If I bought a SB-200, I would: 1. Change it from negative-V RL-Control to positive. 2. Remove the cockamamie, not-standard R/T bias arrangement and orig relay. 3. Add the high-speed switching mod so
** agreed. However, Newtonian physics works fairly ok below 99% of the speed of light. Valid points, Dave, however for analyzin' 100MHz or so L/R parasitic-oscillation suppression, the albeit archai
** Choertle. On Towertalk, there's an ASSertive control freak. ** which key is that ? later, Skipp - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.vcnet.com/measures. end
Reducing VHF gain in HF amplifiers is not all that hard to understand. My guess is that there are more than a few who have a handle on it. - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.v
** General Electric engineer G. W. Fyler was apparently the first person to write much about parasitics, (''Parasites in Transmitters'', Institute of Radio Engineers journal. Sept. 1935). H. F. Ditt
** They solemnly profess such but when there's a pileup, all bets are off. I used to run a tube with a 75A filament at c. 1200w out in Class A (steady I-anode) by turning down the mic gain. However,
** Not quite. A person on this group who professed that AC circuit-analysis does not apply to VHF R/L suppressors [reference available on request], subsequently mentioned that he had not taken a cou
** Surely, Tom, but my Heath SB-220's tank-L has never melted. However, it has forced cooling air on the tank and the amplifier Carl is working on does not. - R. L. Measures, a.k.a. Rich..., 805.386
** True, Tom. but operating Q is designed in. ** Again true, but such was apparently not the case. ** was such reported by Carl? ** No forced air cooling on the tank-L would cause heat buildup - esp
** Overdriving could be a possibility only if the tube was capable of substantially more emission than was needed to produce normal RF output. For example, If a 3CX3000A7 were used in a 1500w amplif
** Good point, Art. Few Hams have experience with tubes that draw over 30A of filament current. My guess is that there are currently more CB amp builders who have experience in this area than Hams.
It looks like a standard appliance switch, so I would try a large appliance parts house such as Orange County Appliance.. To avoid an encore, add a stepstart. [Fig 1 on my Web site]. good luck, Bob
The problem of illegal amplifiers is not unique to CBers. Amateur Radio has them too. My neighbor has a car that will do 155mph. This ought to be illegal since my '73 Dodge van will only do 95 with
** Oscillation is an issue that effects all amplifier builders -- except those who use 813s. Good point. Non-switching PS design is old hat. There are still those who believe that a FWB is superior
** Agreed. One camp seems to understand how impedance can be found by solving for admittance. The other camp seemingly does not, so they label the process voodoo. ** The VHF and UHF amplifiers I bui
** Rp is more like an equivalent Shunt VHF load at the anode resonant freq. ** Quite true, Ian. However, since 2, 3-500Z HF amps typically have anode resonances of 95MHz to 120MHz, Wes' measurements
My guess is #30 Cu. Modern wire intended for rewinding electric motors is excellent. See notes on my Web site for details. I use gloss urethane varnish to secure the finished winding so that the wire