Re: [AMRadio] single 833

[k9muf]

I built a transmitter with a single 833A modulated by a pair of 810s. I chose 
that combination of tubes because of their looks and also because they do not 
require any forced air cooling.
I put windows in front of the tubes so one can see the tubes glow.What a 
beautiful sight.

I used my own design based on ideas from many of the old handbooks, mostly the 
Editors and Engineers. Most of the information was not specific to an 833A but 
to triodes in general. The circuit was varied to fit the parts I had on hand 
and to the specifications of the 833A.

I used a modulation transformer and reactor from a 1kw broadcast transmitter. 
I am using a pair of 6L6s to drive the 810s. For the interstage transformer I 
rewound the secondary of an output transformer from an old broadcast receiver 
that used a pair of 6L6s in the output stage.

I am using a common plate power supply for both the RF and modulator tubes that 
puts out about 2200 volts.

The RF carrier power is about 300 watts when driven with about 35 watts.

Now here is the problem I am having with it. 
I am getting acoustical talkback when it is modulated and I can't find out 
where it is coming from. I have temporarily substituted a different mod 
transformer and bypassed the mod reactor, but I am still getting it. 
So that is where I am at now. I don't want to put it on the air until I get 
that problem resolved.

DonK9MUF



- Original Message -

From: Mike Sawyer 

To: Discussion of AM Radio in the Amateur Service 

Sent: Mon, 9 Feb 2009 21:13:24 + (UTC)

Subject: Re: [AMRadio] single 833



I always wanted a rig that uses the 833. It such a neat and different tube. 

I have a good supply of 810's so I figured a pair will modulate one nicely. 

I like the BTA-500/1MX's. As a matter of fact, I was supposed to be wheeling 

and dealing on a -500MX with Eric, WB4VVI (SK) before he went SK. Oh well. I 

like the prospects of the 810's and the single 833. It won't weigh near as 

much as one of those boxes. I have some nice black krinkle panels so a 

krinkle motif is in the cards.

Mod-U-Lator,

Mike(y)

W3SLK

- Original Message - 

From: John Lyles 

To: 

Sent: Monday, February 09, 2009 9:39 AM

Subject: [AMRadio] single 833





There's a fellow near me that built a single 833 modulated by a single 833, 

one of a class A bias-changing heising design. I gave him a big reactor for 

it. I can get details if anyone wants.



73,

John

K5PRO

on the road from Oklahoma City this morning







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[AMRadio] Meissner ID and schematic wanted

[K9MUF]

I have a 14 tube Meissner radio similar to their Traffic Master but it is 
not the same.
The obvious differences are as follows:

The Traffic Master has a slide rule dial with a separate bandspread tuning 
knob, mine has a unique oval dial with a 2 speed tuning knob.
The Traffic Master has 4 IF cans, mine has 7 IF cans.
The Traffic Master uses a pair of 6V6s in the audio output, mine uses a pair 
of 6L6s.
 
I have searched the internet and old copies of QST (mid 1930s) and cannot 
find any reference to it.
If anyone has any information on this radio especially a schematic, I would 
certainly appreciate it.
 Photos can be seen here:http://www.shutterfly.com/view/pictures.jsp

Don   K9MUF



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Re: RE: [AMRadio] 4D32 rig testing

[K9MUF]

In a message dated 1/23/4 9:59:58 AM, [EMAIL PROTECTED] writes:

 Collins runs them at over 700 volts in class C plate
modulated service (32V series).
If they don't arc over, and you don't exceed the plate dissipation,
what would be the problem?
 
Brett,

I have a 32V-3. I can't find anywhere in the manual where they specifically 
say wherher to use 600 or 700 volts except to use 600 volts for initial 
adjustments.
They do say in the description of the HV supply The tube manufacturer 
recommends no more than 600 plate volts for phone operation, but this is for 
CCS 
rating. So without saying it I guess they are implying that 700 volts is 
allright for amateur use. 
The 4D32 is probably pretty conservatively rated. I have been running mine at 
600 volts, but perhaps now I will try the 700 volt position. Still, I would 
not run the 4D32 at over 700 volts.

Don