[MRCA] Fw: [Army-Radios] Question about cable CG-67/MRQ-2 used with AB15 and BC659.

[J Mcvey]

 There were 3 iterations of the coax antenna terminal box for the BC659.
The first two TM210 and TM211 were electrically similar, having matching transformers built-in to match a coax cable.These are described in TM11-615 , page11, 12 and 13 of the manual ( not the PDF page #). They say that the cable  CO-282 ( which could be RG8) can be cut to the length, no restriction.
The TM218 has NO matching transformer and connects the radio output DIRECTLY to the coax port. They specify to use the mysterious cg-67/MRQ-2, which is a 9 foot length of some kind of coax with a PL259 on each end which is NOT to be  to cut , The length is CRiTICAL to perform the impedance transformation instead of the transformer used in the predecessors. 
The manual uses an AB-15/GR mast with sections ms116, ms117, ms118, which is about 9 foot, closer to quarter wave than half wave the the radio was designed to load.
I tried to reverse engineer it , but it doesn't work too well even with a 95 ohm cable .

    On Monday, August 19, 2024 at 05:27:06 PM EDT, J Mcvey via MRCA <mrca at mailman.qth.net> wrote:  
 
  

   ----- Forwarded Message ----- From: J Mcvey via groups.io <ac2eu=yahoo.com at groups.io>To: army-radios at groups.io <army-radios at groups.io>Sent: Monday, August 19, 2024 at 05:19:15 PM EDTSubject: [Army-Radios] Question about cable CG-67/MRQ-2 used with AB15 and BC659.
 Anybody know the impedance of the coax used?
They are quite specific about it must be 9 feet in length, which seems to imply that the impedance/length  is critical to get a correct match to the antenna.
Jim
_._,_._,_Groups.io Links:
 You receive all messages sent to this group. 

View/Reply Online (#72518) | Reply To Group | Reply To Sender | Mute This Topic| New Topic
Your Subscription |Contact Group Owner |Unsubscribe [ac2eu at yahoo.com]

_._,_._,_  ______________________________________________________________
MRCA mailing list
Home: http://mailman.qth.net/mailman/listinfo/mrca
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:MRCA at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20240821/0bc10497/attachment.html>