The AM Forum

Good day,

Picked up an 851 and was curious from the prior posts, is the 851 same L values as the 850A? L range, 13.6 uH down to 0.8 uH. Z transform range from 2.5 k to 5 k down to 50 ohms?

Tnx, Alan

A search of our forum brought up this info on the 850, 851, and 852.

http://amfone.net/Amforum/index.php?topic=25579.0

Thanks Pete. Yes, that post I reviewed and had a great deal of the information. However, the 851 was not mentioned except for power rating, 250-500W. I am looking for the L total and its taps. One post in another forum mentioned a total L of 15.5 uH. While the 850A appears to be 13.6 uH. So a bit different.

Alan,

I have a scanned copy of a Barker & Williamson catalog from 1987.  It lists the specifications for the 850, 850A, 851, and 852.

For the 851 it gives the following:
Power: AM 250 W, CW/SSB 500W
DC Plate Voltage: AM 1250 @ 200 mA, CW/SSB 2000 @ 250 mA
Plate Load Impedance: 2500 - 5000 ohms
Output Impedance 50-75 ohms
Inductance Taps 14, 6.3, 1.5, 0.8, 0.52 microhenries
Capacitance to Resonant Each Band 150, 80, 70, 55, and 50 pF

I hope that helps.

Regards,
Dean, AE7DB

Perfect Dean!

Thanks,

The 1962 Orr Handbook has a 4-400A amp which uses the B&W 850.  It lists 13.5uh for 80, 6.5uh for 40, 1.75uh for 20, 1.0uh for 15 and 0.8uh for 10.

This should make it easier:

Wow. I knew the "official' document had to be some where on the planet!
Tnx Pete,

Alan

I have lots and lots of "official" documents and many more to come  :D