This is the content of the box. Everything is well packed. All high-quality components and powder-coated aluminum enclosure! Very good kit indeed!
The PCB comes with all of the SMD components factory preinstalled and tested and they are not that many. Here is a picture during the building process with all of the IC sockets installed. I actually replaced the supplied sockets with machined socket type as they are more reliable and provide better contact. The values of all of the discreet components were double-checked!
Picture of the attenuator board located in the coupler! These SMD resistors are pretty big in size and very easy to install! Larry provides some spares should something goes bad during soldering!
One of the unique features of LP-100 is that the power detection is not done in the coupler (as is the case in all other digital wattmeters). Instead, the coupler samples the voltage and the current and the main unit detects the power, which allows for more complex calculations and more data like Z, phase angle, etc. This is a picture of the voltage (left) and the current (right) sample transformers. The transformers are wound in a very specific manner (they are mirror image on each other) on large ferrite toroids. Winding those transformers is probably the most difficult part and requires great precision to achieve for highest possible accuracy! The little piece of silver-teflon coax is the primary winding of the current transformer. Larry provides in the manual exact measurements for cutting and stripping the coaxial and detailed description of how to wind the transformers. Pieces of special self-adhesive tape on the nylon bushings are helping to keep the windings in place and to have proper coverage of the ferrite cores. The windings need to be evenly spread.
The aluminum enclosure of the coupler with connectors and attenuator already installed. The coupler must be build with precision for good accuracy! The instruction in the manual are pretty good and easy to follow. Optional N connectors are sold by TelePost but any standard chassis N connector will work should such connectors are desired.
Picture of the coupler with both transformers in place! The wiring inside the enclosure can be a little tricky. One should not rush thru the building process - this is lab equipment and accuracy of the measurements is essential.
The RF coupler is ready. It has very professional construction and look! Before soldering the primary of the current transformer, the walls of the enclosure have to be pre-tensioned to a specific size, so when the cover is screwed on there is no stress on the connectors and coax.