speeddemon wrote:witch new serial ppl chip should i buy
At this stage, none. We've got a project on the go at the moment to replace an unobtainable one we've been using for a while to convert 23 channel crystal era radios to 40+. Looking at both Analog Devices DDS and Silabs PLL types, they will both cover the frequency range but both are too dirty to use directly - the radio would have increased spurs and reduced receiver performance.
Trying a few different ways to clean them up. I want to have the radio at least as clean as it was before the conversion, but preferably a bit better.
It's a long term "spare time" project that will be done hopefully around the middle of the year, but this could be sooner if things quieten down or later if things get really busy again.
The MC145170 is a serial PLL we've used before to replace some non expandable types such as the uPD2824, uPD2816, LC7131, and TC9106.
This works well, but a proper PCB is needed (perfboard won't work due to RF issues), and obviously it can't be used to convert radios without a VCO such as the earlier 23 channel crystal synthesized models.
They can be had for under $2.00 (less than a pound) each on eBay in an SMD SO16 package. Thru hole ones are rarer and 10 times the price. Not really an issue though as you need a double sided board anyway to keep them stable.
They are very easy to program, two lines of code to wake the chip up when you first turn the radio on, and one line of code to set the frequency every time you change channel. Frequency / channel range is 0.1 to 120 MHz and 65500 channels, way more than will ever be needed in a ham or CB conversion.
trc459 elbex pd8500d
A TRC459 conversion could be anywhere from a simple hi band and +10Kc mod, right up to a full blown microprocessor replacement to add new features such as instant "555" or internet / PC connectivity. Would be an interesting learning project.
Never heard of an "elbex pd8500d" down here, you'll need to provide more detail on that one.