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Newbie needs help with antenna

Stryker

Member
Jan 16, 2007
5
0
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Just getting in to cb radios. I purchased a Uniden PC76XL. The seller said its been peaked and tuned. Swings to 28 watts over 120% mod(I don't know what that means if someone could educate me please). Anyway, I'll be putting this cb in a chevy cavalier and was wanting to know what kind of antenna you guys would reccomend. Thanks.
 

Stryker,
What antenna depends a lot on what you are willing to do to mount and tune the thing. There are a few 'general' things, bigger (longer) is better than shorter, drilling a hole is 'better' than a mag-mount, and everything ought to be tuned. [All generalizations are only that, not hard and fast 'rules'.]

All power and modulation percentages are open to 'question' with modified radios. Power output should be taken with a large dose of 'salt'. Modulation percentages are sort of like your bank account. '100%' is the best you can expect, seriously doubt if your bank is ever going to make 120% available to you without sone 'interesting' intere$t added. Anything over 100% is a complete waste of time and only causes distortion, among other problems. Actually, something on the order of about 85% is all that's needed for clear and reliable communications [Ever turned the volume up on a stereo till things got really distorted? Same thing with over 100% modulation.]
Good luck!
- 'Doc
 
Think of the 120% modulation thing like this. What happens when you try and stuff 120 pounds of crap in a 100 pound box? Once it is full you still have lots of crap left right? That is what happens with the modulation,100% is as good as it gets and anything over that is just crap. :LOL: As for the antenna a Wilson 1000 will work quite well.
 
thetnhillbilly said:
120 pounds of crap in a 100 pound box equals 220 pounds, now that is heavy.
I can do antenna math! woo-hoo!
:roll: I think you know I meant a 100 lb. CAPACITY box. :LOL:

Now don't go telling me that capacitance is measured in farads not pounds. I know that too. :p
 
I would go with the Wilson 1000.

Mag mounts have the ability lose their grounding property (at higher speeds/wind resistance) if the mag mount is too small for the antenna. I have ran into this problem before but not with a Wilson 1000 Mag mount. (something to consider on taller antennas with small mag mounts/contact area the ground becomes somewhat compromised)

Isn't the legal limit 120% modulation for AM (commercial) stations (positive peak) and 100% (negative peak)? Maybe I have that confused with another standard...

:roll:
 
Geekster said:
Isn't the legal limit 120% modulation for AM (commercial) stations (positive peak) and 100% (negative peak)? Maybe I have that confused with another standard...:roll:

That is correct.In order to achieve that you must have an audio circuit that is capable of providing assymetrical audio whereby the positive peaks are amplified greater than the negative peaks.The typical diode and resistor thing just does not do it properly.I used to run Gates Solidstatesmen limiter/amps in my AM audio chain that would do just that.It would also flip the phase of any assymetrical audio (typical voice) going in that had greater neg. peaks than pos. peaks ensuring that the pos. peaks were always greater than the neg.I still have one of those in my basement along with an AGC unit that I hope to connect to my RCA BTA-1A broadcast transmitter when I get it converted to 80m AM.Ahhhh.... a pair of class C 4-400's with a 750 watt carrier (legal here in Canada BTW) modulated by another pair of class B 4-400's at 120% positive peak modulation.Life on 80m should be good. 8)
 
:)

Good grief! He's a 'Nooby'! Must be a product of living next to all them "Blue Nosers"...Aye,aye?
- 'Doc


Heard about the 'nooby' that went to see the taxidermist? Heard he had a 'Mounted' Policeman...
 
QRN said:
I still have one of those in my basement along with an AGC unit that I hope to connect to my RCA BTA-1A broadcast transmitter when I get it converted to 80m AM. Ahhhh.... a pair of class C 4-400's with a 750 watt carrier (legal here in Canada BTW) modulated by another pair of class B 4-400's at 120% positive peak modulation. Life on 80m should be good. 8)


We're NOT worthy! We're NOT worthy!

133303857644ec80e95b836.gif
 
...thinking to self...
oh oh. Or are 'nooby's from New Brunswick? Oh sh**, now I'm gonna have to appologize. Probably won't understand about the taxidermist either. Me and my big mouth...
- 'Doc
 

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