TS DX 350 HDV enroute.. couple questions

[Handy Andy]

I'm siding with you on this...

Three that's 3! different SWR meters. Two ordinary ones plus a radios' internal one. So something in the process of elimination - isn't right...

Again linearity of scale - if they can't make the meter work right on low-power - how is it going to handle low level ORP rigs' using Fleapower?

Ya' gotta' blow that 10-ohm smoke into it?

No! Two "simpleton" low-power meters show differently and both acquire similar results as SWR is fine - only thing that messes this up was from the improper power ratings - and when we do put in a meter rated for that power - it can't register the radios' low-level power - SIGH...

Why doesn't the MFJ set??

I'm supposedly at 3+ w with stock radio.

Also the radio has built in SWR meter and thus far has proved accurate in my truck for over a year and also matches the Astatic readings within a .

Also antenna is new A99 that is tuned from factory and I only moved a hair hence the 1.2 I'm getting probably.

I get 1-1 and 1-1.2 across band with out anything inline.. and then with Astatic only inline the same..

Oh this is bad, and sad...understandably questionable... But! If you have not changed anything except the meter, you're fine. The SWR the system says you have, via two meters, is ok as far as low power to even higher levels within the ratings of the individual meters - so judging by scale of events - MFJ is simply not able to produce ACCURATE readings from the low-power levels the radio has, and requires to produce, in order to make his system work.

I've been there - done that - and with 2 out of 3 - it ain't bad!

I've gone into brand new meters to verify the case to coax shield (the outer ring of the SO-239 and PL259 shield) - is tightened so there are no doubts about case to shield contacts. I've had meters with poor assembly problems before and radios with goofy SWR got fixed by an 11/16th wrench on the SO-239 nut to tighten it down to the rear panel...

But this symptom? Means the CONSTRUCTION internally to the MFJ onto the parts used and circuit design for it, is not built for flea-powered QRP rigs...the sensor - detector design as well as the parts used - are simply not set up for this - power can't be properly detected if you have to skew the calibration of the unit to suit the needs (hard over full stop).

 

[CB590]

All setup. Just running as planned. 1.75w dk on AM and DAW on at 70w.

For SSB switch out and going..

 

[Low_Boy]

I had a very nice Swan meter very accurate but it needed 4 Watts minimum to work properly.

 

[Ranch55]

I did it at full stock DK of like 3.5w.. that's as far as it got in the set mode..

When flipped to SWR it said 5..

I did flip it ref..

Here's a pic of the reading.. like 1.2-1.3

View attachment 25230

From what I understand is the SWR has to be set as well at the AMP dk as well in order to get an accurate amp reading as well.

That is a reflected watt reading, not an SWR reading........
1) ... Set your radio am dead key to maximum (according to you, this is about 3,5 watts) MIC gain off ..
2) ... Set meter to SWR SET ...... 300W range setting .....
3) ... with Texas Star Green button out, (no dial-a-watt), key radio and quickly adjust SWR SET knob to bring the needle to the SWR CAL point/line ....
4) ... Unkey the radio ....
5) .... ONLY move the FUNCTION knob to the SWR position .....
6) ... Key the radio and read the SWR measurement .... Also take another quick photo of the SWR measurement
7) ... Post the new photo for us to see ......

 

[sp5it]

... and keep in mind, that this meter is very inaccurate.
Mike

 

[CB590]

That is a reflected watt reading, not an SWR reading........
1) ... Set your radio am dead key to maximum (according to you, this is about 3,5 watts) MIC gain off ..
2) ... Set meter to SWR SET ...... 300W range setting .....
3) ... with Texas Star Green button out, (no dial-a-watt), key radio and quickly adjust SWR SET knob to bring the needle to the SWR CAL point/line ....
4) ... Unkey the radio ....
5) .... ONLY move the FUNCTION knob to the SWR position .....
6) ... Key the radio and read the SWR measurement .... Also take another quick photo of the SWR measurement
7) ... Post the new photo for us to see ......

Too late meter shipped back to dealer.

At this point I think my SWR is good as said before 2 meters can't be wrong..

But that's for pointing that out.. Handy Andy mentioned the ref position..

 

[Handy Andy]

Hence the rub of the linearity of scale...

When meters have "open leads" or have their knobs go "full stop" you don't quite know what that reading will be when it hits' there. Can be infinite or zero - we can only presume that the wiper arm trails off to something in the circuitry for this.

However, if the pot can NOT make contact or strikes against the rivet and loses contact - that wire floats at whatever is left on it and that can reflect back to the meter.

That is from personal experience with SWR (or any analog) metering systems - they have to go somewhere and if the company is too lazy to put a stop, do an indent or prevent the user from overrunning the pot composition - a construction issue - then all bets are off - it's that simple. A simple dissipation or shunt resistor across that pots extreme levels can and could prevent erroneous read errors - he spent enough on the meter already - he has two others that show their own results that agree between the two - but this one is the odd one out...can't help MFJ if they won't take the time to ease my mind to the fact that I bought something that SAYS it is as accurate as the others I've used in my own toolbox...this hurts guys - really - because it reflects (SIC) poorly on MFJ as a company to do business with and gets your moneys' worth...

Uniden and Cobra do that additional precautionary resistor linearity to their stuff - and it saves the rest of us from having to deal with scratchy or jittery pots - but if MFJ can't - or if K3ACZ is not following instructions - we have evidence already the reflected power was not severe even in that meters' REF setting. SWR reading is a different story and REQUIRES the CAL knob to work, REF doesn't it's simple meter directional indication thru their switch knob for multiplier / Attenuation factor on the front panel...so if that is wrong too - then he's in a lot bigger trouble than what that meter ever could display...

So for it to say "5" - unless the amp was on and the SWR CAL FWD setting was set purposely to 30 watts and he put 100 watts thru it - I can see the 5 as an error - but again, no matter what - the meter isn't set right per standard - so one issue is, the meter itself - the other - the install - you figure that out.

I tend to give people the benefit of the doubt first - then shame on me the next time...