A Complete Solution for 70 MHz – 70.5 MHz 1500W Transmit-Receive 4 meter Competition System with Low Loss Receive Band Pass Filter and Preamplifier: EME2-70

QRO – Extreme power on transmit and low noise on receive with integrated band-pass filter.

QRO made on low loss dielectric RT/duroid® 5880 Laminates (not on FR4 Important!).

 

 

EME2-70 device consists of three components:

1. 70 – 70.5 MHz High Selectivity, High Q, Low Loss RX Bandpass Filter. Specially designed to suppress HF, 50MHz, FM and 2m signals. Its characteristic is shown in the following graph. The filter itself has an extremely low attenuation of only 0.12 dB:

 

 

2. Wideband Low Noise Amplifier.

3. Double High Power Relays with 16A contacts.

Receive gain:

 

Frequency:	Gain:
1.82 MHz	< – 65 dB
7.1 MHz	< – 65 dB
14 MHz	< – 63dB
21 MHz	< – 50 dB
28 MHz	< – 43 dB
50 MHz	< – 17 dB
70 MHz	+20 dB, NF= 0.8 dB, Input RL= -15dB, IP3out >36dBm
70.5 MHz	+20 dB, NF= 0.8 dB, Input RL= -15dB, IP3out >36dBm
88 MHz	< – 11.8 dB
98 MHz	< – 27 dB
108 MHz	< – 26 dB
144 MHz	< – 26 dB
222 MHz	< – 26 dB
432 MHz	< – 19.5 dB

 

The characteristics of Receiving Gain can be seen in the following graphs:

– HF Attenuation:

 

 

– 50 MHz Attenuation:

 

 

Transmitting Output Return Loss (Measured):

 

Frequency:	Attenuation:	Return Loss:
65 MHz	0.02 dB	30 dB
68 MHz	0.02 dB	40 dB
70 MHz	0.015 dB	50+ dB
70.5 MHz	0.015 dB	50+ dB
76 MHz	0.02 dB	30 dB

 

Extreme Low Loss on transmit side thanks to RT/duroid® 5880 Laminate. Less than 0.03 dB.

With Excellent Wide-band Return Loss 70 – 75 MHz. Better than 50 dB.

 

Details:

 

Power consumption:	+ 12 V, 220 mA
Max. power SWR 1:1	1500 W
Max. power SWR 1:1.5	1000 W
Max. power SWR 1:2	750 W
Max. power SWR 1:3	500 W
Connectors:	“N”
By order:	7/16 DIN
Outdoor version:	+9 EUR

 

With this equipment, sequencer is mandatory. To switch from receiving to transmitting put on sequencer 200 ms delay.

Outdoor version with IP63 protection.

EME3-70 Low Loss Bandpass Filter Low Noise Preamplifier Transmit/Receive High Power Relay Switches Block Diagram.

 

 

Our EME – Earth-Moon-Earth famil. Band-Pass filters + Amplifiers + High Power Relays

 

6 meter band, EME2 – 50: EME2-50

6 meter band, EME3 – 50: EME3-50

4 meter band, EME2-70: This one.

4 meter band, EME3-70: EME3-70

2 meter band, EME2-144: EME2-144

2 meter band, EME3-144: EME3-144

70 cm band, EME2-432: Soon

70 cm band, EME3-432: Soon