24 Jan 2015

Micro 40 - 40m DSB transceiver

See http://home.alphalink.com.au/~parkerp/projects/projmicro40.htm .

Also: https://aa7ee.wordpress.com/2013/10/19/the-vk3ye-micro-40-dsb-transceiver/ .

Well designed DSB transceivers are much simpler than SSB rigs as no SSB filters and mixing to final frequency is needed. They must not be over-driven to avoid a spreading signal. The PA needs to be linear too. These issues being carefully considered, you end up with a rig that has the same bandwidth as an AM rig but with a suppressed carrier. DSB transmitters are usually received as an SSB signal. The downside is that if a simple direct-conversion receiver is used then there is no rejection of stations sitting on the other sideband. So, they are best on quieter bands, rather than busy HF bands. Bands like 10m, 6m and 4m are probably good candidates.

Although not impossible, it is quite difficult to demodulate a DSB signal on a simple direct-conversion receiver. DSB rigs are ideal as simple transceivers to communicate with SSB rigs.

1 comment:

Anonymous said...

Yes Roger, DSB is really a cheap and effective alternative especially for novice. A well designed rig is usually easier to duplicate and performs well. I do like to recommend SPOTTO DSB at ham radio India site. It is a simple high performance transceiver and the beauty of the design is its simplicity and use of common components.