The device is good no doubt, but now I have started to show nepravilno.Bez load on all ranges of small values​​, and used to be> 1500 ohms. Need diagram of MFJ-269. help me

Do you know, how put the mfj-269 to test mode?

thank in advance

Nice review of the 269 unit... I used to live within 5 min of the MFJ factory in MS, and in fact I have a well worn 269 which is #10 off the production line, and I went to the factory to watch them build it and pick it up.

Their production line on this unit is pretty slick using almost all surface mount parts, whereas my 259b (also an early unit) was an almost totally thruhole design.

Both of my units have exhibited good calibration in my expierance, though like I said...I ordered and purchased both of mine factory direct "over the counter" as it were, so it is possible that they recieved more personal attention, but I doubt it.

I will say this for MFKJ... I recently had a friend that mistakenly fed 100w cw into his 259b and smoked the front end. When he sent it back for service, they fixed it and shipped it back for $50US and it had long been out of warranty!

They have always had good customer device with everyone I knew, and when you talk to so

some on the phone THAT is actually the guys repairing your gear... Not someone in a call center.

I will say this, I have an Eagle RLB-150N5A and my 269 is close enough to it at 100mhz and below that I can't imagine most hams needing more accurate measurements for what they are trying to do. Possibly those doing surface mount design would be accepted.

That being said, I have had a friend for several years N40GW who swears by his AEA HF analyzer, and 8 have wanted to get one for myself or maybe a AEA bravo...

They are a lot more cash than the MFJ, but have pc connection via serial port, and I think might be a little higher end device.

Peter,

Thanks for the loan of the unit mate. I enjoyed experimenting with it.

You might want to investigate getting a kit of new diodes for it from MFJ in case they are the cause of the calibration problems. It should be easy to replace them and align it properly yourself. You only need to make up dummy loads with 1% resistors (a short, 12.5, 50, 75, 100, and 200 Ohms, doesn't hurt to have a 25 Ohm too). Despite the process sounding kinda complicated it isn't too bad, it is really only the harmonic minimising adjustment that needs any exotic equipment and this unit seems to be pretty good in that respect already. The bridge or correction amplifiers are definitely a little suspect and need attention.

Regards,

Alan

Alan,

An excellent review, I'm sure this will be of great interest to many readers.

As you say, the combination of reasonably priced VNAs like the MiniVNA and low cost netbooks probably mean the end of this style of device for many applications.

Great stuff.