The AM Forum
April 29, 2024, 04:12:28 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: NC-300/303 Mounting ?  (Read 11031 times)
0 Members and 1 Guest are viewing this topic.
WA2ONK
Contributing
Member
*
Offline Offline

Posts: 225


« on: September 17, 2008, 10:19:43 PM »

I've never  seen one "up close and personal", can the 300/303 be rack mounted?
I have some room in the rack......     Chuck..
Logged
Steve - WB3HUZ
Guest
« Reply #1 on: September 17, 2008, 10:27:54 PM »

The 303 can and I'm pretty the the 300 is the same.
Logged
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 8169


CQ CQ CONTEST


WWW
« Reply #2 on: September 18, 2008, 12:26:28 AM »

You could also use a rack shelf.
Something like this:
http://www.racksolutions.com/rack-shelf.shtml
Saves having to store a cabinet somewhere unless you don't have a cabinet for it.
Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
W1ATR
Resident HVAC junkie
Member

Offline Offline

Posts: 1132


« Reply #3 on: September 18, 2008, 09:04:42 AM »

Yup, they are both the same chassis.
Logged

Don't start nuthin, there won't be nuthin.

Jared W1ATR


Click for radio pix
KB5MD
Contributing
Member
*
Offline Offline

Posts: 614


« Reply #4 on: September 18, 2008, 01:27:39 PM »

While we're on the subject, what is the difference between an NC 300 and a 303, other than the extra knob on the front?
Logged
WBear2GCR
Member

Offline Offline

Posts: 4135


Brrrr- it's cold in the shack! Fire up the BIG RIG


WWW
« Reply #5 on: September 18, 2008, 03:45:18 PM »



...ummm?

maybe...


         Three?      Wink


_-_-bear


(sorry couldn't resist the temptation...)
Logged

_-_- bear WB2GCR                   http://www.bearlabs.com
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 8169


CQ CQ CONTEST


WWW
« Reply #6 on: September 18, 2008, 03:58:31 PM »

While we're on the subject, what is the difference between an NC 300 and a 303, other than the extra knob on the front?

The "Dream Receiver" (NC-300) probably was conceived during a bad nightmare. National issued a number of service bulletins during its life cycle. Over the years, I've had 3 NC-300's and none of them agreed completely with the schematics that came from the factory.

Second try, "Dream Receiver" (NC-303), some additional features and the design was far more stable and not subject to numerous changes.

NC-300 Complete Specs
NC-303 Complete Specs
Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
Steve - WB3HUZ
Guest
« Reply #7 on: September 18, 2008, 05:47:06 PM »

The biggest difference in front panel function are selectable upper and lower sideband filters and a better product detector for SSB.
Logged
WA2ONK
Contributing
Member
*
Offline Offline

Posts: 225


« Reply #8 on: September 18, 2008, 06:44:45 PM »

Thanks......
Logged
W1ATR
Resident HVAC junkie
Member

Offline Offline

Posts: 1132


« Reply #9 on: September 18, 2008, 10:42:50 PM »

Bear, lemmee help ya out.

They're in the bathroom, in the medicine chest on the second shelf to the right....

Take two, with food.. Roll Eyes Roll Eyes
Logged

Don't start nuthin, there won't be nuthin.

Jared W1ATR


Click for radio pix
John K5PRO
Member

Offline Offline

Posts: 1033



« Reply #10 on: September 19, 2008, 12:54:41 PM »

The NC300/303 have a wierd way of mounting the receiver into the cabinet. Instead of having flat rails that are tapped with threaded holes, on the sides, and using rack screws (like standard #12), they have threaded studs sticking out front, and a trim strip covers this. Nuts are applied on the front panel to the threaded studs. Backwards from any radio I've seen.

See them here:
http://www.virhistory.com/ham/nc300/nc300.jpg

Nick, KD4CPL, has a nice site on these RX.

Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #11 on: September 29, 2008, 08:19:43 PM »

In addition to the above:

The NC-300 uses a free running oscillator for the 2nd conversion and the 303 is crystal controlled. Any 300 that came thru the National Service Dept had the crystal conversion done at no charge. That alone contributes to the majority of the stability improvement.

SSB reception is marginal even with the 303 mainly due to the 6BE6 PD/BFO. The audio output is loaded with distortion products and the tube itself is extremely noisy. A 6BY6 is a bit better but a dual triode ( consider a 6J6 in a Pullen) would be a huge improvement as a PD with a seperate BFO.

Carl
KM1H
National Radio 1963-69
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.058 seconds with 18 queries.