[TowerTalk] Help with Ameritron RCS-12C

Wed Mar 19 17:38:39 EDT 2014

I looks like a design problem since the voltage on any unused port 
should be zero and not enough to trigger another relay on the 
DX-engineering switch.  I have, however, come up with a fix and that is 
to drive a bank of eight 5VDC relays to be controlled with the  4.9 VDC 
that appears voltage that appears on the remote RS-232 out put on the 
unit. This is a clean 5VDC with zero volts on any unused pin. This relay 
bank will then send out 12VDC to the DX-Engineering switch.  In looking 
at the schematic for the RCS-12C it appears to be insufficient bias on 
the the MJF-3055 switching transistors to cut them of when not 
triggered.  Or it could be a bad production run of this component.  I 
tried bleeding off the phantom voltage with a 2.2 Kohm resistor but this 
had no effect.  So I sent one of the problem boxes back to MFJ for 
evaluation.I will post the results when i get them.

Herb Schoenbohm, KV4FZ

On 3/19/2014 5:11 PM, Mark Robinson wrote:
> MFJ/Ameritron is sort of like Heathkit...but you don't get to build it 
> from new however you do get to fix it from new...hi hi
>
> The customer is the MFJ QA inspector
>
>
> Mark N1UK
>
>
> ----- Original Message ----- From: "Mike Reublin NF4L" <nf4l at comcast.net>
> To: <herbs at vitelcom.net>
> Cc: "Joe Subich, W4TV" <lists at subich.com>; "towertalk reflector" 
> <towertalk at contesting.com>
> Sent: Monday, 17 March, 2014 6:45 AM
> Subject: Re: [TowerTalk] Help with Ameritron RCS-12C
>
>
>> Herb,
>>
>> I had a bad RCS-12 out of the box. Maybe yours is too. The 
>> replacement worked as expected. I love it!
>>
>> Good luck.
>>
>> Mike NF4L
>>
>> On Mar 16, 2014, at 6:23 PM, Herb Schoenbohm <herbs at vitelcom.net> wrote:
>>
>>> Joe,  You are always so very helpful in solving problems....but in 
>>> this case I must have read and re-read the skimpy Ameritron manual 
>>> 10 or more times.  The jumpers are in the right setting per the 
>>> manual JMP1 is 1 of 8 and JMP4 is "direct" as the manual suggests.  
>>> Even on the bench on the "Relay Connection Jack" multiple votages 
>>> appear on different wire in one setting of the switch in the manual 
>>> mode.  this is with both my RCS-12C one just purchased to see if I 
>>> have a bad controller. As I mentioned the previously the RS-232 9 
>>> pin has individual voltage output 1-8 and no ambiguity.  However 
>>> this output is only 5 volts DC on either controller as it appears to 
>>> be for the purpose of switching other external devices. Absent a 
>>> detailed schematic my ability to troubleshoot the 8 higher current 
>>> switching transistors is limited.  Any suggestions?
>>>
>>>
>>> Herb, KV4FZ
>>>
>>>
>>>
>>>
>>>
>>> On 3/16/2014 6:03 PM, Joe Subich, W4TV wrote:
>>>>
>>>> Herb,
>>>>
>>>> Read the RCS-12 manual.  The answer you need will be found on pages 4
>>>> and 5.  See the 1 of 8 configuration for the "Relay Connection Jack"
>>>> and the appropriate setting for JMP 1.
>>>>
>>>> RTFM OM!
>>>>
>>>> 73,
>>>>
>>>>   ... Joe, W4TV
>>>>
>>>>
>>>> On 3/16/2014 5:16 PM, Herb Schoenbohm wrote:
>>>>> I am trying to get my RCS-12C Ameritron antenna switch interface 
>>>>> working
>>>>> with a DX-Engineering  8-Port Antenna Switch in a 1-8 configuration.
>>>>> However the Ameritron box outputs switching voltage on more than one
>>>>> wire simultaneously even in the manual setting  via the 8 pin 
>>>>> connection
>>>>> jack thus causing more than one relay to reference an antenna. The
>>>>> switching closures from the common main feed port to the various
>>>>> antennas are all over the place thus causing high VSWR on the 
>>>>> selected
>>>>> antenna. One would think that Ameritron would have 12 VDC or what 
>>>>> ever
>>>>> the switching voltage might be to only output one wire at a time but
>>>>> that is not the case.  There is however on the RCS-12C an Auxiliary
>>>>> Output DB9 connector which provides a single voltage of 5 volts DC 
>>>>> with
>>>>> respect to ground and these are all correct and non are duplicatd on
>>>>> other ports like the Din Relay box port Unfortunately the 
>>>>> DX-Engineering
>>>>> box type RR8B-HP Remote Antenna Switch requires a control voltage of
>>>>> 10-14VDC, not 5 volts. The cable used is CAT 5 of very good 
>>>>> quality and
>>>>> I have even made a new run with a new Din connection to the antenna
>>>>> control port on the RCS-12. All my setting inside the Ameritron are
>>>>> simple 1 through 8 switching.  I have searched for solution and maybe
>>>>> the only way the RCS-12C will control the DX=Engineering Antenna 
>>>>> Switch
>>>>> is by building a board of 8 five volt relays which then send 10-14 
>>>>> volts
>>>>> out to an external supply.  Yes the Ameritron 12-RCSC has 
>>>>> provision for
>>>>> inputing up to 30 volts and an internal jumper for a direct feed 
>>>>> to the
>>>>> Din relay box connector.  However there is enough voltage on non
>>>>> switched wires to cause the remote antenna switch to do all sorts of
>>>>> unfortunate things.  Sometime the 20 meter antenna shows up on 
>>>>> position
>>>>> 8 even though the coax is into port 5.  Sometimes the 10 meter 
>>>>> port and
>>>>> the 160 meter port are cross connected.  This is all very strange 
>>>>> and I
>>>>> would like to know if any other user of this configuration has had
>>>>> similar problems and discovered solutions.  I have even purchased 
>>>>> a new
>>>>> RCS-12C controller and this performs the same way.  Again I have a 
>>>>> BCD
>>>>> connection to my Icom but this is not the problem  since the bad
>>>>> switching occurs in manual mode  as well as auto mode.
>>>>>
>>>>> Please let me know if you have a solution to this.  I would like 
>>>>> to get
>>>>> it running before the CQ WPX contest or else try to switch this 
>>>>> box with
>>>>> some clip leads and a 12VDC supply.  This must be something simple to
>>>>> correct.
>>>>>
>>>>> Regards,
>>>>>
>>>>> herb Schoenbohm, KV4FZ
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk at contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>>
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