Connecting Accessories; Linear Amplifier; Ptt Out; Alc - Apache Labs ANDROMEDA ANAN-7000DLE MKII User Manual

8 Connecting Accessories
8.1 Linear Amplifier
8.1.1 PTT Out
Most modern Linear Amplifiers have a connection for keying the amplifier. The radio includes a back
panel RCA connection for this purpose.
The PTT Out feature is best used to switch 25vdc and 1A. Exceeding these values may damage the
PTT OUTPUT circuit.
How to test your PTT Linear Amplifier circuit BEFORE connecting your Apache Transceiver:
1. Power your Linear, connect the control cable to your linear but do not connect the other
end to your Apache Transceiver.
2. Using a DC Voltmeter, measure the voltage between the center pin and the outer
connection of the cable. This must be less than 25vdc.
3. Connect a DC Ammeter between the center pin and the exciter connection of the cable. This
should ACTIVATE the Linear Amplifier and give you a clear measurement of the current
requirements. The ANDROMEDA PTT circuit should not draw more than 1A.
4. If either of these values are out of the required range, then use an external keying interface.
There are many keying interfaces available from many sources such as MFJ, Elecraft, DX
Engineering.
Important: Connecting a Linear Amplifier that does not meet the above voltage and current
requirements is likely to cause damage to the Apache Transceiver linear switching transistor and
extreme cases, serious damage to other parts. Damage to the radio caused in this manner is not
covered by Warranty.
Linear Amplifier Keying ISOLATION adapters
http://www.dxengineering.com/search/product‐line/kd9sv‐products‐sv‐kr‐keying‐relays
http://www.ameritron.com/Product.php?productid=ARB‐704
http://www.sultantronics.com/product.html
8.1.2 ALC
ANDROMEDA does not offer ALC control for an external amplifier. It is important to set the drive
level so that the amplifier is not driven into saturation. Drive shows a % of ANDROMEDA full power;
setting the PA gain in the setup form is the best way to achieve this.
8.1.3 OpenCollector BCD keying
Automatic Band Selection can be accomplished using the Open Collector Outputs available on the
OC DB‐9F connector on the back panel.
This is an example shows how to prepare Open Collector Outputs for BCD [binary coded decimal] for
control of external devices [such as band information for a Hercules Linear Amplifier].
ANDROMEDA Manual Page 41 of 56