& MarkV







Keying SB220 with Mark V

Problem: Just began the connections to a new MK V and find that the 120VDC from the relay in the SB220 amplifier is not compatible with the MK V relay which is good for only 100VAC or 60VDC. However, the manual states it is compatible with the 220 and 221 in the instructions for hooking up a linear amp. Anyone know the real deal here? I do now wish to fry the internal XCVR relay but also do not relish the thought of adding another external relay just to drove the SB-220 relay.
Al, N6TA

Solution 1: You can order a kit from Haubach Electronics or an external interface from the HeathKit Shop http://www.theheathkitshop.com/ampkeyer.html


Solution 2: Best to use the Band data connector to key the 99, and disable the relay switch on the back. No clicking and super fast and smooth QSK. Pin 2 and 3 to amp PTT and ground pin 8 permanently. 73 Saad N5FF

Solution 3:You should buffer the puny PTT from the MP's band data plug, or risk de-smoking things. K6XX goes into this in detail here: http://www.k6xx.com/radio/mpbandbx.html  Blake N4GI

Solution 4: The following link may be helpful: http://www.qsl.net/icom/auxrelay.html  Whilst applicable mainly to Icom radios, this page contains some useful general information on keying tube amplifiers from a transceiver. Adam VA7OJ/AB4OJ




This site was last updated 08/21/07