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Showing posts from April, 2017

Japanese TRX use JIS not Phillips screws

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Japanese TRX use JIS not Phillips screws
Ever wonder why it is so easy to damage a screw on a Japanese made radio using a Phillips head screwdriver? Obscure, but simple, they use JIS screws not Phillips!

I haven't checked, but I think they are on made-in-Japan cars, certainly lots of other gear.

JIS screws, which pre-date Phillips by 20 years, usually have a dot or other indent on the head.

The solution is simple, buy a set of JIS screwdrivers, about $25 on eBay.


http://themtblab.com/2016/01/tools-vessel-jis-screwdriver.html

RF tap for panadaptor/second SDR after IC-7300 bandpass filters

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RF tap for panadaptor/second SDR after IC-7300 bandpass filters (First draft) Introduction It is possible to tap into the IC-7300 after the bandpass filters, just before the ADC. There is a coax connector that allows an SDR tap to receive the filtered RX signal. It is shared with the low-level TX path, but the levels are low, giving a TX monitor too. Using CAT controls, the SDR can be controlled by the TRX. It can also operate as a second RX in the operating band. The RF tap is an alternative to the INRAD RX7300-receive antenna cable, with some advantages and disadvantages.

Finding the RF tap In an SDR-based TRX there is no IF tap point, but on the IC-7300, there is a RF tap point after the band pass filter and RF amplifier, where an SDR has the good filtering of the IC-7300, but can access the whole operating band.

The RF tap point J1431 is shown in a portion of the RF unit schematic from the service manual. The schematic shows the RX, TX and power paths in green, brown and red resp…