I know the existing hardware cannot do that, but would it be possible using one of ebay programmable attenuators as seen regularly on the KLB show? Not sure what the control interface is but could be worth investigating...
The underlying attenuatior is usually a Peregrine, Analog Devices or Hittite chip - e.g. the aforementioned PE4312 http://www.psemi.com/pdf/datasheets/pe4312ds.pdf and the Analog Devices HMC1119 http://www.analog.com/en/products/rf-microwave/attenuators/digital-step-attenuators/hmc1119.html have both SPI and parallel interfaces and cost under £10. Unfortunately these are in SMD packaging with the connections on the bottom, so difficult to use.
The PE4302 board project Colin and I did is in the Wiki. Later the same board was used with the PE43703 which has 1/4 dB steps but the new code never made it to the Wiki. The IC uses the same type interface as the ADF4351 local oscillator so it could share the control lines with the addition of another latch enable line (LE).
I liked the look of this and made the controller over the weekend on Veroboard as pictured. My PE4302 is on the slow boat from China. I hope to fit the controller [complete with the missing M2 stand-offs] into the lid of my Portsdown and mount the attenuator board on a bracket above the filter modulator. Thank you for all your hard work.
- PE4302 controller by M0YDH.jpg (397.49 KiB) Viewed 635 times
The Chinglish descriptions on Ebay mention switch changes but I don't understand.
One for the Wiki to save others anxiety?
- PE4032 DIP & SOLDER BLOB Settings.JPG (75.04 KiB) Viewed 467 times
Before you start drilling holes in the Portsdown case, I believe our RSGB construction competition winning Portsdown guru is implementing attenuator control in to the Portsdown software
I'm sure that I'm the only individual who has built the first and second place entries. Well done to team Crump and to Heather's powermeter.
Who is online
Users browsing this forum: No registered users and 1 guest