Clifton Laboratories 7236 Clifton Road  Clifton VA 20124 tel: (703) 830 0368 fax: (703) 830 0711

E-mail: Jack.Smith@cliftonlaboratories.com
 

This page describes installing a Z10000-U broadband buffer amplifier in a Yeasu FT-1000MP transceiver owned by Mike, W4XN.

The purpose of the Z10000-U buffer amplifier is to provide an isolated sample of  the FT-1000MP's 70.455 MHz first IF, ahead of the transceiver's roofing filter, so that it might be used in conjunction with a panadapter.

I've provided these notes based on W4XN's installation. However, I assume no liability for any damage you may cause to your transceiver should you follow these notes.
 

I built the Z10000-U buffer amplifier for 6.7 dB nominal gain. It is a standard Z10000-U amplifier—for more details see my associated page Z10000 Buffer Amp.
 

At 70 MHz, the Z10000-U's input impedance is dominated by capacitance on the input coaxial cable, if any, and the PCB and AD8007 IC's input capacitance. The Z10000-U's input impedance, with zero input cable, at 70 MHz is about 350 ohms, as illustrated in the SPICE input impedance simulation shown below. My measurements show the SPICE simulation is acceptably close to the measured impedance.
 

T1016's secondary and T1017 form a coupled resonator filter and impedance matching arrangement for XF1001, the first 70.455 MHz monolithic crystal roofing filter.

The selected signal pick-up point, T1016's secondary winding, is the best point available. It turns out that T1016 and T1017 are at the back edge of the RF PCB, so it's possible to make this connection with a very short length of coaxial cable to the Z10000-U's input.

To obtain access to the RF PCB, it is necessary to remove the FT-1000MP's top and bottom covers.

Then, remove the mounting screws for the blower assembly and  the RF Power Amplifier Output module. It is possible to carefully move these modules out of the way without removing any of their wires.

Then remove the mounting screws securing the shield and RF Input PCB. In addition, the rear of the PCB is attached to the FT-1000MP's rear panel via two screws in the remote band selection DIN connector. Remove the two screws that go into the DIN connector.

There are  two connectors on the left rear edge of the PCB that must be removed before the board can be tilted up for work. One is a ribbon cable. Slide the connector locking mechanism up and gently remove the ribbon cable. The ribbon cable does not have separate pins, but rather the cable conductors are the mating surface. The second connector is a small conventional wired connector adjacent to the ribbon connector.

With these two cables disconnected, it is possible to carefully lift and rotate the PCB to obtain access to the bottom of the board.

The board has a number of PCB-mount RCA connectors as well. When removing the board, slide it away from the  rear panel to clear the connectors.

In addition to the RF and ground pickup, it is necessary to obtain +12V for the Z10000-U buffer amplifier. This may be accomplished by connecting  to the auxiliary +12V output fuse, located on the RF Input board. Connect to the fuse output, not the input, of course.

The RF connection should be made with a very short length of coaxial cable, about 3/4 inch long, or 20 mm for metric readers. The connection is made from the bottom of the PCB.

Angle the Z10000-U at right angles to the RF Input board, as illustrated in the photo below.

Adding the Z10000-U will detune T1016 and T1017 and it is necessary to re-peak both after remounting the RF Input board. It is critical that the cable connecting the Z10000-U to the RF Input board be kept very short, as even an extra half-inch of coaxial cable beyond the recommended 0.75 inch may add so much extra capacitance that these two transformers cannot be brought back into resonance.

To peak the transformers, apply a signal generator to the FT1000-MP's input, tune the receiver to the signal generator input frequency in either CW or SSB mode. Watching the S-meter, adjust T1016 and T1017 slugs for maximum signal strength.

This installation used the optional SMA female bulkhead connector. We added a 0.25" (6.3 mm) diameter hole to the FT-1000MP's rear panel near  the remote band DIN connector. In making the hole, several points should be observed:

1. The back panel's  top rail is easily bent, as the heat sink ventilation holes reduce its strength. Be careful not to bend the rear panel when working on it.

2. The RF Power Amplifier module takes up most of the vertical space above the RF Input PCB and limits the output connector hole placement.

3. The usual precautions in making a hole apply. We used a Roper-Whitney XX hand punch,  rather than an electric drill. The punch leaves a clean hole without a burr and is much safer as it can't get out of control and damage other parts of the  transceiver like an electric drill can.