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GS35B 2m amp
Tim and anyone interested : Here¡¯s looking inside the RF box. You can see the original blocking cap - just like yours ! This is a YU1AW ¡°Lazy Builder¡± design. Suited my construction capabilities
By John Sparkes · #39897 ·
Stuffed blocking cap
Tim - here¡¯s what happened to my 2200pF blocking cap. Cracked and a little burnt. This caused ALL of the ¡°thermal¡± power output drift in my 2m amp. She¡¯s rock solid now, for complete JT65B
By John Sparkes · #39896 ·
Re: Gi46b on 2m - Thermal drift problem
No probs. An even better option, if your tank is well insulated (as mine is) is to remove the blocking cap entirely and connect the anode directly to the tank. I used large Teflon standoff posts and
By John Sparkes · #39895 ·
Re: Building my first amplifier. Where to start?
The G2 volt is 850V£¬ yes£¬ very large G2 current, hundreds milliampre Hsu Steve <k0xp@...> ÓÚ2023Äê12ÔÂ28ÈÕÖÜËÄ 04:08дµÀ£º
By Hsu · #39894 ·
Re: Building my first amplifier. Where to start?
Hsu, what g2 did you use? It seems as though the GU-81M consumes a LOT of g2 current, too... 73 & HNY, Steve K0XP
By Steve · #39893 ·
Re: Building my first amplifier. Where to start?
It seems that the GU-81M is what you want. I just built an amplifier using a pair of FU-81/FM-8 (GU-81M/GI-8) with output power: 1.8-14MHz, 2900W, 21-28Mhz, 2500W.grid driven, if you only want 1KW,
By Hsu · #39892 ·
Re: Building my first amplifier. Where to start?
Des, Ian's callsign is GM3SEK. When I was involved in Underground Coal Mining many of the Vehicles ran on 3 phase a.c., with stout umbilical cords connecting To 4160, 3-Ph distribution xfmrs dragged
By HaL Mandel · #39891 ·
Re: Building my first amplifier. Where to start?
I would have to disagree with the 2500V in the case of the GS35 specifically.? To get 1.5KW out, I think the Ig will be too high at that low of a voltage. I ran 4300V on mine and that was very nice
By Jeff AC0C · #39890 ·
Re: Gi46b on 2m - Thermal drift problem
Thanks! I'm down with COVID right now, the junkbox has some other Ceramic button caps, I switch it out in a few days and let you know how I got on. vy73 Tim
By Tim Fern · #39889 ·
Re: [Amps] [ham-amplifiers] Fw: [yccc] Followup: KM1H
Hi John, hope you had a Merry Christmas and do have a Happy New Year. Sent from the all new AOL app for iOS
By Louis Parascondola · #39888 ·
Re: Building my first amplifier. Where to start?
Peter, You are of course correct. But due to the tappings I have options to get the voltage to where I want. The rectifier and the DC produced would be better if I settled on 3 phase, but I prefer
By desmond auld GI0UTE · #39887 ·
Re: Building my first amplifier. Where to start?
Steve, I haven't measured idle current of the transformer so I will do that when I dig it out from long term storage. To be fair, even if it idles absorbing a 1kw, which I doubt, I only get maybe 8
By desmond auld GI0UTE · #39886 ·
Re: Gi46b on 2m - Thermal drift problem
Hi Tim. Yeah, those big caps are no good on 2m ! She works great now with a smaller value cap. Rock solid power out. John VK6JX
By John Sparkes · #39885 ·
Re: [Amps] [ham-amplifiers] Fw: [yccc] Followup: KM1H
Ha ha ! We sure are, Lou ! Some of us, learn a lot from you guys. BTW, my W1QJ converted SB220 6m amp works bloody well. The Japs don¡¯t know what¡¯s hit them !! Happy new year to all. John VK6JX
By John Sparkes · #39884 ·
Re: Gi46b on 2m - Thermal drift problem
+1 on the blocking cap. I have a 2xGI7B project on the go for 144MHz with a very similar set up, and the looming possibility of thermal drift is a great concern. I thought about employing one of those
By va3dxv · #39883 ·
Re: [Amps] [ham-amplifiers] Fw: [yccc] Followup: KM1H
We are always learning! ? Sent from the all new AOL app for iOS
By Louis Parascondola · #39882 ·
Re: Gi46b on 2m - Thermal drift problem
G'day Tim. Check (physically and electrically) your plate blocking/coupling capacitor very carefully. John, VK6JX, had the exact same problem with his GS35B model 2m amp, using what looks to be the
By Alek Petkovic · #39881 ·
Re: Fw: [yccc] Followup: KM1H
Thanks for that information Lou and thanks to Doug for the leg work. Carl, along with Rich, Tom, Ian White, Tony King, yourself, Jim and lots of others are the ones that have fed me with knowledge,
By Alek Petkovic · #39880 ·
Re: AL80B Smells Hot on 10M and 160M
This amp was made in 2001 indicated by 11-01 all over the inside of the amp. No Heat on the Plate Choke. Looks bright red all over. I see no cracked caps at all neither. I just had time to take it
By Scott Hostetler · #39879 ·
Gi46b on 2m - Thermal drift problem
Hi Everyone, I built this little 2m amp a couple of years ago, it works perfectly in every way..... except for the thermal drift. Tuned up with key down, 300W out with 12W drive, within a few seconds
By Tim Fern · #39878 ·