The quickest and easiest way I have found to make a CB into a 10 meter
beacon….. Something
about another approach 19 Oct 09(see GREEN below)
There must be millions of the older 23 channel CBs that use the 12 crystal synthesizer
set-up with a 23 MHz oscillator and 14 MHz oscillator setup.
Check "Garage Sales & Flea Markets" for the bargain rigs
In this rig, the 23MHz signal mixes with the 14MHz signal to produce a signal in the 38MHz plus range.
To receive, this 38MHz signal is mixed with the receive oscillator signal (11.730MHz) to have a signal that is 455KCs offset from the operating frequency.
Example… 23.290MHz mixes with 14.950MHz for the 38.240 frequency and then mixed with 11.730 to get 26.510MHz …. This 26.510 is .455 lower than 26.965MHz which is channel one..
To Transmit, this 38MHz signal is mixed with the transmit oscillator signal (11.275) to have a 26.965MHz operating signal.
Example…. For channel 23…. 23.540 mixes with 14.990 to get a 38.530MHz signal. The 38.530MHz signal is mixed with 11.275MHz for a 27.255MHz transmit signal.
Now find a crystal from almost any 40 channel PLL controlled CB…… the reference frequency crystal is
10.240MHz (Most common ….. almost universal use by manufacturers)......
actually, a 10.180MHz or a 10.000MHz will work equally well...... it just causes
the beacon frequency to be a different channel to start at 28.290MHz (with the
10.180MHz crystal... this starts at channel 19)... and (with the 10.000MHz
crystal.... this starts at channel 5)
Substitute the 10.240MHz crystal for the 11.275MHz transmit oscillator crystal.. Now, channel 1 becomes a transmit frequency of
28.000MHz. .
Channel 10 becomes 28.110MHz.
Channel 19 becomes 28.220MHz
Channel 20 becomes 28.240MHz
Channel 21 28.250MHz
Channel 22 28.260MHz
Channel 23 28.290MHz
With a little capacitance added .... the crystal will "bend" a few Hertz either way. In parallel the frequency goes lightly up maybe 1 KHz ... in series, it goes down. I like to use a "trimmer" in series for frequency "tweaking"....... 3 to 5 KHz easy. For a tiny amount of capacitance a couple of twisted wires will work. gimickCap.jpg
The CARRIER output should be about 2 Watts after the "cans" in the transmit circuit are "tweaked" .....Do not adjust any of the "cans" except those that "follow" the TRANSMIT OSCILLATOR to the output.
Typical adjustment locations
Currently the Ten meter "beacon band" is considered to be 28.175 to 28.300MHz
The FCC rules only state that if the beacon is automatically controlled… it must be 28.200 to 28.300MHz…..
Please refer to a current listing of ten meter beacons to select a frequency.
Please coordinate Your frequency selection.
[email protected]
A short piece of Co-Ax connected to a receiver tuned to 28 MHz frequencies
can be used as a "sniffer" when tweaking the "cans".....
watch the S meter and adjust the "cans" to the highest reading at the
selected beacon frequency.
To transmit a CW signal, a person only needs to interrupt the PTT circuit of an AM rig.
There are many ways to "key" the PTT circuit……. Any memory keyer …. Computers….
---- MEMORY KEYERS? There are many memory keyers on the current market. One good Deal on the market is the "TICK 2B" at 15 dollars for the SMT kit with 25 character memory for beacon operation. Takes "close" eye work and a steady hand. Two beacon keyers that can be computer programmed are the "Freakin' Beacon" and the ID-O-Matic II Kit. (Google for info)
BEST DEAL...... PICOKEYER by
NØXAS http://www.hamgadgets.com/store/product_info.php?cPath=21&products_id=89 ...
currently $8.00 for the Chip and Socket......Or 17.95 complete kit. With 62 memory
characters. Minimal external parts....... "homebrew breadboarded"
in less than 15 minutes. (please check the latest... I think the memory is
now doubled) NO INTEREST...JUST A VERY SATISFIED CUSTOMER
NOTE: With the December 2013 update to version 4.5 firmware and other
refinements..... A person must modify the board slightly to accommodate a power
supply other than the built-in battery.
(see page 19 of the user manual labeled
optional) ......If the message sidetone is
annoying it can be silenced via menu item "T".
ADDED 6 October 2009...update 15 June 2012
(see comment at the end)
Other ideas for easy beacon rigs from
CBs
3 crystal O2A set up 1977-1978 series
KNOWN RIGS USING THIS SETUP
Delco (GM)CBO-10 GE 3-5810-8 Hygain 2679, 2680, 2681, 2683, 2710X, 2716, 3084B
Kraco KCB-2320B Lafayette COM-Phone 23A, HB650, HB750, HB-950,
Micro 223A, Telesat 1050, Midland 13-830, 13-857B, 13-882C, 13-888B, 13-955.
Pearce-Simpson Tiger MarkII, RCA 14300, 14T301, Truetone MCC4434B-67, CYJ4732A-77.
(The numbers 2.24 through 2.53 indicate the binary code of the 02A PLL...Channels 1 through 23)
The 11.8066 is the "loop mixing crystal frequency.... the 10.695 is the transmit oscillator crystal frequency
11.8066 X3 = 35.4198 plus 2.24 -10.695 = 26.965 (CB channel 1)
11.8066 X3 = 35.4198 plus 2.38 -10.695 = 27.105 (+2.38 - 9.6 = 28.200 MHz)
11.8066 X3 = 35.4198 plus 2.39 -10.695 = 27.115 (+2.39 - 9.6 = 28.210 MHz)
11.8066 X3 = 35.4198 plus 2.40 -10.695 = 27.125 (+2.40 - 9.6 = 28.220 MHz)
11.8066 X3 = 35.4198 plus 2.41 -10.695 = 27.135 (+2.41 - 9.6 = 28.230 MHz)
2.42 (+ 2.42 - 9.6 = 28.240 MHz)
11.8066 X3 = 35.4198 plus 2.43 -10.695 = 27.155 (+2.43 - 9.6 = 28.250 MHz)
11.8066 X3 = 35.4198 plus 2.44 -10.695 = 27.165 (+2.44 - 9.6 = 28.260 MHz)
11.8066 X3 = 35.4198 plus 2.45 -10.695 = 27.175 (+2.45 - 9.6 = 28.270 MHz)
11.8066 X3 = 35.4198 plus 2.46 -10.695 = 27.185 CB channel 19 (+ 2.46 - 9.6 = 28.280 MHz)
2.47 (+ 2.47 - 9.6 = 28.290 MHz
11.8066 X3 = 35.4198 plus 2.48 -10.695 = 27.205 (+ 2.48 - 9.6 = 28.300 MHz)
11.8066 X3 = 35.4198 plus 2.49 -10.695 = 27.215
11.8066 X3 = 35.4198 plus 2.50 -10.695 = 27.225
2.51
2.52
11.8066 X3 = 35.4198 plus 2.53 -10.695 = 27.255 (CB channel 23)
9.6 crystals avail at BG Micro 50 cents each (Oct 09) 52 cents May 12
seven
available beacon frequencies with the 9.6 crystal
nine with a
little "bending "
ADDED 19 Oct 09 2.42 & 2.47 binary code frequencies activated
I found
a way to get nine beacon frequencies plus 2 more with
a bit of crystal "bending"
THE END COMMENT (15 June 2012)
Some frequencies are difficult and takes a bit of O2A PLL manipulation to achieve. Today working with a Midland 13-882C I needed to adjust to a frequency that falls within the 20 KHz "skip" between channels 15 & 16 . With the 9.6 MHz crystal installed the frequency indication was 28.224 MHz for channel 15 and 28.244 MHz for channel 16. The Midland 13-857B has the same O2A setup....Convert to beacon band with simple alteration of the O2A connections. Midland 13-857B O2A
I installed a 2-26pF trimmer in series with the crystal and was able to move the frequency from 28.224 MHz to a range down to 28.218 MHz. I adjusted the frequency to 28.220.5 MHz........ Flipped the chassis over and cut the #15 pin trace between the PLL and the switch...... (determined via the truth chart) turned the rig back over and turned on the power....... Great! Channel 16 now indicating 10 KHz up from channel 15 instead of the original 20 KHz........ The channel 16 right on the desired frequency of 28.231.5 MHz.
