Some comments on the history of ALC, especially with older transceivers, that do not have a variable RF output control.
During the early years of transceiver designs, such as the Kenwood TS-930S and other rigs from that era, these radios were not designed with variable RF power output controls. For example, I have my original TS-930S radio from the early 1980s, and it runs about 130 watts output at full power. My TS-930S has a Mic Gain control and a Carrier Level control on the same concentric shaft. Also, this same rig has an input and output Processor level control. However, there is no variable RF output control. As soon as the carrier level control is increased above a certain threshold, the RF output power immediately jumps up to full output or about 120 to 130 watts. Note: A Carrier Level Control is NOT an RF power level control. So, with these older style rigs, ALC is more important when running into an amplifier that only wants to see 50 to 75 watts. Any of the modern transceivers all have RF output controls to vary the power outputs from 5 to 200 watts and also allow you to set the proper RF drive level. Therefore, with newer rigs that allow the RF power output to be set, the ALC is unnecessary. However, rigs that go to full output, as well as that have power spikes, would probably save some amplifiers, unnecessary grief by having ALC voltage protection, against full power drive levels or power spikes on the RF input of the Amplifier. Jim K4PV -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ed K1EP Sent: Monday, December 03, 2007 7:18 AM To: Albert Crespo; elecraft@mailman.qth.net Subject: Re: [Elecraft] ALC I do not own an amp or use one when I operate from home. I also do not have any involvement with Elecraft other than being a customer. I have used amps while guests at other stations (many times I forget to even turn them on!). When I purchased my K3, the ALC was not a issue for me, as I don't use it. I have used my K3 with an AL1200 without connecting the ALC. That being said, I can understand your specific concern. When I checked the manual for my Icom radio, I saw that the ALC went from 0 to -4V. I guess these ALC voltages are a holdover from the older pure tube generation of amps. Apparently some modern amps kept that standard and some decided to go positive. I would also think that it would have been a trivial addition to the K3 to have the polarity of the ALC selected in a CONFIG menu item. I am sure that Wayne, Eric, et al are quite smart and had their reasons to implement ALC the way it is today. Whether it was the right way to do it or not, it is the way it is at this point in time. I can tell you for certain one of two things will happen. Either it will stay the same or they will change it. Personally, I think it is foolish to cancel an order for this issue. For probably less than $5 in cost (either to the end user or absorbed by Elecraft for customers who demonstrate a need) a simple device can be constructed to plug in to the 15 pin ACC connector and the amp's ALC connector and deliver a negative ALC voltage. Yes, I think it sounds on the surface as an oversight, but we weren't involved with the design over the last three years. At 12/3/2007 07:33 AM, Albert Crespo wrote: >I recently purchased a SPE 1K A linear solid state amplifier. It >does not operate properly without negative ALC on SSB. >Why produce a new rig that is not compatible with present solid >state amplifiers? >I hope this is corrected before mine is ready to be delivered, or I >will just cancel my order. >73, Albert _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
