As a G1 returning to the hobby after many years I found your explanation of ATE's and Manual/Auto ATU's the clearest and easiest to understand. Many thanks.
more inductance for the lower freqs and less inductance at higher ones is what I was told. But another informative video and nice to see people like yourself pass down basic knowledge to the younger or new hams with out the jargon etc.
Thanks for the video and detailed explanations. Can you extend this topic a little further and talk about bringing in coax and balanced line / window line. Into the shack via ATU to the transceiver. Regards Paul
Thanks Peter. I thought this was good, clear, straightforward advice. Good introduction to antenna matching options. I didn't know about the extender device - a variable impedance transformer. It reminds me a little of the old KW-107 which did a similar job for ladder line fed doublets.
An antennasystem tuner gives also pre-selection to your frondend of your reciever. If you use a wideband antenna system your recieve signals are sometimes better cleaner less noise. On 160 and 80 meter no mediumwave stations breaktrouth for example.
Auto ATU extender is an interesting concept and potentially useful /cheap addition to a rig with autoATU. Note according to MFJ literature switch position ‘D’ (not ‘A’) is the direct or bypass position. Worth also pointing out that with an external AMU w/o built in power/current/SWR meter then put the SWR meter before the AMU (not after). One related item to the subject that I find really useful in ‘lash-up’ situation is the MFJ ‘artificial ground’ connected in-shack with a random counterpoise under carpet or thrown out of car window to tune away stray rf that might otherwise degrade your transmission or get into other peripherals like laptops or external data interfaces. 73
When you say put the put the amu before the sir meter, do you mean TX-SWR-AMU-ANT or TX-AMU-SWR-ANT? Im assuming that you mean starting at the TX end as it's tuning the TX signal?
@@jackofalltrades1206 Tx-swr-amu-feeder-ant. You are correcting the SWR for the transmitter, so the meter needs to be seen by that. Ideally you are also correcting for problems with the feeder and antenna combined, though this can mask problems with the feeder. Clearly this is not the case with a remote amu, as the feeder is before any correction equipment. In simple terms it doesn't matter where in the feeder the amu or SWR are unless there are faults and the kit is in the above sequence.
Great video !! I’m left with a couple of questions about automatic tuners, first do you have any opinions on built in swr functions versus separate swr meters that can be used for other things? (Locations in the transmit path) and secondly what are your thoughts about the automatic tuners with “data cable” connections to the transceiver ? (like ic-7300 and MFJ-939I)
Richard, an external VSWR meter has bigger display, usually Peak feature, several power levels and. as you say, can be used for other things, I cannot see much advantage in data leads with the current tuners. They RF sense and are super quick. 73s Peter,
You have to be a brave man to make a video on this contentious subject. I remember being a bit irritated by the term “ASMU” or similar that one of the technical contributors in Radcom was pushing as being more accurate than “ATU”. I have adopted “Matcher” now. A very trivial point regarding internal/external is that radios (particularly with sub receivers) bypass the tuner on receive, this can work for you or against you. The high pass characteristic of a T-match can help if your receiver is being bashed by a local MW broadcaster. Your video is excellent, unlike my pedantic points you knew when to stop. There are a few videos on this platform that are absolutely incorrect, there are some that are accurate but bamboozle beginners with Smiths charts etc. Keep up the good work
Hi there, You make some interesting points. Sometimes in life we have to go with "Biro" means ball-point and "Hoover: means vacuum cleaner! Thanks for the input. 73s Peter.
I think antenna system tuning unit is fitting to what a tuner does, Mr Varney was describing how his antenna was brought to resonance with the astu just the same as any doublet antenna
Thank you for this and your many other videos. I am considering the MFJ-914 - 1.8-30 MHz AutoTuner Extender for my Icom 7300 connected to a 53' end fed wire on a 9.1 unun and a 1.1 line isolator. Would the MFJ-914 - 1.8-30 MHz AutoTuner Extender help my situation and the ic7300,s internal ATU?
Thanks Peter.. I'm always perplexed that some operators don't quite get the resonant antenna verses impedance issues.. (i.e. you can have one without the other ) Your suggestions are all very valid though, and you're very brave for even entering this particular arena. 😁 73...
Enjoyed your video, been a Ham for 26 years now so nothing new. However it's refreshing to see something taylored for the new Ham. I really hated to see The New Ham Compainion article drop from QST magizine. Not everyone that becomes a Ham is an Electrical Engineer! 73
Very helpful! I now see why an external tuner often provides a better SWR than a solid state transceiver internal tuner. I've successfully used a manual external tuner with my end-fed antenna to get a low SWR, but have had problems getting a usable SWR with an automatic external tuner. Does this indicate an external automatic tuner limitation or defect? Or are external manual tuners simply better at achieving a low SWR with end-fed antennas?
Glad it helped! Generally a manual tuner has the best capability. You do not describe your antenna in detail. The best end fed is an End Fed Half Wave with a 49:1 transormer. it should work well with an auto ATU. 73 Peter. www.hamradiostore.co.uk
@@watersstanton Thank you for your prompt reply! I believe you've answered my questions. Due to severe space limitations and the need to hide any HF antennas from public view, my antenna is a stealth 71' end fed non resonant sloper with a 9:1 unun, 50' of RG8u, two 15' counterpoises and a common mode choke at the transceiver. It's definitely a compromise antenna setup but using my MFJ - 904 manual external tuner I can get a 1:1.5 SWR or better on all bands, 80 - 10 meters. I was extremely surprised recently that using that compromise setup and carefully adjusting the manual tuner for 1:1.1 SWR, I worked VK4KW in Australia using 1OO watts SSB on 40 meters at 3 am local California time. However, I wondered if an automatic tuner would tune my setup to the same SWR faster or better, and I believe you're saying the manual tuner would likely do better for me.
Hi Peter I recently purchased a IC7300 from a Canadian supplier. I also bought a LDG auto tuner for it IT-100. I am using a G5rv antenna which a fellow ham gave to me it is a mfj 1778. During the first 3-4 months while using a FT-990 I notice a big improvement and then with the addition of a 45 ft fiberglass pole an even bigger improvement in both receive and tx I find the LDG tuner unsatisfactory as it will not tune the g5rv unless it is close to the freq that the internal tuner will tune. In one of your vids you mentioned using a 4:1 balun on the g5rv. question will that improve the conversion from balanced to unbalanced or am I looking down the wrong rabbit hole (should it not be 9:1 450 ohm to 50 ohm) Jim ve4jim
My set up, end fed 49:1 with 134' of AWG14 wire. 40 to 10 is ok. Even high 6 meters. On 80, is very high, as high as SWR 6:0 or so. Already cutted from 135' to 134. Now, a capacitor in the middle of the wire length, will bring 80 meters higher, as my good swr on 80 is around 3.7 mhz, so the antenna is really a 80-10. Now, to avoid cutting the wire and adding a capacitor, will an external tuner take care of that? In other words, bring 80 to 3.8 mhz to 3.9 mhz? Even no cap in middle of wire added instead? Thanks.
Hello Peter, I really like the video's very helpful & reminder to us, who forget things, MFJ made at one time a 6 metre transceiver, do they still make these, as you never see them advertised any more. Paul de M0BSW
Paul, I think one of the problems was that the price landed in the UK + VAT made it rather expensive, particularly as many HF rigs now have this band built-in. Appreciate your enquiry. Keep in touch. 73s Peter.
Hello. Perhaps you can make a short video on antennas which are trimmed so you don`t need a tuner (maybe you already have one- I am pretty new to your channel). My first homebrew consists of a fan dipole inverted V for 40, 15 and 10 maters. My Kenwood TS140S has no built in tuner, so I have trimmed the antennas to be around 1:1- 1:7 :1 SWR. The Kenwood works just fine. I keep it at 100 watts. Thanks KC3BXZ Joe 73
Hi there, If you can trim the antenna as you have done, then there is no need for an ATU. But some antennas such as doublets and end fed wires can rarely be used without an ATU. Keep in touch and nice to hear from you. 73s Peter.
I live about 7 miles from Piqua Ohio the home of Palstar. They hand build the variable caps and roller inductors in house. I have alway call them Trans matches instead of tuners.
Hi there, Great to hear from you. I have been to Piqua, quite a few years ago, and visited their factory. Yes, nice gear. Thanks for checking in. 73s, Peter.
Hi, Thank you for your video, I would like to know your opinion, I have a Kenwood TL-922 Amplifier, is reasonable to buy an Antenna Tuner ? Thanks in advance!
Just a thought...…….why not just have a matched antenna in the first place? Having been a ham for a while now, I graduated from a G5RV, and then dipoles ultimately to all band antennas - the Hexbeam, the fan dipole, the DX Commander, the screwdriver for mobile, the Cobwebb, the SteppIR (if you have more money than sense), the trapped mobile whips, the horizontal loop, the vertical loop. Just get a system that is matched on the band you want to use. I no longer have an ATU in the shack. I simply switch to the antenna I want to use. Currently have a Hexbeam, a loop and a DX Commander. Job done.
Hi there, Iinteresting comment. Not everybody can accomodate a resonant antenna. Some are forced to use an end fed wire. The extremely popular doublet also requires a matcher. 73s Peter
There isn't many resonant antennas that don't need matching for maximum power transfer, why limit yourself to one band, the doublet is a very efficient antenna brought to resonance with the atu
The "ATU" or better. "matching unit" is best understood as a GEAR BOX.. In a car engine, power cannot be delivered to the wheels of a stationary vehicle in top gear. (Unless you've got 4 litres!) The gear box "matches" the load to the engine at low speed..As the speed changes, a new ratio is selected to maintain the requirements of the engine with respect to its load. It's a mechanical transformer.. an EMU.... Engine Matching Unit! With the MFQ extender box, the unsuitable Z on the incoming coax, is transformed to something the rig can handle but the SWR on the line to the antenna and its consequent losses, is unchanged. Correct that and the extender box isn't necessary with its additional PL259 joints! Our workshop kept the PL259 plugs in a drawer marked 3dB attenuators! G3NBY
@@watersstanton Are they really as good as that? Great. I think that they vary within manufacturers. I heard that they were designed as audio connectors. Of course I use them anyway. What about open to weather? Not recommended ? Weather proofing? 73... Fab series of videos.. Very attention holding....Loved the demonstration of overtones on the guitar..... Saxophones do it but usually out control. It's called squeaking! Earl Bostik totally mastered it...73 G3NBY
@@watersstanton Bottom of inductor is shown connected to slider. Clearly shorted turns. It's a mistake I've seen repeated since I was building crystal sets. The lower end of the inductor should be open circuit. ;)
@@Graeme_Lastname That has been a long standing concern in my mind......never satisfactorily resolved. As the adjustment, be it a slider or switched taps or croc clips, reduce more and more of the inductance, there is the absolutely inevitable condition of very lossy shorted turns. Some designs insist that a coil mounted at 90 degrees to a chassis should have some clearance because the very metal of the chassis can display some "sorted turn effects". Two adjacent shorted turns on a mains transformer can be pretty spectacular. Even failing to unwind completely a mains extension lead when on a heavy load can be a bit graphic in this regard. That ATU coil and shorted turns continues to be a mystery. I'm amazed that you found it noticeable on a Crystal Set. Observable loss in gain? Lower Q upsetting selectivity? At higher power levels, it doesn't bear thinking about! Would be interesting to hear. 73 G3NBY
@@MauriatOttolink Put a single turn around a power transformer. When it's open circuit it does, basically, nothing. A voltage is induced across the ends of the single turn but no current flows through it. There is zero power dissipation and the voltage across any other windings is unaffected. However, when the ends are connected current flows and power is dissipated. That simply means there is less for any other windings so there is lots of heat and all other windings have much reduced outputs. I know it's not a transformer in the classic way but the results are the same. Make a crystal set and try it out, or, short the secondary on a power transformer and watch the magic blue smoke come out. Mounting any coil too close to the chassis will cause huge losses. Long time ago, 1KW linear amp, poor placement of output tank. All my own doing. But, output stage had to be rebuilt to increase the clearances just to reduce all the nasty effects on plate current, Q etc. Build a crystal set and give it a try, just be sure you're not just making the antenna bigger with your fingers. Keep well m8. :) _ . _
@goinghomesomeday1 It's a shorted turn(s). Simplest way to see what happens is to give it a try. Just imagine, amongst other things, what it does to the Q. Bring a closed loop near the output tank of a transmitter and watch the output power drop off. Best not used with solid state TX, may well make funny noises. :)
I think you are confusing yourself. A mismatch certainly does reduce efficiency. This can be corrected with a matching unit. A doublet is generally not regarded as a resonant antenna. Once the element is a half wave or more, it has excellent radiation and only the pattern changes with length.
@@watersstanton if the feedline was lossless then all reflected power from a mismatch would be radiated by the antenna, the reason a non resonant doublet is so efficient is the feeder has little loss even with high swr,or in your words from a previous video,' the swr from the mismatch doesn't represent loss' , the atu does correct the mismatch as it brings the system to resonance, but efficiency is reliant on feedline, feed the same antenna with rg58 the antenna won't be anywhere near as efficient
@@stevenlawhon3695 did the chart take feeder loss into consideration, reflected power encures loss as it returns to the tuner then again on its way back to antenna, if a low loss feeder is used like balanced line then most of the reflected power is radiated by the antenna
Peter is a very nice bloke, but he is wrong. Antenna tuners actually alter the phase relationship between the Voltage and current leaving it, to where it is complementary to the matching error between the antenna (load) and it's feedline. This artificially alters the apparent match between the load and feedline. (also making the tank circuit that is an antenna "resonant" with the electron bouncing between the capacitance and inductance smoothly as though it was resonant at your chosen frequency) Ron W4BIN
A tuner provides a conjugate match by adjusting the capacitive and inductive reactances to cancel each other out, also as you mention Ron corrects the phase of the voltage and current, in this condition the antenna system is resonant, reflections by Walt Maxwell covers this subject in great detail and is a must read for any amateur
Perhaps the least understood concept in this hobby. A.C! Even in the UK full course there is no great detail on phase or complex impedance calculations. Give the harmonised qualification and recognition schemes i expext the same is true around the world. For everyone new to this. The tuner/matcher is there to help present an impedance match to the transmitter only. This will help the power amplifier work more efficiently and reduce any harmful back e.m.f, high voltages, circulating currents, resonance etc being generated in the output stages and killing your rig. While you should now get more actual power output from the back of the TX this doesn't mean there is more radiated power at the antenna. There may be. But you will equally be dissipating power in the matcher/tuner. That is to say the output power of the TX will be divided between the antenna and the matcher with some losses in the feeders and connections too. Suffice to say its best to read about this from quality textbooks written for engineers and physicists than anything related to the hobby. It is not a slight on help that other offer but a sad fact that much of what is offered is inaccurate or simply wrong. For anyone else who wants to argue a point about radiated power they should investigate imaginary power and question why energy providers charge you for such stuff. Thumbs up for a helpful video.
