It’s just better to load the radio with the SSR’s 12mA, not the amp’s 100mA. A direct connection would mean that HSEND closure would be sinking the amp’s 12V to the radio’s ground, and yes, their grounds are connected, but I don’t want to risk it, so I built the isolated interface so each side can sink its own power to its own ground. The 7100’s HSEND line can sink 200mA, and the AL-80’s RLY jack supplies 12VDC (through the coil) and when grounded draws 100mA, so it looks like they could be directly connected-but wait! Each side supplies its own voltage source and ground. My radio is an IC-7100 and the amp is an AL-80B.
#REAMP WITH ID10V2 HOW TO#
It also shows how to build one using a mechanical relay. I built the following isolated solid-state keying interface according to KK5DR’s article. The switch-on time is an incredibly fast 50μsec. It appears to work at 13.8 volts also, drawing 12mA. With thanks to KK5DR, I discovered the Crydom DMO063 (Mouser p/n 558-DMO063), a solid-state relay (SSR) with an SPST-NO MOSFET switch rated at 60VDC at 3A. If you fry something, it’s your own fault! This article is intended for people that know how to look up specs, solder, and test simple electronic circuits. My Interfaceĭisclaimer: The author is not responsible for your mistakes. The one I used is about $22 (plus shipping) from. Prices are a little higher than comparable mechanical relays. The device is small enough to simply “float” in the cord assembly. No other parts are needed, not even a perf board or enclosure. These typically have an LED, photo-detector, and power MOSFET encapsulated in a very small package.
A better solution is to use a solid-state relay. They also require extra parts, such as a resistor (in-rush current-limiting), a capacitor (RF bypass), and the diode. Mechanical relays have that nasty coil spike, switch relatively slowly, can get dirty contacts, and are noisy. This pulse will greatly exceed the peak inverse voltage (PIV) rating of the radio’s switching transistor and POOF! - time for an expensive repair… The diode is connected across the relay coil reverse-biased, and the pulse (which is reverse-polarity) forward-biases it, causing it to conduct and absorb the pulse. Also, a relay coil will need a very fast power diode across it to absorb the high-voltage pulse generated by the collapsing magnetic field in the coil when it is switched off.
(Some Icom models, like the 706, are limited to 20mA.) Most third-party amp’s keying circuits will overload it and blow the switching transistor in the radio. Icom radios use a pin on the accessory jack called “HSEND” that when transmitting can sink 13.8V at 200mA to ground. The relay is selected to comply with the needs of the radio typically the coil is 12VDC at 10-20mA. Icoms come with an 8 or 13 pin DIN plug with pigtails (short wires), so you can look up the colors and connect to the wires without having to solder to the tiny pins in the DIN connector. At the radio end is the accessory plug that comes with most radios. Most amplifiers use RCA phono jacks for both keying line and ALC line. One cable (with relay) for amplifier keying, and the other (directly connected) for ALC. Cut the phono plugs off one end and wire them to the radio’s accessory jack and relay. The audio cable is the typical stereo RCA phono plug cable, 3 to 6 feet as desired.
#REAMP WITH ID10V2 PATCH#
You can build an interface for $10-$30 all you need is an old stereo audio patch cable and a small relay. If that’s your goal, then by all means buy one, but if you’d rather roll your own, please continue reading. They are plug-n-play, so you don’t have to look up specs for your radio and amp or do any designing. The problem is that they cost too much! Why? Because they are built to be compatible with a wide range of radios and amplifiers, and thus have a high parts count. Other companies make amps that are much lower cost-per-watt, and just as good, but the keying circuit is generic, with interfaces provided at extra cost.
Of course, radio manufacturers sell (very expensive) amps that will plug right in to their radios, but most hams opt for less expensive options. Each manufacturer uses their own voltage and current for this simple operation. The problem is that there are no standards for connecting the keying circuits of transceivers and amplifiers. You order a nice amplifier, only to discover you also need an “interface” to connect the radio and the amp. So you got your nifty HF transceiver and now it’s time to move up to the big leagues and add some power to your signal.
#REAMP WITH ID10V2 FULL#
New! 7/21 I built a full breakout box for the 7100’s accessory jack. Home » Ham Radio » 2018 Projects » Amp Interface
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