[Thursday] Suggested Radio-Related Interactive Exhibits

Craig Moody cmoody3453 at gmail.com
Thu Aug 29 04:47:26 MDT 2019 

Just for fun (and that’s what this is!), I quickly made a demonstration of
the 9v battery transmitter. It does spark curiosity (pun intended!)

https://youtu.be/dBOAVWDz1Cw

Craig

On Tue, Aug 27, 2019 at 7:02 AM David Caldwell via Thursday <
thursday at newsm.org> wrote:

> A few of you have gently pointed out that making sparks, even small ones,
> close to one's body can be a hazard to pacemakers and other electronic
> medical devices, and also that it's easy to overheat a 9v battery by
> shorting it out with a coin. (Thank you for not starting your messages with
> "You damn fool...") While we'd never do those dangerous things at Steam-Up,
> we would be giving a lot of kids ideas they could easily hurt themselves or
> others with later.
>
> Maybe we should stick to the receiving side and leave transmitting to
> those with licenses.
>
> Dave
>
>
> On Mon, Aug 26, 2019 at 3:33 PM David Caldwell <david.t.caldwell at gmail.com>
> wrote:
>
>> I like this. Fits in with the Morse code demo; involves a minimal amount
>> of (unexplainable) magic; totally harmless and cheap. Could easily be
>> expanded to teach some basic electricity. Encourages experimenting: more
>> batteries (series or parallel?)=more distance or louder static? Effect
>> of coin size? Could it work with a switch/key? Could you add an
>> antenna/radiator? Can you receive it with a crystal radio?
>>
>> On Mon, Aug 26, 2019 at 6:37 AM Craig Moody <cmoody3453 at gmail.com> wrote:
>>
>>> Here's another idea for a hands-on simple radio transmitter that may
>>> pique a visitor's curiosity.  I found this cool little demonstration online:
>>>
>>> By tapping the terminals of a 9-volt battery with a coin, you can create
>>> radio waves that an AM radio can receive.
>>>
>>> 1) Take a fresh 9-volt battery and a coin.
>>>
>>> 2) Find an AM radio and tune it to an area of the dial where you hear
>>> static.
>>>
>>> 3) Now hold the battery near the antenna and quickly tap the two
>>> terminals of the battery with the coin (so that you connect them together
>>> for an instant). You will hear a crackle on the radio that is caused by the
>>> connection and disconnection of the coin. Your battery/coin combination is
>>> a radio transmitter! It's not transmitting anything useful, just static,
>>> and it will not transmit very far, just a few inches, because it's not
>>> optimized for distance.
>>>
>>> 4) If you use the static to tap out Morse code, you can actually
>>> communicate over several inches with this crude device!
>>>
>>> Craig
>>>
>>>
>>> On Mon, Aug 26, 2019 at 12:06 AM Randall Snow via Thursday <
>>> thursday at newsm.org> wrote:
>>>
>>>> Guys,
>>>>
>>>> These are great ideas and I think we're starting a discussion that will
>>>> have a huge impact in the years to come.  Ken, your list and component
>>>> aspects are very thorough and engrossing.  Dave, you've summarized years of
>>>> discussions and have a keen eye on all the possibilities for the museum's
>>>> evolution.  Also, the website for the Exploratorium is great, and they have
>>>> a lot of resources there we can explore.
>>>>
>>>> A lot of this has to do with the long-term plan for the museum, and of
>>>> course will be years in the making.  With Steam-Up on the horizon, we don't
>>>> have a great amount of time, but I think one or two of these could be
>>>> rolled out in primitive form at least.  I'm thinking we make it something
>>>> quick and effective.
>>>>
>>>>  A couple of versions of early radios that people can actually tune
>>>> into a modern broadcast would be great.  Something as incredibly simple as
>>>> a crystal set would be amazing to show what little you really need to
>>>> receive a signal.  I'm hesitant to add in any sort of amplifier just
>>>> because it detracts from the simplicity and could have people confused
>>>> about what's going on in the black box.  Getting sound with some coils of
>>>> wire, a chunk of rock ( or razor blade, or 1 diode) and no batteries will
>>>> undoubtedly astound most folks.  Then of course adding a few steps of
>>>> evolution in, open and working for people to play with, would be great.
>>>> Along with this, if there is time, and if we have the manpower for
>>>> Steam-Up, we can probably run the "build a foxhole radio" session a couple
>>>> of times during the day.  I'm a little torn on the typical razor blade
>>>> idea.  I think the only way we could do that safely would be to glue them
>>>> down to the base board ahead of time so they couldn't be handled.  I can
>>>> also get blue tempered spring steel sheet in just about any thickness that
>>>> we could cut up.  I'm just guessing that we could get that to work in the
>>>> same fashion as a razor blade.  The other idea, safer and quicker, is just
>>>> to use a modern diode in it's place.  It could be explained or even
>>>> demonstrated to them how it would be done with the blade and pencil, and
>>>> how a diode serves the same modern day function.  At that point they are
>>>> being shown a tie to something more modern too and the functional
>>>> relationship.
>>>>
>>>> The radio tuning could be done in the wireless building, among the
>>>> radios that are there, or upstairs in Massie.  Foxhole radios could be done
>>>> outside if the weather cooperates or possibly in Mayes.  Let's think about
>>>> these a bit more and see if there is time to make them happen or not.
>>>>
>>>> Thanks, and I'm excited to see where the whole discussion leads!
>>>>
>>>> Randy
>>>>
>>>>
>>>> On Sun, Aug 25, 2019 at 4:35 PM David Caldwell via Thursday <
>>>> thursday at newsm.org> wrote:
>>>>
>>>>> Just a few thoughts in no particular order.
>>>>>
>>>>> 1. Some exhibits can be engaging without being interactive. Some
>>>>> people like to play with stuff; some people like to look, read and figure
>>>>> stuff out.
>>>>> 2. Many visitors, especially on busy days like Steam-Up, won't be with
>>>>> a docent and won't take the time to sit down. We need some exhibits that
>>>>> are 'self-service. (This is related to #1.)
>>>>> 3. It's important to decide at the beginning of planning who the
>>>>> audience is for a particular exhibit. Every exhibit has to assume some
>>>>> things about it's intended audience--what ideas they are familiar with,
>>>>> what language can work for them (eg, vocabulary, complexity), physical
>>>>> dexterity, etc.
>>>>> 4. We need to consider potential accessibility issues.
>>>>> 5. We need to consider safety always. Safety of the visitors, and
>>>>> safety of the artifacts and exhibits.
>>>>> 6. We need a mix. What works for kids isn't going to engage retirees
>>>>> who have been hams from childhood.
>>>>> 7. Exhibits need to be bulletproof--always working, durable--
>>>>> especially self-service ones and browsable displays of artifacts (see #5)
>>>>> 8. We should consider taking advantage of the devices people carry
>>>>> around with them.
>>>>> 9. We need to start at the beginning, as Ernie suggested. Many people,
>>>>> and not just those under 30, have no idea what electricity is nor much of
>>>>> anything about how it works, no clear idea about what a radio is or does
>>>>> (they just expect sound to come out of any box--a radio, a TV, an iPod,
>>>>> Alexa), no understanding that the driver for almost all the history on the
>>>>> wireless side of the museum is communication (getting a message from one
>>>>> place to another) not entertainment, and no awareness of all the codes that
>>>>> make it possible (Morse code, ...)
>>>>> 10. We should look for examples to emulate and borrow from, and not
>>>>> only radio museums. The Exploratorium (
>>>>> https://www.exploratorium.edu/exhibits) comes to mind. And Spark (
>>>>> https://www.sparkmuseum.org). The best of them seem to take little
>>>>> bites--exhibits that each try to get an 'aha' about just one important
>>>>> concept in one small chunk of time.
>>>>>
>>>>> Dave
>>>>>
>>>>>
>>>>> On Fri, Aug 23, 2019 at 11:19 PM Ken Carr via Thursday <
>>>>> thursday at newsm.org> wrote:
>>>>>
>>>>>> This post is mostly directed at the NESWM hams.
>>>>>> Suggestions and comments are welcome from all.
>>>>>>
>>>>>> Randy has asked for some suggestions for additional interactive
>>>>>> (engaging)
>>>>>> radio-related displays at the museum.
>>>>>> We already have an excellent start with the interactive displays in
>>>>>> the
>>>>>> wireless building. I believe *Craig* and several other people were
>>>>>> responsible
>>>>>> for that (my favorite is the little tubes that light up ... can't
>>>>>> recall their name).
>>>>>>
>>>>>> Below I have a list of some suggested exhibits. One of them, the
>>>>>> scanning
>>>>>> disk TV, was suggested by Chris Prata last Wednesday night as we were
>>>>>> touring the museum with some guests.
>>>>>>
>>>>>> The list I came up with is short on particulars and I'm not sure what
>>>>>> is
>>>>>> workable. It is just a bunch of quick ideas.
>>>>>> It would be good if everyone could come up with a list and we could
>>>>>> all
>>>>>> discuss particulars.
>>>>>>
>>>>>> ----------------------------------------------------------------------------------------
>>>>>>
>>>>>> *Interactive Radio Displays*
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Operating an old radio*
>>>>>>
>>>>>> Computer station displays photos of a sampling of old radios from
>>>>>> NEWS collection... Clicking on any radio brings up 3-minute video of that
>>>>>> radio being operated. Show a little about what was done to revive radio,
>>>>>> feature period ads from catalogs or museums for this radio, and finally
>>>>>> show how to operate it. Period accessories should be used (headphones,
>>>>>> speaker, meter to monitor filament voltage, radio premiums of period, etc.)
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Can you play this radio?*
>>>>>>
>>>>>> Complex looking radio receiver is on small desk with table. Sign no.
>>>>>> 1 with instructions (i.e. 1-5) guide patron to tuning in local broadcast
>>>>>> station or our own transmission on BC band. Sign no. 2 is “Expert
>>>>>> Challenge” which steps through process of tuning in live ham radio QSO in
>>>>>> single side band (SSB). Demonstration includes antique headphones and
>>>>>> antiseptic wipes.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Build a Crystal Radio in 5 Minutes or Less*
>>>>>>
>>>>>> Group challenge. Museum guide seats 5 patrons at radio construction
>>>>>> booths (cubicles) arranged in semicircle. Booths and walls feature photos
>>>>>> of crystal radios and accessories from our collection along with period
>>>>>> advertising. Docent gives 5-8 minute talk about crystal radios and
>>>>>> specifically fox hole radio. Each cubicle has instructions (displayed on
>>>>>> placard) for constructing radio. Docent passes out parts kit to patrons and
>>>>>> tells them to begin making a radio. Docent provides guidance if needed.
>>>>>> Each person’s first name is put on scoreboard with time they took to make
>>>>>> functional radio. As patrons leave they are given handout that illustrates
>>>>>> how to make 3 different crystal radios at home: simple, intermediate,
>>>>>> advanced. Learn More: Web and book references provided at end of handout.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Morse Code Challenge*
>>>>>>
>>>>>> 1 Watch short video or read simple instructions on placard on how to
>>>>>> operate code key.
>>>>>>
>>>>>> 2 Patron follows instructions and sends message with straight key.
>>>>>> Message is ‘received’ on computer screen (old iPad running audio to code
>>>>>> interpretation app). Patron encouraged to persist at keying until message
>>>>>> is ‘properly received’ (display reflects what patron intended to send).
>>>>>>
>>>>>> 3 Advanced Challenge no. 1: Perform as above with sidewinder key.
>>>>>>
>>>>>> 4 Advanced Challenge no. 2: Perform as above using antique wireless
>>>>>> age key and sounder.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Antennas* : Make an antenna. Docent demonstrates how radio without
>>>>>> antenna receives nothing. Then constructs dipole. Next switch in dipole
>>>>>> that is outside and tune same spot on radio.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Or:* Station consists of radio and labeled antenna switch (A, No
>>>>>> antenna; B. 10 foot wire; C, Outside dipole). Patron switches antennas to
>>>>>> demonstrate difference.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Match The Tubes:* Patron presented with 5 different vacuum tubes
>>>>>> from different eras (tubes are in a basket or wood block with hollowed out
>>>>>> areas to receive tubes). Below are five descriptions of each tube in
>>>>>> chronological order.  Patron must place proper  tube in the slot with the
>>>>>> matching description.  This encourages  them to read about the different
>>>>>> tubes and recognize features.
>>>>>>
>>>>>> Bonus: If they get the tubes in the correct order they will light up
>>>>>> and radio station will be heard. To make this work each tube has a stiff
>>>>>> pin/wire or dowel attached to its central indexing tab. Pins vary in
>>>>>> length. If all pins are placed correctly each one will activate a relay in
>>>>>> a string of relays which collectively will turn on the radio.
>>>>>>
>>>>>> *Make the Radio Work*;  Circuit diagram of radio is drawn on wooden
>>>>>> easel. The drawing has actual binding posts and tube sockets. Hidden below
>>>>>> is a real radio. At each position where a tube belongs there is a real tube
>>>>>> socket. Flip chart explains how to ‘activate’ the radio:
>>>>>>
>>>>>> 1 attach the indoor antenna (patron ties in antenna with alligator
>>>>>> clip and lead … 10 foot wire antenna)
>>>>>>
>>>>>> 2 Insert mixer / converter tube, no. ****** (text briefly explains
>>>>>> what this does)
>>>>>>
>>>>>> 3 Insert First IF tube, no. ******* (text briefly explains what this
>>>>>> does)
>>>>>>
>>>>>> 4 Insert 2nd IF / detector tube no. ******* (text briefly explains
>>>>>> what this does)
>>>>>>
>>>>>> 5 Insert audio amplifier tube no. no. ******* (text briefly explains
>>>>>> what this does)
>>>>>>
>>>>>> 6 Turn on radio (volume/on switch attached to board)
>>>>>>
>>>>>> 7 Adjust station with tuner control
>>>>>>
>>>>>> 8 Unhook antenna lead and attach to bigger antenna (antenna no. 2, up
>>>>>> 25 feet outside)
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Tune a Radio:*
>>>>>>
>>>>>>
>>>>>>
>>>>>> 1.      Presented with a 1920’s regenerative radio. Instructions
>>>>>> show how to turn on and tune. Patron does so. Warned about excessive
>>>>>> feedback and howling. Turn off and go to second radio.
>>>>>>
>>>>>> 2.      Presented with a 1920’s 3-dialer (Tuned Radio Frequency)
>>>>>> radio. Proceed as above
>>>>>>
>>>>>> 3.      Presented with a 1940’s superheterodyne console radio.
>>>>>> Instructions show how to turn on, tune station, and turn off.
>>>>>>
>>>>>> At each stage patron is informed about merits and faults of each
>>>>>> design.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Do You Cohere?*
>>>>>>
>>>>>> Station has several coherers that work on different principles.
>>>>>>
>>>>>> Patron is briefly informed of function of coherer and is then
>>>>>> encouraged to make each one work.
>>>>>>
>>>>>> 1.      Patron dials up power on rheostat and then presses code key
>>>>>> (massive) and sends ‘spark wireless radio transmission’ (actually a nearby
>>>>>> but hidden transmitter is activated).
>>>>>>
>>>>>> Audio creates sound of spark transmission. As rheostat voltage is
>>>>>> increased more of the coherers activate , thus demonstrating the relative
>>>>>> sensitivity of each design.
>>>>>>
>>>>>> Coherers begin to cohere and as they do a sounder next to each is
>>>>>> activated just once.
>>>>>>
>>>>>> 2.      Next the theory of the decoherer is explained and patron
>>>>>> performs same task as above but with set of coherers that include
>>>>>> decoherers. Constant buzz with interruptions (long and short Morse code
>>>>>> characters) is heard. Communication is now possible.
>>>>>>
>>>>>> *Amplify This !*
>>>>>>
>>>>>> Patron is presented with working crystal radio. It is explained that
>>>>>> since they work on very little current (whatever is present in the radio
>>>>>> wave itself) it is not enough to make loud noise. How might they make it
>>>>>> louder (amplify)?
>>>>>>
>>>>>> Solution no. 1  Attach two sets of earphones to one crystal radio so
>>>>>> more than one person can listen in. Unfortunately with the addition of each
>>>>>> earphone the volume in each is reduced.
>>>>>>
>>>>>> Solution no. 2 Make the output of the earphone reverberate against
>>>>>> the walls of an expanding horn. Connect earphone to the end of a horn
>>>>>> speaker. *(Randy's idea)*
>>>>>>
>>>>>> Solution no. 3 Attach output of crystal radio to a crude amplifier.
>>>>>> We may build one or better still attach the crystal receiver to the kind of
>>>>>> amplifier that was sold as an accessory to the Radiola III (we have at
>>>>>> least one of these on display in the museum. I suspect more are squirreled
>>>>>> away somewhere). Other solutions are offered in various crystal radio
>>>>>> enthusiast books. We can also provide tube and transistor-based amplifiers
>>>>>> that can be switched in from a control panel.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Create Electronic Components From Scratch*
>>>>>>
>>>>>> Patron presented with samples of production electronic / radio
>>>>>> components. Each is explained and its operation in a circuit is
>>>>>> demonstrated (connect to circuit, push button to activate, effect seen on
>>>>>> attached meter, lamp, speaker, etc.)
>>>>>>
>>>>>> Next patron is given material to ‘make’ their own components. They
>>>>>> then test them by inserting into circuits. Resistors and capacitors may be
>>>>>> taken home. Printed labels provided for outside of capacitors and resistors.
>>>>>>
>>>>>> Everything is run on battery power, no high voltage danger.
>>>>>>
>>>>>> Components: Resistor, Capacitor, transformer
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Mechanical Television Camera*
>>>>>>
>>>>>> Mechanical television camera is activated by patron and image of
>>>>>> patron is seen on vintage TV (round porthole style) CRT. *(Chris
>>>>>> Prata)*
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Library*
>>>>>>
>>>>>> Open the library for study by anyone. Although we will not lend
>>>>>> publications, patrons are free to purchase photocopies of select pages of
>>>>>> old publications. We make the copies and charge 50 cents per page (or
>>>>>> whatever fee schedule that gives us some revenue and keeps the patrons
>>>>>> happy). The library can have rotating theme displays that feature such
>>>>>> items as: original patents, advertising illustrations, collections that
>>>>>> address one particular field, etc.
>>>>>>
>>>>>> Posters that are reproductions of illustrations might be on sale in
>>>>>> the library.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Radio Drama Room (Old Time Radio)*
>>>>>>
>>>>>> Small groups (5-20 at a time) enter our ‘living room’ which is set up
>>>>>> like a living room from 1939. There is a large console radio with a tuning
>>>>>> eye, a rug on the floor, upholstered couches and chairs, etc. Make it look
>>>>>> just like 1939 … real comfy. When everyone is seated the radio comes on (a
>>>>>> child patron is asked to do the honors). The lights dim and the only bright
>>>>>> light in the room comes from the radio. An announcer comes on and does the
>>>>>> intro for today’s show.
>>>>>>
>>>>>> It may be The Shadow, Buns and Allen, Johnny Dollar, Jack Benny, etc.
>>>>>> Choose titles that are appropriate to the season (horror during the fall,
>>>>>> Christmas shows in December, etc.). The show will run for about 20-30
>>>>>> minutes. The room should be well ventilated (AC) and sound proof.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Make a radio transmitter in 5 seconds*
>>>>>>
>>>>>> Display radio is tuned to portion of the band that does not have a
>>>>>> station playing. The patron is given several items with which they may
>>>>>> create electric discharges through the rubbing together of dissimilar
>>>>>> materials. If the humidity is correct (low humidity, dry weather; AC will
>>>>>> help) they will hear the discharge on the radio. Placard explains that this
>>>>>> was the basis for early spark transmitters. Note that the emission can be
>>>>>> heard anywhere on the band. This would never work for broadcast radio.
>>>>>> Eventually radio transmitters that used vacuum tubes and finely ‘tuned’
>>>>>> circuits were able to create distinct ‘radio stations’ on specific
>>>>>> frequencies.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *How is your Radio Eyesight?*
>>>>>>
>>>>>> Present patron with an operating radio that has a tuning eye (magic
>>>>>> eye, miniature cathode ray tube). Explain the theory of how it works.
>>>>>> Encourage patron to ‘tune’ the radio to various stations using the tuning
>>>>>> eye for accuracy.  If possible lighting should be subdued at this exhibit.
>>>>>> Point out how the eye opening varies with signal strength.
>>>>>>
>>>>>>
>>>>>>
>>>>>> *How do you put a value on an antique radio?*
>>>>>>
>>>>>> Display 6—10  antique radios and speakers. They are in various states
>>>>>> of repair and completeness. Provide overall guide as to what features
>>>>>> determine the value of a particular radio. This can be text that is
>>>>>> displayed above the radios or it may be audio that can be accessed with
>>>>>> earphones (disinfected earphones like those in airplanes are given to all
>>>>>> patrons with admission ticket).
>>>>>>
>>>>>> After listening to the audio discussion on radio values the patron
>>>>>> uses a  ‘score card’ that is keyed to the display radios. They must grade
>>>>>> each radio on certain characteristics and finally put a dollar value on the
>>>>>> radio (pencils available). When they have completed the score card they
>>>>>> press an ‘answer’ button that reveals the values and explains why each
>>>>>> radio has a particular value to collectors.
>>>>>>
>>>>>> *Radios of Rhode Island*
>>>>>>
>>>>>> Special exhibit put together by *Len A.*
>>>>>>
>>>>>> *How is a radio restored?*
>>>>>>
>>>>>> Static exhibit of about 5 models of the same radio, each showing the
>>>>>> progression of steps involved in restoring that radio.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Interactive Analogue Demonstration of Stages of Superheterodyne
>>>>>> Radio Receiver*
>>>>>>
>>>>>> Most explanations of how a simple superheterodyne radio works are too
>>>>>> complex or vague to keep a person’s interest or to convey understanding. If
>>>>>> each electronic stage of the superheterodyne radio is displayed alongside a
>>>>>> working mechanical (not electronic) analogue of the separate stages it may
>>>>>> be possible to illustrate how a radio works in an intelligible manner.
>>>>>>
>>>>>> The setup:
>>>>>>
>>>>>> Front and center (controllable and accessible to the patron) are 6
>>>>>> working devices that convey each successive stage of a radio receiver. None
>>>>>> of these devices are electronic or necessarily electric. They demonstrate
>>>>>> physical properties or observed mechanical phenomena that are similar
>>>>>> (analogous) to the electrical or electromagnetic functions of each stage of
>>>>>> a radio receiver. Some examples (not necessarily accurate):
>>>>>>
>>>>>> Tuning forks and multiple piano strings: fan dipole antenna as a
>>>>>> medium that electronic vibrations (radio waves)  pass through and vibrate
>>>>>> within, some better than others, due to ratio of antenna length to waveform
>>>>>> length. (Represent antenna by fan dipole).
>>>>>>
>>>>>> Structure consisting of mass suspended by springs and set in motion
>>>>>> by eccentric drive which reaches maximum amplitude when spring-capacitor
>>>>>> and mass-inductor are in phase or what would be called resonance in radio
>>>>>> circuit. (p. 444, Sutton, Electrical Oscillations). This mimics the local
>>>>>> oscillator of the radio.
>>>>>>
>>>>>> Competing waveforms may when they collide result in addition and new
>>>>>> (sum) waveform is produced as demonstrated in rod model (p. 139, S-28,
>>>>>> Sutton (1937). This is analogous to the mixer stage of radio although in a
>>>>>> radio sum and subtraction of RF is produced. The difference is the
>>>>>> frequency that is selected out. This mimics the mixer section of the radio.
>>>>>> (Note: the mixer and local oscillator are usually combined in one vacuum
>>>>>> tube and together referred to as the converter stage.
>>>>>>
>>>>>> The output of the converter / mixer is fed to the Intermediate
>>>>>> Frequency stage which is a circuit tuned to a particular frequency. It has
>>>>>> an amplifier (tube) that is optimized to amplify only that one frequency,
>>>>>> the intermediate frequency, which is allowed to pass through this stage and
>>>>>> pass to the vacuum tube for amplification. Analogue representation of this
>>>>>> stage: 4 different tuning forks are tapped. In front of them is one piano
>>>>>> wire. It only responds (vibrates/ oscillates) in response to one of the
>>>>>> four tuning forks since its length allows it to vibrate optimally at just
>>>>>> one frequency.
>>>>>>
>>>>>> And so on through the remaining stages of the radio.
>>>>>>
>>>>>> Behind the Mechanical models is a large labeled and color coded block
>>>>>> diagram of a radio.
>>>>>>
>>>>>> Rather than a block diagram you might use actual radio parts within
>>>>>> the blocks.
>>>>>>
>>>>>> Activating any physical model will cause the analogous radio stage to
>>>>>> light up. Where appropriate actual radio tubes (with clear designations in
>>>>>> front of each) can be used. Safe DC battery power would be applied to
>>>>>> filaments only as each stage is selected.
>>>>>>
>>>>>> Finally patron will be encouraged to turn on the ‘radio’ and tune in
>>>>>> a station. 5-part fan dipole has numerous colors (frequencies along its
>>>>>> length). Only one color at a time appears in ‘glow’ of the converter stage.
>>>>>> Local oscillator (LO) within converter stage has a different color. The
>>>>>> color that emerges from this stage and goes to IF amplifier is always the
>>>>>> same color as the LO (others are filtered out). As tuning dial is rotated
>>>>>> you see that the color entering the converter stage change, one color for
>>>>>> each station frequency.
>>>>>>
>>>>>> And more stages follow …….
>>>>>>
>>>>>> This display could have several things that the patron could control.
>>>>>> A lot of planning would need to go into this. It would be good for an
>>>>>> electrical engineer to supervise the design.
>>>>>> *Comments and additional ideas welcome*.
>>>>>>
>>>>>> ------------------------------
>>>>>>
>>>>>> *Ken Carr* ...
>>>>>> KE1RI, A New England Ham <http://www.idlenot.com>
>>>>>> Westerly-Pawcatuck AACA <http://www.wpraaca.com>
>>>>>> N.E. Steam & Wireless Museum <https://www.newsm.org>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>> http://host194.hostmonster.com/mailman/listinfo/thursday_newsm.org
>>>>>>
>>>>> _______________________________________________
>>>>> Thursday mailing list
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>>>>>
>>>>
>>>>
>>>> --
>>>> Randy Snow
>>>>
>>>> Snow Findings Company <http://www.snowfindings.com>
>>>> Lovements.com <http://www.lovements.com>
>>>> New England Wireless and Steam Museum <http://www.newsm.org>
>>>>
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