#385

[@DrStormaggedon]

I never got to finish my electrical masters (2 classes away!!) but coming back to your videos give me more confidence to go back. Thanks for the upload!

[@Ran-tan-tan]

Tried this with my MFJ-941E, chose the inductor setting with loudest noise, then proceeded as in the video. First time I have ever gotten my CB-antenna matched on 80m! I could probably have done it anyways, but I always lost interest as the match seemed to evade me forever... This method worked perfectly and was pretty darn fast to boot! Thanks!

[@wadepatton2433]

My first HF antenna was a loop that needed tuning every band, and I don't miss those days. But now I might consider using an non-automatic tuner again. Thanks

[@Radiowild]

Redundancy "bypass" tuning! Love it!

[@Lyndon_K]

Thanks Alan, another great video! I have written down the capacitor settings for the different bands and I find that gets me very close. However, I am definitely going to try your "just past the null" method the next time I am out. The weather up here in Ontario is getting warmer so I want to get out for an activation with my TR-45L as soon as possible. 73! DE VE3IGS - Lyndon

[@MikeFikes]

The Patented NJ Fastune Overshoot™: Nulling so fast, the SWR won’t know what hit it!

[@Swamp-Fox]

I'm gonna give that technique a try on my ZM-2.

[@Tom-W7TMD]

Nice! I cant wait to get one!

[@w2aew]

Better hurry - WA3RNC announced his retirement and will only be making a limited quantity of these units until then.

[@sasines]

Alan, thanks for the great video. I’ve got one of those tuners so now I’ll have to go try your technique. Can you explain what’s happening here?

[@w2aew]

It's just a faster way to getting to the final solution, which would eventually get to my alternatively adjusting for nulls.

[@sbelectronicaindustrial6652]

👍👍👍👌👌👌

[@kcscarecrow]

I find that technique works also on my mfj 949 e

[@clems6989]

Alan, have you ever done a video on the SIDAC ? This component is a tricky little bugger.

[@w2aew]

I haven’t.

[@artbremer4076]

I watched a presentation of some amateur radio club and the the presenter said that tuners suck up radiating power and when doing QRP, one absolutely doesn't want to use tuners....I became quite incredulous when I heard this. Being new to the hobby, Is this something worth pondering over next time I take my IC-705+ random wire and AH-705 tuner for a walk?

[@w2aew]

The presenter was ill-informed. A well designed tuner has very little loss. There may be some additional loss in the coax when the antenna is non-resonant, but often is of little consequence. I have well over 5000 QRP contacts operating 5W with a tuner into non-resonant antennas as evidence that says that using a tuner is just fine.

[@andrewverran3498]

Hi Alan , I am trying to find one of your videos where it begins regarding how much power the front end of a radio can safely handle , it may have been a S9 type video but I can't find it. Can you help please? Cheers😊

[@w2aew]

Maybe it was this one that deals with using RF Switches to switch between radios? kzbin.info/www/bejne/on6wop9nnKqCiLM

[@andrewverran3498]

@@w2aew that was the one..cheers.

[@ohaya1]

Hi Alan, I'm asking in this video since I'm not sure how else to reach you. What is the main difference between a dedicated RF signal generator and a function generator (AWG)? Is it perhaps that the RF signal generator can more easily generate VHF and above frequencies and very weak signals strength, whereas the typical funciton generator generates relatively lower frequencies compared to the RF generator and is and would tipically require external attenuators for RF work? Is there really a difference between say a 14MHz sine generated by an RF generator vs a funciton generator? Would you considering covering this in a video? Many thanks, Alex M0OOV

[@w2aew]

You’ve got the major differences. Internally they are quite different.

[@ohaya1]

@@w2aew Thanks so much for your reply. In the meantime I've also learned a bit more but I feel that this topic is not that well covered on YT. PS. Excellent presentation you did for the RSGB on the Nano VNA, I thoroughly enjoyed that! 73

[@lynnbailey1948]

How do you feel about tuning for max power out (forward power) instead of minimum SWR? I guess that may depend on whether your rig's output transistor is protected for high SWR and puts out max power at minimum SWR.

[@w2aew]

This rig doesn't have output protection. The meter is reading REV power, so minimizing that is the goal so the max power is delivered to the antenna system. Not sure if the FWD power will be accurate when there is reflected power present (depends on the standing wave), so minimizing reflected power is better.

[@warplanner8852]

Wonder what the reason for that would be, Alan. Do you have an idea?

[@w2aew]

You’re still winding up with the same solution, only you’re taking an extra half step with each adjustment to get there faster.

[@warplanner8852]

Alan, understand. Every time I use a tuner, it takes me back to my [first] Novice days in 1961 when I'd tune up my DX-40. Tune, dip, tune etc. and try to keep the 6146 plate from turning cherry red! A segue here: having a world of fun with my QDX doing FT8 when the little beast started belching smoke. Come to find out that the old LDG Auto Tuner I used would send an horrendously high VSWR when I switched bands and the poor BS170s gave up the ghost. Well, new finals and my little 4SQRP manual tuner and a little more sedate band switching and things are right as rain. 72 de k6whp

[@aduedc]

Great Clip. Here is a circuit challenge: We have Capacitor Multiplier circuit, can any one design a Resistor multiplier circuit?

[@w2aew]

No, because there is no energy storage in a resistor.

[@aduedc]

@@w2aew Thanks, of course you are right we cannot use passive circuit to do that, but we might be able to do that using active circuit. Here is my idea how to design such circuit: 1. Resistor to voltage converter (easy by passing a fixed current through a resistor) then 2. Voltage to resistor converter (using MOSFET in Ohmic region) That is: R->V->R' Another idea is to connect the resistor to the emitter or source of BJT or MOSFET transistor and look into the impedance of base or gate of transistor. The input impedance is about (Beta + 1)Re We might also be able to use current-voltage feedback loop (on an opamp) to do that. I wonder is there other circuits such as gyrators or opamps to achieve this. Applications: 1. Measurement of low resistors (like 1mOhm) without using high current. 2. Tunable low frequency RC filter and oscillators.

[@w2aew]

@@aduedc Without some energy storage (capacitor or inductor), you can't generate a voltage greater than the supply voltage, AFIAK.

[@aduedc]

@@w2aew As you know looking in the base of the transistor make the emitter resistor looks much larger. The question was can we design a circuit that multiply a resistor.

[@tamaseduard5145]

73' 88'