Some of my old 144 Mc equipment
In the "old" days (1970 and earlier) of 144 Mc activity only home-made equipment and modified ex-commercial equipment was used.
PA0CIS started with an old VHF Maritime AM base-station, equiped with a QQE 03/20 in the final and a pair of 6V6's as modulator. Total output was approx. 15 Watts.The transmitter was built in a 19" cabinet of 25 cm height. The transmitter was using tubes in every single stage. (transmitter and AM modulator) The output frequency of 144 Mc was achieved by using several frequency multiplexers in series.
Most equipment used a crystal oscillator at a frequency of 4 Mc, 6 Mc or 8 Mc as a starting point.
VFO's in the transmitter were almost non-existent in these days, given the unstability and frequency drift.
The crystals used were mostly modified dump-crystals. The crystal was a little plate of approx. 1 cm2 which was pressed between two pieces of copper, by using a little spring.
These crystals could be opened and the actual crystal plate could be taken out.
With some abrasive it was possible to remove a very small layer of the crystal plate. This caused the frequency to go upwards a little.After multiplication a frequency change of several 10 Kc could be achieved.
By applying some "dust" of a carbon pencil the frequency could be shifted down a little bit.
The readily available standard range of FT-243 series crystals only provided certain frequencies. These frequencies were well known by everyone and frequently used.
However to obtain a "clear" frequency of your own it was needed to have a crystal which was not on one of the "common" frequencies, hence the change of the original ones to another QRG. (nowadays, you just turn the knob of the VFO a little bit).
Operational procedures on 144 Mc
Given the fact that everyone was using crystals a two way QSO could take place on two different frequencies. It was not always the case that you had the same crystal frequency as the station you were in contact with.
So a typical QSO would start as follows :
You inserted a "common" crystal in your transmitter and started calling CQ. Within your CQ you announced the way you would start listening for other stations. They could reply on or around your calling frequency (in case they had the same crystal). However, in most cases they were using another frequency. So it was important to tell other stations what your intentions were, so they could choose the correct crystal.
In case of good conditions of high activity you inserted one of your "modified" crystals in the transmitter. Just to assure the frequency was not used by someone else.
So the CQ would be: "CQ CQ, PA0CIS calling CQ 2 meter. I will listen this QRG and upwards". So in case the CQ was made on 144. 800 Mc (one of the standard FT-243 frequencies) PA0CIS would listen around that QRG first and than tune the receiver up towards 146 Mc to find out who was calling.
The announcement "I will listen this QRG and upwards" would prevent other stations from calling in vain in the 144.000 - 144.800 segment. You could increase your chance to have a QSO by using a frequency as close to the calling frequency as possible. That way you were among the first stations which were spotted by PA0CIS, while he was tuning his receiver upwards.
So it was important to have two crystals ready. One above and one below the frequenct of the calling station. Depending on his announcement, "tuning up"or "tuning down", you inserted the correct crystal in the transmitter.
It was also important to know the "local" custom". For instance GM stations could mostly be found around 145.400Mc, while G's were mostly active around 144.600. So choosing your frequency well could enhance your success.
At a later stage I added an 8 Mc VFO to the transmitter, which provided a hugh operational advantage. No need to say the (tube) VFO was "on" 24/7 in order to minimise the drifting.
While receiving the VFO was given a little frequency off-set, in order to prevent the VFO harmonic from blocking the received frequency.
With a VFO it was relatively easy to add FM modulation. Just a varicap diode and some circuitry to supply the (filtered and limited) audio were sufficient.
Commercially made FM and CW equipment came on the market. Minix was one of the brands which produced nice tranceivers. These were still having separate frequency controls for rx and tx (actually 2 VFOs), just to "interface" with the still widely used dual-frequency way of QSO-ing.
This mode was still in it's early days on 144 Mc. For SSB experiments a small portion of the band was reserved around 145.450 Mc. Home brew equipment with VCXO's, providing stability as well as 10-20 Kc band coverage, were often used. In a later stage also transvertors behind hf-rigs became popular.
In the "SSB beginning" no dedicated commercial equipment was available for 144 Mc, the market was just to small and the mode still in it's early days of use on 144 Mc. After a while the first SSB tranceiver appeared. The famous Götting & Griem 2G70.
However I decided to build my own SSB transmitter, a DJ9ZR design which has been described in UKW Berichte 3/67. It produced 5 Watt PEP output.
The tranceivers came in my possesion later.
This transceiver is a hybrid one. Partly transistorized, partly with tubes.
The receiver is all solid state, but most of the transmitter amplifier and mixer stages are with tubes. The final is a QQE 03/12, capable of approx. 10 W output.
The transceiver looks like a piece of home brew equipment with lots of hand-made soldered compartments.
The transceiver contains a single super-VFO, but still the possibility to transmit in AM while receiving in FM, or other combinations if needed.
Semco provided the first, fully transistorized 144 Mc transceiver. It could be bought ready made.
Semco also sold the various units of the tranceiver, like AF amplifier, cabinet, VFO, mixers, IF board, etc.
With all these components it was possible to built your own transceiver.
Both the 2G70 and Semcoset were quite high priced, so only the "happy few" could affort to operate such equipment.
The real breakthrough of the use of SSB came with the introductioon of the Belcom liner. A mobile type of SSB transceiver which produced approx. 8 W rf and was relatively cheap.
However the rf was not only produced on the wanted frequency, but also an every multiple of approx. 40 Kc above and below that frequency.
The Belcom Liner was famous for its "dirty" signal.
Nevertheless it gave the use of SSB quite a boost. Lots of stations became active in this mode.
It's still a VCXO type of frequency generation which was used. The large knob provided 10 Kc segments which can be tuned by the VXO knob.
Scanning of the band was quite cumbersome.
The Multi 2000 was introduced a bit later and never really became a hit.
It was quite large, relatively expensive (although not as much as the famous Semcoset) and the limited tuning range, just as the Belcom Liner, has neven been very popular.
With the introduction of the Icom IC-201, TS 700, etc. 2 meter transceivers became a commodity.