Home
Shopping Cart
Contact Us
Search: Advanced search
 
Printable version 
Categories Categories
Products by radio
Accessories
Crystals
Filters
Filter Kits
Mods
Publications
Small Parts


Inrad News Inrad News
News
FAQ
Announcements
Equipment Repairs
Catalog
Price List
Dealers


Your cart Your cart
Cart is empty
 

View cart
Checkout
Wish list
Orders history
Returns



Authentication Authentication
Username

Password

Log in 
Register 
Recover password

If Javascript is enabled in your browser click here



Help Help
Contact Us
Privacy Policy
Terms & Conditions



International Radio :: Products by radio :: Collins :: 75S-3B/C

DISCONTINUED: As of 9/25/17 we have exhausted our supply of daughter boards for Collins 75S-3B/C radios for the now out-of-production 455 kHz mechanical filters. Information below is for legacy purposes. The board layout, schematic and parts list for the discontinued board is downloadable below.

Inrad has designed an adapter board to allow the use of the newer Collins mechanical filters in the 75S-3B/C radios. The filters available are listed below. All filters have a center frequency of 455 kHz.

Two specially designed networks are included on the adapter board to match the input and output impedance of the new series filters to the radios. The original filters had a very high impedance whereas the new series are 2000 ohms. The resulting signal level through the adapter board is very close to that of the original filters.

The adapter is constructed on a double sided FR4 pc board with plated through holes. Surface mount components are used in the production units. The board contains pads for through hole components which can be supplied for special uses. Gold plated pins are swaged into the board so it may be plugged directly into the 75S3B/C filter sockets.

Installation consists of plugging the adapter, assembled with the filter of choice, into the radio. The resonating capacitors in the radio can be set to fully CW, then backed off 1/4 turn.

Full installation instructions are available here:

Schematic, parts list, and board layout for the discontinued circuit board:

Bandwidth (Hz) 58003800290025002000500300
ModeAMAMSSBSSBSSBCWCW
Filter #707 #724 #726 #706 #720 #705 #712

75S-3B/C
Sort by: Product Sort direction Price Default

#707
5800 Hz 455 kHz AM 8-pole...
See details

 
#705
500 Hz 455 kHz CW 7-pole...
See details

 
#706
2500 Hz 455 kHz SSB 8-pole...
See details

#720
2000 Hz 455 kHz SSB 8-pole...
See details

#724
3800 Hz 455 kHz SSB 7-pole...
See details

#726
2900 Hz 455 kHz SSB 8-pole...
See details

453.65 kHz Crystal
453.65 kHz 30 pF USB Carrier...
See details

456.35 kHz Crystal
456.35 kHz 30pF LSB Carrier...
See details

#712
300 Hz 455 kHz CW 7-pole...
See details

 
 
 
 
Inrad Copyright © 1972-2024 International Radio