work

#include <ArduinoJson.h>
#include "Arduino.h"
#include <Encoder.h>

// Initialise the encoder and freq.button
Encoder encoder(3, 2);
const int pinButton = 8;
long oldPos  = -999;

// Initial frequency
long frequency = 451000000;

// Timeouts
unsigned long reqTime       = 0;
const long    reqInterval   = 10;
unsigned long respTime      = 0;
const long    respInterval  = 500;
boolean gotAnswer = true;

void setup() {
  Serial.begin(115200);
  pinMode(pinButton, INPUT);
}

void loop()
{
	int stateButton = digitalRead(pinButton);
	if(stateButton == 1 && gotAnswer && (abs(millis() - reqTime) > reqInterval)) {
		reqTime   = millis();
		respTime  = millis();
		gotAnswer = false;
		//send to sdrsharp get comm.
		Serial.println("{\"Command\": \"Get\", \"Method\": \"Frequency\"}");
		//Json get frequency
		String inData = Serial.readStringUntil('\n');
		StaticJsonBuffer<200> jsonBuffer;
		JsonObject& root = jsonBuffer.parseObject(inData);

			if (!root.success()) {
			Serial.println("cant_get_frequency");
			delay(1000);
			return;
			}

		frequency = root["Value"];
		inData = "";
		//Clear encoder counter
		encoder.write(0);

			if(Serial.available() > 0) {
			gotAnswer = true;
			String inData = Serial.readStringUntil('\n');
			inData = "";
            }

			if ((abs(millis() - respTime) > respInterval) && !gotAnswer) {
			respTime = millis();
			gotAnswer = true;
            }
	}
//Get the encoder position
long newPos = encoder.read();
	 if (newPos != oldPos && gotAnswer && (abs(millis() - reqTime) > reqInterval) ) {
     reqTime   = millis();
     respTime  = millis();
     gotAnswer = false;
     oldPos    = newPos;
	 //Set feq.
     long newFrequency = frequency + (newPos * 3125);
     Serial.println("{\"Command\": \"Set\", \"Method\": \"Frequency\", \"Value\": "+String(newFrequency)+"}");

	}
			if(Serial.available() > 0) {
			gotAnswer = true;
			String inData = Serial.readStringUntil('\n');
			inData = "";
            }

			if ((abs(millis() - respTime) > respInterval) && !gotAnswer) {
			respTime = millis();
			gotAnswer = true;
            }
}