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Old 6th Mar 2021, 4:54 pm   #72
G0HZU_JMR
Dekatron
 
Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
Default Re: Spectrum Analyser TR4172

Those readings look good to me now so it looks like the amp section is working again. I really don't know if soldering the gold connections is a bad thing or not. Over time there might be an issue. I felt I had no choice but to solder mine at the output of the IF1 amplifier to the connection to the first BPF section.

I used 60/40 solder and I was very quick with the iron. The biggest fear for me was lifting the microstrip trace at the start of the BPF board due to heat stress. If this happens then I think it would be difficult to repair. From memory I hardly touched the PCB traces with the iron. I think you need to explain to the person that solders it that the copper may lift off if the iron temperature is too hot or if the iron is held there for more than a tiny fraction of a second. If it lifts off and shrivels to nothing then the only option is to use sticky copper tape cut to the same width as the microstrip. At 2GHz this won't really affect the performance as long as it is quite short.

Maybe someone else can suggest a better way to bond the gold strips. Whatever method is used it mustn't involve any upward pull on the microstrip or it could float away if the absorber glue has got to it.
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Regards, Jeremy G0HZU
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