Hi, updated block diagram.
hello Geotge , on ebay pcb swr display based link ? I was interested in building it to make measurements on my feed
73 de iw5bsf Roberto
iw5bsf Hi Roberto, I bought something like this. You need also two directional coupler if you buy something like this. You need only one if you do something like this . Also two same value attenuators are possibly needed. You have to translate the output voltage to SWR. Is it clear or if you need more info tell me.
Thanks, I see in the image that you used a 2x16 line display and a swr gain stage and an ebay kit? what you use
iw5bsf Roberto usualy for projects like this you can use a standard UNO with LCD keypad shield. you only need some definitions to adjust from other codes to this solution. I did this many times before.
Thanks for the information, arduino UNO standard if I'm not wrong? I've never used it
yes standard not more..
What should I look for beyond pcb ad8302
Hi, as I describe I use an ATMEGA8. I also use a 2 wire custom driver for 2*16 LCD. Software is written by SV1EED.
Hi updated roof box. Lo SMA chassis connector was desoldered and resolded. The IMD is improved after this mod. May be this was the reason of IMD improvment. Also working the MAX 2671 mixer at -22 dBm output instead of -5 dBm has improved also the IMD performance. To archive this a SGA6389Z was added at the 2.4 GHz path and a SBB5089Z was removed from the 430 MHz path as described in the updated block diagram.
good morning thanks, in the meantime I ordered ad8302 on eBay how can I get the software?
Hi, as I try to improve performance of my QO100 station setup I realize that some topics are important. This is a writedown in order to help anyone in areas for improvment and for me if someone has something to add.
- feeder performance
- power output
- CW signal vs CW beacon in dB
- Tx audio quality
- Tx & Rx frequency accuracy
- Tx & Rx frequency stability
- Tx at same Rx frequency
- Rx while Tx
- SNR of CW beacon
- IMD Tx performance
- 13.8 V operation
- Pwr & SWR indication
- SWR of Tx antenna
- Tx key down time (how many time can stay in Tx without be burned ...)
- no self oscillations
- dBm of parasitic Tx
- SWR protection
- same antenna for Rx & Tx
- degree of homebrewing
- weather conditions proof
- mechanical conditions proof
- roof 2.4 Ghz unit
- length & loss of pigtail (cable from Pa to feeder)
- size of Rx & Tx antenna
- power output control
- spectrum view of Rx
- total signal performance of Tx (power, pigtail, feeder, Tx antenna)
- portable capability
- PC audio connection
- modes supported
thank you George for me yes atmega8 easier arduino never used it yet
WARNING: the resistor divider on the 18650 will discharge the batt if not cut by the main switch
batt res div is: 4.2V - 330K - 220K - GND
db on ADC0
phase on ADC1
vbatt res div on ADC2
AD8302 display 16x2
Gain SWR Phase !
+xx.x x.x xxx°
the '!' prints when low batt
avrdude -p m8 -c usbasp -U lfuse:w:0xE4:m (8 MHz int clock)
Also 10 Kom pull up at Reset pin.
Two 10uF MLCC at each side of power of ATMEGA8.
VREF of AD8302 goes to AREF of ATMEGA8 , add a 100 nF cap
2*16LCD driver IC is 74HC164
I use a 2.5-4.2 V to 5V PCB from eBay for powering the system via a 18650 and a charger-protecting PCB also from eBay.
iw5bsf any questions ?
OK George thank file I look at the schematic then I'll let you know
73 de Roberto
hello George let's see if I understand vbatt res div on ADC2
atmel pin 25 : I enclose the reference drawing
Even 10 Kom lift the reset pin. I have to press a button
I use a PCB from 2.5-4.2 V to 5 V from eBay to power the system through a 18650 and a PCB to protect the charger also from eBay send me ebay link
the reset pin has to be pulled up with
10 kom without a button.
the adc2 circuit is ok.
One correction : the circuit of lcd driver is not connected to adc0 and adc1 !!! the 1,2 pins of the 164 goes to pin 14 of the ATMEGA8 and pin 8 of 164 go to pin 15 of the ATMEGA8.
At the charger border I changed the pcb leds with a common anode red green dual led.
What direction coupler do you plan to use ? If you are outside you will have wrong swr or burn the AD8302. If you are not sure pls tell me. It is critical that you must be inside dynamic range of AD8302.
SWR indication displayed only in one direction of inputs. If you do not see SWR just reverce inputs. reverse if you do not see negative gain.
AD8302 pcb has internal termination R so you just connect them to coupler.
thank George enclose the reference drawing schematic
with corrections, check if they are OK
for the directional coupler I would have a narda if it can go well or what you advise me
I ordered the modules but it will take a month