THE UBIQUITOUS 6146

[VE3WI Dave]

These days everything is solid state, but some of us became hams when vacuum tubes were everywhere.  No other tube has powered more ham rigs than the 6146 & its cousins:

6146A: improved heater
6146B: completely redesigned, not interchangable with earlier ones
6146W: ruggedized military version
6883A/B: 12V heaters. 

RCA introduced the 6146 in 1952, and they are still going strong in lots of vintage ham rigs. 

When I first got licensed in 1968, the UNB ham club had the big Heathkit twins - Mohawk RX & Marauder TX.  The Marauder used two 6146s for 180 watts PEP.  They were great rigs, a real pleasure to operate.

My first TX was a little EICO 723 which had a 6DQ6 PA, giving 60 watts on CW.  It's big brother was the 720, which had a single 6146 for 90 watts CW or AM.  After I graduated & got a job I splurged for a Heathkit SB-102, which had: 2 - 6146s.

I've been searching for parts to recreate my original station. I didn't think I'd ever find an EICO 723 so when I saw a reasonably-priced restorable 720 I bought it.  Of course immediately thereafter, I saw a 723 so now I have both!  I'll be listing the 720 one of these days.

Here's what they look like:



If you want to buy one, RF Parts has new Chinese-built 6146Bs for about $60US.  Also many NOS & used/tested ones listed on eBay & several online stores.  

Recently I saw a thread on QRZ.com where people were posting lists of rigs that used the 6146.  It's a long list.
73
Dave, VE3WI
----------------
Collins
KWM-1
KWM-2
32S-1
32S-2
32S-3

E. F. Johnson
Ranger
Ranger II
Viking II
Navigator
Pacemaker
Valiant
Valiant II
Invader
Vanguard
Victor

Heathkit
DX-35
DX-40
DX-60
DX-60B
DX-100
DX-100B
Apache (TX-1)
SB-100
SB-101
SB-102
SB-400
SB-401
HW-100
HW-101
HX-1680
HX-10 (Marauder)
MT-1 (Cheyenne)
HX-20
SB-500
VHF-1 Seneca
SB-110 (A)

Kenwood
TS-520
TS-830
TS-500
TS-510
TS-515
T-599

Yaesu
T-101ZD
FT-102
FT-902
FT901D
FT-901DM
FTV-650B

Inoue (Icom)
IC-700T

Hallicrafters
HT-32 (A)
HT-32B
HT-37
FPM-200

Hammurland
HX-500

Swan
250

Eico
720

Knight
T-150
T-160

Multi Eimac
AF-67
AF-68

WRL
Scout
HG 303
HG 602

Eldico
T-102

Gonset
Commander
G-77

Barker & Williamson
B&W 5100 (B)
B&W 6100

Lafayette
KT-390

Morrow
MB-568

Geloso
G.222.TR
G4-225
G4-228
G4-229

KW Electonics
KW2000
KW204
Viceroy
Vespa Mk I

Miniphase
SB7M

Mosley
Commando II

Frontier Electronics
FE-600

Panda
Explorer

Tiger
Tigress

Uniden/Tempo
2020 6146B

GE
Progress Line (VHF)

Clegg
Venus (12 volt version of the 6146, the 6883)
Thor

[Adam_VE3FP]

These tubes have been around for years and used into early 90s. I still have a Heathkit SB-101 and a spare set of 6146s somewhere. I would like to get it on the air again but have to find or make some pullies for the tuning capacitor which disintegrated over the years. 
Back in a day I had one of those EICO 723 (seven drifty three), there was a reason they were called "seven drifty three",  you had to find the station again you were having a QSO with after you got done transmitting. (exaggerated a little). 
One thing about tube finals, you didn't have to worry much about high SWR, they were forgivable for most part.
Good luck building your vintage station. We'll have to get on the air with these rigs, specially in the winter just to keep the shack warm. Hi Hi.

[VE3WI Dave]

I've read lots of criticism of the EICO 753 on account of the drifting, never used one.  It had two 6DQ6s in the PA, same tube as used in my 723.  TV sweep tubes, an inexpensive way to get RF power, used by many ham manufacturers (e.g. Swan, Drake).

At the UNB club where I learned ham radio we obviously knew what SWR was, but we never gave it much thought.  We had a triband yagi & an 80m inverted V on the roof of our building, & as long as the TX would load into the antenna it would work.  Of course all the tube rigs had a built-in "manual antenna tuner" (called the pi-network plate circuit), and the tubes could tolerate a certain amount of reflected power.  It was only when solid state rigs with fragile PA transistors & fixed broadband output circuits came along that constantly worrying about SWR became part of routine ops.  Nowadays we take the need for low SWR for granted and have moved on to stamping out other evils like common mode current :-)

73
Dave, VE3WI

[Adam_VE3FP]

 You're right Dave, it's the EICO 753 (seven drifty three). I didn't own too long, it was given to me by my wives uncle.
The PA did have a pair of 6DQ6Bs and would put out abt 120w cw and 30 am. I would be very surprised if there any still in use, probably just a collectors item.