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123upmichigan
| | Posted on Sunday, October 27, 2002 - 4:19 pm: | 
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hello this is 123 upper michigan and i have a problem i have a siltronix 90 vfo and i am not surehow it works. it has a 5 position switch on it and it says cb, hf, or xtal1 xtal 2 xtal 3. now i am trying to wire this into a siltronox 1011d comanche but i am not sure on the crystals. the radio itself has been expanded to 26.550 to 27.550 with a 5.500 and a 5.5046 crystal/. i do not have any idea how the vfo box works and do not know what crystals to put in the vfo to make it work on the comanche. crystal radios are kinda before my time and any help would be greatly apprteciated. thank you 123 upper michigan |
2600
| | Posted on Tuesday, October 29, 2002 - 10:45 pm: |
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Hi 123,
Well, before your time, a 23-channel CB radio would contain 12, or 14, or 20 or more quartz crystals. In those days, a PLL like a new CB uses would have taken a cabinet the size of the radio, just for it alone.
You could add crystals, install switches to substitute them for the legal ones, and add channels that way.
That slider sure LOOKS like it should work with the 1011 radio, but it won't. The slider was a completely separate product, sold as an accessory to fit various 23-channel CB radios. You would pluck one of the crystals from the radio, and wire a cable to the crystal socket that went to the jack on the rear of the slider. It would feed a variable frequency (from the dial setting) into the radio when you set its channel selector to the 'slider channel'.
Because 23-channel radios were built with different internal crystals from brand to brand, the sliders came in multiple versions, to match the different crystal frequencies. There should be a single black numeral rubber-stamped onto the rear panel of the slider. Unless someone has modified it inside, this digit identifies the crystal frequency it was meant to substitute for. If it has "3" stamped on the back in black ink, it fits the Browning Mark III SSB transmitter, and some others. Somewhere I remember a link to the list showing what radio fits which number version. I'll look for it.
The 'XTAL' positions on the band switch were meant to let you keep the crystal channels you lost in taking a crystal out of the radio. Typically, the crystal you removed from the radio would cover four channels in a row. So you wouldn't have to kiss four fixed channels goodbye, you would plug the old radio crystal into one of the three sockets inside the slider. In theory, the trimmer cap next to the crystal socket would let you put your old crystal back on frequency. Some crystals would do this okay, some would not. Never saw many people use that feature. I have seen folks re-wire the 'xtal 1' position for a third tuneable band to cover below channel 1.
One thing you can do, if you have a 'bench' type frequency counter (one with a single jack on the front panel) and a patch cord from the RCA jack on the slider to the jack on the counter. Plug 'em together and see what frequency comes out with the selector on 'CB' and the dial to channel 1. If the digit on the rear has been rubbed off, this is the only way to tell anything much about it.
73 |
123upmichigan
| | Posted on Friday, November 15, 2002 - 3:06 pm: |
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thank you 2600, i appreciate it. i am gonna get the vfo back and take a look at it. it originally came on a cobra 139, and the guy has found another 139, they are rare up here. but here is a question. could you add it to the mixing crystal if an ic radio if you could get the frequency to match up? i always seen those things as an awesome way to add cyannels. well take care |
Viking
| | Posted on Friday, November 15, 2002 - 4:21 pm: |
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http://www.cbgazette.com/siltronix_chart.html
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