ham radio

[va7aax]

this is a Amateur Radio history quiz.

1) what is the "old Betsy"(hint:think ARRL's founder)
2) what is the first year that Field Day was held?
3) which year was the first Ham-to-Ham SSB QSO held?


first one to answer gets an 807 or 6L6 from me!!! # #http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif # #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[kl7aj]

Quote[/b] (va7aax @ Oct. 02 2007,15:25)]this is a Amateur Radio history quiz.

1) what is the "old Betsy"(hint:think ARRL's founder)
2) what is the first year that Field Day was held?
3) which year was the first Ham-to-Ham SSB QSO held?


first one to answer gets an 807 or 6L6 from me!!! # #http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif # #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif
1) 1AW rotary spark gap transmitter
2) 1933
3) 1948

[VO1GXG]

1. It was a spark Gap transmitter.
2.1933
3. the patent for it was in 1915 and the telephone companys used it in the 1930's . So i would say the late 30's early 40's

[va7aax]

KL7AJ has it right!

[va7aax]

GXG, the first ham to ham SSB qso was in 1948.interesting to know that the patent was issued in 1915.

[kl7aj]

Quote[/b] (VO1GXG @ Oct. 02 2007,15:33)]1. It was a spark Gap transmitter.
2.1933
3. the patent for it was in 1915 and the telephone companys used it in the 1930's . So i would say the late 30's early 40's
Cool!

I'll have to check my tube caddy. I have some 807's but not sure if I have any 6L6's left. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif Actually what I REALLY need is a plate transformer!

Keep up the great quizzes. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

eric

[kl7aj]

I've got an even better idea. I'll donate my winnings to the first noobie, newbie, or tyro who can tell us what the 6L6 and 807 combo were used for. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

(No OF's allowed!)

http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

eric

[WA2ZDY]

A 6L6 and I could have recreated my first transmitter!

[kl7aj]

Quote[/b] (WA2ZDY @ Oct. 03 2007,09:06)]A 6L6 and I could have recreated my first transmitter!
I said NO OF's! http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[K8ERV]

Quote[/b] (kl7aj @ Oct. 03 2007,08:02)]I'll donate my winnings to the first noobie, newbie, or tyro who can tell us what the 6L6 and 807 combo were used for.
They were used for winning the prize of course-- oh, I'm not allowed, sorry.

Tom K8ERV Montrose Co.

[n2cfj]

6L6 is a station in Korea and 807 is the number I play in the lottery

[K3UD]

Quote[/b] (kl7aj @ Oct. 02 2007,17:31)]Quote[/b] (va7aax @ Oct. 02 2007,15:25)]this is a Amateur Radio history quiz.

1) what is the "old Betsy"(hint:think ARRL's founder)
2) what is the first year that Field Day was held?
3) which year was the first Ham-to-Ham SSB QSO held?


first one to answer gets an 807 or 6L6 from me!!! # #http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif # #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif
1) #1AW rotary spark gap transmitter
2) 1933
3) 1948
Are you sure about the first ham to ham SSB QSO?

For some reason I thought that SSB QSOs predated WWII and I think that QST started running a column in 1946 or 1947 called 'On The Air With Single Sideband'.

Here is some anecdotal evidence for an earlier date:

History of SSB (http://www.hamradiomarket.com/articles/SSBHistory.htm)

Excerpt from the website:

"By the time the 1930’s came along, licensed amateurs were hard at work on the problem. Apparently the all-time ham radio SSB pioneer was Robert M. Moore, W6DEI. He published three articles on the subject in R9 magazine in 1933 and 1934. At that point, this experimental mode was referred to as "single sideband suppressed carrier" transmission, or SSSC. The articles reveal that what Moore was talking about was real single sideband. In his articles he acknowledges the prior work of Bell Telephone Laboratories in developing the techniques he was using. (Moore, 1933, 1934.)

Another pioneer in this endeavor was J. Evans Williams, W2BFD, who in 1948 wrote a letter to QST pointing out that Moore was indeed the original 1930’s ham radio SSB pioneer. Williams himself build a 500 watt SSSC transmitter based on Moore’s designs, and reported in his letter that a half-dozen or so sideband stations had been on 20 meters during the 1930’s."

73
George
K3UD

[K9STH]

UD "beat me to it"!

Now the first "SSB" QSO that has been noted "may" have been in 1948. However, before 1948 the emission was known as SSC or SSSC instead of SSB and was exactly the same type of emission.

The first "true" SSC / SSSC QSO was in late 1933 where amateur radio was concerned although experiments were being made before that date.

Another type of "narrowband" emission which was started before World War II and gained popularity during the late 1940s and early 1950s was NBFM ("narrow band frequency modulation"). This emission had a frequency deviation of under +/- 3 KHz and was generally slightly more efficient than "conventional" AM (actually double sideband carrier present) which was the primary phone operation at the time. Collins Radio, Hammalund, National, Hallicrafters, and quite a number of other companies produced equipment including receiving discriminator adaptors during the late 1940s into the 1950s.

Glen, K9STH

[K9STH]

By the way, it would take two 807 tubes to recreate my first "real" transmitter (a Globe Chief 90A which used a 6AG7 driving a pair of 807s). My first home-brew transmitter used a 6AG7 and a single 807. However, I "hand wound" the r.f. chokes and although it had an input power of at least 75 watts the output power wasn't much (all the r.f. went into the power supply and not out through the antenna). I built that transmitter before I even took my Novice Class examination (took it on my 15th birthday, 13 February 1959).

Glen, K9STH

[kl7aj]

Does this mean we'll have to split the 807 three ways? http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[WA2ZDY]

Quote[/b] (kl7aj @ Oct. 03 2007,12:09)]Quote[/b] (WA2ZDY @ Oct. 03 2007,09:06)]A 6L6 and I could have recreated my first transmitter!
I said NO OF's! #:) #:D
I wasn't answering the question!

[KC7YPJ]

a transmitter most likely, 6l6/807 were used for damn near anything you could sceme up,
around here I refer to 6lq6's as numbskull swan learning experience fuel.. (don't ask and yes I stopped feeding it for the time being)
I guess I could cheat and cough up an answer or in this case another long and twisted road through the dredges of homebrew wonderland
compliments of n6ev's glowbug bibliography:: (I started down this path a month ago and got lost, please send help or beer)

ARRL Handbook, 27th Edition, 1950, Page 183 "A 500 Watt Link Coupled All Band Xmtr"
6AG7 Xtal Osc, 6L6 Buffer/Multiplier, 807 (2 push-pulled) Buffer/Doubler,
812A (2 push-pull) Finals.
Power supply: +300VDC, +500VDC, +1500VDC using 5Z3, 816 (2ea), 866 (2ea)

the glowbug bibliography can lead you down so many side roads you forget where you started
the combo could be for a multitude of uses though so it's hard to say from a noob's perspective what the common use you refer to is

[n2cfj]

Quote[/b] (KC7YPJ @ Oct. 04 2007,12:55)]a transmitter most likely, 6l6/807 were used for damn near anything you could sceme up,
around here I refer to 6lq6's as numbskull swan learning experience fuel.. (don't ask and yes I stopped feeding it for the time being)
I guess I could cheat and cough up an answer or in this case another long and twisted road through the dredges of homebrew wonderland
compliments of n6ev's glowbug bibliography:: (I started down this path a month ago and got lost, please send help or beer)

ARRL Handbook, 27th Edition, 1950, Page 183 "A 500 Watt Link Coupled All Band Xmtr"
6AG7 Xtal Osc, 6L6 Buffer/Multiplier, 807 (2 push-pulled) Buffer/Doubler,
812A (2 push-pull) Finals.
Power supply: +300VDC, +500VDC, +1500VDC using 5Z3, 816 (2ea), 866 (2ea)

the glowbug bibliography can lead you down so many side roads you forget where you started
the combo could be for a multitude of uses though so it's hard to say from a noob's perspective what the common use you refer to is
That's why every ham's library should have some older editions of the handbook. If you know how the hollow state worked, you may have a leg up on knowing what happens inside an IC.

[kl7aj]

Quote[/b] (n2cfj @ Oct. 04 2007,13:30)]Quote[/b] (KC7YPJ @ Oct. 04 2007,12:55)]a transmitter most likely, 6l6/807 were used for damn near anything you could sceme up,
around here I refer to 6lq6's as numbskull swan learning experience fuel.. (don't ask and yes I stopped feeding it for the time being)
I guess I could cheat and cough up an answer or in this case another long and twisted road through the dredges of homebrew wonderland
compliments of n6ev's glowbug bibliography:: (I started down this path a month ago and got lost, please send help or beer)

ARRL Handbook, 27th Edition, 1950, Page 183 "A 500 Watt Link Coupled All Band Xmtr"
6AG7 Xtal Osc, 6L6 Buffer/Multiplier, 807 (2 push-pulled) Buffer/Doubler,
812A (2 push-pull) Finals.
Power supply: +300VDC, +500VDC, +1500VDC using 5Z3, 816 (2ea), 866 (2ea)

the glowbug bibliography can lead you down so many side roads you forget where you started
the combo could be for a multitude of uses though so it's hard to say from a noob's perspective what the common use you refer to is
That's why every ham's library should have some older editions of the handbook. #If you know how the hollow state worked, you may have a leg up on knowing what happens inside an IC.
I plan on having an extensive section on hollow state in "The Opus of Amateur Radio Knowledge and Lore." Stay 'tuned"

eric

[va7aax]

6L6 oscillator , 807 amp (TRANSMITTER)

[W5HTW]

6L6 = Koolaid
807 - Beer

250-TH = moonshine

[VE7DCW]

An excellent article on narrow band HF fm is in the september 2007 edition of CQ magazine.It appears that the eventual availibility and popularity of SSB spelled doom for NBFM as a mode on amateur hf bands.Pity http://www.qrz.com/iB_html/non-cgi/emoticons/rock.gif

73

[k4kyv]

Quote[/b] (K9STH @ Oct. 03 2007,19:30)]UD "beat me to it"!

Now the first "SSB" QSO that has been noted "may" have been in 1948. However, before 1948 the emission was known as SSC or SSSC instead of SSB and was exactly the same type of emission.

The first "true" SSC / SSSC QSO was in late 1933 where amateur radio was concerned although experiments were being made before that date.

Another type of "narrowband" emission which was started before World War II and gained popularity during the late 1940s and early 1950s was NBFM ("narrow band frequency modulation"). This emission had a frequency deviation of under +/- 3 KHz and was generally slightly more efficient than "conventional" AM (actually double sideband carrier present) which was the primary phone operation at the time.
I have those articles in the 1933 and 1934 R9 magazine. They first describe the theory of SSB and then go on to supply a detailed construction article. It is a filter type SSB generator, using a bandpass frequency just above the audio range to achieve enough selectivity to separate the sidebands.

NBFM never even approached the "efficiency" of regular DSB AM modulated 100%. At best, it was about the same as running AM somewhere around 20-30% modulation. The main advantage was that the amplifier could run full class-C efficiency without the expensive modulator section that required a large audio transformer that would handle as much as 500 watts of audio.

To gain efficiency comparable to AM, the deviation would have to be set to about 15 kHz, about the same as what hams now use on 10m and VHF, and even then it only works when the signal stands out above the background noise and QRM well enough to realise the "capture effect" at the receiver. According to the rules, on the lower HF bands, the total bandwidth of the NBFM signal must not exceed that of a DSB AM signal with the same modulating signal, so such a large deviation would be illegal under Part 97.

[K9STH]

KYV:

Actually, the FCC regulation concerning FM/PM operation on frequencies below 29.000 MHz (excluding the 60 meter band) is that the modulation index cannot exceed 1. In years past the regulations stated that it could not exceed the bandwidth of a DSB AM signal, however, those regulations were changed some time back. The modulation index is found by dividing the absolute value of the deviation by the maximum modulating frequency of the signal. Now most amateur radio equipment has a maximum transmitting audio frequency of 3000 Hz (3 KHz) which equates into a modulation index of 1 at +/- 3 KHz. There are quite a number of "modern" HF transceivers that do have a "narrow" position on FM which results in +/- 2.5 KHz deviation which has a modulation index of 0.83333 when the maximum audio frequency is 3000 Hz.

Now it would be technically legal (but not necessarily in the best interest) to have a maximum modulation frequency of, say, 5000 Hz and a deviation of +/- 5 KHz. This would still meet the requirement of the modulation index not exceeding 1. However, exceeding 3000 Hz in maximum modulating frequency is definitely "frowned upon" in today's amateur radio world.

One of the major problems with NBFM is "audio recovery". That is the amount of audio actually acquired from the receiver which, in turn, has to be amplified. When the commercial two-way FM units had to be "narrowbanded" (drop from +/- 15 KHz deviation to +/- 5 KHz deviation) which happened in 1957 for lowband and highband and in 1962 for UHF ("drop dead" dates of 1962 and 1967 for the latest date of implementation) there was some concern that the audio recovery could not be made sufficient to overcome the drop in deviation. However, that was easily overcome by narrower filters and more amplification in the receiver audio circuits.

The bandwidth of the receiving filter is paramount to the efficiency of the NBFM signal. Of course SSB proved to be much more efficient than either DSB AM or NBFM by both a reduction in bandwidth and the elimination of the carrier. Both NBFM and DSB AM required a bandwidth of at least twice that of SSB as well as the carrier.

Over the years I have "toyed with" the idea of trying VNBFM ("very" narrowband FM). That would require deviations of like +/- 0.5 KHz or even as narrow as +/- 0.25 KHz. Getting the basic receiver is really no problem since I do have a Collins 75A-3 with the optional NBFM adaptor. Using the crystal filter in the 75A-3 I can get the bandwidth down to 500 Hz. However, to get enough audio amplification I might have to add additional stages.

There are those who say that VNBFM would not work. However, such was "said" about going from wideband to narrowband on the commercial circuits. Transmitter design is much simpler than either SSB or DSB AM. All that is required is either an FM modulator or PM modulator, both of which are relatively simple to build especially using crystal control. Then Class "C" can be used which is more efficient in terms of power output than those classes normally associated with SSB. The FM or PM modulator requires much less circuitry than either SSB or DSB AM.

Unfortunately, I just have not had the time to really try to even think of doing such experiments. But, "someday", when I do get the opportunity I definitely plan on trying VNBFM.

Glen, K9STH

[kl7aj]

Quote[/b] (K9STH @ Oct. 05 2007,10:17)]KYV:

Actually, the FCC regulation concerning FM/PM operation on frequencies below 29.000 MHz (excluding the 60 meter band) is that the modulation index cannot exceed 1. #In years past the regulations stated that it could not exceed the bandwidth of a DSB AM signal, however, those regulations were changed some time back. #The modulation index is found by dividing the absolute value of the deviation by the maximum modulating frequency of the signal. #Now most amateur radio equipment has a maximum transmitting audio frequency of 3000 Hz (3 KHz) which equates into a modulation index of 1 at +/- 3 KHz. #There are quite a number of "modern" HF transceivers that do have a "narrow" position on FM which results in +/- 2.5 KHz deviation which has a modulation index of 0.83333 when the maximum audio frequency is 3000 Hz.

Now it would be technically legal (but not necessarily in the best interest) to have a maximum modulation frequency of, say, 5000 Hz and a deviation of +/- 5 KHz. #This would still meet the requirement of the modulation index not exceeding 1. #However, exceeding 3000 Hz in maximum modulating frequency is definitely "frowned upon" in today's amateur radio world.

One of the major problems with NBFM is "audio recovery". #That is the amount of audio actually acquired from the receiver which, in turn, has to be amplified. #When the commercial two-way FM units had to be "narrowbanded" (drop from +/- 15 KHz deviation to +/- 5 KHz deviation) which happened in 1957 for lowband and highband and in 1962 for UHF ("drop dead" dates of 1962 and 1967 for the latest date of implementation) there was some concern that the audio recovery could not be made sufficient to overcome the drop in deviation. #However, that was easily overcome by narrower filters and more amplification in the receiver audio circuits.

The bandwidth of the receiving filter is paramount to the efficiency of the NBFM signal. #Of course SSB proved to be much more efficient than either DSB AM or NBFM by both a reduction in bandwidth and the elimination of the carrier. #Both NBFM and DSB AM required a bandwidth of at least twice that of SSB as well as the carrier.

Over the years I have "toyed with" the idea of trying VNBFM ("very" narrowband FM). #That would require deviations of like +/- 0.5 KHz or even as narrow as +/- 0.25 KHz. #Getting the basic receiver is really no problem since I do have a Collins 75A-3 with the optional NBFM adaptor. #Using the crystal filter in the 75A-3 I can get the bandwidth down to 500 Hz. #However, to get enough audio amplification I might have to add additional stages.

There are those who say that VNBFM would not work. #However, such was "said" about going from wideband to narrowband on the commercial circuits. #Transmitter design is much simpler than either SSB or DSB AM. #All that is required is either an FM modulator or PM modulator, both of which are relatively simple to build especially using crystal control. #Then Class "C" can be used which is more efficient in terms of power output than those classes normally associated with SSB. #The FM or PM modulator requires much less circuitry than either SSB or DSB AM.

Unfortunately, I just have not had the time to really try to even think of doing such experiments. #But, "someday", when I do get the opportunity I definitely plan on trying VNBFM.

Glen, K9STH
What a lot of people don't realize though, is that extremely low modulation indices can totally eliminate any possible advantage over A.M. The capture ratio goes to NOTHING. That's why you hardly ever hear of "sliver band" FM any more. At least A.M. sidebands are easier to figure out...no reason to do FM at all under such restrictions.

eric

[k4kyv]

At low indices of modulation you have almost the same thing as an AM signal with low percentage of modulation. The FM signal generates orders of sidebands, the more the deviation the higher the order of significant sidebands. So, essentially what happens with sliver-band FM, the first order sidebands are transmitted, but the higher order sidebands are so attenuated as to be neglibible. With FM, the carrier is reduced as sidebands are generated, so that the total power output remains constant regardless of modulation, and the envelope pattern on a scope looks the same, whether an unmodulated carrier or full modulation with in index of >1.

[K9STH]

Originally "narrowband" (+/- 5 KHz deviation) FM had a modulation index of 1, not the 1.6667 of today. Until relatively recently (last couple of decades) 20F3 was licensed for the commercial two-way market. This meant +/- 5 KHz deviation with 5000 Hz as the maximum modulating frequency. Eventually this was replaced with 16F3 which meant +/- 5 KHz deviation with a maximum modulating frequency of 3000 Hz.

One of the advantages of SSB over DSB AM is the reduced bandwidth. Going from a bandwith of 6 KHz to 2.1 KHz (which is a pretty common bandwidth for SSB) shows to be almost 4.6 dB with the reduction in carrier adding another 6 dB. However, when comparing DSB AM with VNBFM the only advantage should be in the reduction of bandwidth. If the bandwidth was reduced to 1 KHz (+/- 0.5 KHz deviation) then the "apparent" increase in effective signal would be almost 7.8 dB. Of course this is still almost 3 dB under what is acquired with SSB.

If the deviation is reduced to 500 Hz (+/- 0.25 KHz deviation) then the apparent gain due to the difference in bandwidth would be almost 10.8 dB which is pretty darn close to the 10.6 dB difference between DSB AM and SSB at a bandwidth of 2.1 KHz. If the SSB bandwidth is 2.4 KHz (also a very common bandwidth these days) then the difference between SSB and DSB AM is almost exactly 10.0 dB. This would give the VNBFM an advantage of 0.8 dB. Of course even 1.0 dB is effectively the same signal reliability.

However, using VNBFM would increase the number of signals on the bands by between 3 and almost 5 times depending on the shape of the receiving filters and the actual bandwidth of the SSB signal. When compared with DSB AM up to at least 12 signals could occupy the same bandwidth when using VNBFM.

Now I realize that there is a lot more involved than just reducing the deviation of the transmitted FM/PM signal. This includes receiver filters and, even more important, the amount of amplification of the recovered audio necessary to produce a satisfactory speaker output.

Whether or not the theoretical "gain" among the various types of emissions now used for voice communications will be achieved is definitely "up in the air". However, it is a subject for experimentation.

Glen, K9STH

[VO1GXG]

Quote[/b] (kl7aj @ Oct. 03 2007,05:02)]I've got an even better idea. I'll donate my winnings to the first noobie, newbie, or tyro who can tell us what the 6L6 and 807 combo were used for. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

(No OF's allowed!)

http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

eric
The 807 is a transmitting tube used in the late 30's early 40's so that would be your RF output. A 6L6 is a audio power triod tube so you would use that in the audio section of the transmitter and or receiver

[K9STH]

The 6L6 was used in many thousands of transmitters from the 1930s through the 1960s in r.f. circuits. There were many circuits in the various ARRL Amateur Radio Operator's Handbooks in that time period using the 6L6 in lower stages (i.e. crystal oscillator, buffer, and driver) as well as low powered (up to around 30 watts input) output stages. The Heath AT-1 transmitter used the 6L6 on 80, 40, 20, and 10 meters (15 meters was not an amateur band in the United States when the transmitter was introduced).

The 807 was an "improvement" on the 6L6 design which was specifically made for r.f. amplifiers up to 60 MHz for full ratings and 125 MHz at "reduced" ratings. The 807 was used in commercially produced amateur radio transmitters until well into the 1960s (i.e. WRL Globe Chief Deluxe).

The 6V6, which is a lower power version of the 6L6, was also used in many lower stages of transmitters and as the final output tube in transmitters running between 10 and 15 watts input. There are also other variations of the 6L6 which were used in the lower stages of transmitters.

Since most of the original 6L6 tubes had metal envelopes a "trick" that was done by some amateur radio operators to increase the power input was to invert the tube(s) in a container with water. This would allow more power to be run without damaging the tube.

A relatively few operators would put like 1000 volts on the plate of the 6L6 to run even more power. However, it was "said" that those operators had to send CW really fast because a short "dah" would turn the plates red and a long "dah" would melt them!

Although originally designed as an audio output tube the 6L6 was very useful at r.f. frequencies up to at least 30 MHz (and a few were used even on the old 5 meter band and then on the 6 meter band). Therefore, there were a "lot" of them used for r.f. amplification.

Conversely, the 807 was used in many modulators for AM operation. For example, both the Johnson Viking I and Viking II transmitters used 807 tubes as the plate modulators. The Heath DX-100 and DX-100B used the 1625 which is the 12 volt heater ("filament") version of the 807 as the plate modulators.

I have attached a schematic from the 1947 ARRL Amateur Radio Operator's Handbook showing a transmitter with a 6V6, 6L6, and 807.

Glen, K9STH

[WA2ZDY]

Quote[/b] (VO1GXG @ Oct. 05 2007,21:18)]A 6L6 is a audio power triod tube so you would use that in the audio section of the transmitter and or receiver
My first transmitter was a 6L6 crystal oscillator that I built in 1975 and it put out about eight or ten watts. I made plenty of good contacts with that rig too.