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!


  

International Crystal and the crystal synthesizer

How a crystal company reduced the number of crystals needed
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I have always been intrigued by the International Crystal CB radios which had a unique appearance with a channel selector that resembled a telephone dial.    The high end "Executive" models were big and expensive and sported an aluminum trim ring that no other radio had.    So I had to buy one to play with.     It was cheap, like $25 and ...  READ MORE
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KBCX - US Forest Service Regional Radio

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Category: Historic
Hams, especially those who enjoy operating AM and QRP should be aware of the pioneering efforts of the US Forest Service to adopt and advance the radio art in the early decades of the 20th century.The history of radio in the USFS literally takes a book to cover, but an interesting example can be found in station KBCX, the Region 1 Radio Operations Center in Missoula Montana.    It w...  READ MORE
- Robert Nickels (ranickels),  02/11/2021 
   Working on various vintages of equipment gives one a better appreciation for what we have today.    Example - this is a frequency counter from the "HF Manual Receiver" which was part of a wideband surveillance receiving system that extended from VLF to microwave frequencies using a bank of front-ends to cover the range.    It was designed as "ESM":...  READ MORE
- Robert Nickels (ranickels),  02/09/2021 
  

The John Meck T-60 Transmitter

the only ham product from this famous radio/TV manufacturer
Category: Vintage Ham Radio
Plymouth Indiana might not be famous for too many things, but John Meck Industries was the first manufacturer to start producing radios for home us in the US after World War II.   He'd started the namesake company prior to the war but like most others in the radio business it was converted to wartime production, making quartz crystals among other things.   Later, thousands ...  READ MORE
- Robert Nickels (ranickels),  01/30/2021 
   If, like me, you enjoy flipping through old issues of 73 magazine from the 60s, you're bound to have at least seen the ads for the Transcom SBT-3 three-band SSB tranceiver.  Being made in Escondido CA in the mid-60s, my guess has always been that engineers from other San Diego SSB compnanies such as Don Stoner, Les Earnshaw from Southcom, Herb Johnson, founder of Swan or Faust Gonsett may...  READ MORE
- Robert Nickels (ranickels),  01/16/2021 
  

Model FP-1 "FORESTPHONE"

The Amalgamated Wireless Ltd. (AustralAsia)
Category: Vintage Ham Radio
This short article about the AWA Forestphone was the last one put on the Midwest Classic Radio Net website by for former webmaster George K9GDT before he unfortunately became a Silent Key.  MCRN articleNow that a longer version has been published in Electric Radio magazine I thought I'd include it here as well.Throughout most of the 20th century AWA was Australia's leading electr...  READ MORE
- Robert Nickels (ranickels),  01/13/2021 
   Alexander M. Lewyt died in 1988 at the age of 79, a holder of patents on scores of inventions. His penchant for invention, he once said, was so strong that he had chronic insomnia from lying awake at night envisioning new products. When he learned of undertakers’ difficulty in fastening neckties on corpses, the teen-age Lewyt devised a new kind of bow tie that clipped on. He sold 50,000 of t...  READ MORE
- Robert Nickels (ranickels),  01/08/2021 
  

AN/GRC-9 Bias Battery replacement

Cheap and easy fix using coin cells
Category: Technical
The Korean-war vintage AN/GRC-9 is one of the most useful and fun military field radios for ham use, as with AM and CW modes and 2-12 MHz coverage and a VFO it's all ready to go on several ham bands.    The battery tube superhet receiver is also power-friendly and sensitive and stable enough to copy CW and SSB but has one annoying flaw - the 4 volt bias battery used by the audio...  READ MORE
- Robert Nickels (ranickels),  01/03/2021 
  

Beware of the LED Noisemaker!

MR-16 lamps have no home in the hamshack!
Category: Technical
Halogen type MR-16 lamps are commonly used in track lights and other spot lighting applications so what would be cooler than to drop in LED replacements!   A lot, as it turns out.   The LED replacements are HORRIBLE RFI emitters that totally trashed several ham bands when I unknowingly installed them.Halogen spot lights are 12 volt devices so it's long been common prac...  READ MORE
- Robert Nickels (ranickels),  01/02/2021 
  

Ham radio operators honor legacy of Mars Hill company

Hammarlund was an industry leader for generations
Category: Historic
Here's a link to a nice story in the Madison NC newspaper about area hams paying tribute to the former Hammarlund company that manufactured radios in Mars Hill NC for decades.   There are some neat historiic photos as wellThe paper has a paywall but it looks like you get 5 free articles:HAMMARLUND ARTICLE...  READ MORE
- Robert Nickels (ranickels),  12/12/2020 

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