Re: The GLB Preselector- Preamplifier
> Kevin Custer <kug...@...> wrote: > I bought several of these when they were first on > the market. I think enough of the GLB designs that I'd like to buy anyone's used working or dead unit if they're not trying to retire on the sale price. > When this unit was first in production from Gil, he > made it available like this: Under 200 MHz was Bi Polar, > over was GaAs FET - HOWEVER, you could custom order > under 200 MHz the GaAs option. Which agrees with the limited vintage paper work I have here. > The Bi Polar device was MRF-901 Motorola. > I don't know what the FET was... I only ever owned > one GLB Preselector/Preamp above 200 MHz (it was custom > built for 222 MHz) and it had a MRF-901 in it -- go figure. One group member here was nice enough to send me a GLB unit during the last series of posts about them and my shameless request to obtain more. It has a dual gate mosfet... I reverse engineered the circuit and a logical guess was the BF981 device. I then went around the net looking at BF981 preamplifier circuits where I found the web page going through bias versus IMD performance and related trailing tuned circuits. I'll get motivated and go look for the site... > GLB stand for Gilbert L. Boelke W2EUP inventor of > the Hybrid Ring Duplexer - a design sold to Sinclair > Radio Labs in Tonawonda NY > Kevin Custer Smart guy... cumbersome type of duplexer that worked fairly well. I survived living near Tonawanda NY in Cheektowaga where snow is no fun. s.
