Sunday, July 28, 2019

Double sideband on HF

How many of you have operated double sideband (suppressed carrier) on HF? 

Not many, I'm guessing. 

DSB had a brief 'golden age' around 1960 when SSB was taking off. Like SSB it had no carrier and you could tune it in on an SSB receiver. But it was easier to generate, with no crystal filter or phase shift networks required.

It's had a second renaissance amongst builders, particularly those using direct conversion gear. A DSB transmitter is basically the reverse of a direct conversion receiver and you can use many of the same parts if you wanted to build a transceiver. 

While a DSB signal is difficult to hear on a homebrew direct conversion receiver, the chances are that you'll be talking to people on commercial SSB gear. In may cases they won't know you are even transmitting two sidebands unless you point it out. 

Here are some videos of DSB gear. 

Beach 40 40m DSB rig. Very simple. This is the first of several videos. 

Using the OzQRP DSB rig from the beach

DSB isn't just for voice. Here I'm transmitting 30m WSPR DSB. 

Have you tried DSB? What have been your experiences? Please leave your comments below. 

PS: Want to read about antennas? Consider this selection of antenna books. They are affiliate links meaning that I receive a small commission (at no extra cost to you) if you decide to purchase.


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