Author Topic: CB and Ham Radio Techs Love Their Bird Wattmeters  (Read 182497 times)

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Offline bd139

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #375 on: July 02, 2022, 08:14:22 pm »
I have a car that when started the message center would display brake failure.  Rather than fix the firmware, they actually have a note in the manual about restarting and if it clears, it's not a problem.  They did eventually fix the firmware.  That's some shit code.  Would like to know the inside story how shit like this would ever make it to production....  Then again....  I think I know.   :-DD

The software that’s in that car was put together by people with at least two orders of magnitude more competence than the ones I deal with on a daily basis. I watch the world burn a little bit more every day.

True story just happened yesterday. A guy comes around once a year and his business is re-painting the house numbers on the curb if you want to pay him. I signed up and yesterday for a green background with white letters.

He came by and painted the green background rectangle and left to do other houses while that dried. He comes back in a few hours and finishes by painting the house number, which is written on the order paper. I saw him outside and went ahead and paid him for the job and went back inside. I didn't feel I needed to supervise him painting the number.

After a while I went out to get my mail and looked at the job. He'd painted the wrong number - off by 1 digit. I saw him up the street and told him and he came back and fixed it. I can't even trust a person to do a simple thing like that anymore.

I can't imagine trying to get good people for any type of complicated project. Frankly it would scare the hell out of me worrying about the job they were doing unless I already knew them.

Oh hell that's terrible  :palm: :palm: :palm: :palm: :palm: :palm: :-DD

I can't really tell you what shit I experienced recently as it ended up in the trade press and on Twitter  :palm: :palm:
 

Offline vk6zgo

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #376 on: July 02, 2022, 11:03:14 pm »
I have a car that when started the message center would display brake failure.  Rather than fix the firmware, they actually have a note in the manual about restarting and if it clears, it's not a problem.  They did eventually fix the firmware.  That's some shit code.  Would like to know the inside story how shit like this would ever make it to production....  Then again....  I think I know.   :-DD
My older generation car had a similar problem, bringing up the "brake" warning light---turned out to be the microswitch on the handbrake lever mechanism. ;D

More on topic is the very early iteration of EEC in a VW, which stopped it when in the immediate vicinity of a 55kW/10kW Dual MF Broadcast site.
VW fixed that quick!

Yet another was the "after market" immobiliser on a TV Studio Toyota "Lexcen" (a "badge engineered" Holden Commodore) that would set OK, but not release at the TV Transmitter site.
You had to use the "hidden" key operated switch if you wanted to leave the site.
 

Offline vk6zgo

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #377 on: July 03, 2022, 12:16:14 am »
I have a car that when started the message center would display brake failure.  Rather than fix the firmware, they actually have a note in the manual about restarting and if it clears, it's not a problem.  They did eventually fix the firmware.  That's some shit code.  Would like to know the inside story how shit like this would ever make it to production....  Then again....  I think I know.   :-DD

The software that’s in that car was put together by people with at least two orders of magnitude more competence than the ones I deal with on a daily basis. I watch the world burn a little bit more every day.

True story just happened yesterday. A guy comes around once a year and his business is re-painting the house numbers on the curb if you want to pay him. I signed up and yesterday for a green background with white letters.

He came by and painted the green background rectangle and left to do other houses while that dried. He comes back in a few hours and finishes by painting the house number, which is written on the order paper. I saw him outside and went ahead and paid him for the job and went back inside. I didn't feel I needed to supervise him painting the number.

After a while I went out to get my mail and looked at the job. He'd painted the wrong number - off by 1 digit. I saw him up the street and told him and he came back and fixed it. I can't even trust a person to do a simple thing like that anymore.

I can't imagine trying to get good people for any type of complicated project. Frankly it would scare the hell out of me worrying about the job they were doing unless I already knew them.

We had a POTS service, where the phone would get noisy, & the ADSL would get slower & slower, then die, altogether.
In Jan 2013, we originally called it into our ISP as an ADSL fault.

After a lot of threshing around by the ISP, it got passed to Telstra, who sent a bloke out, who (correctly, as it happened) diagnosed the problem as a faulty lead in cable from the pit on the street verge.

He, for some reason, couldn't pull a new cable through, & had to organise a "contract crew" to do it, a week later.
We had to go away, but they wouldn't need access to the inside of the house, so that was no problem.

When we returned there was no sign the cable run had been disturbed, but everything was back to normal, so I assumed they had been very neat in their work.

Over the next seven years, we had multiple repetitions of the "noisy line" problem, & having learnt our lesson about going through the ISP, reported  a phone fault to  Telstra.

I followed their Techs around like a Lab cat, trying to nudge them in the direction of the lead in.
They would fiddle around with the terminations in the pit, or where it connected to the house, & usually get it back, still a bit noisy but useable.
Looking at the ends of the cable, it was obvious that it had not been replaced back in Jan 2013, or, perhaps, ever.

In 2020, we were going to get NBN "fibre to the curb" so I decided we had better get it sorted out before Telstra handed the thing over, so called them out, as the noise level was quite high.

For once, they sent a Tech worthy of the name, who agreed the problem was the lead in cable, "bit the bullet" & pulled a new one through.
if the first guy, seven years earlier had done that, we would have been spared all that exasperation.

When Telstra was Telecom Australia, the first Tech would have pulled a new cable through, and the job history would have been recorded.
Apparently the "Telstra way" is to regard each job as a separate entity, with no history maintained.

I have run into a bunch of people over recent years that seem to be "all at sea" doing the job they were supposedly experienced at.
Maybe they all have to "use the App" to boot their brain! ;D

« Last Edit: July 03, 2022, 12:18:00 am by vk6zgo »
 

Offline bd139

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #378 on: July 03, 2022, 08:31:59 am »
Sounds like Openreach here. When they were BT tech they had clue. Now they are just procedure monkeys.
 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #379 on: July 03, 2022, 11:47:11 am »
RF shielding for front / back panels..

Will use the tape.

May use pieces from old PC panel.
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Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #380 on: July 03, 2022, 12:43:59 pm »
Planning to use an N? 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #381 on: July 03, 2022, 01:23:17 pm »
Planning to use an N?

No, I already got some SMA to SO-239 panel mount pigtails. If this get to any hams they won't want N connectors. They would just put an N to SO-239 adapter on it so it would be useless to put N on it for that crowd.

I'm thinking about another design for my own use but with changes on how the software works. This wouldn't be for hams so I'd just put a female SMA on the back.  :)
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Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #382 on: July 03, 2022, 04:22:09 pm »
They like the SO-239 as much as their Bird meters, maybe even more!!   

I wonder how it will effect your precision Watt meter's results.   Especially when the ham is using beat up old junk connectors from their box o parts...    :-DD
 
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Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #383 on: July 03, 2022, 06:38:58 pm »
Look at the rear panel of two current Icom transceiver models. The IC-9700 and the ID-5100. The 9700 has an N connector for UHF and another one for 1.2 GHz. This is great. The ID-5100 has only one connector and it's not an N it's a SO-239. Yet this output must handle UHF. It should have an N which is perfectly fine for the 2m band as well (see video below).

This is why most hams stick with the SO-239. The manufacturers aren't consistent with what's best, they are consistent with what has been in use. On that 9700, I'd bet $100 most hams just put an adapter on the UHF band N to get right back to the old SO-239 so they can use the same old coax they have. Most hams I know have no idea even how to put an N connector on because they've never done it.

As far as the 1.2 GHz band, you really need to get serious and re-think your whole setup, like what coax you are going to use and how far can you run it, and you really need to use an N connector. Oh yea - and is there even anyone to talk to ...  :-//

The losses on that frequency are going to be really high if you do a sloppy job getting the RF to your antenna. I know of several hams that got the IC-9700 but that 1.2 GHz band goes unused anyway, which is probably just as well.

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Offline bd139

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #384 on: July 03, 2022, 07:02:44 pm »
Indeed. Those infernal unspoken connectors are what is compatible with the damp bit of coax dangling out of the hole in the wall. Once they're installed they're not terrible.

The killer with SO-239 / PL-259 is that the idiot who installs the PL-259 usually mangles it. The centre conductor soldering is really difficult to get right so people end up getting solder on the outside of the pin. And because everyone uses crappy little firesticks to solder it, the dielectric slug that holds the pin in place tends to go soft.

The ultimate example I saw of this was at a hamfest where someone was selling a Mighty Fragile Junk AMU which had the PL-259's so badly wedged in the back of it that they just cut the coax off with cable shears  :palm:. Either that or they were Chinesium PL-259's and had melted into the sockets.

Urgh.

It was always BNC (clamp+solder and crimps) and low power for me. Works a treat.
 

Offline mansaxel

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #385 on: July 03, 2022, 07:47:44 pm »
Indeed. Those infernal unspoken connectors are what is compatible with the damp bit of coax dangling out of the hole in the wall. Once they're installed they're not terrible.

The killer with SO-239 / PL-259 is that the idiot who installs the PL-259 usually mangles it. The centre conductor soldering is really difficult to get right so people end up getting solder on the outside of the pin. And because everyone uses crappy little firesticks to solder it, the dielectric slug that holds the pin in place tends to go soft.

The ultimate example I saw of this was at a hamfest where someone was selling a Mighty Fragile Junk AMU which had the PL-259's so badly wedged in the back of it that they just cut the coax off with cable shears  :palm:. Either that or they were Chinesium PL-259's and had melted into the sockets.

Urgh.

It was always BNC (clamp+solder and crimps) and low power for me. Works a treat.

In my shack there are N and [B|T]NC. Radios with connectors "Unsuitable for High Frequencies" get connectors swapped or an adapter lead, depending on frequency band.

Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #386 on: July 03, 2022, 08:15:47 pm »
Towards the end of that video, he attempts to show the connector has problems at 300MHz.   I watched one of his other videos where they attempt to show how to connect a transfer relay to their Nano.  Of course, there was no calibration back then to pull it off.   Anyway....

I have a brand new, really cheap CB/ham to N adapter.  2 for $10 sort of quality.   I cal'ed the Lite using my home made standard, then measure the load.  I then measured with the SMA to N, N to CB/ham, CB/ham to BNC and BNC to SMA.  This is with the same load.   I then replaced that mess with a SMA to SMA, SMA to N, N to SMA, again with the same load.   I don't really have a good way to do an A/B compare.  More just for a sanity check.   

Still the question remains, how using the CB/ham connector (maybe they are still used somewhere else??) effects your Watt meter.
 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #387 on: July 03, 2022, 08:45:32 pm »
As I said I bought some pigtails that have on one end an SO-239 (panel mount) and the other an SMA to connect to the AD8310 board.

If it was for myself or you or bd139 (or others here) for example, I'd have used an N or SMA on the panel which would be better. But this version is for ham use. I know from years of experience they will not use any other cable than one that has a PL-259 on it to measure a transmitter. If I put on an N or SMA connector they will simply defeat it and adapt it to a SO-239. So the end result will be worse than what it started with.

Now, the additional element consisting of all the parts of the pigtail will introduce some attenuation that was not there before. There is nothing wrong with that. Why? Because I am going to re-calibrate the cal constants after the whole thing is finished and in it's case. This will compensate for the additional introduced loss for each frequency band. But if you want to know I can check it just for grins.
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Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #388 on: July 03, 2022, 09:08:23 pm »
As I said I bought some pigtails that have on one end an SO-239 (panel mount) and the other an SMA to connect to the AD8310 board.

If it was for myself or you or bd139 (or others here) for example, I'd have used an N or SMA on the panel which would be better. But this version is for ham use. I know from years of experience they will not use any other cable than one that has a PL-259 on it to measure a transmitter. If I put on an N or SMA connector they will simply defeat it and adapt it to a SO-239. So the end result will be worse than what it started with.

Now, the additional element consisting of all the parts of the pigtail will introduce some attenuation that was not there before. There is nothing wrong with that. Why? Because I am going to re-calibrate the cal constants after the whole thing is finished and in it's case. This will compensate for the additional introduced loss for each frequency band. But if you want to know I can check it just for grins.

Yes, for grins.  IMO, for the reasons you describe I would use something the ham/CBers don't.  It's one more layer of protection to tell them don't plug it directly into your radio.  Then again, even with the NanoVNA having SMAs, it wasn't enough of a deterrent for some of the smarter hams.   :-DD 

Are you making a power attenuator  with the CB/ham connectors to go with it?  Seems like it may be a difficult thing for them to source.  On the other hand, if you did use N, N-N attenuators are  common, then they can use their ham adapter there. 

***
Running a search on Google, I could not locate any attenuators with the PL-256s, let alone any for 5W and up.   
« Last Edit: July 03, 2022, 09:13:49 pm by joeqsmith »
 

Offline bd139

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #389 on: July 03, 2022, 09:22:06 pm »
Why would they want to attenuate their signals?  :-DD
 

Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #390 on: July 03, 2022, 09:26:42 pm »
It adds error to the measurement and indeed, I don't see how the end user is going to cal that out.   
**
It being the attenuator, but sure, everything adds error....
« Last Edit: July 03, 2022, 10:44:42 pm by joeqsmith »
 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #391 on: July 03, 2022, 09:31:16 pm »
Why would they want to attenuate their signals?  :-DD

Well if they want one they're going to leave here understanding why or it ain't leaving my house!  :box:

OK that didn't take long. I re-checked the measured uncorrected power with and without the pigtail as shown. Only the UHF band changed a bit. Looking at it the same cal constants would work except for a 0.1 dB adjustment for UHF.

As you can see I had to add some adapters to get the job done between tests - no way around that.

Test with -10 dBm

Band (MHz)      with pigtail   w/o pigtail

HF (14)            -10.2         -10.2
50               -10.9         -10.9
146               -12.6         -12.6
222               -14.2         -14.2
450               -19.5         -19.6
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Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #392 on: July 03, 2022, 10:43:48 pm »
I am not sure I follow.  Is the w/o pigtail still using the UHF connector?   I was wondering direct to SMA compared with direct to SMA-CBham to pigtail. 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #393 on: July 03, 2022, 10:57:16 pm »
I am not sure I follow.  Is the w/o pigtail still using the UHF connector?   I was wondering direct to SMA compared with direct to SMA-CBham to pigtail.

I have to use some cable with some connector on the end from the generator. So I chose the one you see. If I choose one with an SMA at the end I'll still have to adapt it to the SO-239 of the pigtail when I put it in line. Using the one with a PL-259 I can go direct to the pigtail, but then have to adapt it to the SMA otherwise I'll have to introduce another cable and have more changes in the experiment.

What different does it make when we're just testing the insertion loss of the pigtail. Or am I not following why you are not following?
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Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #394 on: July 04, 2022, 03:38:20 am »
I have to use some cable with some connector on the end from the generator. So I chose the one you see. If I choose one with an SMA at the end I'll still have to adapt it to the SO-239 of the pigtail when I put it in line. Using the one with a PL-259 I can go direct to the pigtail, but then have to adapt it to the SMA otherwise I'll have to introduce another cable and have more changes in the experiment.

What different does it make when we're just testing the insertion loss of the pigtail. Or am I not following why you are not following?

My question pertained to what effect the choice of connector has on the accuracy, not the coax.  I suspect this is what the video you linked is attempting to show where they replicate the same setup using the two different connector types.   

However, your question of what difference it makes, in general I would say is very valid.  The idea of making such a project and the goals you have are just that, your goals.  I only ask because I am curious.  The video you linked shows a measurable error.   

With the attached picture, my goal would be to determine how much power the RF Source can put into a 50 ohm load.  The PCB has a perfect 50 ohm load and can measure the drop across it to give you exact power at that that point.  That resistor is a long way from the source.  What the RF source sees may not be 50 ohms.   If any of the ?'s were an open for example, the voltage across the sense should be zero.   We hope it's not that bad but each will contribute to the error.   With the CB/ham connector, we expect the amount of error will increase with frequency.  My question was how much. 
 
The attenuator seems like the bigger problem.  I thought for sure some ham/CB supplier somewhere would have such things with CB/ham connectors on them but I did not find one.   This means even more poor adapters are added to the model.  Or the ham is making their power attenuator.  In the end, because it's all unknown, I'm not sure how you would go about compensating for them.   Which gets back to,  does it really make a difference.   Maybe knowing the power at the sense resistor is good enough.

We have already established that my only real goal is playing around and I have no future customers to delight.  Unlike the Bird meter, my last experiment shows an in-line meter that can measure both incident and reflect magnitude, along with the phase.  We basically have S11.  Calibrating it would be similar to a VNA using known return loss standards.  I doubt this is anything a ham or CBer would want but I do find it fun to play with.   

Offline vk6zgo

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #395 on: July 04, 2022, 04:04:27 am »
Why would they want to attenuate their signals?  :-DD
"
Yes, quite a few hams have proper inline probes with a lot of attenuation between the transmitted signal & the "sniff".
This, of course, brings the accuracy of that attenuation into the calculation.
 
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Offline vk6zgo

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #396 on: July 04, 2022, 04:20:16 am »
Indeed. Those infernal unspoken connectors are what is compatible with the damp bit of coax dangling out of the hole in the wall. Once they're installed they're not terrible.

The killer with SO-239 / PL-259 is that the idiot who installs the PL-259 usually mangles it. The centre conductor soldering is really difficult to get right so people end up getting solder on the outside of the pin. And because everyone uses crappy little firesticks to solder it, the dielectric slug that holds the pin in place tends to go soft.

The ultimate example I saw of this was at a hamfest where someone was selling a Mighty Fragile Junk AMU which had the PL-259's so badly wedged in the back of it that they just cut the coax off with cable shears  :palm:. Either that or they were Chinesium PL-259's and had melted into the sockets.

Urgh.

It was always BNC (clamp+solder and crimps) and low power for me. Works a treat.
You do know that you can get crimp PL259s?

I hate the solder ones with a passion, & always bought the crimp type, but for some reason, the "bricks n' mortar" shops I go to have stopped stocking them, & only have the solder type.
I hate solder type BNCs & Ns just as much, as I have run into too many where the guts just pulled out!

If PL259s are properly fitted, the impedance "bump" from them is minimal, as they are usually only a very small fraction of a wavelength.
In any case, they are a quantum leap better than "Belling Lee" connectors, which were widely used at VHF, & even UHF, in previous years.


 

Offline bd139

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #397 on: July 04, 2022, 06:41:57 am »
Crimp PL259’s seem not to exist here. You can get them from Farnell (Newark) but no respectable ham would be seen buying stuff from there, preferring to buy no brand Chinese solderable ones from the lowest bidder while ironically complaining that all Chinese garbage sucks.
 

Offline xrunner

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #398 on: July 04, 2022, 11:11:31 am »
 
The attenuator seems like the bigger problem.  I thought for sure some ham/CB supplier somewhere would have such things with CB/ham connectors on them but I did not find one.   This means even more poor adapters are added to the model.  Or the ham is making their power attenuator.  In the end, because it's all unknown, I'm not sure how you would go about compensating for them.   Which gets back to,  does it really make a difference.   Maybe knowing the power at the sense resistor is good enough.

There may not be any local hams that want one. Right now I only talked to one guy who I know can adapt to using all N connectors for a test setup if he wanted to, but again most ham radios, even ones with the UHF band, do not have N connectors on them so at least one ham adapter will be used. It would be simple enough to change the pigtail assembly which will be inside the unit for one with an N connector if desired.

A while back I did a "sanity" test comparing the AD8310-based power meter I'm making with what an hp 437b power meter measured. You may remember it, but I didn't go into details on the cables and connectors I used. But below is the pic. I have a 40 dB atten. that came out of commercial equipment (not sure what the brand name is). It has N connectors on it. You can see it in the pic with the yellow labels.

From the Agilent 8648A (which has a stated output accuracy of +/- 1 dB it has an N connector built-in which in that pic has an adapter to go to an SO-239 (Hammy stuff right?). Then that first black coax is a "ham" ...

OK for convention I guess we all know what we mean by "ham" cables - SO-239 or PL-259 so when I say ham that's what I mean from now on.

... it's a ham cable. That goes to a ham adapter then into the 40 dB atten. On the back of the 40 dB atten, I use a coax that actually does have N connectors on it. Then it has a female N to N adapter ... then a N to BNC adapter ... then a BNC to SMA cable going into the little power meter.

In theory if everything was perfect the power out of all that would be +13 - 40 = -27 dBm at the end of the black cable on the table, But it's not perfect the Agilent has small errors, the adapters, the coax, the instruments, etc.

However, the little power meter measured -28.3 and the hp 437B measured -28.7 at the end of the black coax on the table. So I'm not too concerned about those kind of errors now. I'm going to move on to getting rid of the breadboard and getting this thing wired up and in a shielded case. Then I'll do more checkout and adjust any cal factors I need to.

By the way I finished the shielding using copper tape as you can see in the pic.

I told my friends I could teach them to be funny, but they all just laughed at me.
 

Offline joeqsmithTopic starter

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Re: CB and Ham Radio Techs Love Their Bird Wattmeters
« Reply #399 on: July 04, 2022, 05:48:37 pm »
I think ham cables and connectors are fine to use.   

Dropping the crappy BNC adapter and using the two cheap ham to N adapters back to back with an old Amphenol adapter.   To get the same number of connection points, I used 3 X N adapters.  Used the Lite to measure S21 of the two configurations. 


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