NOTICE: ALL CRYSTALS I SELL ARE MARKED 10KHZ HIGHER IN FREQUENCY THAN WHAT THEY OSCILLATE AT IN THE JOHNSON RADIOS! A 29.010 and 28.555 labeled crystal pair operates on 29.000 TX and 28.545 RX (Fo+455 khz) in a Messenger 1 or 2. Price for each TX/RX pair is $15 plus shipping. SPECIFY OPERATING FREQUENCY WHEN ORDERING, NOT CRYSTAL FREQUENCIES!
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For around $80 plus shipping and tax, you an order the above AM/FM radio from Amazon that will cover the entire 10 meter band as well as out of band. It will do CTCSS tones for FM and also has 100 khz repeater shift built in. The downside is the FM mode is narrow band 2.5 khz deviation. Click here to visit Amazon.
WARNING : You must be able to solder and use small hand tools. THE SOLDERING IRON IS HOT AND WILL BURN YOU IF YOU TOUCH IT IN THE WRONG PLACES! The smell of rosin can become addictive.
Messenger Ones (White face) and Messenger Twos (black face) turn up on a regular basis at estate sales and flea markets. They can usually can be bought at a bargain price if it’s not on Ebay. Many have sat in storage for many years. If you are interested in purchasing either radio, try to get one that includes the 9 pin round connector as that is the most expensive item to source if its missing. If the microphone is missing, any high impedance microphone such as a D104 or Turner series can be wired for use on it.
Radios should be carefully examined before powering up. The 80 uf 450 volt OEM capacitor should be replaced before powering on for the first time as it is usually degraded the most and ready to fail if not already failed. The paper capacitors also should be replaced, as many times you will find one split open or it will fail after being on awhile. Most radios will come with at least a few CB crystals installed but may be off frequency or some may be dead.
The radios can be easily converted to 10 meters with a crystal change and retuning. Unfortunately the days of of “cheap” custom made crystals for amateur frequencies are long gone and only a few crystal companies are still around that will make them. Yes, you can construct a DDS VFO or perhaps use one of the programmable oscillator modules, but that requires a lot of time and experimenting.
I think JAN Crystal and Bomar Crystal may be the only custom crystal manufacturers left in the US. The cost of ordering a small quantity of crystals from them could easily make you decide there were better radios out there to play with. Read on for an alternative.
After stumbling across computer grade clock crystals that were in the 10 meter range, I ordered a few and to my surprise, they oscillated not too far off frequency with no modifications to the circuit when used in the old Messenger Two I was working on. Stability was great as measured on my IFR service monitor. At power-on the oscillator does exhibit some drift that can be attributed to the oscillator tube, the ambient temperature, and the components themselves. After a 5-10 minute warm-up period, they exhibit almost no drift and stabilize after 15-20 minutes. Lead length between the crystal and the selector switch as well as contaminants on the switch surfaces itself do affect the operating frequency slightly so its not unexpected to find the frequency varies slightly with each crystal socket if they are swapped around. Cleaning the switch contacts with Deoxit usually addresses any intermittent swings in frequency.
Unfortunately the computer grade crystals do not oscillate on their marked frequency due to not being made specifically for the transmitter. Testing shows they also oscillate in the receiver with the same frequency error as the transmitter oscillator exhibits. Padding can introduce issues such as lowered drive and or stability issues which is more of a problem in the RX oscillator than on the TX. Factoring in an offset from the cut frequency to actual operating frequency has proven successful.
FCC specifications for the Messenger transmitters state .005%. This equates to plus or minus 1.34 khz from center frequency. A 29.000 TX crystal can oscillate from 28.99866 to 29.00134 and still be within spec according to the math based on 26.965 mhz (CB channel 1). Typically I see a plus or minus spread of under 1 khz with the crystals I offer, usually no more than plus or minus 800 hz and many times it is less. Keep in mind there are no individual crystal adjustments so the frequency error has to be balanced out between all frequencies with a single adjustment coil for each bank of RX and TX crystals. Your radio could balance out more or less.
Crystals For Sale
I have for sale RX and TX crystal pairs for 29.000, 29.010, 29.020, and 29.050 mhz.
VERY IMPORTANT – WHEN ORDERING, PLEASE SPECIFY THE 10 METER OPERATING FREQUENCY AND NOT THE CRYSTAL FREQUENCIES SO YOU WILL RECEIVE THE CORRECT CRYSTALS.
Cost for the crystals are $15 per pair and I only sell them in pairs. The refurb kit mentioned elsewhere is no longer available. All prices are less shipping charges. I do accept Paypal and ship to verified addresses only.
Sometimes I am asked which radio works best or is the easiest to work on. Both have their advantages and disadvantages. The One is the easiest radio to work on as it does not have the extra wiring with the external accessory plugs and more room on top because of the smaller crystal bank. It sometimes requires more work as some of the high value resistors seem more prone to be out of tolerance. The Two has better selectivity but the larger crystal bank on top can get in the way and the rats nest of extra wiring underneath the radio makes it more difficult to troubleshoot sometimes. Also alignment of the IF stages on the Two are more critical.
If you have a local 10 meter AM net, please let me know and I will list it.
If you are interested in crystals contact me at my call @ yahoo.com.