I believe there are some who still monitor the 87a yahoo group. Here are comments I collected over the years on Fault 33: "Hopefully, it could be just years of accumulated dirt/grim causing some stic
Thanks Larry. Ill check into it. Also not sure if the Alpha 87A Yahoo group still exists. Good news is fault 8 is fixed with PIN diode change (rx and tx). But now fault 33. My friend bought this at a
That answers a lot of questions... I doubt cathode current would ever reach one amp. So, essentially adding a DC bucking winding is an academic exercise is and not needed, I added the neutralization
Hi Dan, Thanks for the reply. I did run across your old post on the subject however I am not sure you were talking about the same capacitors that I have. I found on the rf parts web site the 850s cap
Gary, a similar question was asked several years ago on amps and I replied to it with values from some info I have on CRL doorknob ratings. I can't seem to locate my data but here is my post. My unde
Working on my TMC amp with the pair of 3-500Z finals and the toroidtankcoil. 1.6-18 MHz. I tried a tankcoil for 20 meters that I made out of ¼ inch copper tubing, 2? diameter and 8 turns. I
On Sun, 14 Mar 1999 13:59:38 -0600 "Roy Koeppe" <royanjoy@ncn.net> writes: I should think not! B&W used a 3 stack of T225-2A in the PT-2500A ( 2x 3-500's at 3500V) for 160M and a seperate 2 high stac
Thanks 73 Jim W7RY <DO NOT use toriods. I speak from experience. Had a reaction when on 10 <meters with my 8877 amplifier. The 160 meter toroid coils would start <smoking when on 10 meters. I was usi
<DO NOT use toriods. I speak from experience. Had a reaction when on 10 <meters with my 8877 amplifier. The 160 meter toroid coils would start <smoking when on 10 meters. I was using a shorting switc
A quick question, does anyone on this list have a working amplifier that gets to it's rated output on 10m with a grid driven tetrode with no neutralisation? If so, can you post a picture of its pi ta
Paul, there is some confusion because there are 2 Commander amps. I apologize for just glancing over your post and replying in a hurry while heading to dinner (-; Yours is the original built by Comma
The current in the shorted turns is such that it produces a magnetic field opposing the magnet field in the rest of the coil. Or you may say that the shorted turns resist a change in the magnetic fie
The side you short on makes no difference at all. Current in the coil is essentially equal all through the coil, as long as the coil is not so large it acts like a transmission line or antenna or th
Hi Ian Alpha has been doing this in the "L" section toroid of the 87,89,91b, and 99 with no apparent problems. They use a pick-up and hold type switch, (9 wiper contacts) with the wipers connected to
To: <amps@contesting.com> I between mention The following post is long and I'm trying to answer all the questions that were asked from various emails that I received (quit a few I might add). I apolo
This is a multi-part message in MIME format. --=_NextPart_000_0068_01BF65E5.76C80780 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable UrgentSwedish questions
Author: Steve Thompson via Amps <amps@contesting.com>
Date: Sun, 24 Nov 2024 15:54:53 +0000
You certainly don't want a small series C anywhere at the tube end of the matching, it pushes everything in the wrong direction and you end up with higher loaded Q. Steve G8GSQ I'm not sure I'm using
Adding an inductor between the tube and the pi network creates a new network which can perform the necessary impedance transformation with a more practical value for the tuning capacitor. If it helps
not to my problem, but the Pi-L values for the plate capacitance are lower Pi L2-Less values. On default settings the pi-L circuit also shows much lower plate capacitance for the Pi-L network. Furth
Thank you for your reply. I'll calculate this. I was considering adding a small (12pF) series capacitor that would be shorted on all other bands than 10m. Are there some hidden dangers with this idea