The New Mini-Kits EME221-70CM is a High Performance RX/TX masthead Pre-amplifier, and is specifically designed for the 70cm 430-450MHz Amateur Band. The design uses the Mini-Circuits PGA-103 E-PHEMT amplifier that has a very high dynamic range and ultra low noise figure, and provides superior performance to Mos or GaAs FETs. The gain is adjustable so that the gain distribution can be optimized for coaxial cable loss that can be significant on the 70cm band, and also to suit the receiver gain. The design incorporates VOX RF sensed changeover Relays for Trasnsceivers up to 50 Watts CW without using sequencing, or can handle up to 100 Watts PEP if sequencing is used. An on board bias tee ( DC power injector ), allows the pre-amplifier to be antenna mounted and powered via the coaxial cable. A Tuned input T type filter and output low pass filter provides high rejection of signals at 144 and over 500MHz.
THIS KIT IS NOT FOR BEGINNERS AND REQUIRES VERY EXPERIENCED SOLDERING SKILLS
The Product picture shows a completed EME221-70CM KIT1 product with Optional TNC connectors. BNC connectors are not available on the masthead version.
This product is ideal for use with the Icom Multimode UHF transceivers including the IC475, IC820 / 821, 910, IC9100, and IC9700 that have a PREAMP switch to supply +12vdc out of the antenna connector on RX mode. Transceivers without this function will require an external bias tee like the Mini-Kits EME168-2-70 to supply DC power up the coaxial cable. When using a high power RF amplifier up to 100 Watts, additional sequencing will be required to protect the pre-amplifier from damage. The Mini-Kits EME166 Sequencer can be adapted to be used for correct sequence timing of the Rx to TX changeover.
For more information see the EME221 Kit Webpage
Please Note: Built products usually need to be constructed and can take up to 2 weeks to ship depending on work load, but are normally shipped in few days.
EME221-70CM KIT1 is a Basic Kit that includes the PC board, Instructions, and all on board components. No connectors or enclosure are included. Requires Complete construction.
EME221-70CM KIT2 is the KIT1 but also includes the TNS03 female TNC connectors and Nickel sprayed GME enclosure. Requires Complete construction.
EME221-70CM KIT3 is the KIT1 but also includes the BNC connectors, Hammond 1590S enclosure, and 2.1mm DC cable. Requires Complete construction.
EME221-70CM-MH Is a fully constructed product in a Nickel sprayed GME enclosure with female TNC connectors.
EME221-70CM-BNC-S Is a fully constructed product in a Hammond 1590S Die cast enclosure with female BNC connectors, and 2.1mm DC cable.
BNC connectors are not available on the masthead versions as they can be unreliable outdoors.
The basic EME221-70CM KIT1 Does Not include connectors, miscellaneous hardware, or enclosure. Do Not construct this Kit unless you are very experienced with surface mount construction, and only if you have a quality soldering iron and 60/40 Tin Lead solder.
|Frequency Range: ||430 to 450MHz ( BW 20MHz @ 1dB ) |
|Band Rejection:||Typically >35dB @ 145MHz, >60dB @ 900MHz |
|Gain Adjustable:||Typically +29dB Max, 20dB Min @ 435MHz |
|Noise Figure: ||1dB ( Typically <0.9dB @ 435MHz ) |
|Through Loss: ||0.3dB @ 435MHz ( Bypass Mode ) |
|RF Power Handling: ||50W CW ( Un-Sequenced ) 100W PEP ( Sequenced ) |
|Minimum RF Input: ||+20dBm ( 100mW ) To activate the RF sensing circuit|
|Operating Voltage:||+11 to 15vdc ( +12vdc @ 220mA Recommended )|
|Board Size:||80mm L x 84mm W x 17mm H ( with TNC connectors ) |
|Kit Webpage:||For actual product Tests see the EME221 Kit Webpage|
For more information please see the EME221 KIT WEBPAGE
70cm 430MHz UHF RX/TX Preamplifier
- Brand: Mini-Kits
- Product Code: EME221-70CM KIT
- Quantity In stock: 30