Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

SHOULD I BELIEVE MY MFJ 828?

Sonar

Sonar

Sr. Member
Apr 8, 2016
1,501
1,018
173
When reading the swr on my MFJ 828 I get 1.89 but the readings I get on my workman, Micronta and the rig's (madison) swr meters I get 1.5:1 (on all three).
I know the readings are high either way but I feel a bit more comfortable with the 1.5:1.
I thought the MFJ was not working properly for other reasons but when I sent it to MFJ I was told and sent a written report the meter is functioning properly and has no issues.
I don't know how accurate the workman, Micronta and Madison's swr meters are but I'm leaning towards believing the MFJ isn't correct.
My reasoning is that three to one I should go with the odds.
What's your opinion?
Ps I'll soon be getting the antenna from 10' (where it's at currently) to about 26' and hoping that brings the swr down substantially.
 

Sonar you keep asking this . What do you want to hear?
Most Amateur radio SWR meters are 10% accurate at best . Many Cb meters are more like 20%
You decide which is more accurate !
Here's how to check

Sorry about the quality of the photo's couldn't get the light right.
DSCF2144 (2).JPG
 
Last edited:
  • Like
Reactions: Sonar
DSCF2149 (2).JPG Now reverse the connections
Check that the Set (full scale deflection )and readings are the same , but reversed.

You can do the same with the crossed needle watt meter, but use the watts reading not full scale deflection ( ie the reverse is calibrated lower watts that the forward)
 
Last edited:
  • Like
Reactions: bob85
DSCF2153 (2).JPG And last using a 150 ohm dummy load you should see 3 to 1 swr. make sure the load can handle the wattage.

This will take all the guess work out for you.
 
Last edited:
Interesting side note.
The swr meter built into my ICOM 746 PRO shows that as a 2.2 to1 swr My Yaseu shows 2.4 to 1 yet both show 50 ohm as 1 to 1. Thats Two to One against my Oskerblock is it faulty ? No Never trust the inbuilt meter. My SWR analyzer shows 3.01 to 1 at 148 ohm ,close enough! I'll go with the OSKERBLOCK
 
The problem with having more than one meter is that you never really know the truth.


they both could very well be in cal and with one at the lower side of the tolerance limit and the other at the high end, you can easily have a 20% difference between them.

Measure with a micrometer and cut with an axe.
 
I have found the 828 and 826b meters are sensitive to, and like to show, a higher reflect than what is actual and in general are calibrated for better accuracy at lower frequencies. I recalibrated my 826b (same board) using the process in the manual, but I used 27.385 as the calibration frequency instead of 7.xxx. I use other meters for frequencies outside 27 mhz.
 
vkrules said:
Sonar you keep asking this . What do you want to hear?
Most Amateur radio SWR meters are 10% accurate at best . Many Cb meters are more like 20%
You decide which is more accurate !
Here's how to check

Sorry about the quality of the photo's couldn't get the light right.
View attachment 18478
Click to expand...
Sorry to have annoyed you annoyed you. I ask because I don't have the answers.
If I did I wouldn't ask.
If I ask questions that seem absurd it's because I've no knowledge about the subject of which I ask. My questions pertaining to this wasn't to figure out how much of a percentage my meter was off but if the meter wasn't working properly.
 
It's ok not annoyed at all. It's just the third or fourth time I've seen you ask the same question, and got pretty much the same answers.
Wondered if I was missing something. Test your meters for your own piece of mind.
 
@vkrules the oskerblock is a ok meter however it is not great across the whole frequency rage its claimed to cover..a 3:1 reading for a 150 ohm load at say 27mhz will not be the same at 3.5mhz or 150mhz (i believe that model was originally claimed to have a 3.5-150mhz range) any stripline type vswr meter has inbuilt inaccuracy across its full range..however if you are only using it for 25-30mhz and have it calibrated for this range it will be ok (look at the bird43 a bird has calibrated slugs for each band for a reason)
hence why the okserblock had a calibration chart with them when sold new (each meter sold had a diff chart to match the serial number of that meter)
http://www.radioworld.co.uk/Second_Hand_Oskerblock_SWR-200

your test is valid ..a 150 ohm or 16.666 ohm resistor will show the same result at both phase angles
a 100 ohm load or a 25 ohm load will give 2:1 vswr
remember any lead lengths will induce inductance which can skew readings at higher frequencies (high vhf ranges)
get your learn on here www.ad5x.com/images/Articles/PrecisionMismatches.pdf
can see vswr meter testing slugs being sold on ebay next week ..meh

as for the 828 ..no idea
 
Yeticom, well aware of the limitations of said meter, Although 30 years old it is still better than most.Yep never buy a used oskerblock without the cal chart !.I do have the original calibration chart but added the WARC and CB bands myself. Used that meter as it was easier to photograph.

Company I worked for had a dozen or so bird meters, even birds don't all read exactly the same unless they are calibrated regularly.

At this stage reactive errors might be a bit much for Sonar.
 
  • Like
Reactions: Sonar

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back