Go Back   WorldwideDX Amateur Radio Forums > Citizens Band Related > CB Radio Modifications


Amateur Callsign Lookup
Enter Callsign:

Cobra 148 gtl Philipi

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-22-2012, 07:35 PM
Junior Member
iTrader: (0)
 
Join Date: Dec 2011
Posts: 2
flash1van is on a distinguished road
Default Cobra 148 gtl Philipi


I am trying to mod my 148 for 10 meter operation. I got the crystal but can only get it to key up at 28.245 but no higher. I was hoping to use a switch and keep 11 as well but don't realy care. Any ideas?


Reply With Quote
  #2  
Old 01-22-2012, 07:50 PM
Robb's Avatar
Yup
iTrader: (3)
 
Join Date: Dec 2008
Location: Silicon Valley CA, Storm Lake IA
Posts: 7,829
Robb is on a distinguished road
Default

Sounds like you picked the wrong crystal for 10m - to me.

Using a DPST switch, stock/and 10m crystals, small piece of breadboard, and two variable caps, it might be possible to run both. Two parallel circuits and a switch between them - basically. Never done it myself; but in theory it might work. All you would need to do is wire both crystals/variable caps on a board and then wire them to the main board where you took the stock crystal from. Only one problem that I see, is that the VCO voltage might not be right for both bands and might unlock the PLL on one band or the other. Even that can have a workaround.

The OTHER consideration is to open the clarifier and use a 'super diode' (diode/choke) so that it will slide ~6kc's.
Re-aligning the VCO, 1st osc, and 2nd osc will be necessary too.

Will it work?
Maybe; maybe not . . .
__________________
BASE: Kenwood TS-2000, GAP Titan DX, Diamond X50A, Sirio SY27-4, and IMAX 2000.
MOBILE: Galaxy DX99V w/RF Limited CR-577 mic, Sirio Z-180. Yaesu FT-8800R & Diamond NR-770.

Reply With Quote
  #3  
Old 01-23-2012, 04:32 AM
RatsoW8's Avatar
Supporting Member
iTrader: (5)
 
Join Date: Nov 2009
Location: West Central Michigan
Posts: 1,945
RatsoW8 is on a distinguished road
Default

Quote:
Originally Posted by flash1van View Post
I am trying to mod my 148 for 10 meter operation. I got the crystal but can only get it to key up at 28.245 but no higher. I was hoping to use a switch and keep 11 as well but don't realy care. Any ideas?
What frequency crystal did you install?
__________________
Closet Biker, CB'er and snooty Ham!!
20 wpm Extra

Reply With Quote
  #4  
Old 02-08-2012, 08:11 AM
Junior Member
iTrader: (0)
 
Join Date: Dec 2011
Posts: 2
flash1van is on a distinguished road
Default

Used an 11.730 crystal, got it to work up to 28.240 even after adjusting the vco. As for the slider, got 16 kc down and 6 up...

Reply With Quote
Reply

Bookmarks
Worldwide Radio Forum



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
COBRA 148 GTL Review Robb CB Band and CB Radios 47 11-12-2013 05:04 AM
Cobra 148GTL VS. Galaxy DX-949 CTStallion CB Band and CB Radios 51 08-20-2012 11:37 PM
Schematic/Service Manual for Chinese Cobra 148 GTL? unit248 General CB Services Discussion 3 09-12-2011 11:40 AM
cobra 148 gtl chan display mod SHOCKER CB Radio Modifications 6 09-05-2010 07:21 PM
Nice Cobra 148 GTL Malaysia with Extras Wire Weasel CB Radio Gear SwapShop 0 08-01-2010 12:26 PM


All times are GMT -7. The time now is 07:40 AM.


Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Worldwide Radio Forum