[1000mp] Important question

[Pete Smith]

Nice job as usual, Mark, both the box itself and the documentation.  I learn things every time I go to your web site. 

I don't think you need the vacuum relay if you place the protector in the RXOUT/RXIN loop - the radio then takes care of switching.  I have a switch on the front of the protector box that allows me to select either the transmit antenna or an optional RX antenna, both passing through the RX protection circuitry. 

I used garden variety silicon diodes in shunt, but included an SPST switch so I could remove them from the circuit altogether if they raised intermod problems.  So far I have heard none.

The pilot bulb is intended to blow at approximately 1/2 the estimated minimum rating of any single resistor in the front end, as calculated by W2VJN in his book on interstation interference.  George gave me a lot of help selecting the right bulb.

73, Pete N4ZR

At 07:02 AM 12/5/2005, you wrote:
>Hi Pete, Yuri et al
>
>I made similar protection units for contesting with MPs & Mk5. Using
>stacked back to back PIN diodes it has been tested for intermodulation,
>check out  http://granta.digital-crocus.com/RxProtect.php3 
>
>73, Mark G4AXX
>
>
>-----Original Message-----
>From: 1000mp-bounces at mailman.qth.net
>[mailto:1000mp-bounces at mailman.qth.net] On Behalf Of Pete Smith
>Sent: 05 December 2005 11:03
>To: Yuri Onipko; All about Yaesu 1000mp
>Subject: Re: [1000mp] Important question
>
>When I set up for SO2R, I figured I needed to hedge against doing
>something dumb, so I built a receiver protector that sits in the RX
>OUT/RX IN loop on the Mark 5, and run always with the RX ANT button
>pushed.  It uses a small pilot light bulb (1.5V 60 ma) in series as an
>indicator and fuse, and back to back stacks of 3 1N914 diodes in shunt.
>The first time I made the bulb light, I was glad I'd done it.
>
>73, Pete N4ZR
>
>At 10:14 PM 12/4/2005, Yuri Onipko wrote:
>
>
>
>>> Well, I am not too surprised.  In my station my 20m harmonic from the
>
>>> Mark
>>5 on 40 is ~S7 with bandpass filters on both radiops - 80 feet is not a
>
>>long way in terms of isolation.
>>>
>>>>
>>> 73, Pete N4ZR
>>>
>>
>>I have 80 and 160 m antennas very close to each other (within 20 feet
>>probably) and I use BPF's on each radio. Still blew the front end on 
>>one of the MPs Mark V (80 m ) while operating the other one barefoot on
>
>>160... I just wonder if adding stubs would help?
>>Thanks.
>>
>>Yuri  VE3DZ
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