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I
do not mind adjusting a manual matching network with changing
frequencies.? I have a very robust differential matching network with
all of two, yes, just 2, adjustments.? It's an L-network, of course.
Yesterday
I took a somewhat in-depth online look at the higher-end matching
networks (a.k.a., "antenna tuners") from various suppliers.? I note some
of the really high-end units incorporate a fan in the box.? Why, pray
tell, must an "efficient" antenna matching unit require a fan???!!!? If
it is efficient as the marketing write-up has you believe, there should
be no amount of heating that requires forced air ventilation!!!? My home
brew unit does not produce anything much above 5-degrees F above
ambient - barely perceptable.? Absolutely nothing which would even
approach requiring forced air cooling.? And remember, heat indicates
loss.? So, I would conclude these expensive matching networks are not
what they claim to be!!!! ?
Once again:
1)? Do not trust marketingeeze or supplier claims 2)? Measure everything 3)? Buyer Beware
-- -- Please join me.
Dave - W?LEV
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Hi Dave.? I've had a couple of tuners that had heating problems.? One had an inductor with too-small wire diameter.? Two had undersized relays in the signal path and the relays got rather hot.? One tuner I had heating problems with was a Palstar autotuner that overheated when running 750 watts with digital modes.? Later we found out that their 2KW tuner was really rated at around 375 watts for continuous carrier modes.? The two tuners I have now that never get warm: Ameritron ATR-30 and J.W. Miller AT2500.
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73, Floyd - K8AC
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I was given a Toyko Hi-Power HC-2000.? On 160 the inductor heats badly and on 40 the variable capacitors arc badly.? This all at even 500-watts!? It sure looks good and extremely high quality inside, but.....?
My home brew differential matching network uses an inductor made of 1/8-inch x 3/16-inch copper bars which is silver plate.? Even at 1.5 kW on my worst band, the heating is absolutely minimal, maybe 5-degrees above ambient for a 3-minute key-down spring.? The variable caps are two matched 3 kV variables each max of 250 pF.? I wish I had two matched 500-pF variables, but I didn't. ?
On Sat, Mar 1, 2025 at 5:02?PM Floyd - K8AC via <floydsense= [email protected]> wrote: Hi Dave.? I've had a couple of tuners that had heating problems.? One had an inductor with too-small wire diameter.? Two had undersized relays in the signal path and the relays got rather hot.? One tuner I had heating problems with was a Palstar autotuner that overheated when running 750 watts with digital modes.? Later we found out that their 2KW tuner was really rated at around 375 watts for continuous carrier modes.? The two tuners I have now that never get warm: Ameritron ATR-30 and J.W. Miller AT2500.
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73, Floyd - K8AC
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Dave - W?LEV
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Dave . . . On Sat, 1 Mar 2025 20:56:11 +0000, "W0LEV via groups.io" <davearea51a@...> wrote: I was given a Toyko Hi-Power HC-2000. On 160 the inductor heats badly and on 40 the variable capacitors arc badly. This all at even 500-watts! It sure looks good and extremely high quality inside, but.... Wow. Not what I would have expected from a Toyko Hi-Power matchbox. I thought those were very high quality units. Was the arcing at high altitude? You've mentioned that, at high altitudes, capacitor gaps have to be larger to prevent arc-over, and you had that happen in an MFJ tuner when it was fine at low altitude. The Toyko Hi-Power HC-2000 is rated at 2 kW PEP. Was your 500 W during SSB or some other mode? (I think you prefer SSB over other modes.) Maybe the heating of the inductor on 160 meters was a feature, allowing you more bandwidth due to a lower Q? :-) Seriously, I would have bought one of those Toyko Hi-Power HC-2000s if the price was right, but based on your experience, it's probably no better than the LDC, MFJ, and other reasonably-priced matchboxes. There's one made over in Europe somewhere that sells for maybe $2500 USD that reportedly uses good quality components. It might be one from this company (these are the three I see on their website): Donald KX8K ---------------------------------------------------- Some ham radio groups you may be interested in: /g/ICOM /g/Ham-Antennas/g/HamRadioHelp /g/Baofeng/g/CHIRP
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I have used Dentron MT-2000 and 3000 matching networks since the 1970's and found that they will tune almost everything, including my rain gutter (yes I tried it once just to see if it would work) at full legal power. I say tune because they will reduce the SWR to match the antenna to my transmitter. I have also measured the output power of my transmitters at the transmitter and at the antenna to gauge the I feed line and tuner loss and found the loss to be reasonable depending on the length and type of coax used. The Dentrons do not "suck up power" through resistance or reactance. If adjusted properly, I have never had any arcing, sizzling, overheating or other destructive activity and I have tuned everything from quads, yagis, verticals and random wires of practically every conceivable length on field days and other temporary locations, even using CB antennas on 10 meters.
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I have tried many tuners from Drake, Kenwood, Yaesu, the Nye MB-V-A, and Ten-Tec without the same wide ranging results. Some of those tuners had difficulty tuning a fairly resonant antenna. There has never been a situation where I could not match my piece of wire to the transmitter with the Dentron MT tuners. The only other tuner that was close to their equal was the Murch UT-2000A, because of the roller inductor. I always wanted to remove the switched inductor from the Dentron and put in a roller inductor, but never wanted to cut up one of my units. I still have the Dentrons and several others, but I now mainly use a Palstar At-5K because of the roller inductor. It will also tune almost everything at high power levels. Mine is a little iffy on 10 meters because I have an early version before they increased the range of the roller inductor. Yes, it has a fan, but I never use it because there is no heat build up. I have never had the opportunity to try a Tokyo Hi-Power tuner.
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As to the MFJ tuners, I have never tried one other than a small low power unit I use mobile. However, I did talk to a very large dealer at Dayton one year (still at the Hara Arena location) about one of the larger MFJ tuners. He asked me what kind of amplifiers I used and when I told him, he then asked me if I really wanted to trust those expensive tubes and input networks to an MFJ tuner. So, I never did.?
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I have also constructed some antenna matching units myself and they worked OK, but they seemed to have too much power loss and didn't have repeatable tuning results where the Dentrons and other quality tuners always did. I am not related to Denny Had and never worked for Dentron but over the years I have found them to be an excellent way to match the transmitter to the antenna at a reasonable cost. They work well and the increasing value of those tuners on the used market show that they are also respected by many other hams.
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No matter how effective your antennas are, they always have a narrow resonant frequency range, especially on the lower bands (80 & 160 especially) unless you are using an antenna that is like a dummy load because of its wide band, power robbing matching network. An antenna "tuner" is a valuable piece of equipment and like everything else, you get what you pay for. However, it all depends on the type of antenna you have. A T-Network tuner works well on resonant antennas and random wires, but other tuner designs work well on other antenna types. YMMV.
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Have you tried one of the old Z Match tuners such as a KW Ezee Match ?
I have used Dentron MT-2000 and 3000 matching networks since the 1970's and found that they will tune almost everything, including my rain gutter (yes I tried it once just to see if it would work) at full legal power. I say tune because they will reduce the SWR to match the antenna to my transmitter. I have also measured the output power of my transmitters at the transmitter and at the antenna to gauge the I feed line and tuner loss and found the loss to be reasonable depending on the length and type of coax used. The Dentrons do not "suck up power" through resistance or reactance. If adjusted properly, I have never had any arcing, sizzling, overheating or other destructive activity and I have tuned everything from quads, yagis, verticals and random wires of practically every conceivable length on field days and other temporary locations, even using CB antennas on 10 meters.
?
I have tried many tuners from Drake, Kenwood, Yaesu, the Nye MB-V-A, and Ten-Tec without the same wide ranging results. Some of those tuners had difficulty tuning a fairly resonant antenna. There has never been a situation where I could not match my piece of wire to the transmitter with the Dentron MT tuners. The only other tuner that was close to their equal was the Murch UT-2000A, because of the roller inductor. I always wanted to remove the switched inductor from the Dentron and put in a roller inductor, but never wanted to cut up one of my units. I still have the Dentrons and several others, but I now mainly use a Palstar At-5K because of the roller inductor. It will also tune almost everything at high power levels. Mine is a little iffy on 10 meters because I have an early version before they increased the range of the roller inductor. Yes, it has a fan, but I never use it because there is no heat build up. I have never had the opportunity to try a Tokyo Hi-Power tuner.
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As to the MFJ tuners, I have never tried one other than a small low power unit I use mobile. However, I did talk to a very large dealer at Dayton one year (still at the Hara Arena location) about one of the larger MFJ tuners. He asked me what kind of amplifiers I used and when I told him, he then asked me if I really wanted to trust those expensive tubes and input networks to an MFJ tuner. So, I never did.?
?
I have also constructed some antenna matching units myself and they worked OK, but they seemed to have too much power loss and didn't have repeatable tuning results where the Dentrons and other quality tuners always did. I am not related to Denny Had and never worked for Dentron but over the years I have found them to be an excellent way to match the transmitter to the antenna at a reasonable cost. They work well and the increasing value of those tuners on the used market show that they are also respected by many other hams.
?
No matter how effective your antennas are, they always have a narrow resonant frequency range, especially on the lower bands (80 & 160 especially) unless you are using an antenna that is like a dummy load because of its wide band, power robbing matching network. An antenna "tuner" is a valuable piece of equipment and like everything else, you get what you pay for. However, it all depends on the type of antenna you have. A T-Network tuner works well on resonant antennas and random wires, but other tuner designs work well on other antenna types. YMMV.
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No, Dave, I have never tried one of those. There are several vintage tuners that are probably great, such as the Miller and a few others that I cannot recall the brand names. In the late 70's and 80's there were several good, high end tuners on the market, but they are pretty rare now as the sales volumes weren't that high.
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73,
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Tye, W8ZM
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I have found virtually ALL commercially available antenna matching units (a.k.a., "antenna tuners") marketed into amateur applications are sorely over rated when it comes to power handling claims.? The best solution to this is to build your own.? And,.......in doing so, you'll save a whole bunch of $$$!!
Dave - W?LEV
No, Dave, I have never tried one of those. There are several vintage tuners that are probably great, such as the Miller and a few others that I cannot recall the brand names. In the late 70's and 80's there were several good, high end tuners on the market, but they are pretty rare now as the sales volumes weren't that high.
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73,
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Tye, W8ZM
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Dave - W?LEV
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On Tue, 4 Mar 2025 16:46:00 +0000, "W0LEV via groups.io" <davearea51a@...> wrote: The best solution to this is to build your own. And,.......in doing so, you'll save a whole bunch of $$$!! Then there's the ugly factor, Dave. I have nowhere near the skills of a metalworker, so any matching unit I would build for the station use would look unsightly. I am all for making my own antennas for HF, maybe for VHF and UHF, too, but the kind of metalworking needed to make a good looking tuner is a bit above my pay grade. For now. I eventually intend to try building a super tuner with a large roller inductor and wide spaced capacitors, after I get a set of good metal hole punches. ---------------------------------------------------- Some ham radio groups you may be interested in: /g/ICOM /g/Ham-Antennas/g/HamRadioHelp /g/Baofeng/g/CHIRP
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There's at least one that's not overrated: The Ameritron ATR-30, designed by W8JI.? The rotary inductor uses a thick ribbon instead of wire.? I've run the legal limit on RTTY in contests with no problems.
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73, K8AC
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Yep.? That's likely very similar to the roller inductor I use with my home brew differential matching network.? And, yes, the included inductor, roller or switched and tapped, is most times the downfall of many/most commercial matching networks.??
The inductors, not to mention the claimed "broadband balun" to 200-ohms.? And why 200-ohms?? To match a 200-ohm XMSN line?? Absolutely and technically WRONG!!!? In reality, these are nothing but a transformer and do not serve very well as a transition a from common mode matching network to a differential mode transmission lines - common marketing claim.?
Amateurs need to learn what's inside that "magic" and "mysterious" antenna system matching network and hold the suppliers accountable for bad and improper marketing claims (and engineering designs - the engineers SHOULD know better!).
Dave - W?LEV
On Wed, Mar 5, 2025 at 5:44?PM Floyd - K8AC via <floydsense= [email protected]> wrote: There's at least one that's not overrated: The Ameritron ATR-30, designed by W8JI.? The rotary inductor uses a thick ribbon instead of wire.? I've run the legal limit on RTTY in contests with no problems.
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73, K8AC
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Dave - W?LEV
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Comments on problems with the Ameritron ATR-30 - MFJ.
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Floyd - K8AC
