Next Galaxy Mod. Change Crystal to Move Ch13 Birdie

[Wire Weasel]

This is next on the list. Understand it's in all 99's and affected the 77's and some other models. Bad birdie on/near ch 13. I've heard you can replace one of the mixing crystals with a different one and it moves the birdie up into 10 meters somewhere.

Similar birdie on 13 but effect not quite as bad on my 94HP too. Can't find the mod detailed anywhere on the net or which crystal to get/which one it replaces.

After crystal change will need to realign freqs which can at least roughly be done with on board freq. counter.

Any help?

 

[Robb]

10.240 MHz PLL REFERENCE:
RX Mode, AM,
Freq. to 26.965MHz Band E
Fine and coarse clarifier control to center detent. Connect Frequency counter to IC5 Pin 4.

Check for 10.2400MHz ±200 Hz. If tolerance is beyond this, replace
X1 (10.240MHz).
That was from CB Tricks.
Galaxy Radios DX99V Service Manual

Never had a birdie problem with my 99V; but it does drift when cold. If I have any problems with this xtal - I'd change it to a better brand/part.

 

[fnkycoldmedina]

near all my exports have a channel that does that.i just dont use that channel.

 

[Wire Weasel]

near all my exports have a channel that does that.i just dont use that channel.

Yeah that's the easy thing. But dontcha know our local group uses Ch 14 as primary.

Maybe with all the Galaxy's around I can convince the group to change channels

 

[JoeDirt]

Im lost whats a Birdie on a Galaxy???

 

[Robb]

"Birdies" are a particular noise that can heard in the receive on a radio. Sounds like a chip or a tweet. Usually, the cause is the power supply. None of my exports have this problem, as I run a Magnum Omegaforce and a Galaxy 99V.

 

[JoeDirt]

Thanks for the explanation Robb! I have a few exports and never heard of that!

 

[Highlander_821]

From whatis.com:



"A birdie is a false, or phantom, signal that appears in a superheterodyne wireless receiver. Birdies are internally generated, resulting from the outputs of the oscillators that form part of the receiver circuit. They usually sound like unmodulated carriers -- signals with "dead air." Occasionally they are modulated by clicks, humming sounds, or audible tones.
Birdies can occur as a result of the receiver being tuned to a frequency that is a multiple of the output frequency of one of the internal oscillators. These signals are known as harmonics. A birdie might also be heard at a frequency corresponding to the sum or the difference of the internal oscillator frequencies. These signals are called mixing products. Birdies are inevitable in any superheterodyne wireless receiver. However, in a well-engineered receiver, most or all of the birdies occur at frequencies outside the normal range of operation, so they have little or no detrimental effect on receiver performance.
A birdie is not the same thing as a spurious response. If a receiver picks up a signal whose transmitter is operating at a frequency other than that to which the receiver is tuned, the modulation of the unwanted signal will be heard or decoded. In some cases, two or more strong external signals can combine in a receiver's radio-frequency amplifier, causing numerous spurious responses. This phenomenon, called intermodulation ("intermod"), can be a problem in downtown metropolitan areas where many wireless transmitters operate simultaneously."


ALL superhet receivers have birdies, but in good quality radios, they are minimized to the point that a good signal on the frequency in question will overcome them. They generally are not caused by the power supply. More likely the microprocessor or synthesizer. I'm not saying that the power supply can't produce noise in the RX, just not usually birdies.



I really wonder if WireWeasel actually has a birdie. Interference yes, birdie maybe not. Is it still there if you disconnect the antenna? If not, then it's probably not an internally generated noise.
​

 

[Wire Weasel]

"Birdies" are a particular noise that can heard in the receive on a radio. Sounds like a chip or a tweet. Usually, the cause is the power supply. None of my exports have this problem, as I run a Magnum Omegaforce and a Galaxy 99V.

Birdies aren't always a tone based noise. This 99V has an elevated constant noise level sounds like someone is throwing a carrier off in the distance.

So Robb, when the channels are quiet your 99 doesn't sound any different at all on channel 13 compared with the other nearby channels?

If it doesn't....then it's been fixed.

 

[Wire Weasel]

From whatis.com:



"A birdie is a false, or phantom, signal that appears in a superheterodyne wireless receiver. Birdies are internally generated, resulting from the outputs of the oscillators that form part of the receiver circuit. They usually sound like unmodulated carriers -- signals with "dead air.​

Here ya go and there ya got it.

Thanks​

 

[LOX]

"Birdies" are a particular noise that can heard in the receive on a radio. Sounds like a chip or a tweet. Usually, the cause is the power supply. None of my exports have this problem, as I run a Magnum Omegaforce and a Galaxy 99V.

Good post

Many switching type power supplies cause receive birdies. Alinco has a P/S with a "notch" adjustment just for that reason.

 

[HomerBB]

I have two 88's. One in the house for base, one in the SUV for mobile. Both of them have that hollow sound like a distant station throwing a carrier on ch 13. I could close my eyes and have someone change the channels and tell them when they had arrived on ch 13. There is no switching power supply in the SUV. The base radio is on one, but it makes the same sound when on the regulated PS, too. Never noticed it before in any other import radios I ran.

Not gonna worry with it, though. Channel is too close to the alligator stations running skip on ch 14 when conditions are in, and no local traffic use ch 13 regularly here.

As has been said already, if a transmission is sufficiently strong on ch 13 itself then the listen-to-the-ocean-in-a-seashell sound is overcome.

 

[IMD262]

Change the 13.560 MHz (13.56 x2 = 27.120 MHz) crystal to a 14.010 MHz crystal, the birdie will move to 28.020 MHz (14.01 X2 = 28.02 MHz).You will also lose your bottom most band and gain 1 band on top.

 

[Highlander_821]

Change the 13.560 MHz (13.56 x2 = 27.120 MHz) crystal to a 14.010 MHz crystal, the birdie will move to 28.020 MHz (14.01 X2 = 28.02 MHz).You will also lose your bottom most band and gain 1 band on top.

You might need to re-align the set after doing that.

 

[Wire Weasel]

Change the 13.560 MHz (13.56 x2 = 27.120 MHz) crystal to a 14.010 MHz crystal, the birdie will move to 28.020 MHz (14.01 X2 = 28.02 MHz).You will also lose your bottom most band and gain 1 band on top.

Thanks to IMD262 !! That's what I was looking for!