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LOL LOOK AT THE SCOPE. Especially when he says it looks good
- Thread starter Low_Boy
- Start date
Just for the record I'm not being testy or trying to beat anything just pointing out little things since they seem to mean so much.
He starts off by stating he was off by 1 ohm and then proceeds to use an instrument that can't possibly be accurate to 1 ohm.
as I'm watching this video the first thing I can point out is MFJ259 is and never will be accurate to "1" Ohm when it comes to impedance. it's okay and as long as you understand it's tolerance is around 5% you will be fine but seeing 50 ohms on the reading along with a 1.0 match well it's doubtful that it's that accurate. I would not have responded at all if he had not stated that he was off by about "1 OHM" when the mfj said 49/51 ohms then he certainly still is off by "1" possibly more than 1 ohm. Do I think that is an issue on the bench with respect to what I do? "NO" this kind of hair-splitting is pretty much a waste of time in the CB and HF rig world.
how does having tuned lengths of coax between pieces of test equipment help troubleshoot a radio?
you and i both know Mark does not repair radios. he sells radios.
LC
Has nothing to do with him but everything to do with the laws of physics which lots of people like to ignore.
The more accurate your measurement the more accurate your adjustments will be.
oh please enlighten us as to which measurement inside a radio benefits from a higher degree of accuracy than those provided by any instrument accurate to a tenth of a volt.
Is it the VCO?
Is it the PLL?
bias on the gate of the driver or finals?
inquiring minds want to know!
LC
Ok, I will take a stab at this! You do it with an MFJ259b which we all know is accurate to .0001 ohms. Now you know oh and don't use RG58 cable it's limited to 30mhz. Now LC start the bench redo using these simple rules and the next Galaxy 94HP you align will maintain -65db down from the fundamental and after if you split a few hairs you can completely eliminate them altogether.
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Bandpass filters are cheap compared to a good tech's labor rate.
Does mark install the radios and antenna systems for all of his customers and verify it is still up to snuff with his test equipment? If he doesn't you are taking the radio, amp and everything else out of his controlled test environment and assuming it is still performing the same.
How the antenna is tuned or even where youre parked will effect modulation percentage and the effectiveness of his tuned jumpers. Not enough to bother normal people but you're a perfectionist.
In the intrest of splitting hairs there will be no consistency in performance across the band when connected to a mobile antenna. It may be more consistent with a broader banded base antenna but still out of your unrealistic standards.
He should also be taking note of the normal charging system voltage of their vehicles so he can adjust the power supply at his bench accordingly. It varies a bit from one vehicle to the other so if you're going to split hairs get them all.
Not to mention how the coaxial cable is laid out in the vehicle laying against metal will definitely add inductance to the circuit.
I would agree to fine tune such a beast, (or brat) would make it difficult to interface to the real world.
I look at Asymmetry a little different - symmetry would simply refer to a planet with no life on it.
Asymmetry is what re-directs energy into different directions - even forms for that matter - either as heat, light or sounds - so I tend to take a much more broader approach to asymmetrical discussions.
To be fair, I didn't want to know what CB's can or cannot be - I'm already there with the rest of ya'. Let alone the variables of antennas, the mountings - the whimsical fantasies of the installer - let alone the tastes of the owner of the radio(s). Whom without any warning, is about to have a considerable level of funds to be surgically appendectomied, thru their throat. By using their wallet as the illuminated target under the laser as they, the shop owners' circle above to await final approval of the unsuspecting customer - and begin their final approach and strafing run on a piece of electronic equipment that doesn't deserve to be treated as a "test subject for my bench - I'll prove it to ya'."
Yeah, been there ...
Ok, but for a real purpose, I was just hoping to "get past" the CB Reactance, Conjugate - Ohmic relevance and Einstein's theory on Relatives...
Einstein's Theory Of Relatives: A set of persons, related as Aunts or Uncles' that gather, Marry and produce Cousins - which you become responsible in various duties; for babysitting and raising as well as other simple forms of entertainment. Playing. Providing Financial Support is also a strong possibility.
Ok, the above has to be said to establish where I stand - in the VENN of things - I'm way outside the circle - somewhere over there - with the guy at Walmart. Offering them, the hapless, clueless, soon to be inundated by information they cannot even begin to process - radio operator with some cheap advice - "If It Works, Don't Fix It"
I just want to get into his mind (Read MSG #60 for references) and figure out the why the 1 ohm, why the reactive, when resistive is used for testing, why not just "tune" for lowest SWR for the end user and just offer to be there for them when things don't go their way.
Upgrade the Office/Shack/Store (insert repair shop location) Lavatory's rack of reading material to a subscription of Wall Street Journal and perhaps a Scientific American or two - for quick moments even Time or Newsweek - but for the ladies, use People or Readers Digest - make it a Doctors Office for those that need to hold a microphone constantly - endlessly keying up asking for radio checks. All the nurses have to do is answer "If you can hear this, it's working".
In the psychology of this threaded endeavor, I realize that there is more, FAR MORE, to life than to spend endless hours debating a finite scenario of intricacies using infinite variables. It's the reason why we do what we do - many don't like it, but to find ourselves, like a herd of deer exposed to a wasting disease - spending our days in recursive arguments, is not benefiting the hobby in any way that is productive.
I have to withdraw from this - there is no possible way I can even provide a measurable means or offer a method to settle a debate that does not want to end.
Am I angry? No, far from it - I have fun here, just the hardship, embarrassment, frustration
(insert metaphor here) exiting from a thread I thought I can interact with and learn something from even provide some insight to, but to know what this thread has become - I made an error in even getting involved. I apologize to those that I have offended - if any, and I offer support for those that cannot avoid the inevitable Rules Of Operation, Rule #1 - the customer is always right. Rule #2, If the customer is wrong - see Rule #1.
:+> Andy <+:
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The bird manual doesn't mention Mark's name but it does mention a specific test procedure to be followed for the most accurate measurements.
RPC,
Are we going to go down this road again?
Are we going to do quotes from the Bird manual again?
here is a quote from the Bird 4314 manual that RPC so loves to post about:
"When a Model 4314B is used to match a load to a transmitter and a good match is obtained, removing the instrument will not cause any change in the conditions. A well matched 50 ohm load can be placed at the end of a 50 ohm transmission line of any length without altering conditions at the transmitter."
What on earth does this video have to do with connecting different pieces of test equipment together with tuned lengths of coax on a test bench?
Why would Mark use anything but a purely resistive load when doing his testing?
why would the accuracy of whatever measurement is taken using a reactive load in his shop matter at all to the person hooking the transmitter up to their personal antenna?
Is mark recreating the exact conditions of someone's antenna setup in order to tune their amplifier?
Do professional RF labs work this way?
LC
Are we going to go down this road again?
Are we going to do quotes from the Bird manual again?
here is a quote from the Bird 4314 manual that RPC so loves to post about:
"When a Model 4314B is used to match a load to a transmitter and a good match is obtained, removing the instrument will not cause any change in the conditions. A well matched 50 ohm load can be placed at the end of a 50 ohm transmission line of any length without altering conditions at the transmitter."
What on earth does this video have to do with connecting different pieces of test equipment together with tuned lengths of coax on a test bench?
Why would Mark use anything but a purely resistive load when doing his testing?
why would the accuracy of whatever measurement is taken using a reactive load in his shop matter at all to the person hooking the transmitter up to their personal antenna?
Is mark recreating the exact conditions of someone's antenna setup in order to tune their amplifier?
Do professional RF labs work this way?
LC
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