Sue, AF6LJ, a great technician has suggested (on QRZ) checking the 3 VCO's for correct voltage level (around 5v, as I recall).  They typically require just a tweek to the trim pots.  Just requires a DMM and screwdriver, as I recall.

The procedures are in the Service Manual.

Ok, lets talk real world application for the ham.

Deviation:   
-Over deviation will cause audio distortion
-Under Deviation problems are usually most common when a handheld can hear repeaters well, but the audio signal is clear but weak.

Adjustment:  A audio tone generator (typically 1,000 hz) and a Deviation Meter is needed.  The tone is applied to the mic in\put (or microphone) while keying the radio and the deviation pot is adjusted to show no more than 5 Khz.
 
Modulation:
Modulation values are normally fixed by the radio design. 

-Sub Audible Tones:
The DTMF or PL tones are mostly below normal hearing abilities.  Sometimes the level drifts and either goes low, causing failure to activate repeater functions, or may drift high level, causing the very highest tones to become audible and cause annoyance.  Adjust the tone level pot as necessary.  A Service Monitor is helpful for checking tones.

The repeater is supposed to strip the tones with a high pass filter, but occasionally this fails or needs adjustment.

b.

FM sidebands are not something that are commonly discussed among non-engineers, nor typically a problem.  They are a common concern for AM/SSB transmitters.  

Of course, with either type of transmitter, appropriate filters must be included in the design to suppress sidebands to meet FCC specifications.

So, at face value, sidebands of an FM signal are not something addressed in calculating or applying the basic Carson rule.   Typical usage would be evaluating if our signal will remain within allotted bandwidth, and whether we need to adjust the Deviation or Peak Modulation to remain within standards.

[edit]  Practically, we would check the sideband levels with a Spectrum Analyzer.  We might compare this against the transmitter specifications for sideband suppression (measured in dB).   I'm not familiar with a method to mathematically estimate sideband levels or width, not being an engineer.

cheers,  bill

Carson's rule is typically used to calculate bandwidth of FM transmitters.

Let's work an example for ham applications.

Peak Deviation:  5khz (typical for repeater FM operations, this is an arbitrary number based on the transmitter design).  This actual number varies depending whether you are whispering or yelling into the mic at any given moment.   [is an equipment setting].

Deviation is caused by the signal being applied to the carrier, whether voice, music, packet/aprs waveform, etc.   Commercial two-way users are switching to 2.5 Khz 'narrowband' deviation to allow more channels.  Commercial FM  stations typically have 75 Khz deviation.  Wideband, indeed!

Peak Modulation:  Alexander Bell determined the optimum frequencies for communications were between 300hz and 3,000hz.  This is typical for telephone and most amateur operations.  So, the Peak Modulation is 3,000Hz/3Khz.

Bandwidth = 2 * (Peak Deviation + Peak Modulation ) = 2*(5,000 Hz +3,000 Hz)
Bandwithch = 2*(8,000 Hz)
Bandwidth = 16,000 Hz or 16 Khz

So if our center/carrier frequency is  146.000 Mhz, we will occupy 8 Khz on either side from 145.992 Mhz to 146.008 Mhz.

You didn't like the answers you got on QRZed? 

3/8-24 mounts are so troublesome that I have used them for over 25 years on 2m/70cm! 

I am in the process of getting ready to drill holes in my car (gasp) and try out NMO mounting though for a sleeker installation.

Oh, heck, we've been incredibly successful at having Hamfest sales drop for the last 20 years! 

I installed a 'music on hold' system for the telephone exchange at work.  It played light pops music.   Honest!

A couple weeks later my boss called me into his office and handed me a strong letter from one of our customers complaining about the automated system that asked intrusive personal questions while she was on hold.  *Bizarre*.

Don't forget the A&E channel had "Arts and Entertainment".  Actual by gosh, ballets, symphonies, plays....

The  June 1992 QST has an article "The Repeater Eater" for a simple two element quad antenna for 2meters which is adaptable for portable use.

The Amsat folks have developed some 'Cheap Yagis" for combined 2m/70cm operations,3 elements and small handheld size.  Google or check out www.amsat.org/

 

You won't find any antenna that offers any sort of signal gain across so many bands. 

Practically, you will will only find antennas that are designed to operate on 2m/70cm. 

The biggest concern is avoiding heavy antennas that will place to much strain on the tiny SMC connector and perhaps cause permanent damage  to the radio printed circuit board.

One cheap and easy way to improve 2m/70cm performance is to add a wire counterpoise.  about 19 inches long with about an inch stripped bare and wrapped around the antenna base. 

You will have to build antennas for specific bands along conventional lines.  You can't beat physics, and there is no way to shrink a shack into a tiny cheap handheld radio.

A friendly reminder that it not legal to use amateur radios on other services like GMRS, Marine etc.  Radios that are part 90 (commercial certification) may be used on both amateur and commercial and personal bands, with some other restrictions like power and antennas.

cheers, bill

If they were selling "Emconn Flying Rocket Boots", we would be fully justified in demanding specifications and proof, regardless of the quality of materials and workmanship.

Edit:  The same ridiculous statement could be said of an airplane.  Is it really impossible to tell me how fast, slow, high, fuel consumption and landing distance?  Pick a configuration, state your specifications and stand by your product.


And sometimes you get a lot less than what is claimed.  I understand the Trojan Horse was very well  built but turned out to be different than expected!

Radio is based in science and engineering.  Refusing to provide specifications for their antennas is a result of only three possible things on the part of the manufacturer:  Lack of formal education/training, deliberate intent to deceive customers, or placing profit above honesty through benign neglect.

There is no place for "Works good, lasts a long time and it's well built, so you can't criticize us".

No, it was Art BELL on late night radio, knocking on your brain! 

IC 746 and 756 series....

No sense guessing.  Either test the old cable or install the new LMR type.

If you install the LMR type, you need to use a short section of something flexible. [edit] It would still be a good idea to add a more flexible sections if you continue to use the RG-8 feeder. 

Typical UHF connectors have negligible loss from HF up into high UHF bands if installed with reasonable skill.  Period.  UHF Female-Female barrel connectors have even lower loss than the male PL-259.

Stop agonizing, Get crackin'!    Bill