How to calibrate your Daiwa CN-901HP SWR / Wattmeter

[@zbyszekpodchmielony2642]

Thank you for the video and link - very useful! Best 73!

[@radioaxe6964]

I'm glad it helped you in some way. 73.

[@mark1161]

I thought I had a problem with my FLEX 6400 in terms of RF output. In troubleshooting, I used a different MFJ meter and found that the problem was with the CN-901. This video allowed me to fix the problem. Thanks for taking the time. 73 KK2L

[@radioaxe6964]

Nice! Good job in fault finding and correcting. I am very glad this helped you rectify your meter. Your valued feedback makes it worth while spending the time making these videos :) Best 73s

[@TheManFrayBentos]

Handy, thanks. I've just bought one and hoping it arrives unwrecked and doesn't need recalibrating. If it just needs a tweak, it's handy to know the ins and outs.

[@gooberminther3tik25]

Yes thank you for taking the time with this particular meter. Just purchased one. USA AL

[@radioaxe6964]

Your welcome. I hope it helps in some way 🙂

[@LEEBO-56]

JUST RECEIVED NEW CN-901 HP TODAY..THX FOR POSTING VIDEO AND SHARING YOUR KNOWLEDGE..BE SAFE AND STAY WELL EVERYONE.( DESPERADO 56 NORTH OF TAMPA FLORIDA ) 73's

[@rjollis]

Nice video. It all makes sense. I just received my CN-901HP. It hasn’t even been connected yet but shows an indication of 9W Fwd and 2.5W Rev. This is not an electrical calibration problem since the meter is not powered. An attempt at zeroing the meter using the zero set screws using a small jewelers screw driver makes absolutely no change to the meter movements. Is this device defective? I made a call to Daiwa’s US distributor support who tell me that there is nobody to take my call. The retailer does not answer their phone.

[@radioaxe6964]

I would keep trying to return it. There is no way you should accept that as a new "working " meter.

[@jimw7ry]

4:09 The Diamond reads 2.8 watts. Its on the 20 watt scale? The selector switch shows reflected... Not forward. Better take a look again!

[@noneofyourbusiness1603]

Nice video, just to let you know the diamond was measuring reflected when you said it was 20w, as the switch was on "ref"

[@radioaxe6964]

Thanks for pointing this out... 👍

[@maulanagp893]

I have a Daiwa swr too, but the V series version, it's only capable of up to 200 watts, so the question is can it be made into 2 kilos, because if i look at the PCB, the paths for the calibration potential, and others are same like that a hp series...

[@JoshauaDolfi]

So what about the watt loss through the multi coaxial connections??? DA

[@1OFGODSOWN]

I may have missed it but did you mention that you should adjust the needle on the front to the ZERO mark if it's not already there? I have discovered that many videos show the needle is either above or below the ZERO mark which is Not the proper position for an Accurate reading.

[@radioaxe6964]

On the zero for sure... Just make sure you are looking directly / straight at the needle to avoid parallax error.

[@alan6064]

Mine arrived today and like yours it was all over the place. Both meter were not set at zero, the calibration was out on all three settings and the light switch on the back was broken. I fished all the bits out, re-built the switch and refitted it, calibrated it and all is working now. Would of been sending it back had it not been for your video, thanks. What are the 3 pots on the left of the circuit diagram doing?

[@chrishall6443]

which one sets the Reflected back to zero. Didn't want to chase blindly to try to turn all of them. Thanks for the help ahead of time.

[@gixerags750]

Hi M8 , i have the HP2 , Hp3 NS660 Daiwas , instead of using a radios power is there any other way to generate a type of more accurate REFERENCE power output, ie a signal generator ?you probably would have to boost the signal? PeaceFromOz 🇦🇺

[@radioaxe6964]

G'day. Other than a "radio" you would need an RF power amplifier of some sort which could output at the desired frequency, in a constant carier fashion. If you managed that, then all the steps in this video can then be applied. Don't forget you would need an appropriate input signal into the RF amp as well. A bit of mucking around if you must go down that path. I hope this helps....

[@gixerags750]

@radioaxe6964 cheers, I guess you're average of a few reliable swr/power meters is the go Thanks for the reply.

[@andyholloway2549]

hiya, I got one of these meters and its not that old and its just suddenly started to show a forward power reading of about DOUBLE of what it should be !!! so looked around for some info and found this.... ( according to my meter, my Kenwood TS50 is putting out 250 watts!!!-- anyways I notice on your meters a big difference in SWR from the Digital which shows 1.66 and the Daiwa shows 1.3 ??? that's a BIG difference ???many thanks anyways for the Video

[@harrybatt998]

Those Nissei dg-103 and dg-503 meters are wildly inaccurate on HF. I have 4 different accurate working SWR meters here, and they all showed a 1.6 > 1.7:1 SWR on the 10m band - whereas the Nissei showed 1.04:1. They're notorious for incorrect readings & there's a good few reviews about it on the web. I had to return mine & wouldn't have one given to me now, no joke!

[@markgutierrez2024]

Good video, I wish you would've explained a bit more how you actually calibrate the meter. Do you turn the knob you showed inside? Also, do you have to go through the 20W, 200W and 2kW knobs and adjust them all? What meter do you prefer, Daiwa analog or the digital MFJ you have there? Thanks!

[@gixerags750]

TonyAlbus does a similar calibration on a Daiwa swr/power and goes into more detail regarding the pots. 😊

[@Andy-up6li]

Thanks for the video and your time. Did you calibrate the meter on Avg or Pep?

[@radioaxe6964]

@@Andy-up6li PEP, for FSD (full scale deflection) and then cross check at say around 60 - 70% of FSD on average.

[@mandrake3919]

Good description but what is the purpose of VR1, VR2, and VR3 on the left side of the diagram. Are these used for calibration purposes and if so how are they to be adjusted?

[@williamrahmkb2gf947]

LOOKING FOR THE SAME INFORMATION.

[@WPGinterceptor460Interceptor]

What do you use to power this meter? how many amps? or do you just connect it directly to your 13.8 v power supply

[@radioaxe6964]

Any 12-13.8v power supply will do.

[@albinchilinski]

Great video just done mine and downloaded the circuit diagram thank you G0UOB

[@radioaxe6964]

Awesome, glad it was somewhat useful :)

[@machineme]

Calibration work on at both average and peak? How's the av/peak buttom supposed to be?

[@radioaxe6964]

It can be either peak or average. As long as your reference meter and the meter you are calibrating are the same. Personally I would use peak then check in average as well.

[@miguelsalami]

Good Show Mate I like your digital meter the best then the diamond Cheers & 73s

[@HamRadioNewb]

Useful stuff, mine is low by about 20%. Going to compare to a bird that another local ham has. If I can get within 5-10% ill be happy! How accurate would you say they should be? Say if I went for calibration on 40m, would 80/20 be pretty close still? How much of a difference do you think one should expect?

[@radioaxe6964]

If you can calibrate it against a Bird on the band and power you mainly use, that would be fantastic! Personally, I would be happy with anything less than 10% given what we pay for these cheaper Chinese power meters. What is acceptable is very subjective. 73 :)

[@HamRadioNewb]

@@radioaxe6964 thanks for getting back to me, me and another local guy are trading favors tonight, I'm programming a radio and he's bringing them along. Plus I'll be able to get a good output reading on my Amp now! I know Im putting a heck of alot more out of my al-811h than 450w!!

[@radioaxe6964]

@@HamRadioNewb for sure. Especially on the lower bands.

[@stevefabricant1477]

How do you calibrate reflected power???

[@mx1209]

The PEP hold is 300 watts higher than the standard non hold PEP????? Any idea on how to adjust this?

[@gixerags750]

If you are in the 2KW mode that sounds about right eg PEP would show 50 -60w and when switched PEP HOLD 80-90w.. on SSB 😊

[@dimitrisvichas5554]

Thanks for the description... However, in my watt meter same model, it seems that the pep button shows the mininum watt in ssb while the AVG shows the maximum... I think that they are place up side down somehow... Do you have any idea???

[@radioaxe6964]

Thats really strange. You can try to reversing the mechanical operation of the switch but that would be difficult I'd say. Sorry can't help any further.

[@dimitrisvichas5554]

Thanks for your answer! It is really strange,that's true...but, I was thinking... changing just the buttons would be enough or I should change the trimmers inside the watt meter... And that would be appropriate???

[@tubetone74]

Set to average not pep, correct?

[@radioaxe6964]

Corre t. Definitely average as the readings are more stable whilst you are calibrating. Good question 👍

[@ronedwards8239]

Rubbish about 60% range being the most accurate. I actually built and calibrated the Bird watt meters. I have built countless Jeweled and Taut Band suspension meters. They are calibrated at full scale and must track within a certain tolerance or be rebuilt or scrapped.

[@gixerags750]

I have heard that somewhere too, don't know if it was regarding cross or single panel needle meters..I think Alan W2EAW mentioned it on one of his repair and replacement of different panel meters Peace.