[1000mp] RX antenna port

[scarroll at mchsi.com]

I plan on hooking up a K9AY Loop as well (don't have room for a beverage) for 
160m/80m. In my case, after studying the FT-1000 MkV Field's schematic and 
querying Yaesu Tech Support, it was verified that during transmit ALL receive 
inputs are completely disconnected & attenuated. According to the tech support 
person I spoke to, he was quite confident that you wouldn't be able to produce 
enough signal to fry the receiver front-end given the internal configuration. 
Although, I'd sure like to hear more technical data on this from anyone who is 
actually using such a configuration with a Field, etc. It nevers hurts to get 
more inputs BEFORE it's too late.

73, Steve - K2SC



Thanks !!!


> I thought I recalled being told on this list any number of times that the 
> "RX ant in" jack is, in fact, disconnected from the receiver during 
> transmit.  Not so?
> 
> For SO2R, rather than disconnecting or shorting the RX antenna terminal, 
> wouldn't you need to use a passive limiting protective device, one with a 
> small resistor in series and maybe 4 diodes in shunt? On the Mark 5, I 
> believe you can use the RX antenna switch position and all received signals 
> will pass out through the "RX ant out" jack and in through the protector 
> and the "RX ant in jack."
> 
> At 02:42 AM 3/18/2005, Jeff Maass wrote:
> 
> 
> > > -----Original Message-----
> > > From: 1000mp-bounces at mailman.qth.net
> > > [mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Barrie Smith
> > > Sent: Thursday, March 17, 2005 8:22 PM
> > > To: All about Yaesu 1000mp
> > > Subject: [1000mp] RX antenna port
> > >
> > >
> > > I'm going to be installing a K9AY loop as a 160M RX antenna soon.
> > >
> > > Is the RX port in any way protected during transmit on the MKV?
> > >
> > > Or, will I be building/buying something to short the port out during
> > > transmit?
> > >
> > > 73, Barrie, W7ALW
> > >
> >
> >Barrie:
> >
> >The "RX In" port of the MKV is not shorted during
> >transmit. It's a good idea to protect it.
> >
> >First thing, any RX antenna will work best if
> >located as far as possible from the resonant transmit
> >antenna. If in close proximity, noise will be couple
> >from the transmit antenna to the receive antenna.
> >A little distance also decreased the amount of signal
> >coupled back to the RX In port when transmitting.
> >
> >Protection is easy to provide. You can build a simple
> >disconnect relay to mount at the radio, or commercially,
> >there are:
> >
> >    KD9SV's Front End Saver ($60 from Radioware):
> >       http://www.radiobooks.com/products/fes.htm
> >
> >    K9AY's RIP-1 ($35 from Array Solutions)
> >       http://www.aytechnologies.com/Products/RIP1data.htm
> >
> >These are quick, and disconnect the RX antenna from the
> >transceiver before the amplifier is keyed. The AY Technologies
> >RIP-1 link above includes a schematic so you can get an
> >idea of how it is connected.
> >
> >I've been using one of the KD9SV Front End Savers since
> >1997, and have a couple at the PJ2T contest station. I
> >just bought one of the RIP-1 to try as well.
> >
> >73,
> >
> >Jeff Maass  K8ND
> >
> >
> >
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