Henry HF RF AMPLIFIER

Henry HF RF AMPLIFIER Henry RF Amplifier Information Center

Henry RF AMPLIFIER

Information Center

Page Updated on: 05/18/2022

2K Classic (left) / Pair 2K-4 (center) / 3K-A (right)

*** DANGER ***

RF Amplifiers Have Lethal HIGH VOLTAGE Inside

About This Web Site:

The information contained on this web site is a FREE knowledge exchange for older Henry vacuum tube RF amplifiers. All information listed is an accumulation of lessons learned by multiple different individuals when modificating or repairing their Henry RF amplifiers. There is no guarantee the information is error free, so utilize it as reference only. Perform all modifications and repairs to your equipment at your own risk. If you have additional information on Henry RF amplifiers which you would like to share with others, email ~~mayo(at)ne7x(dot)com~~ bob@n3xkb.com and I will add your information to this web site.

---------------------------------------------------------------------------------------------------------------------

Manuals:

Henry 1KD-5

3KD Premier
3KD Premier again
Henry 2KD-3

Henry 2-K, 2-KD and 2-KR

Henry 2K Ultra

Henry 2K-4

Henry 2KD/3KD

Henry 2K-2

Henry 2KD-5

Henry 2K Classic

Henry 2K Classic X

Henry 2K-3 3K PSU Schematics
3K RF deck Schematics
From VY2NX Henry 3K Classic and Classic X with 8877
from W0ARM SS750_SS1200

Henry 3K-A
from W0ARM

Henry 3K/8K Ultra

Henry 3K Classic Mark II and Classic X Mark II

Henry_3KD_Premier (8877)

Henry 4K-2

Henry 4K Ultra

Henry 2002/4/6 VHF

Henry 5K

CAUTION when using or referencing original factory Henry Radio schematics.

The schematics are known to have wiring errors.

Double check wiring against other designs and do not assume the Henry Radio schematic is 100% correct.

EXAMPLE: The 2K-Classis schematic shows BIAS zener 'D1' in backwards.

Henry Radio RF Amplifier Model Numbers and Specifications

Past ARRL QST Magazine Product Review Articles

Henry Radio; 2-K Linear Amplifier; Jun 1965

Henry Radio; 2K Ultra Amplifier; Jun 1972

Henry Radio; 2K-2 Linear Amplifier; Nov 1967

Henry Radio; 2K-4 Amplifier; May 1974

---------------------------------------------------------------------------------------------------------------------

Overviews:

Henry 4K Ultra

By: KF8OD

Place Holder 2K-4 RF Output Video Place Holder

3K Ultra RF Output Video Place Holder 3CX10000A7 Video

---------------------------------------------------------------------------------------------------------------------

Procedures:

Dip-N-Load

Amplifier RF Output Tuning Procedure

By: NE7X

Tuned Input Adjustment

SWR Match Between Transceiver Output & Amplifier RF Input

By: NE7X

Internal RF Deck Chassis Removal

Pedestal Cabinets

By: NE7X

-----------------------------------------------------------------------------------------------------------------------------

Modifications / Upgrades:

Henry 2K Classic

Metering Circuit and HV Protection Upgrades

By: NE7X

Tear-Drop Meters

Information about Tear-Drop meter replacement

By: NE7X

Henry 5K Classic

Blower Fan Mod
Step Start Mod

by: K7EM

Soft-Start

2K-4 / 3KA / 2K Classis

By: NE7X

Henry 2K-Classic 10 Meter Modification
By: AB8VJ

Henry 3KA Conversion to 5K

By: KA1CDE

Henry 2K Classic X Conversion to 5K

By: KA1CDE / W2ISB

The Henry 2K Project

By: Fred KC5RT (For: WS0B)

-----------------------------------------------------------------------------------------------------------------------------

QSK Modifications:

Henry 5K Classic

By: K7EM

Original Henry 2K

By: NE7X

Henry 2KD-5

By: NE7X

Henry 2K-4 and 3K-A

By: NE7X

SEQ-QSK Sequencer & Vacuum Relay Issues/Fixes

By: NE7X

-----------------------------------------------------------------------------------------------------------------------------

Troubleshooting / Repairs:

Troubleshooting Tips

By: Henry Radio

Blower Fan Replacement - Henry 2K-4

By: W4CLM

Blower Fan Replacement - Henry 5K

By: K7EM

HV Drops to Zero when Amplifier is Keyed

By: NE7X

HV Arcing / Popping

By: NE7X

Intermittent High SWR

By: N6MMW

BIAS Zener Failure

By: NE7X

Low RF output, No Ip Dip

By: N6DKA

ALC Zener Failure

By: NE7X

300ma Plate Current When HV is Applied, No Drive

By: K2MF

AC Breaker/Fuses Blow When Powered ON

By: AA7A

Ip & RF Output Slowly Increases After Amplifier is Keyed

By: NE7X

-----------------------------------------------------------------------------------------------------------------------------

RF Amplifier Parts:

Radio Dan - W7RF Henry Radio RF Parts Company

eBAY Henry Radio Ameritron 3-500G RF Tubes

Gigavac GH-1 Vacuum Relays SEQ-QSK Sequencer - NO LONGER BEING PRODUCED Harbach Electronics

Ohmite Power Resistors Electrolytic Capacitors BIAS Zener D1

RF Junk Plate Caps for 3-500Z 3-500G RF Sockets QRO Parts

RF Band Switches eBAY RF Band Switches Refurbished Front Panels

The Medallion shape of the MM-series by Jewell Instruments is a close design substitute
for the original Tear Drop design by Parker from the 1960s.
http://www.jewellinstruments.com/wp-content/uploads/2012/11/Jewell-MM-Series.pdf

For Henry amplifier restorers, this is an option when desiring to retain design aspects of these original Henry classics.
http://www.jewellinstruments.com/meters-and-avionics/panel-meters/analog-meters-product-list/

-----------------------------------------------------------------------------------------------------------------------------

Non-Henry RF Amplifier Information:

External QSK-2KW Interface

External QSK interface that can be connected to any vacuum tube RF amplifier

By: NE7X

Ameritron AL1200 QSK Modification

By: W2NO

RF Amplifier Technical Web Site

By: W8JI

T/R Relay Escalator

Inexpensive way to increase the switching time for slower mechanical T/R relays

By: K6KK

Adding 160 Meters

By: AG6K

Heathkit SB-200 Modifications

By: PA0FRI

-----------------------------------------------------------------------------------------------------------------------------

RF Vacuum Tubes:

3-500G

By: NE7X

Triode Data Sheets

By: G8WRB

-----------------------------------------------------------------------------------------------------------------------------

Web Page Editorial:

Henry RF amplifiers maybe big (34" tall), heavy (150+ #s) and old (1960-1990s), however high power RF amplifier technology has not changed much over the years. Transistor RF amplifiers are becoming smaller and more reliable, however most are not built to commercial continuous duty-cycle specifications like Henry RF amplifiers are. Plus newer solid-state RF amplifiers can be 4X the cost over an older gently used Henry RF amplifier.

Henry RF amplifiers are very easy to work on with lots of room to get your hands and tools inside, and parts are still available and affordable. A well maintained Henry RF amplifier will still be around putting RF output and breaking DX pile-ups long after I become a SK.

Some hams may say "dip-n-loading the plate Ip is a pain," however I find this a feature. Having a pi-output network allows me to bring the RF amplifier to maximum RF output resonance when the antenna is a few Z-ohms off. Unlike a transistor solid-state RF output circuit, an adjustable pi-output circuit allows for maximum transfer of RF power while tolerating a higher SWR.

There is also the "Fun Factor" in owning and operating a Henry RF Amplifier. The thrill of receiving a signal report and comments from the stations you are in QSO with, "You are the loudest signal on the band!" Or the impressive looks and comments you receive by visitors to your shack when they see the heavy metal Henry RF Amplifier sitting next to your operating desk. Just look the the picture at the top of this webpage. Having that "BIG GUN" shack appearance is worth another 10dB !

Personally I prefer Henry RF Amplifiers with 3-500Z type tubes. The 3-500Z tube in my opinion is: very durable, will tolerate abuse (miss-tuning), relatively available and easy to obtain, instance-on, a pair provides full-legal-limit RF output and best of all, has the best "Power-To-Dollar" value ratio. Having multiple Henry RF amplifiers all using the same type of RF tube allows me to only need to stock one type of tube for inventory spares.

I have received emails asking me to repair a Henry amplifier if its shipped or delivered to me. At this time I have to decline. I am still working full time for a living and have many personal commitments consuming my time. However if you have a particular issue or question, I will gladly respond to all emails and provide some suggestions what you can try doing to resolve the issue yourself. Once you have the issue resolved, I would appreciate a return email informing me what the final solution was.

So whatever your manufacturing choice is in RF amplifiers, tubes or transistors, life is too short for QRP! Enjoy the hobby & happy DXing.

73s Thomas NE7X

This page is currently maintained by N3XKB

Henry 1KD-5	3KD Premier	3KD Premier again	Henry 2KD-3
Henry 2-K, 2-KD and 2-KR	Henry 2K Ultra	Henry 2K-4	Henry 2KD/3KD
Henry 2K-2	Henry 2KD-5	Henry 2K Classic	Henry 2K Classic X
Henry 2K-3	3K PSU Schematics 3K RF deck Schematics From VY2NX	Henry 3K Classic and Classic X with 8877 from W0ARM	SS750_SS1200
Henry 3K-A from W0ARM	Henry 3K/8K Ultra	Henry 3K Classic Mark II and Classic X Mark II	Henry_3KD_Premier (8877)
Henry 4K-2	Henry 4K Ultra	Henry 2002/4/6 VHF	Henry 5K

Radio Dan - W7RF	Henry Radio	RF Parts Company
eBAY Henry Radio	Ameritron	3-500G RF Tubes
Gigavac GH-1 Vacuum Relays	SEQ-QSK Sequencer - NO LONGER BEING PRODUCED	Harbach Electronics
Ohmite Power Resistors	Electrolytic Capacitors	BIAS Zener D1
RF Junk Plate Caps for 3-500Z	3-500G RF Sockets	QRO Parts
RF Band Switches	eBAY RF Band Switches	Refurbished Front Panels