From: Patrick Jankowiak (eccm@swbell.net)
Date: Sun May 11 2003 - 23:23:14 PDT
Well the CB I have here, it puts about 85VDC on the mike contacts to
operate the relay! I will have to deal with that..
Trish & Carla wrote:
>
> The secret to microphone operation in noisy
> vehicles is the use of "noise-cancelling" microphones..
>
> The H-250 handset, and M80 microphones are examples, as
> they have entry points for sound on both sides of the
> mic elements ...
>
> external noise sources tend to hit both sides of the mic
> element, therefore cancelling out, while when you talk
> into a handset or mic, it is from only one side ...
>
> Shure makes commercial noise-cancelling mics, and I modified
> one some years ago for a Cobra 146-GTL AM/SSB CB radio..
> In order to use it, however, I had to install a relay inside
> the radio in order to switch the 12-volt power from tx to rx..
>
> I really dislike rigs like the 146-GTL where power is switched
> to the receiver and transmitter via additional contacts
> in the microphone switch .. YUK!!..
>
> --
> Patricia E. Gibbons & Carla Satra
> Tactical Link Systems
> In California:
> "She sells D-cells by the seashore"
> <ICQ#: 72818195>
> <http://www.tactical-link.com>
> see my comvan at:
> <http://www.tactical-link.com/wa6ube.htm>
> ......................................
> My Public Key is available at:
> http://wwwkeys.pgp.net:11371/pks/lookup?op=index&search=0xedecb44f
> Key ID: 0xEDECB44F
> This key is RSA, NOT Diffie-Hellman !!
>
> -----Original Message-----
> From: Military Vehicles Mailing List [mailto:mil-veh@mil-veh.org]On
> Behalf Of Patrick Jankowiak
> Sent: Sunday, May 11, 2003 18:47
> To: Military Vehicles Mailing List
> Subject: [MV] CB in MV
>
> Here's some commo thoughts for long range drivers. Long winded, yes.
>
> A CB radio is needed in the M35 becaue I like to drive the wide open
> roads of the great State of Texas. CB is the road
> language..
>
> The antenna installed is made of MS-116, 117, and 118, with an
> AB-15-like base (the rubber shaft part is thicker and the
> base is plastic). It resonates at 22 MHz but will be fine with an
> antenna tuner.
>
> I have a vanner 50 amp battery equalizer, so 12VDC is no problem
>
> I do not like the modulation quality (transmit audio quality) of
> most modern (foreign-made) CB radios, and I just can't
> picture one of those cheap plastic things in there, even painted
> green. Let's face it, even a Cobra 148-GTL does not sound
> anything like the old plate-modulated boat-anchors of ye olde
> American manufacture.
>
> I have just repaired and aligned a Sonar FS-23 tube-type CB made in
> 1965. 3 tubes and 4 resistors later, the CB is
> working.
>
> I will have to remove its covers and front panel and give them the
> ol' green treatment. Replace the meter with a GRC-106
> type meter.
>
> The knobs are another issue.. They are not military-looking, but are
> held on by setscrews. Knobs like those on the
> VRC-12/RT524, or GRC106, PRC77, etc. are held on by screws put in
> from the front,. I don't have the means to deal with
> that.
>
> For starters, a small PA speaker in the cab should provide enough
> volume from the CB to be heard in the M35. The issue
> will be the CB's mike. It will surely pick up all the noise.
>
> This brings up the question of microphones in general. MIL aircraft
> and trucks are real noisy. Yet the radio operator's
> voice is always clear and above the noise (re: the AC130 gunship
> video). What's the secret? (besides the CB mike is
> uuuugly!)
>
> (integration to VIC-1 is possible, another subject for later)
>
> Now, some will say it's not right to do this, putting a CB in a
> military vehicle, that I should use military radios.
>
> I agree to a point of aesthetics, but where to find a 'small'
> underdash military radio which is low powered and will
> easily do the 23 or 40 channels of the 27 MHz band?
>
> A 27 MHz FM rig like in G. R. Baker's M5 Stuart is quite big and
> would have to be modified heavily for more than
> rudimentary AM use. I will not chop up a good military radio!
>
> A PRC104 is too expensive.
>
> The GRC106 won't fit under the dash and although I could mount one
> on the passenger seat, I would be distracted trying to
> change channels, fiddling with the fine tuning because CB's are
> often slightly off frequency and the 106 is essentially a
> SSB radio, forever shooting thieves in my driveway, and its 400
> watts is a bit excessive for CB!
>
> So therefore a resurrected tube type CB, saved from the junk box.
>
> I'll have some pictures of it later when it is green.
>
> soapbox off.
> flame away!
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