1152 Cavity Oscillator Hamradio
100%, but a fair amount sure seems to clean things upl
On some APX-6 models, you will still need to carefully remove a bit from the transmitter cavity plunger On one of mine, I did not have to do anything but tune On the other, it required trimming, but someone else did it for me (on a lathe), so I suggest you obtain copies of the articles in the bibliography and digest them well before chopping away, ¡he modification of the cavity plunger would make an article in itself (as it did several times in the past) and mine was done strictly using their technique and only after trying to run it stock, firstAll of this brings us down to having our transmit signal on 432 or 1296 MHz, but I have not mentioned the receiver. On 432 MHz you are somewhat on your own, but many converters are available to convert to 2*meters, or to a low-band receiver for receive. On 1296 MHz, where I was headed, it is simpler, since you already have the converter—the APX-6. Instead of hacking up the rest of the cavities and plungers to raise the APX-6 to the 1296-MHz range, I plan to cheat and ignore their noisy and ineffective 60-MHz i-f in the APX-6, The local oscillator cavity and oscillator will cover a wide range of frequencies, one of which is 1152 MHz. Mine did it with the stock cavity and plunger. Taking 1296 MHz minus 1152 MHz equals 144 MHz, or just right for the input to the receiver of the 2-meter transceiver you started with for transmit, You can rig the 1152-MHz oscillator to be tunable from 1152 to 1148 MHz for outputs from 144 to 148 MHz on receive, That is touchy at best, and I wanted to tower-mount the APX-6 part of the system near the antennas. Therefore, for the time being anyway, I am settling for using a Hamtronics 2-meter converter into the 14-MHz
1-f of my TR-6 and using 0.5-MHz coverage per converter crystal
There are some places the system happens to work out just right using the transceive idea and APX-6 alone At 144.0 MHz, you have 144 x 3 x 3 = 1296 MHz and 1296 MHz -1152 MHz = 144 MHz. That's fine, but now try 144.1 MHz] 144.1 X 3 X 3 = 1296.9 MHz and 1296.9 MHz - 1152 MHz - 144.9 MHz. Oops! That's an 800 kHz offset and thus requires a separate converter and receiver for simplex operation. If you try FM on one of the multi-mode rigs like my KLM 2700, you can also cheat and use the repeater offset at one frequency. At 144,07 + 5, or 144.075 MHz, you have 144 075 X 3 X 3 = 1296.675 MHz and 1296.675 - 1152 = 144.675, a natural 600-kHz offset normally used for repeaters, I'd like to suggest that frequency as a simplex FM location, so we can all have some coordination,
The APX-6 cavity is broad, but not the 4 MHz necessary to cover the entire 1296 to 1300 MHz, so why not use the 144 MHz start point for CW-SSB and a 1296-MHz output, and the 144.075-MHz start point for FM and a 1296.675-MHz output? It's not so crowded up there that we couldn't all live together and a lot more contacts might be the result of it Laterr we could worry about separate receiver-converter combinations and then spreading out a bit, In some ways, I hate to see channelization of any band, but even when it comes, I hope it is in ,010-MHz increments at the
2-meter frequency or .090MHz at the 1296-MHz fre quency. It would make looking for each other a lot easier until the population up there increases. Please, let's hear your ideas and suggestions concerning this band and my ways of reaching it CE and RCA gear like the Progress line and CMU-15s should work just as well as the tripier amplifiers and there is a large quantity now available cheap, along with articles on getting them on the 432-MHz band I just had the Motorola, so 1 used it! ideas from the stripline, cavity, and plumbing group of hams would sure be appreciated to eliminate our biggest bug in getting from 432 MHz to 1296 MHz. It would also help to see more receiver, preamplifier, and antenna ideas specifically for 1296 MHz, instead of everyone trying to extend 432-MHz article ideas to work up there,
If you can help with an article or two, please do, but be realistic about it. Give up a precious dB or two and stay away from the gold-plated antennas and $50 solid-state devices few can find or afford. Some of the UHF TV tuner solidstate devices surely must work up there or how about a modified UHF tuner?
1296 MHz does not have to be a short-range band! Remember when 2 meters would get you across town— maybe? I have 11 states confirmed on 2 meters now using SSB and the barefoot KLM 2700 in the 7-Watt position iJm not saying this for ego, but to show you what a little population will do for a band. When the 1 Watt runs out, I'll go to the 10-Watt position and wring it out, and only then will I go back to building the 100-Watt 5894 amplifier I started to build when I bought the KLM, QRP has turned out to be too much fun. I do run decent antennas in the form of an 8 over 8 J-slot with a screen relector, but even it is homebrew, and was an article in 73 Magazine„ June, 1978, p. 140; The same sort of homebrewing can happen for 1296 MHz if only a bit of help starts appearing im the way of articles,
I hope, most of all, that this article has stirred up a renewed interest in 1296 MHz, I could not find a single article on this band and its use over the last 5 years in my files \[73f CQ, Q57", and Ham Radio) with the exception of the solidstate peanut whistles suitable as iab bench items or beacons, or if your DX interest lies with the guy next door! I'm not knocking an\ of these articles, believe me, because it at least reminded me that 1296 MHz was still around.
Remember Wayne's "220 — use it or lose it'? Don't laugh —it could happen to 1296 MHz more easily, and we almost lost the 220-MHz portion as it is. The sting of that one should still be sharp in everyone's mind, and it wasn't the hams that
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