I recently brewed up a small portable NBFM tranceiver for the local
ham group. Smallness and low cost were a requirement. My initial
design which is working well is based on an 18MHz crystal that i
multiply in balanced doublers three times over to 144MHz (using two
transistors in push-pull at each stage) followed by a 500mW 2N3866 PA.
I have found that without a high bandwidth oscilloscope (I used a tek
465) it is impossible to correctly align the tx. I am now considering
switching to a scheme where i can run a VCO at 144MHz directly and
lock it to a lower fundamental crystal. i can do this by:
a) injection locking the VCO with the a crystal oscillator. I have
seen almost no use of this method (EMRFD just mentions it in one line)
in amateur literature. my last post on this topic went unanswered last
week.
b) using a simple first order PLL. is there a way to simplify this?
the cost of a PLL IC or even an SBL mixer would be too high.
c) use an overtone directly on 144MHz (9th overtone in a butler
config) and phase modulate its output. Any pointers to a phase
modulator operating at VHF?

- farhan

Gertch used injection lock for years on their frequency meters. Had
several good papers on the operation. I used a 100 kc xtal to "Jam"
lock the LO on FM tuners for years in My frequency measuring service.
Back when stations subscribed to a service on a monthly basis. Basicly
I have divided down to 10 kc then "Jam" locked LO's at the broadcast
band also. Regards, Sparks Broadcast Consultant

Gertch used injection lock for years on their frequency meters. Had
several good papers on the operation. I used a 100 kc xtal to "Jam"
lock the LO on FM tuners for years in My frequency measuring service.
Back when stations subscribed to a service on a monthly basis. Basicly
I have divided down to 10 kc then "Jam" locked LO's at the broadcast
band also. Regards, Sparks Broadcast Consultant

I don't know why you're having so many problems. I've aligned many the VHF
Engineering and Hamtronics VHF (and UHF) Transmitters through the years
using the volt meter alignment information.

I was at Kinkos (my office anywhere) making copies of the VHF Engineering
2 meter tx strip yesterday. If you are actually serious about building
this type of transmitter, drop me a note through the
http://sonic.ucdavis.edu web server Email icons and I'll send you copies
or scans of the paperwork.

chow for now
skipp
http://sonic.ucdavis.edu

: Ashhar Farhan wrote:
: I recently brewed up a small portable NBFM tranceiver for the local
: ham group. Smallness and low cost were a requirement. My initial
: design which is working well is based on an 18MHz crystal that i
: multiply in balanced doublers three times over to 144MHz (using two
: transistors in push-pull at each stage) followed by a 500mW 2N3866 PA.
: I have found that without a high bandwidth oscilloscope (I used a tek
: 465) it is impossible to correctly align the tx. I am now considering
: switching to a scheme where i can run a VCO at 144MHz directly and
: lock it to a lower fundamental crystal. i can do this by:
: a) injection locking the VCO with the a crystal oscillator. I have
: seen almost no use of this method (EMRFD just mentions it in one line)
: in amateur literature. my last post on this topic went unanswered last
: week.
: b) using a simple first order PLL. is there a way to simplify this?
: the cost of a PLL IC or even an SBL mixer would be too high.
: c) use an overtone directly on 144MHz (9th overtone in a butler
: config) and phase modulate its output. Any pointers to a phase
: modulator operating at VHF?

: - farhan

I don't know why you're having so many problems. I've aligned many the VHF
Engineering and Hamtronics VHF (and UHF) Transmitters through the years
using the volt meter alignment information.

I was at Kinkos (my office anywhere) making copies of the VHF Engineering
2 meter tx strip yesterday. If you are actually serious about building
this type of transmitter, drop me a note through the
http://sonic.ucdavis.edu web server Email icons and I'll send you copies
or scans of the paperwork.

chow for now
skipp
http://sonic.ucdavis.edu

: Ashhar Farhan wrote:
: I recently brewed up a small portable NBFM tranceiver for the local
: ham group. Smallness and low cost were a requirement. My initial
: design which is working well is based on an 18MHz crystal that i
: multiply in balanced doublers three times over to 144MHz (using two
: transistors in push-pull at each stage) followed by a 500mW 2N3866 PA.
: I have found that without a high bandwidth oscilloscope (I used a tek
: 465) it is impossible to correctly align the tx. I am now considering
: switching to a scheme where i can run a VCO at 144MHz directly and
: lock it to a lower fundamental crystal. i can do this by:
: a) injection locking the VCO with the a crystal oscillator. I have
: seen almost no use of this method (EMRFD just mentions it in one line)
: in amateur literature. my last post on this topic went unanswered last
: week.
: b) using a simple first order PLL. is there a way to simplify this?
: the cost of a PLL IC or even an SBL mixer would be too high.
: c) use an overtone directly on 144MHz (9th overtone in a butler
: config) and phase modulate its output. Any pointers to a phase
: modulator operating at VHF?

: - farhan

I have had success as well using an RF probe and voltmeter. Tuning for peak
and once you start into the multiplier stages, the wattmeter should start to
get a tickle and then climb as you go through them as well into the final
stages. When you get this far, a freq counter near by should show some freq.
Then go back and touch it up if need be. G.W.

"Skipp" wrote in message
...
I don't know why you're having so many problems. I've aligned many the VHF
Engineering and Hamtronics VHF (and UHF) Transmitters through the years
using the volt meter alignment information.

I was at Kinkos (my office anywhere) making copies of the VHF Engineering
2 meter tx strip yesterday. If you are actually serious about building
this type of transmitter, drop me a note through the
http://sonic.ucdavis.edu web server Email icons and I'll send you copies
or scans of the paperwork.

chow for now
skipp
http://sonic.ucdavis.edu

: Ashhar Farhan wrote:
: I recently brewed up a small portable NBFM tranceiver for the local
: ham group. Smallness and low cost were a requirement. My initial
: design which is working well is based on an 18MHz crystal that i
: multiply in balanced doublers three times over to 144MHz (using two
: transistors in push-pull at each stage) followed by a 500mW 2N3866 PA.
: I have found that without a high bandwidth oscilloscope (I used a tek
: 465) it is impossible to correctly align the tx. I am now considering
: switching to a scheme where i can run a VCO at 144MHz directly and
: lock it to a lower fundamental crystal. i can do this by:
: a) injection locking the VCO with the a crystal oscillator. I have
: seen almost no use of this method (EMRFD just mentions it in one line)
: in amateur literature. my last post on this topic went unanswered last
: week.
: b) using a simple first order PLL. is there a way to simplify this?
: the cost of a PLL IC or even an SBL mixer would be too high.
: c) use an overtone directly on 144MHz (9th overtone in a butler
: config) and phase modulate its output. Any pointers to a phase
: modulator operating at VHF?

: - farhan

I have had success as well using an RF probe and voltmeter. Tuning for peak
and once you start into the multiplier stages, the wattmeter should start to
get a tickle and then climb as you go through them as well into the final
stages. When you get this far, a freq counter near by should show some freq.
Then go back and touch it up if need be. G.W.

"Skipp" wrote in message
...
I don't know why you're having so many problems. I've aligned many the VHF
Engineering and Hamtronics VHF (and UHF) Transmitters through the years
using the volt meter alignment information.

I was at Kinkos (my office anywhere) making copies of the VHF Engineering
2 meter tx strip yesterday. If you are actually serious about building
this type of transmitter, drop me a note through the
http://sonic.ucdavis.edu web server Email icons and I'll send you copies
or scans of the paperwork.

chow for now
skipp
http://sonic.ucdavis.edu

: Ashhar Farhan wrote:
: I recently brewed up a small portable NBFM tranceiver for the local
: ham group. Smallness and low cost were a requirement. My initial
: design which is working well is based on an 18MHz crystal that i
: multiply in balanced doublers three times over to 144MHz (using two
: transistors in push-pull at each stage) followed by a 500mW 2N3866 PA.
: I have found that without a high bandwidth oscilloscope (I used a tek
: 465) it is impossible to correctly align the tx. I am now considering
: switching to a scheme where i can run a VCO at 144MHz directly and
: lock it to a lower fundamental crystal. i can do this by:
: a) injection locking the VCO with the a crystal oscillator. I have
: seen almost no use of this method (EMRFD just mentions it in one line)
: in amateur literature. my last post on this topic went unanswered last
: week.
: b) using a simple first order PLL. is there a way to simplify this?
: the cost of a PLL IC or even an SBL mixer would be too high.
: c) use an overtone directly on 144MHz (9th overtone in a butler
: config) and phase modulate its output. Any pointers to a phase
: modulator operating at VHF?

: - farhan

i guess, i didn't explain the nature of the problem clearly. i CAN
tune my current transmitter easily. I just don't think that many will
be able to do so as i am building this as a club project.

The reason is that .. it is easy to mistune your transmitter to
another harmonic. this is especially true of VHF where the preset
capacitors can swing a wide frequency range within their 22pf range.

i was thinking that, instead, it might be a better idea to depend upon
generating the signal directly at 144MHz.

that said, as of now, i am continuing to use the a crystal at 18MHz
fundamental and multiplying it through three balanced doublers to
144MHz. In my second version, i have replaced variable capacitors in
the doubler outputs with fixed capacitors and tunable inductors. that
way, i hope to be able to restrict the tuning range of each doubler
output centered around the required second harmonic. it is tough work,
but that is what differentiates homebrewing for yourself from
homebrewing for a group project.

- farhan

i guess, i didn't explain the nature of the problem clearly. i CAN
tune my current transmitter easily. I just don't think that many will
be able to do so as i am building this as a club project.

The reason is that .. it is easy to mistune your transmitter to
another harmonic. this is especially true of VHF where the preset
capacitors can swing a wide frequency range within their 22pf range.

i was thinking that, instead, it might be a better idea to depend upon
generating the signal directly at 144MHz.

that said, as of now, i am continuing to use the a crystal at 18MHz
fundamental and multiplying it through three balanced doublers to
144MHz. In my second version, i have replaced variable capacitors in
the doubler outputs with fixed capacitors and tunable inductors. that
way, i hope to be able to restrict the tuning range of each doubler
output centered around the required second harmonic. it is tough work,
but that is what differentiates homebrewing for yourself from
homebrewing for a group project.

- farhan