Author Archives: retrovoltage

DIY SDR HF Up-Converter by WA7JHZ: Another good choice for your RTLSDR.

Posted on February 2, 2013 by retrovoltage

Reader David Forsman, WA7JHZ, read the round-up of RTLSDR upconverter choices and sent me a photo and build schematic of one he designed which was featured in the January 2013 issue of QST, the ARRL‘s monthly magazine. This circuit up-converts … Continue reading →

Posted in DIY, Electronics, Projects, Radio | Tagged , , , , , , , | 2 Comments

Depression-Era Radio: 1934 Grunow 460 Tombstone

Posted on January 24, 2013 by retrovoltage

I’ve had this Grunow 460 sitting in my queue pending for a little while and it’s finally on it’s way home looking great! There was a fun extra bit of detective work to identify and solve the issues that came … Continue reading →

Posted in Projects, Radios and Tubes, Vintage | Tagged , , , , , , , , , , , , | 2 Comments

First Look: 1934 Grunow 750 World Cruiser

Posted on November 19, 2012 by retrovoltage

I picked up this Grunow 750 “World Cruiser” radio from eBay a little while ago for an incredible deal and now it’s time for it’s turn on the bench. These radios are fairly uncommon and frequently sell for several hundred … Continue reading →

Posted in Electronics, Projects, Radios and Tubes, Vintage | Tagged , , , , , , , , , , , , | 3 Comments

Visitors From Around the World

Posted on November 9, 2012 by retrovoltage

I’m working on a couple of projects – another Bose equalizer, and a Grunow radio – but they’re not quite finished to post photos, so in the mean time I’d like to post some meta commentary for a moment. WordPress … Continue reading →

Posted in Commentary, Mailbag | Tagged , , , , , | Leave a comment

1950 RCA 9X561 Radio Repair

Posted on October 29, 2012 by retrovoltage

A friend I’ve made through the antique radio community is also a repairman himself, but ran into some scheduling difficulty with a piece of work on his bench and sent the chassis over to me for service: an RCA 9X561, … Continue reading →

Posted in Projects, Radios and Tubes, Vintage | Tagged , , , , , , , , | 4 Comments

First Look: 1934 Grunow 750 “World Cruiser”

Posted on October 10, 2012 by retrovoltage

I’m getting ready to sell some of my radio collection to make room for new ones, but until that happens I’ve been under something of a self-imposed moratorium on new purchases. This one came up on eBay a little while … Continue reading →

Posted in Photos, Radios and Tubes, Vintage | Tagged , , , , , , , , | Leave a comment

First Look: 1934 GE M-125 Radio

Posted on September 24, 2012 by retrovoltage

I was lucky enough to find a very rare, high-end radio for sale on Craigslist and jumped on it as quickly as I could. This particular one is the 1934/35 General Electric model M-125, their highest end offering for that … Continue reading →

Posted in Radios and Tubes, Vintage | Tagged , , , , , , , , , , | 13 Comments

Round-Up of RTLSDR Upconverter Choices

Posted on September 14, 2012 by retrovoltage

1/31/2026: This was originally written in 2012 and hasn’t been updated since 2014, but it’s preserved here in case any of the information is useful and to show the state of the ecosystem when RTLSDR first came on the scene. … Continue reading →

Posted in Collections, DIY, Electronics, Radio, Radios and Tubes | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 49 Comments

Shortwave Radio Reception with the RTL-SDR Dongle

Posted on August 6, 2012 by retrovoltage

Need your own upconverter? Click here! I bought and did a quick setup on my RTLSDR dongle using SDR# a few weeks ago, where I used it to listen to FM radio stations around my area and a few public … Continue reading →

Posted in Electronics, Hardware, Projects, Radio | Tagged , , , , , , , , | 3 Comments

New Project: Jamo MPA-101 Amplifier Repair

Posted on August 1, 2012 by retrovoltage

Project’s Conclusion Here My friend brought me this Jamp MPA-101 amplifier he picked up at a garage sale, complaining in only puts out some rumbling and humming. It looks like it’s suffered a failure in the power supply at some … Continue reading →

Posted in DIY, Electronics, Projects | Tagged , , , , , , , | 2 Comments