hello all,

i have a vfo from a heathkit hw-101. i also have a knight kit t-60.
question is what would it take and how much trouble would it be to build an
external vfo for my t-60 transmitter using this vfo? i have read some of the
old hanbooks but wanted to hear from the group.

tnx and 73 mike


--
73 de KU4YP Member Flying Pigs QRP
Michael Prevatt #225
Bartow, Florida Member Florida Contest Group

"KU4YP" ) writes:
hello all,

i have a vfo from a heathkit hw-101. i also have a knight kit t-60.
question is what would it take and how much trouble would it be to build an
external vfo for my t-60 transmitter using this vfo? i have read some of the
old hanbooks but wanted to hear from the group.

I don't think it's a good choice.

The vfo from the SSB transceiver has a fixed range, I believe 5 to 5.5MHz,
and must have been linearized so the dial comes up properly.

The T60, or any AM/CW transmitter of that vintage uses a 3.5MHz or
7MHz (and that might change with the band) and multiplies up for the higher
bands.

In order to use the first with the second, you'll have to shift the
VFO down in frequency, likely by changing the coil. You'll kill
the linear tuning, and unless you do a good job, you may mess with
the stability. If the dial is still attached to the VFO, you will no
longer have the proper display of frequency.

The best way, though not the simplest, would be to feed the VFO into
a mixer, and then feed a crystal oscillator output into the other port
of the mixer. The output of the mixer will be the 3.5MHz or 7MHz that
the T60 needs, and the frequency readout of the VFO will remain true.
Tradeoffs are that if you don't put a good filter on the output of the mixer,
you will get spurious signals, and while the readout will remain accurate,
it will not show the actual frequency, since the T60 will be multiplying
it's output frequency. On the higher bands, as multiplication goes up,
the actual band will be covered by a smaller swing of the dial, though
that applies to any VFO used with a multiplying transmitter.

Michael VE2BVW

"KU4YP" ) writes:
hello all,

i have a vfo from a heathkit hw-101. i also have a knight kit t-60.
question is what would it take and how much trouble would it be to build an
external vfo for my t-60 transmitter using this vfo? i have read some of the
old hanbooks but wanted to hear from the group.

I don't think it's a good choice.

The vfo from the SSB transceiver has a fixed range, I believe 5 to 5.5MHz,
and must have been linearized so the dial comes up properly.

The T60, or any AM/CW transmitter of that vintage uses a 3.5MHz or
7MHz (and that might change with the band) and multiplies up for the higher
bands.

In order to use the first with the second, you'll have to shift the
VFO down in frequency, likely by changing the coil. You'll kill
the linear tuning, and unless you do a good job, you may mess with
the stability. If the dial is still attached to the VFO, you will no
longer have the proper display of frequency.

The best way, though not the simplest, would be to feed the VFO into
a mixer, and then feed a crystal oscillator output into the other port
of the mixer. The output of the mixer will be the 3.5MHz or 7MHz that
the T60 needs, and the frequency readout of the VFO will remain true.
Tradeoffs are that if you don't put a good filter on the output of the mixer,
you will get spurious signals, and while the readout will remain accurate,
it will not show the actual frequency, since the T60 will be multiplying
it's output frequency. On the higher bands, as multiplication goes up,
the actual band will be covered by a smaller swing of the dial, though
that applies to any VFO used with a multiplying transmitter.

Michael VE2BVW

"KU4YP" wrote in message . ..
hello all,

i have a vfo from a heathkit hw-101. i also have a knight kit t-60.
question is what would it take and how much trouble would it be to build an
external vfo for my t-60 transmitter using this vfo? i have read some of the
old hanbooks but wanted to hear from the group.

The tuning range of the VFO in the HW-101 is 5 to 5.5 MHz. Its output
is low impedance and only about a volt or so.

The T-60 requires VFO output in the 80 and/or 40 meter bands. It needs
more output (several volts at least) than the HW-101 vfo can provide.

The mixer solution suggested by others will work, but it's not simple
and requires a bit of doing to get going.

Knight did not make a matching VFO for the T-60. There *was* a Knight
VFO, but they are relatively rare.

One very good yet simple VFO design is the QST article (February 1962,
IIRC) called "An Easy To Build VFO" by W1ICP. Will drive almost any of
the classic "Novice MOPA" transmitters like the T-60.

73 de Jim, N2EY

external vfo for my t-60 transmitter

I used an Heathkit HG-10B with my T-60. It worked very well.
73
Jim NE6O

external vfo for my t-60 transmitter

I used an Heathkit HG-10B with my T-60. It worked very well.
73
Jim NE6O

"KU4YP" wrote in message . ..
hello all,

i have a vfo from a heathkit hw-101. i also have a knight kit t-60.
question is what would it take and how much trouble would it be to build an
external vfo for my t-60 transmitter using this vfo? i have read some of the
old hanbooks but wanted to hear from the group.

The tuning range of the VFO in the HW-101 is 5 to 5.5 MHz. Its output
is low impedance and only about a volt or so.

The T-60 requires VFO output in the 80 and/or 40 meter bands. It needs
more output (several volts at least) than the HW-101 vfo can provide.

The mixer solution suggested by others will work, but it's not simple
and requires a bit of doing to get going.

Knight did not make a matching VFO for the T-60. There *was* a Knight
VFO, but they are relatively rare.

One very good yet simple VFO design is the QST article (February 1962,
IIRC) called "An Easy To Build VFO" by W1ICP. Will drive almost any of
the classic "Novice MOPA" transmitters like the T-60.

73 de Jim, N2EY