All, There's a lot of useful engineering tips and mods for the TL922 over here: http://www.xs4all.nl/~pa0fri/Lineairs/TL922/tl-922eng.htm I have grounded the grids, fitted a grid fuse and replaced th
I agree. With decent AGM batteries I can't really see the need for capacitors. I have worked with AGM SLA betteries for many years in Ambulance electrical systems. I also use them to power various re
I have several HT packs for 3-500Z, 8877 and 4CX1000A amps. All my HT packs have a glitch resistor that is 25R @ approx 70W comprising 4 x 100R 17W wire-wound resistors in parallel. I use the ones by
On 11/08/2010 15:45, Carl wrote: -- Original Message -- From: "David C. Hallam"<dhallam@knology.net> To:<dezrat1242@yahoo.com> Cc: "Amps reflector"<amps@contesting.com> Sent: Wednesday, August 11, 20
I use RG400 PTFE coax with MHV and SHV connectors for B+ and TNC connectors with RG58 for B- ... works a treat and has become our contest group's defacto standard Mike G8TIC _________________________
It might be worth powering up the amp with the tubes out just in case you have a problem with a tube. I had one tube that was very low emission but was able to re-activate it using the circuit descri
Possible amp working normally and power meter intermittent fault? Mike _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listin
The 4CX1000/8166 is a fabulous tube ... I have about ten of them here that I acquired 10+ years ago from a broadcast station that closed down... I paid GBP £250 for the lot which were mostly pulls bu
I'd suggest a Tohtsu CX-600N on the output and something smaller on the input, or, alternatively a CX-800N which is double throw. Check out Ebay HenryRadio are setting some CX-800N relays and RF Part
David, The single 4CX1000A on 2m was published in the 1990 ARRL handbook and does use grounded screen - its grounded at DC and RF with the cathode at -ve screen voltage. This approach avoids having t
If its MFJ its likely to have been built down to a price and have a significant reactive component. Several thoughts: 1. do an A-B comparison with a *real* dummy load, for example a Bird 8080 for low
Dave... don't use them to regulate the screen supply of one of your big tetrode amplifiers ;-) Mike G8TIC _______________________________________________ Amps mailing list Amps@contesting.com http://
Dave, Get yourself an amplifier using one of those "tubes with handles" as talked about by Rich AG6K and you could probably get him to move...! Alternatively, try 21MHz ... its a more interesting ban
All, I'm looking to make a high power 144MHz amplifier by combining two BLF578 amps and would like to use a branchline hybrid and 90 degree coupling. To make this work at the power levels involved I
Henk, Thanks for the email... that domain name is "available" (not registered) and a Google search takes me to ITT Microwave defence systems instead :-( 73 Mike G8TIC ________________________________
rn I run the "ultra fast" UF5408 diodes in all my EHT packs and I use 12 diodes in each leg rather than 8 ... just a healthy bit of over engineering ;-) I don't use any equalising resistors or capaci
All, I thought I should mention that NXP have just announced a new version of the BLF578 1200W 50V LDMOS FET called the BLF578XR (Extremely Rugged) which is claimed to be "indestructible". http://www
We (Steve G8GSQ) and myself are in the process of putting together a 2m amplifier with two BLF578 devices (not 578XR) at the moment. Big heatsink = 350mm (L) x 250mm (W) x 80mm (H) and two copper spr
The shaft encoders look cool... bet they're pricey! I was thinking about a similar remote control project but to operate a cap and roller inductor for my balanced tuner (AG6K) at the bottom of the ga
I have no pricing on the BLF578XR but new BLF578 (genuine, not Chineese copies) were available on ebay.co.uk for GBP £85.00 each... I purchased some for my QRO 144MHz amp and they're fine. The Freesc