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Cobra 18 WX ST II (don’t laugh)

Discussion in 'CB Radio Modifications' started by ForestRunner98, Feb 11, 2020.

  1. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    @ForestRunner98 - at least you got a good start, I take issues though with companies that short-you...

    Ok, Disclaimer, you say it works, but you had to call-back to the custoemr serivce line and it's loops and hoops. but reading what you had to go thru - reminds me of the days back as Sales and having to deal with Angry customers...



    Some days on the Sales floor, you're Sherriff of Nottingham, others, you're Robin Hood - you were the First and Last line of defense for the Brand you served.​
    • I irritates me that the antenna didn't work for you right out of the box and you have to make changes and take steps to resolve that problem on your own
    You problem is not unique...

    Why do you have these same headaches others that buy such antennas also get?
    • - SWR tuning problems when all other aspects of Roof mounting and Coax have been addressed
    • - you shouldn't have even needed to "extend" your coax to fit the SWR - GRRR...ON them, not you...
    Since this antenna was designed for 10-11 Meters, what length whip did you get?

    I'm thinking the 57" (10-Meter) to 62" (11-Meter) whip problem here...5" inches makes the tuning difference.

    What length did you get with the antenna load?
     
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  2. ForestRunner98

    ForestRunner98 917 SoCal

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    I have come to realize not just this hobby but with anything that you always get thrown a curve ball.

    Not having the correct mount sucked but was corrected swiftly. I get it, stuff happens.

    The whip is 72” so it’s correct for 11m. I think maybe because of 10m/11m it’s tuned to the best for both. Not perfect for one or the other. Adding the extra coax “fixed” it.

    What threw a loop was adding a amp thats known to be dirty. If I was running it barefoot it would be been ok. Not great but ok. Now barefoot barely blips the meter across the channels.

    As for the mag mount I don’t understand why they wouldn’t just have 18’ of coax. Seems like it’s the standard length that’s sold ready made. 12-13’ seems short. And it was for my application. I am looking for a permanent mount in the future. Not sure if I want to go NMO or just a regular PL.

    Having the extra factors does not make it a slap on antenna. Some things need to be tweaked for it work as it’s advertised. But I would like to know other members experiences with this antenna.
     
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  3. Slowmover

    Slowmover Elmer

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    (Maybe I have this right)

    “Dirty”. That’s different enough than spectrally-pure that tuning a Mobile CB with a baby amp won’t cause near the problems Antenna Efficiency issues merit.

    The baby amp highlights other problems when kicked in.

    Yeah, eventually you’ll get to where amp “quality” matters.

    Antenna? Good.
    Mount? Passable

    “Bond” is the thing at this stage.

    IIRC, the words are: “if changing coax length solves SWR, the problem is elsewhere”. (I agree using 18’ a handy baseline).

    Amp not perfect.
    But not YET “the” problem

    .
     
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  4. Slowmover

    Slowmover Elmer

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    Plenty of posts about the several versions

    .
     
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  5. ForestRunner98

    ForestRunner98 917 SoCal

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    I spoke to Breedlove and they recommend the 4.5” puck for the Sirio. I also might get the 6x6 plate that goes inside the cab for extra support.

    They don’t have a S0239 with ring terminals just the NMO. So...I will get the NMO and use an adapter. Not crazy about using the adapter but I could use the NMO for other possible antennas.

    Anybody use a NMO adapter to S0239?
     
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  6. Slowmover

    Slowmover Elmer

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    It’s the way I figure to do it. NMO-Mount antennas (for me) will be low wind-resisting base-load (by comparison to some of the non NMO).

    Consider being parked and swapping in a 108” on a riser. A MOTO 6-40, as example.

    And, in this part of the country the overhead clearance problem almost doesn’t exist as 14-15’ on the Interstate can be done once away from metro roads.

    If one is optimized for BIG at 65-mph (forget 70), all other problems fall into line.

    A KL-7405v sure looks good now

    .
     
  7. ForestRunner98

    ForestRunner98 917 SoCal

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    Ya I like the NMO because of the options but I wanted to make sure my 11m antenna will work(TX/RX) with it. I would think it shouldn’t make a difference.
     
  8. ForestRunner98

    ForestRunner98 917 SoCal

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    So I wasn’t happy with my Cobra power mic. It just didn’t have enough power. I went back to my stock/modded President mic. It worked great with the mic gain down a few clicks.

    I found this mod on CBtricks. Just by removing and jumping a resistor and swapping a 1.8k ohm to a 220ohm resistor this mic came alive! I have it set a 5 and it gets full modulation even with the mic gain kicked down. love it!

    Here is the pic from CBtricks:
    C55F700E-8531-4ED7-99FB-816F8FA9B075.jpeg

    If you have this mic I suggest this mod!!
     
  9. Cabover Bob

    Cabover Bob Tap tap tap......pay attention

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    Did you go to the warehouse in Fremont ?
     
  10. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    You have my (Poster) Permission to move this post ....
    and this post...
    https://www.worldwidedx.com/threads/cobra-18-wx-st-ii-don’t-laugh.252212/page-24#post-751462

    To another location in the forum - I am under the impression of the type of mics discussed here, may benefit others, but may be considered off topic in this thread

    At your Direcretion...


    This answer has been broken down into two posts... this one has your attachements.



    IF you don't have that one...

    I've got more info to help
    http://www.cbtricks.com/mic_manuals/cobra/ca75/CA75index.htm

    There's been several "upgrades" as you can see in the photos from the site...

    So I did rework some more info but CB Tricks "died" before I could get it it posted permanently.

    Below is attachments that show the board above but populated differently - you may or may not come across the upgraded ones, but if you look on the PB board the Mic has inside it, you'll see their level and revision.

    So hopefully the below as well as the link can provide soem direction.

    Below is a TEXT of the attached work...from CB Tricks...

    « on: October 20, 2016, 10:31:12 AM »
    Greetings!

    (LEGACY - effort to preserve for future insight ...)
    Didn't know if you knew this, but the sites' work of the CA-75 microphone - At This Link is mine from a long time ago and I haven't been able to update that information since then. So I've posted my own "critique" of my efforts from back then to reflect the changes and things I've learned about this device by my own use - since then.

    Ok, looks like there are separate issues here...

    One is audio frequency spectrum, other is audio drive - both tie into compression.

    You can't have both at the same time with the current design.

    Mostly due to the Electrets' own frequency response curve and the circuit design is poised for audio compression.

    And your desire to obtain 20Hz to 15KHz full broadcast quality with this microphone - the selection of the Electret generates an equalization issue due to the complex nature of the reactive network used to supply power and acquire the audio off of the DC bias present to power the microphone and limitations of the design used in this circuit as a reactive network to obtain it.

    It's a shame the original posts all got deleted, for you could have seen the development of this drive level and audio frequency rolloff issue throughout the whole series on this mic amp design.

    But, you can review another posters work on a similar mic here at this link - it may give you some insight as to the popularity of this mic amongst the CB world.

    Too bad someone had to come by and gripe, complain and deprecate my own participation in an effort to discredit or to plagiarize my work for perhaps another sites benefit. The posts had to be taken out otherwise Benny may not have been able to stop the theft of ideas or to prevent the poster from abusing their privileges at the expense of others.

    I also corrected some errors - again - lost in the posts of earlier - due to the feedback received - or lack thereof - and the poster used it as bait for others to ridicule.

    The true reasons for such an effort by them are unknown, Just bad karma...

    So it was removed and a boiled down version was posted instead...



    Quote from: Reverend Bow on October 20, 2016, 01:29:18 AM

    Andy,

    Looking at your write up on this circuit, what do you think it causing the bass roll off so darn high?

    http://www.cbtricks.com/mic_manuals/cobra/ca75/CAschematic.html

    You mentioned:
    The purpose of the back to back arrangement is two-fold - to reduce audio drive and offset problems with DC-bias provided to Q1 with R 2. C 4 provides a shunt-path filter for audio and RF. The typical frequency response, or bandwidth, of this mic amp is quite wide. Radios' only need a frequency response peak between 600Hz to 1.1KHz and the use of C 6, C 10 and C 11 provides most the roll off needed.

    You think it is C6, C10, C11?

    The reason I ask is it seems the C2/C3 combination and C7 are still plenty large enough to pass so low end.

    I'd like to "Fill Out" the mic audio the the SS3900 I want to run it on can now pass (20Hz to 15KHz)...




    In an earlier time, an explanation I had was from the drive level and expected amplification "range" or window of operation.

    Using an Electret element already puts plenty of audio drive into this 2 transistor amp.

    I'll need to add that the changes done to the values of the various resistor and capacitor locations was for fidelity and drive improvements - for the purpose of being able to produce output from this design that is similar to another popular microphone, a D-104. Unfortunately it's no longer made. I found that this 2 transistor design was also able to mimic another type of microphone - sold under various brands "Diesel" and "Cobra" as an Echo power mike - only without the echo.

    It also used discretes' which allowed me some considerable freedom in choosing parts to experiment with - even though the circuits' complexity limited features like frequency emphasis and de-emphasis - but at least I could develop various levels of drive and fine tune those effects.

    The Use of the capacitors (across the output resistors') was to offer audio frequency equalization while the altered resistive values were changed and combined to keep their respective transistors from developing too much output; Clipping or Saturation. The capacitors were providing the audio a low-impedance path across the amplifier stages output and the increased resistor drive values were to keep the stage stable at DC values and provide audio output that didn't develop a saturation event I call "starvation"; caused by the frequencies the amp is trying to pass has placed the stage in a mode where output would drop or distort / skew due to the power requirements the stage needed to provide that extra drive were not available. So another form of clipping or distortion - similar to saturation - but on the output - not on the input - formed.

    Although the capacitance values worked, the users on the other end of the mic heard nearly mono-tone-ish sounds reflected by the bandpass the feedback path of the 18K and 103/223 (0.01uf to 0.022uF) Disc cap placed on both emitter outputs (positive feedback - above ground and the respective emitter resistor) so the starvation event placed the circuit design in a level of operation where the bandpass the caps across the emitter resistor could pass audio range - the results sounded like they couldn't because of the biasing and filter feedback bandpass kept the mic amp from developing a true spectral range the electret was capable of - and the filter keeps the amp from having such a frequency response - but the circuit design itself does pass these distortion effects along so the amplifier is capable of such a spectral feat - only it needs some help in proper selection of the filter network values.

    So, when the amp design uses a capacitive coupled feedback filter like that in this amp, unless you can offset the sheer audio rolloff or narrowed bandpass or offset, by using smaller capacitance - which is possible - the second necessary requirement in the biasing needed to both transistors, was their resistors values that are used for biasing needs to be changed. Not necessarily by using smaller values - like what was done previously at their respective emitters ( see the link ) - but by also changing the drive output of the Electret - using a similar design shown in this series of posts, of either by or inclusive of both, the resistor and capacitor selection.

    Each Electret element has a particular "expected" level of power that is required, a DC-based bias, and the output of the electret then "Swings" the voltage up and down as an analog waveform (voice or music whatever the membrane can vibrate using) that can be extracted - thru a reactive network - to be applied elsewhere or to another amplifier/processor.

    It's this (we are talking Electrets' own here) output requirement - being reactive and containing a DC level bias - to extract the audio - requires a reactive network to be idealized to the electrets expected window of operation - so it shows itself to be powered but has an reactive output or impedance.

    This output - along with the DC bias, does place a bottom level on the output in regards to frequency.

    So, when you attempt to drive a 3900, Cobra 29 or an HR2510 - remember their limits of frequency range (Audio bandpass - frequency)are intended - built into the device this microphone will be used on, also place limitations of frequency response.

    So, in an idealized world - the SS3900 should be able to be driven directly by this amp? Yes. But it has limits - mostly due to the filter and bandpass inherent in this design, working against the installed frequency limitations of the devices its being used with to operate/drive. So it also has power limitations, saturation and clipping are some of the expected results - distortion, caused by Electrets' own output network and the biasing and filters installed in the mic amp design itself. Some of my own efforts shown in the earlier work, are from reworking the biasing and filtering thru trial and error as well as trying to idealize - or match - the output of the Electret to the amplifier used in this mic - to improve the audio drive level as well as its frequency spectrum output (fidelity).

    Your mileage may vary.

    This mic amp design can do a nice job of compression with some intelligibility and fidelity - but otherwise the filter / compressor design will have to "Stay in there" otherwise the gain levels are far too high to drive any radios' AM regulator - were talking between the stages of this circuit - so you'll encounter clipping and saturation from it - which when you look at it is why they added this filter network design - idealize the amps output into overdriven - then fold back the output by the addition of a filtering scheme to peak the frequency response to meet audio spectrum range filtering used on most (SIC) CB radios'.

    I hope this helps develop where you wish to take this - so let's continue - I'd like to know more...

    Regards!
    :+> Andy <+:

    Re: CA-75 ... Revisited?
    « on: October 20, 2016, 01:36:48 PM »
    Greetings!

    Not sure of the setup for the input - as in, what "jig" was used to inject the signal?

    Was wondering then, if you placed the input test signal - in to the Mic Amp - instead of the Electret - as in you swap?

    Would like to see those results - not just "specific tone" but more like white or pink noise - voice is pretty complex - even if it's for a narrow range...

    I'd just like to see it from someone elses' perspective...

    To be contuinued....NEXT POST
     

    Attached Files:

    #355 Handy Andy, Dec 24, 2020
    Last edited: Dec 24, 2020
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  11. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    CONTINUED!

    From CB Tricks - 2016 DTD...


    Quote from: Reverend Bow on October 20, 2016, 12:13:32 PM

    Hey Andy,

    Thanks for the reply.

    Don't worry about my SS3900's Audio Bandpass, I have that covered... ;D

    The Graph below is a sweep (with a Function Generator) from 10Hz to 10kHz of the transmit circuit on the SuperStar 3900/Cobra 148 GTL/EX The High end caps (bypass to ground) are stock, so the biggest limiting factor to stop the Audio bleed into the next channel up or down is the Mic Element. The Red Line is the the Superstar, the Yellow Line is the Icom IC-718 in AM Mode.




    Would like to know the impact the Electret and it's frequency response would be in comparison to.

    Plus, would need to know how the Icom's own support (Modulation Method or Theory of operation would be nice for those playing along at home) circuitry works - at least we'd have a comparison. At least to be fair.

    In the SS3900 - are you sure you want to use this platform? I see considerable rolloff past the 3KHz and above, not much is needed after you start to go above Tenor and Alto voice ranges - unless you're looking into broadcast quality. Then there is an issue here with the RF output and neutralization that is needed. (Heavy Capacitance)

    So, before we start to compare Apples to Oranges - let's make sure they're both "fruit" ;D

    If there and Is(?) a way, to post these results I'd love to review what my efforts show - I can't do much here at the moment because I'm locked into being a caregiver to an elderly patient...so I cannot - at this moment in time - reproduce or verify, any of your results.

    All I have at this juncture is the memories and "direct side-to-side" checks before and after conversion on any given CB radio "PC-68", PC-122 Cobra 29 (4-Pin) Realistic TRC-453 and TRC-474 (5-pin DIN) Cobra 148 and Uniden Grant XL (5-pin Amphenol) - to verify keying and audio loudness effect, if that matters. Connector reference can be found here...

    The thread was developed for corrections, additional notes, factory revisions and changes to the mic -amp circuit throughout the course of it's life.

    Regards!
    :+> Andy <+:

    Re: CA-75 ... Revisited?
    « on: October 20, 2016, 05:09:30 PM »
    Greetings!

    Well, ok , I guess - thanks for letting me know I got the colors wrong - ::) but if the SS3900 has what you need, then why use this mic circuit design?

    The mic is set for tonal response - not full broadcast quality.

    If you take a moment and do a little figuring, the Mic Amp in this thread is very similar to those you'd already find in mini chassis like the TRC-453/465 as well as the PC-122 and Cobra 146 - there is only one thing missing in the design (two actually but their routing is what is affecting this response) and that is how the feedback portion of the circuit is constructed.

    In the CA-75, the Feed back path uses the 18K and 103/223 Disc cap - on the EMITTER legs...DC to DC block - but audio imposed from output of one to the output of another - this is where that "Compression" effect comes into play on this design.

    Compare this to a PC-122 or TRC-465 :

    - the feedback path is from EMITTER of one - onto the BASE of another.

    Note, in the link above, R143 is 100K and C107 is 100uF versus R 5 is 18K AND C5 (a 103/223 was used here in TWO different models one for "Noise Cancelling" while the other was a simple "Power Mike" so it's not mislabeled - just confusing due to the nature that it uses two different values in the same spot for different results) Disc cap has to be used IN SERIES and would be connected to the junction of the EMITTER leg of TR26 and R142. As a sidebar... please note that R139 is a 15K - refer back to the Mic amp in this thread - as used in this threads' design - as R 6.

    Because of the type of configuration shown at the link above, the DC block on the bias for both transistors is not needed...compression is achieved thru the positive feedback path back to the base of the 1st stage amp - with DC bias tracking using the capacitor not just for audio but for DC bias value averaging.

    So what I see in what you are trying to do, is a bit of overkill in regards to compression - at least that is how I'm reading this.

    So as to not go beyond the scope of this thread - I'd like to lock this to keep the Mic Amp being discussed here - as per the mic element as a unit - from turning into something I'm not really sure if it can be applied to the method you suggest.

    The SS3900 has it's share of faults in this - one being that the ICOM - (I believe) uses low-level modulated design and uses frequency mixing requirements to achieve that level of drive and performance - places the class of output - let alone the quality - more closer to Class A or Class AB in the TX chain than to use the SS3900's Class D AM regulator design or THEN uses class A to AB design for SSB mode of operation - which is a different beast altogether.

    This may not be a fair comparison...I'm a little cautious to proceed - unless I know that this thread and the information within it - stays as a stand alone unit.

    Which is unfortunate.
    Because - the Mic Amp design in this thread is an Emitter to Emitter feedback design, not an Emitter to Base Feedback design which can give you far greater bandwidth than the Mic amp design this thread is about.
    I see why and thanks for the verification that these AM regulators - once properly developed in both bias drive and parts value pairing together - can make a good wide-range audio driver for broadcast - but I'm worried that this mic amp will not suit your needs due to it's design.

    Regards!
    :+> Andy <+:

    Re: CA-75 ... Revisited?
    « on: October 20, 2016, 07:31:18 PM »
    Greetings!

    Ok, now I see what you really wanted to know - I know you asked this in the first post, but I was, and still am worried that this mic amp may not suit your needs.

    C5 - 103 or 223 (0.01uF up to 0.022uF)
    C6 - 150 pF
    C10 - 102 (0.001uF)
    C11 - 102 (0.001uF)

    All are used around the transistors directly - and are not connected to ground or source - directly.

    Frequency compensation and bypass - affecting gain - frequency dependent.

    Since these values are quite small - they only affect the higher tonal range. To remove them (caps), which I don't recommend - gain would then rely solely on the resistor values.

    All the parts listed you wanted to know about are designed to provide audio frequency feedback paths - so they are affecting overall gain of each stage - so, the resistor values alone would make the gain in each stage - too high - and although, bandwidth would be much wider, it comes at a price I learned about, in removing C6 - that "starvation" effect I mentioned earlier can quench or even kill audio signal and induce a squeal instead.

    C6 - is the biggest culprit - and when you look back in my reference pages - I recommended (regrettably) this part could be removed and substituted with a 270K resistor - unfortunately I found out first hand that this level of resistance caused more squealing issues in radios with a separate ground return for audio - like the 148 or Grant XL - so in reworks I found that this value was better IN A LOWER RESISTANCE range - like 100K or even less - and kept the C6 in there to reduce that "starvation" effect because of the lack of/improperly set bias - handsets own bias and drive - it just tamped / damped down the gain, the benefit I got from it recovers a lot of bandwidth.

    Additionally - we didn't cover the operators own changes internally to their own equipment added another variable that I had to work with in choosing these values.

    One effort to clear this up was adjusting/trimming/changing the gain factor as well as the input level of the Mic Element - I discovered a lot of the distortion was caused by high-input level - it was finally reduced and proper capacitance was applied to drive the amp input correctly (matched) the C10/C11 and even C5 fell more into place and really could have been left alone - they didn't affect the overall performance in a normally driven (unmodified) CB because of the peak response curve the microphone would now have after it's modifications - more closely matched the frequency response the radio had built into it.

    Without the CB Radios limiter, there would be another problem of too much high-tone roll off and perhaps better said "muddy mike sound" so to improve the bandwidth product and offer a greater range of control thru the mikes' own handset the additional 56K resistor added on the C6 foil side as well as keeping the 150pF cap - WAS NEEDED to remove a tonal artifact caused by the element within the handset. This factor was part of the gain, output adjustment range and overall speech performance improvement into radios that had "tightly filtered" or limited audio bandwidth.

    Although not a true fault for the Microphone maker or the operators own installation, if the station or location wasn't properly shielded nor was it properly isolated from wind noises you can easily discover it's ability to pickup background level ( cardioid versus Omni-directional pickup ) noises and amplify it, together with the operators own voice, added problems with compression performance - too much of a good thing - usually is...

    However, again lost in the posts from previous - the C10 and C11 could be removed AS LONG AS YOU DID NOT ADD ANY ELECTROLYTIC CAPACITANCE OR ANY OTHER LARGE VALUE CAPACITANCE across R4 or R11 - this kept DC bias and Amplifier stage gain for audio close to each other and didn't add any equalization or frequency dependent gain factors. In doing this, you then left the stage open for self oscillation in certain RF leakage prone areas that can generate an RF feedback loop that would kill the audio signal and left you with a squeal or no audio at all because of the bandwidth the circuit would have had without those components in there the transistors easily clipped/saturated from the stray pickup of everything - even RF - floating around the cab/shack can be thrown in there.

    To keep the newer amplifier design stable for a larger range of installs as well as radios this mic could be used with I had to reduce or change a lot of values. Why? Because I never anticipated problems that would occur - I used it with my equipment and it worked - even ones that used a Quad op amp for mic/squelch/AGC and audio pre-amp - Midland 77-113/115 and 77-160 - this mike worked well with them. But I had encountered other operators having problems with these mikes so - what you're reading are the results and solutions in solving them.

    Again; you are seeing a "boiled" down version - so when it comes to what you're looking for - I'm not sure you'll find it. I'm adding my notes I have on this circuit once I know what you are looking for in hopes that you can use it - I just don't want any further perdition done to this thread...this is for the benefit of the mic amp and those that would like to experiment and use it.

    So you know, you ask questions that I feel need a base for a proper answer - so it requires me to post these "winded" messages so you would know the why and what I did - in making this thread.

    Regards!
    :+> Andy <+:

    Re: CA-75 ... Revisited?
    « on: October 21, 2016, 12:34:39 AM »
    Greetings!

    I need to add more ...

    Came across some older Stereo Equipment manual with a schematic, I attached it (still a work in progress) to the previous post in an effort to demonstrate that the network used in this stereo - although an IC - used a Series / Parallel Resistor and Capacitor network and in the way they did it shows something I wanted to point out to you in the previous message about C6 (150pF) and my use of a 56K resistor paralleled across it but replace the 8.2K resistor R6 with a 15K resistor.

    There is also the Inverted Input of the IC using a Series filter network to ground, on the input, that still prevents DC (comparator action) but provides an audio frequency response as part of the Equalization network to meet RIAA standards for a Turntable.

    The previous post also shows the Original Discrete Values still in place - before modification so you can "revert" this device back to stock if needed to re-approach from a different selection of values.

    Why is this important? Your needs to provide a good Emphasis for Bass and perhaps a little De-Emphasis for the Treble range.

    This also demonstrates the dynamic effects of using active filter networks and how they interact with each other in both Equalization and Output level. Proper selection is important to achieve the Frequency Response as well as the expected output.

    So it's attached to the previous post for your review - it's a work in progress - but I hope you can glean something out of all this to help you achieve what you want.

    Regards!
    :+> Andy <+:

    CB Tricks - END

    The above is a revised posting to help answer some issues with CA75 since the original link was established back in 2010 - now as of later revisions - much of the info above may have changed from their original - so be aware - but the link to the CA75 mic is still available - so use it as you wish.
     

    Attached Files:

    #356 Handy Andy, Dec 24, 2020
    Last edited: Dec 24, 2020
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  12. Robert Cook Sr

    Robert Cook Sr New Member

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    I have a bearcat 980 in my shack only keys up 2 watts out of the box with 1.1 SWR ,have a uniden 520XL in truck with 1.1 SWR it only keys up 1.5 watt out of box ,engine off engine on it forwards mod to 4 wats and gives 90watts peak, I'm running 1o2" whip on truck & base , they show no SWR, with SWR they would show more dead key Watts
     
  13. ForestRunner98

    ForestRunner98 917 SoCal

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    Have you tried to switch radios and check your results? Honestly it shouldn’t jump from 1.5w to 4w when the truck is on.
     
  14. ForestRunner98

    ForestRunner98 917 SoCal

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    After about 3 months of parts sitting I found time and weather that worked for me.

    Yup..time to drill a hole in the roof and install my NMO Breedlove mount!

    Had to basically take all the rear interior panels off the get the headliner to drop enough to not punch through. I used a Harbor Frieght step bit. It worked but I should have gotten a better bit. It took some pressure to drill to 5/8”.

    My son helped to hold the headliner while I drilled. Ok hole is good and centered. Make sure to triple check your measurements!! Could not install exactly in center of roof because of cross brace. So basically the exact same spot I had the magmount on.

    My Dad was a welder and metal guy. He’s in his 80’s but still likes to get involved. I measured a 14ga stainless steel plate for support under the mount inside the truck. He cut and rounded the corners for me. Good job Pops!!!

    Installed the coax and tried her out. SWR...1.1 across the band! 1.3-4 when amp is on. Super happy with the results! All that bonding sure paid off. Hearing more distant stations and noise floor is lower. Just need to make a gasket to replace Sirio gasket.

    So it’s the NMO to adaptor to antenna.

    90F8B551-7A1D-4553-AD18-851619A3F359.jpeg

    A shot of the interior:

    9233C1F5-A064-4CFC-B21D-89B60AE0F150.jpeg

    It’s real stable if I whip the whip back and forth. Hardly any flex. Even with the 3” mount. Took a drive and no issues.

    Thanks to all that helped me along through this build up to this point!!! All that advice that was given is golden!!
     
  15. Cabover Bob

    Cabover Bob Tap tap tap......pay attention

    Joined:
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    I have to ask - if the antenna has a 3/8" mount, why the NMO puck/adapter ? What did I miss ?
     
    ForestRunner98 and Slowmover like this.

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