[1000mp] Antenna Connector Summary & Technical Overview Manual

[WD8ARZ]

----- Original Message -----
From: "WD8ARZ" <WD8ARZ at IX.NETCOM.COM>
To: <1000mp at qth.net>
Sent: Saturday, December 01, 2001 19:27
Subject: FT-1000MP Three Antenna Options - Grounded?

FT-1000MP Technical Overview Manual (B9200182B 1999.11 QS - not the service
manual) page 7 shows a Figure 2-1 Antenna Selection block diagram.

The text for this diagram is as follows:

(A) Antenna Selection and Switching

The FT-1000MP provides two SO-239 ('M') female connectors on the rear panel,
with 'A/B' selection via a front panel switch. Although multiple antenna
jacks are occasionally seen in other transceivers, they frequently suffer
from poor isolation, leading to signal bleed-through from the antenna(s) not
in use. In the FT-1000MP, the unused antenna jack is shorted to ground to
ensure total isolation.

A separate receive-only 'RX ANTENNA' access path is provided via a pair of
RCA connectors. These allow special receiving filters or preamplifiers to be
inserted into the receive line, or they allow attachment of a receive-only
antenna such as a loop or Beverage antenna for low-band reception.

A surge suppresser is included on the antenna input line, so as to suppress
static 'spikes' which could damage the input diodes and/or transistors.'

The circuit diagram in the Technical Supplement (Service Manual) page 6V-1
Labeled ANT Unit, does show the A and B SO-239 antenna connections
supporting grounding during transmit using relay's.

The circuit for the RX Antenna routes from the ANT Unit to the LPF Unit in
the Service Manual schematic on page 6L-1. This portion does show a
suppression device called a D6007 with a number below it of DSP-201M-S00B,
and it does go to ground off the RX antenna line. D6007 on page 6L-6 parts
listing does call it a SURGE ABSORBER MFGR'S DESIG Number DSP201M-S00B and a
YAESU P/N of Q9000375.

Well, I am pleased that Yaesu went to this detail to protect our antenna
inputs. After all the above, now what?

1) For normal operation's on single antenna I see no need to do anything any
different.

2) Using more than one antenna through the A/B selection, and no linear amp,
I still don't see the need to do anything different.

3) Using the RX Antenna Rca connection, I would want to use some external
protection just as an extra level of protection. Most surge suppressors fail
after so many hits. How do you know when that has happened and it didn't
short out? The next hit takes out other solid state devices...... ugh. An
external relay and or suppressor is still a good idea here.

4) If using a linear amp, I would want ALL antenna inputs with external
protection as covered in previous threads. Would also look at protection for
the computer connector.

None of this information has been verified by me for the FT-1000MkV, though
I would expect it to be the same. I can not say for sure, so can not answer
questions addressed to me about that.

73 from Bill - WD8ARZ

----- Original Message ----- 
From: "WD8ARZ" <WD8ARZ at IX.NETCOM.COM>
To: <1000mp at mailman.qth.net>
Sent: Friday, March 15, 2002 11:22 AM
Subject: RX Ant Input Status Rx/Tx Not Always Open - 160 m reception


It depends on what receive antenna option is selected as to the condition of
the RX antenna input connector during transmit.

On my FT-1000MP:

Antenna A or B selected, no RX antenna in connector selected, DC ohm meter
check shows no reading during receive and transmit (ie open at the rca
connector on the rear of the mp).

However when RX antenna connector is selected using the ANT A/B RX buttons
(rx antenna jack is selected, not A or B for receive), there is a DC 82 ohms
measured during receive OR TRANSMIT on the RX in antenna RCA connector on
the rear of the mp.

This means something internal to the RX in antenna RCA jack is exposed to
the Rf environment when the RX antenna selection option is enabled.

I would be more concerned to a open connection arcing (small relays don't
have much space between relay contact points), than to a shorted input in
place before Rf emitted.

Of course this doesn't detail the switching 'internally' prior to the
connector, or what receive components are exposed to the rf path effects
that are much different than a dc ohm meter path.

Until a trace is made of the information provided by Yaesu on this
circuitry, their information is still what we have to go by (as detailed in
my last email on this topic). Yep, there is generally a difference between
the text descriptions, pictorial flow charts, schematics, wiring diagrams,
and what actually goes out the door in the hardware (or for that matter
hardware and firmware) to the customer ......

What I would do is as summarized in my last email ..........

However, one of these days I plan on doing some verification of the 
pictorial
and schematic information to nail this one once and for all..... ah for the
time .... hi hi

73 from Bill - WD8ARZ

----- Original Message -----
From: "Marc Wullaert" <marc.wullaert3 at pandora.be>
To: "1000mp reflector" <1000mp at qth.net>
Sent: Saturday, December 01, 2001 15:23
Subject: [1000mp] mp RX ANT ???? Grounded
>
> Hi ,
> Is the RX antenna input on the 1000mp grounded while transmitting ?
>
> Or  should I build some input protective circuit like on page 3-15
> from on4un john low-band dxing book.
>
> 73
> marc on4ma

----- Original Message -----
From: "Duncan Cameron" <shangsha at hotmail.com>
To: <1000mp at qth.net>
Sent: Saturday, May 19, 2001 10:28
Subject: Re: [1000mp] Mark V Tech Review Manual
>
> The "Technical Overview" manual for either the 1000MP or MK5 are available
> by mail.  You just need to email and request one from
> " yaesuparts at vxstdusa.com ".  They are free!
> Regards,
> Scott Cameron

----- Original Message -----
From: "Pete Smith" <n4zr at contesting.com>
To: "WD8ARZ" <wd8arz at ix.netcom.com>
Sent: Monday, December 03, 2001 17:51
Subject: Re: RX Antenna from ANT Unit to the LPF Unit - MP
>
> Hi Bill - I've ordered the technical overview from Yaesu.  Unfortunately,
> the Mark 5 owner's manual doesn't even say which of the RX antenna jacks
> (in and out) is to be used for the external antenna, much less what the 
> two
> jacks are for.  I wish there was a diagram such as you describe in the MP
> manual, but no such luck.
>
> Thanks for your help.
>
> 73, Pete N4ZR
> www.qsl.net/n4zr