Antenna Analyser

I start locking in eBay for bye a Antenna Analyser  when i found a lot of interesting design, and i realised hat it is not so many parts needed to build one.

Here is a few links i start lock att.

DG7EAO

K6BEZ

VK3YY

I tried the Arduino code from DG7EAO and the exe it works (no HW just the display), and start to modify the code. I won’t a more standalone without computer control.

I ordered a 2,8” TFT Display.

Power detektor board AD8307.

FTDI Basic, encoder  and a box.

I has a DDS board DDS60 from midnightdesignsolutions.    DDS60

I has a Arduino mini pro board.

I read a lot of information on SWR detectors, first  the ide was to have Pforward and Prevers at the same time, but all result and try was not god enough. So i realise that an RL-Bridge was much better, the bottleneck  that it attenuate the signal from the DDS 12 dB, docent mater for an analyser.  Normally the bridge has a transformer on output, but i realised hat i can change the power detector to have differential input.  Disconnect pin 2 RF- 100nF from ground and connect to input, also change R at input from 100 ohm to 50 ohm, i don’t know how necessary it is! To avoid trafo is good for low frequencies .

The Power meter AD8307 has a dynamic of 80-90 dB. I measured the response from my generator -65dBm and +5 dBm, it give me 25,2 mV/dB.  To use in SW.

The DDS60 has +8dBm out  so i decide to attenuate 3dB if its not 50 ohm out ?

External Aref 2,7V matching AD8307 dc out around 2.5V max.

The only thing i have o do was the RL-Bridge and a 3.3V regulator, all other is parts bye.

So long i am satisfied with the result RL @ 50 ohm termination is as highest value 27dB @ 1 MHz it is 60 dB.

It is more to do with the SW, but i has came to memory limits, but it can be solved, i hope.

Here is the schematics.

After the break i should fix the software and go to a friend with a lot off antennas and do a accepting test.

No i work with the 1296 Transverter, stay tuned.

73 de SM4HNG