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eHam Forums => Mobile Ham => Topic started by: AB6LD on January 18, 2004, 03:36:33 AM



Title: Problem with AH-4 and MK2G
Post by: AB6LD on January 18, 2004, 03:36:33 AM
I'm having a problem with my new AH-4 and MK2G. More often than not, when I try to load up on 20 and 40 meters, the radio shuts off while tuning. I have it in a mobile installation. I'm using a 102 inch stainless steel whip antenna. The tuner is grounded also. Any suggestions?


Title: Problem with AH-4 and MK2G
Post by: K0BG on January 18, 2004, 11:09:54 AM
Assuming the tuner grounding is done properly, and the lead from the AH-4 to the whip is short (inches, not feet, and not coax); The problem is caused by RF getting into the remote cable.

First, make sure you install the screw on the rig end of the cable. Two, install a split bead on each end of the cable (mix 43 works best). This RF turn off problem is a well known malady.

Alan, KØBG


Title: Problem with AH-4 and MK2G
Post by: AA4PB on January 19, 2004, 08:37:12 PM
Easy to tell if its an RFI in the remote cable problem. Just attach the head directly to the radio and see if the problem goes away.


Title: Problem with AH-4 and MK2G
Post by: K4KWH on January 19, 2004, 11:36:16 PM
I believe the posters above are right.  This seems to be a commom problem with remoted 706s.  As said, put the remote head directly on the radio and try it. If it doesn't shut off with the head in place, likely this is the problem.  First check to see that the screw on the control cable is in place. If it still
shuts off, then take a wooden dowel of 1/4" dia and wind 6 turns or so of the control cable around this
dowel closely. Then tape the turns to keep them in place.  This "choke" *should* keep the stray RF off
the cable.  At least, it worked for me.  Mine would
either jump frequency or shut off completely. Hope this helps.

73

Jerry
K4KWH


Title: Problem with AH-4 and MK2G
Post by: AB6LD on January 20, 2004, 04:05:35 AM
I put the head directly on the radio as suggested and it did not shut off during tuning.  After researching several past postings regarding the AH-4, I was able to correct some other problems with my installation,  Like reducing the feed cable to the antenna from 13 inches to 1/2 inch and Reducing the ground strap length to less than 4 inches.  This has enabled me to tune all of the 20 meter band now.  I am going to try the other suggested tips regarding the contril cable to tune 40 and 30 meters.  I'll post my results in a few days.  Thanks for all the help! !

Tom
AB6LD


Title: Problem with AH-4 and MK2G
Post by: AA4PB on January 20, 2004, 07:51:10 PM
Thanks for posting your results, Tom. It helps us all to learn from your experience. So many times people do not do that and we never know if the suggestions worked or not.



Title: Problem with AH-4 and MK2G
Post by: AB6LD on January 22, 2004, 04:07:02 AM
The split beads did the trick!  I can now tune all of the bands with no problems.  However on 20 meters I can not do a the auto SWR check.  The MK2G transmits on RTTY to do a SWR check.  For some reason any RTTY output still shuts off the radio on 20 meters only.  However using the built in SWR meter I can tell that the SWR is good.  So no real problem there.  I did use mix 43 split beads as Alan, KØBG suggested and it seemed to work the best.  They were cheap also, I paid 1.99 each and put one at the head and one at the tranceiver.  The 102 inch steel whip seems to work really well also.  I have made some really nice contacts as far as New Jersey and Florida so far!  And got some really nice reports also.

I must say that I'm really dissapointed with Icom however.  After paying close to 80 bucks for the long remote head cable, you would think that it would work just a bit better.  All in all however I'm glad it works and want to thank everyone, especially Alan for all the help!

73's
Tom
AB6LD