[1000mp] FT-1000MP RX antenna question

[Garry Shapiro]

I just dragged out the MP technical manual and examined the overall 
block diagram and the LPF, HPF and RF Unit schematics.

With the RX ant deselected, the RX path is from the main antenna through 
the TX relay on the LPF Unit (RL6016) to and through the HPF Unit and 
then to RL1001 on the RF Unit, which selects the RX source and passes 
the signal to the attenuator. I do not see any grounding point 
controlled by the TX state.

With the RX ant selected, the RX path is from the RX ant jack direct to 
RL1001 on the RF Unit. If the RX ant is selected, its signal goes to the 
attenuator; the signal from the main antenna is passed to the RX Ant Out 
jack. The TX/RX state has no effect.

To answer the question, the external RX ant is either connected or 
floating dependent upon RX antenna selection--not grounded by the TX state.

Garry, NI6T

Tod -ID wrote:
> Mark:
>
> I went through the schematic a couple of years ago and thought that it was
> not grounded. Yuri suggested I re-examine the schematic and I did. The
> second time through I concluded that the RX input from the RF IN jack on the
> back is grounded during transmit.
>
> I may go through the process once again just to be absolutely certain, but
> maybe this is something the individual owner should do so they feel
> comfortable about the risk. The obvious, no risk method is to put in a
> special grounding relay that is activated when transmitting.
>
>
> Tod, K0TO
>
>  
>
>   
>> -----Original Message-----
>> From: 1000mp-bounces at mailman.qth.net 
>> [mailto:1000mp-bounces at mailman.qth.net] On Behalf Of Marc 
>> Wullaert ON4MA
>> Sent: Tuesday, December 23, 2008 10:46 AM
>> To: All about Yaesu 1000mp
>> Subject: Re: [1000mp] FT-1000MP RX antenna question
>>
>> I'm not so sure it go's to ground ..it open thats all.
>>
>> on4ma
>>
>> ----- Original Message -----
>> From: "Tod -ID" <tod at k0to.us>
>> To: <cqkg8co at yahoo.com>; "'All about Yaesu 1000mp'" 
>> <1000mp at mailman.qth.net>
>> Sent: Monday, December 22, 2008 4:06 AM
>> Subject: RE: [1000mp] FT-1000MP RX antenna question
>>
>>
>>     
>>> It goes to ground. You can check that on the schematic.
>>>
>>> Tod, K0TO
>>>
>>>       
>>>> -----Original Message-----
>>>> From: 1000mp-bounces at mailman.qth.net
>>>> [mailto:1000mp-bounces at mailman.qth.net] On Behalf Of Brian
>>>> Sarkisian, KG8CO
>>>> Sent: Sunday, December 21, 2008 12:37 PM
>>>> To: 1000mp at mailman.qth.net
>>>> Subject: [1000mp] FT-1000MP RX antenna question
>>>>
>>>> I saw this question on another reflector, and haven't been
>>>> able to find the answer to the RX antenna question.
>>>>
>>>> Does the RX antenna go to ground while transmitting, or
>>>> should some sort of front end saver be put in line?
>>>>
>>>> Thank you
>>>>
>>>>
>>>> Brian, KG8CO
>>>>
>>>>
>>>> I have the service manual here for the FT1000MP but I can't
>>>> tell whether = or not the RX antenna is grounded during
>>>> transmit. Does anyone out there = know?? I am using a loop
>>>> receive antenna on 160M and don't have any = outboard
>>>> protection on it at present.
>>>>
>>>>
>>>>
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>
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