RAN Technology

Four Channel Oscillator board


Crystal Replacement 0 Comments 12/08/2018 

One board, up to four frequencies

Posted By: Robert Nickels (ranickels)

Epson programmable oscillators are a good substitute for quartz crystals in many applications, but they're a bit different to use.   First, they are active devices that require DC power, typically 5 volts at 45mA.    Second, like all ICs they are easily damaged by static and voltages that exceed the design limits.   Finally they are in DIP packates that are intended to PC mounting, not hand wiring.

The original four-channel board is a 2" square PCB that addresses these needs by providing sockets for up to 4 Epson oscillators, a voltage regulator that works on any DC voltage from 8 to 20 volts, and proper buffering of all control and output signals so that if excessive voltage is inadvertently applied, a 25 cent IC is all that's damaged.    Buffering also makes it possilbe to select one of the four frequencies with a logic "low" or a contact closure to ground to facilitate interfacing with existing circuits.

In the old days crystals were a few dollars each, but in recent years before International Crystal closed it's doors, the price of a custom one-off crystal had risen to over $40.    The cost of the Four Channel Oscillator board plus four Epson oscillators is less than the cost of a single crystal!   The accuracy and stability is equally good at 50ppm.   Any desired frequency can be obtained in just a few days time from DigiKey, the US authorized distributor for Epson's programmable oscillator products.   These items are "value-added", meaning they must go through DigiKeys's programming department before shipment,, but don't worry - they always have a good stock on hand.    The price is $4.10 for an oscillator programmed to any desired frequency between 1 and 125 MHz, truly a modern-day bargain!


  

The Solvay Conference, 1927

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Category: Historic
The Solvay Conference, founded by the Belgian industrialist Ernest Solvay in 1912, was considered a turning point in the world of physics. Located in Brussels, the conferences were devoted to outstanding preeminent open problems in both physics and chemistry. The most famous conference was the October 1927 Fifth Solvay International Conference on Electrons and Photons, where the world’s most...  READ MORE
- Robert Nickels (ranickels),  12/27/2018 
   Put yourself in 1963...A stamp was a nickel, bread was 22 cents a loaf, and you could buy 3 gallons of gas for a buck.   The average wage in the US was $84 a week.  If you were a ham, you might have been able to build and trade your way up to a really nice AM/CW station - maybe a Valiant or DX-100 transmitter with an NC-300 or HQ-170 receiver - a huge improvement over the S-38 you s...  READ MORE
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Astro...Don Stoner's legacy

How many of these rare transceivers have you seen?
Category: Vintage Ham Radio
A recent post on the Cubic-Astro mail reflector noted the similarities between the rare CIR Astro 200 and the much more common Cubic Astro 150 transceivers.   And therein lies an  interesting story...I have done a little research on the CIR Astro 200, and the commenter was right - it is the progenitor of the Astro line we are much more familiar with as a result of Swan (already owne...  READ MORE
- Robert Nickels (ranickels),  12/09/2018 
  

The DX-60 Family

what hath Benton Harbor wrought?
Category: Vintage Ham Radio
When an engineer at Heathkit in 1962 turned his attention to designing a replacement for the somewhat flawed DX-40 novice transmitter, little would he have expected the DX-60 to remain in the Heathkit catalog for 14 years.    From the new solid-state power supply to the streamlined apeperance and dependable performace, the new transmitter was instantly popular with novices who had t...  READ MORE
- Robert Nickels (ranickels),  12/09/2018 
  

Programmable Oscillators - the modern day "rock"

Cheaper and more accurate and stable than the old type
Category: Crystal Replacement
With the demise of  International Crystal in 2018, hams and experimenters lost the last US-based source of affordable one-off custom crystals.  (And the definition of "affordable" ended up over $30 each).     Sure there are some offshore sources but the reality is, manufacturing one crystal to a specific frequency is not simple or inexpensive, and all crysta...  READ MORE
- Robert Nickels (ranickels),  12/06/2018 
  

"A Pair of 6V6s"

What more does one need to hear good audio?
Category: Vintage Audio
The first audio amplififer I made (that worked) used a single 6V6 to amplify the output of a regenerative receiver.    Ever since they've been my idea of what a good audio tube should be and with a big speaker mounted on a piece of plywood, a 6V6 will produce "room filling volume" as the magazine articles fo the day said.   But as my music tastes grew acousti...  READ MORE
- Robert Nickels (ranickels),  12/03/2018 
   My primary aim when desiging the VERSA-TR was low power transmitters, and to protect the receiver from potentially damaging voltages when transmitting. 100 watts into 50 ohms is a +50dBm signal.  I'd measured the attenuation at the receiver connector in the labe at -60 to -70 dB (depending on frequency), which means that should result in -10 to -20dB at the receiver, which should be ...  READ MORE
- Robert Nickels (ranickels),  11/29/2018 
  

VERSA-TR Panadaptor Video

Use the VERSA-TR to improve your SDR panadaptor
Category: VERSA-TR Information
An inexpensive SDR like my RANVerter Pi Plus can add a panoramic spectrum and waterfall display to almost any vintage (or modern) radio.    The ability to use the SDR as a 2nd receiver that can be tuned to a different frequency or mode from the main transceiver is a real plus, but annoying feedback and delayed audio will be normally heard through the PC speakers in the transmit mode...  READ MORE
- Robert Nickels (ranickels),  11/27/2018 
   The muting relay on the VERSA-TR can be used to control other devices when RF is present.   An example would be an "On The Air" sign, or to key an amplifier.    One specially-wired cable is required - note that no connection is made to the sleeve, which is usually the ground connection on a TRS plug.  A normally-open set of relay contacts exists between the ...  READ MORE
- Robert Nickels (ranickels),  11/13/2018 

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