It seems I have basically a DSB signal with only a small amount of opposite sideband suppression. My next chore is to clean up the SSB signal a bit. Thanks, but much of what I accomplished was through contributions from members like yourself. In all seriousness congratulations for sticking with a project that provided some very interesting complications! You can definitely give yourself a pat on the back for good troubleshooting. I also wanted something that would easily run legal limit AM without stress for use with lower power vintage AM rigs. Between the robust design and protective circuity I built it to survive those mistakes that often occur during the latter part of a contest when I am sleep deprived. It wasn't a 'cost is no object' design but it was a 'cost is little object' design and a lot of fun to build. When I was more serious about contesting 10 years ago I built a rack mount 'contest duty' amp using three 4CX800 tetrodes in class AB1 with a large P. No mixers, oscillators, or modulator circuits and nothing to alignĪmplifiers were the last thing built by most amateurs and they do make a great homebrew project. Like the GSB-100 it is very solid and also has low cost (811A) finals.īut the GSB-101 is so much simpler than the transmitter, just a power supply and a single amplifier stage. Now Marc once again I suggest it is time to find a matching GSB-101 as a payoff/reward for the time and success from your GSB-100 troubleshooting.

Both of my GSB-100 transmitters came to me with replacement transformers so I never had the opportunity to investigate the failure mode. The GSB-100 does have a reputation for going through the original power transformer but otherwise it seems very solid. I have numerous pieces of Gonset gear and most of it strikes me as being a bit on the light side construction wise but the GSB-100 and GSB-101 both seem very solid.

When neutralizing the new final tube, if you don't use the method in the manual and instead opt for the 'traditional' transmitting test neutralization then first adjust on 20 where the final is less likely to take off and then do the final adjustments on the higher bands. A small heat radiating plate cap connector is also of benefit. A small amount of air flow can greatly increase tube life but care is needed in mounting a fan, especially in those transmitters using 7360 or other sheet beam tubes as balanced modulators since they are easily upset by stray magnetic fields. Given the price of most sweep tubes today it is a good idea to provide forced air cooling for any rig that wasn't originally equipped with a fan. Once initial tune-up is complete then record the values so that future tune-up will be faster with no large out of resonance current flow.

This is also the proper method for using a sweep tube equipped SSB/CW rig when the accompanying amplifier requires lower drive. For best life with sweep tube finals, load quickly to rated input and then reduce the input slightly by reducing drive level. Screen grid current soars under high drive/light loading conditions and the screen grid is the most fragile element in most sweep tubes. In addition to minimizing tune-up time and out of resonance high plate current it is also very important to keep the final properly loaded.

Gonset gsb 101 manual treadmill