ARS NB9M

SDR techniques for Boatanchor Radios


SDR for Vintage Radios 1 Comments 08/09/2018 

Posted By: Robert Nickels (rnickels)

W9RAN started playing with RTL-SDR dongles about 6 years ago, and knew they were going to have a big impact on the radio hobby.   But since these $15 receivers only tuned the VHF and UHF bands, he designed a wideband upconverter to make HF coverage possible, and described how it worked in an article in Jan. 2013 QST "Cheap and Easy SDR".   The "RANVerter" as he calls it has evolved since then to become an SDR board for use with small Linux computers like Raspberry and Orange Pi.   

At Jonesborough 2018, Bob showed the latter - a board about the size of a matchbook that fits inside the Orange Pi enclosure and wirelessly streams data to a nearby PC, phone or tablet.   SDR software has evolved too - from an application that required a pretty high-end PC back then to a client-server approach that makes it possible to use any device which has an HTML 5 capable browser.   

It's an ideal way to add a panadaptor to a boatanchor radio since vintage radios have IFs in the 455 to 10.7 MHz range - all of which can be tuned with the RANVerter SDR.   OpenWebRx is a free SDR app developed by a young ham in Romania that is becoming popular for use with remote SDRs, and also works well as a panadaptor.   The signal is picked off of the first mixer so several hundred kHz on either side of the IF frequency can be seen and zoomed-in to provide as much resolution as desired.  And it's more than just t a visual display - complete DSP audio demodulation is available with selectable modes and filters that can be tuned independently from the vintage receiver or transceiver.   This makes it easy to listen to other signals up and down the band or even to receive AM on a SSB transceiver that has no AM detector.   

This blending of old and new technologies brings modern features to older radios without hacking or modification.   Not only can you see and  hear your Swan or Heathkit or Hallicrafters on your smartphone or wi-fi tablet, but with dynamic DNS you can do so from anywhere an internet connection is available - from the back porch to the other side of the world!

 

  •  Bradley Stone (UncleBrad)

    The plan here is to use the soon-to-come RANVerter with a small monitor in a Heathkit HG-10 cabinet. The HR-10 receiver would be tapped at the first mixer, feeding the RANVerter/RTL device. Can you imagine a panadapter and good performance from these classic (but marginal performing) receivers? Also, Bob informed me that the newest RANVerter will have a sidetone and T/R relay handling. Perfect.

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    Posted 08/10/2018  

   Below is a picture of my latest project.  After doing the transceiver thing, with a CE20A, mated to a SX-115, then the next transceiver project, a 10A mated to any Drake R4 series receiver, I had an idea.  Those transceiver projects have a lot of oscillators, and even the crystal oscillators can drift as they warm up, which requires re-zeroing the transmitter to the receiver from time to...  READ MORE
- Bradley Stone (UncleBrad),  10/27/2019 
  

Favorite HF Nets

Sell/Swap, Vintage Radios & More
Category: Nets
All times are in Eastern unless otherwise indicated.  Frequencies are in Megacycles. Recommended HF NetsNet NameDayTimeFREQ/ModeSwan Technical NetWednesday2200 UTC14.2925 +/-  /USB3898 Traders NetWednesday8 PM3.938 / LSBBoatanchor NetWednesday7:30 PM CST3.870 / LSBWA9ZTY Vintage AM GroupSaturday7:30 AM3.885 / AMMidwest Classic Radio NetSaturday8:30 AM3.885 / AMSwan Technical NetSatu...  READ MORE
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W1LSB Finds an EBay Treasure

This 1964 WRL catalog was addressed to Major General Butch Griswold – K0DWC
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I was first licensed as a novice in 1958, and the WRL catalog was really dominant in those days, with the Globe King, Globe Champ,  and all of the lesser models gracing its pages.  I had a Globe Chief 90 and often dreamed of owning the bigger iron in those pages.   I have since collected most of the WRL catalogs from 1954 to 1964, and the last one turned out to be an interestin...  READ MORE
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Pictures of radio suckerbait on the world's largest online auction!
Category: Crazy EBay Prices!
Below are some screen shots of incredible prices demanded by some EBay vendors.  Since posting an auction is free as long as the item is not sold, it costs nothing for the unscrupulous vendor to display their (often unremarkable) wares as if they were priceless artifacts.  Enjoy. ...  READ MORE
- Bradley Stone (UncleBrad),  03/22/2019 
   These excellent examples of the Swan Twins are from the estate of John Thuren, AA5T of Houston, Texas.  John had checked in to the 20M Swan net with these very desirable "big Swans" until a few years ago. A big thanks to Eddie, NU5K, who handled John's estate and placed these on EBay.  He packed them well, knowing they are indeed an important find.  Also...  READ MORE
- Bradley Stone (UncleBrad),  12/21/2018 
  

2018 Cave City Hamfest

Cave City, Kentucky, 3/3/2018
Category: Activities
Barry, AC9NK and I attendended the 2018 Cave City hamfest, which was awesome this year.  The facility was packed, with lots of vendors.  We enjoyed the company of my friend Tom, N4LID for dinner the night before. Tom, who is blind, had not been able to get to the hamfest for many years.  You will find more pictures at the Kentucky Phone Net site.  A big thanks to Rod, N4ZIF, fo...  READ MORE
- Bradley Stone (UncleBrad),  03/04/2018 
   For nearly five years, spanning 1978 - 1983,  I worked as an Electronics Technician in the original Bearcat manufacturing and service facility in Cumberland, Indiana.  Electra was one of the best places I've ever worked, and were among the many innovative consumer electronics companies which sprang up in and around Indianapolis.  Al Lovell, a former employee of Regency (also in ...  READ MORE
- Bradley Stone (UncleBrad),  02/22/2018 
   The tube-type Linear Master Oscillators (“LMO”) used in the Heathkit SB-Line equipment is a very stable and accurate means of controlling the frequency in the equipment. Unfortunately, as the units age, many LMOs develop a “warble” when tuning. This “warble” usually stops when the frequency control knob is not rotated. However, accurately “zero-beating&rdq...  READ MORE
- Bradley Stone (UncleBrad),  02/08/2018 
  

NB9M Studio C Installed

A creative solution to managing big boxes in limited space.
Category: The Radio Shack
(Shown: 1/7/2018 checkin with the DX-60 Net on 3880, using the DX-60/HG-10B/HO-10 and the RME-6900)Using furniture-grade 5/8" plywood, simple tools and cold garage during Christmas vacation, I constructed Studio C, which occupies the south wall of the shack.  Exploiting a sturdy, existing cabinet with drawers that I've had since I was a kid, I devised a scheme to reliably handle the ...  READ MORE
- Bradley Stone (UncleBrad),  01/07/2018 

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