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Author Topic: Amplifier suggestions  (Read 2864 times)
KD8MJR
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« Reply #15 on: May 06, 2019, 01:52:08 AM »

Hey Truman I know it’s a lot to take in.
As suggested you really want to ditch the end fed wire antennas and head for a verticals.
Setting up the radials is the most time consuming part but the more you lay down on the grass is the better it will perform.  Dont worry about your parents, the radials will quickly be covered over by grass growth and become hidden.  If you have the cash take a look at stepir and see if their vertical offers what you need.
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KE6EE
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« Reply #16 on: May 06, 2019, 09:21:49 AM »

I'm a younger ham, and my parents are unlikely to put an antenna on the roof.

Many if not most of us started out in the 1950s or 1960s at age 12 or 14 with, in comparison to today's gear, very
primitive transmitters and receivers. Maximum wattage: 75. Absolutely no thoughts about kilowatts. Kilowatts will
be noticeable as various electronic devices go on the fritz.

We strung wires around our parents' houses with little or no consultation: as long as we stayed out of their hair, all was OK. Our motto: act and then, if actions are even noticed, request permission.

Our parents didn't climb on the roof. We, however, did, and it was as much fun as anything. Some of us at high multiples of 12 years of age still enjoy roof climbing.
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W3RSW
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« Reply #17 on: May 06, 2019, 10:41:58 AM »

Interestingly, modern 240vac dryers now have four prong outlets.  Two hot, one neutral and lastly the safety (no current) ground.

Picking off one of the hots for 120vac , the neutral, and safety ground technically gives the same function as the usual 120vac outlet but of course is dependent on the dryer’s way more than necessary 40 or 50 amp breaker. This makes such a pickoff unsafe, not to mention
Unbalance and problems if the dryer and pickoff equipment are both operating at same time.

I suppose for 120vac emergency or no circuits left in breaker panel situation, a temporary only plug could be made up with an additional 20 amp breaker in series and plugged into the dryer outlet so that the dryer could not be plugged in at same time. 
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Rick, W3RSW
VK6HP
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« Reply #18 on: May 07, 2019, 12:41:37 AM »

Hello Truman

You've received a lot of useful comments and I thought I'd add a couple of angles which haven't yet been discussed with much emphasis.  First off, I wonder what your receive noise situation is like?  You don't mention whether you're in an urban environment but, in parallel with thinking about increasing your transmit power, there is at least as much benefit in experimenting with lowering receive noise levels as far as possible, perhaps by reducing pickup from the house environment. You don't want to be an alligator (all mouth, no ears)!  In this regard, antennas which are inherently electrically balanced and which are amenable to straightforward treatments for common mode current suppression are often useful.  Simple dipoles, well installed, fall into that category and, as a side benefit, offer benign feed impedances requiring minimal (if any) tuning.  I'm certainly not saying you should stop using an end-fed wire, just suggesting that some antenna experiments could be quite beneficial, and quite handy if you do really want to go QRO with a wire antenna. Verticals can also be useful (as others have mentioned) but be prepared to install a good ground radial system or an effective elevated counterpoise.  You may find that the vertical is somewhat noisy as a receive antenna (partly depending on your environment) and eventually go down the path taken by many of us, where we use separate receive and transmit antennas for some bands.

On the subject of the amplifier itself, have a think about the quality of your final signal in addition to the many good considerations already raised.  I don't know if you have a 991 or 991A but the 991 (not the 991A) is one of the "dirtiest" radios around, with even the ARRL making note of its exceptionally poor transmit intermodulation distortion characteristics. (In a significant omission,  they rarely bother to comment on this aspect of transceiver performance). If you are going to use a 991 with an amplifier, I would look for an amplifier that allows you to keep the drive levels moderate and which itself has good IMD characteristics. If you teamed a 991 with (for example) the AL-80B amplifier mentioned by others, at least the IMD is still dominated by the transceiver.  If you teamed it with e.g. some marginal solid state amplifiers, contributing their own IMD products at high levels, you could be less than popular with your ham neighbors.

There are various complexities in a more complete analysis, most of which rely on knowing more about the transceiver distortion versus output behavior but the main purpose of my comment was really to encourage you into the enlightened ham fold, rather than worrying solely about how far the wattmeter swings to the right.  All the best with your deliberation and experimenting.

73, Peter.
 
« Last Edit: May 07, 2019, 12:55:37 AM by VK6HP » Logged
VK3BL
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« Reply #19 on: May 07, 2019, 06:28:12 AM »

Dear Truman,

Please don't take this the wrong way, but I think we need to address realities as well as dreams.

First, let me tell you a reality:
I set myself the goal of achieving DXCC in a year when I first got into the hobby.  Like you living with my parents with an entry level rig, using a 1/4w 20m vertical, and operating barefoot.  This was when the sun spots were much better admittedly, but the new digital mode FT8 more or less makes up for that with its extreme sensitivity (most if not almost all of my original DXCC was made up with phone QSOs).

Now, let me suggest a dream:
Why not try and set yourself a similar goal?  Just like myself, spend time reading the works of L.B. Cebik W4RNL and learning about antennas.  Try a few different things; a vertical with 8 radials laying on the grass can be setup in less than a day cheaply and your parents will likely take at least a month to get sick of it.  A dipole is a very efficient antenna and there are some lovely multiband versions such as the G5RV (80M, 40M & 20M) or the ZS6BKW (which covers a few more bands at the cost of 80M performance).  Lastly, "Cobwebb" antennas are gaining popularity and are a great choice for 20M and above, although it isn't the season for above 20M at the moment. 

Learn about the sunspot cycle; we're in the bottom of it, so you'll probably catch most of your DX on 40M FT8.  There is plenty of DX to be had on 80M FT8 as well, but in my experience that DOES require power and you need to wake up early to catch the worm for the most part.  40M on the other hand 100W is plenty and your rig will put it out without harm; if it does get warm it will just back off slightly to say 80W.  You can ignore the warnings about the FT-991A being a 'dirty' radio as FT8 being a single tone, continuous phase mode does not really require a very linear setup.  Don't worry about that statement so much just be assured that your radio is perfectly fine to run with FT8, even into an amp.  Just make sure you don't set the volume knobs excessively high on the Yaesu SCU-17, SignalLink or your digital mode adapter of choice.

Thats my advice; dream of playing with antennas, getting active with digital modes, learning about propagation in order to achieve your DXCC or even WAS (worked all states) in a year.  You can do it if you put the time in.

Now lets talk about other realities:
You've said you can't afford an amp, and then you've listed some of the highest priced 'toys' available in the hobby.  The Acom 2100 or SPE 1.5Kfa amplifiers ARE NOT 'first amplifiers'.  They are comparatively very complicated devices that ARE expensive to repair if broken, and as others have mentioned, if you don't have your antenna situation well sorted mistakes do happen.

I would recommend you find yourself a nice Ameritron AL-811 or AL-80B, preferably the later model but the former is fine if you chuck a set of 572B tubes in it.  These amps are VERY basic designs, easy to diagnose faults on, easy to service, but do demand care.  Like all tube amps, they WILL BITE HARD (or kill) if you do not follow proper procedure when performing maintenance.  This is mostly as simple as putting the meter on 'HV Voltage' mode and NOT opening the case until the meter reads zero.  Afterwards, the sensible man uses a multimeter to test for voltage on the HV capacitor bank; if there is any residual voltage stay away until it is gone.  If the reading is low (say 50v), no harm should come from using an insulated screwdriver to simply 'short out' the terminals of each cap.

Of course, an AL-811 or AL-80B is not the 'sexiest' of amps, but they ARE popular, still in production, and can be had very cheaply second hand.  They will also match (without an external tuner) loads of up to 3:1 SWR, which is generally considered the most a sensible Ham would want to put power into without knowing every last detail of their antenna setup.  They are affordable, and WHEN, not IF, you have an antenna malfunction (be it an underspecced Balun, too much power for RG-58 Coax, etc etc), you're not going to end up with a huge repair bill and parents questioning your hobby.

Of course, I still suggest trying to get your DXCC barefoot first; one should not rush..  As many a wise Ham knows, what do you do after you've worked 100? 200? 300?  The days of a new one become few and far between the more you work.  Why rush it and lose the excitement by trying to bust the pile up first go?

I'm now at over 200 confirmed countries, and have some of the nicest equipment a Ham can have, but ironically I spend less time in front of the rig than ever before.  Even when a good DXPedition comes on air, I can usually bust that pile up pretty quick and to be honest there isn't much satisfaction in that.  I actually long for the hard pile up, perhaps on a band I cant run power into because I'm pressing the wrong antenna into service... satisfaction is proportional to the work you put in, and busting a pile up in a few calls does not take much work.

The truth is that whilst building a station with nice toys is satisfying, it isn't satisfying for long.  The chase is better than the catch, as many of us seasoned DXers know all too well.

As for another dream?
Keep lusting after that equipment, keep learning about it; keep dreaming.  Whilst I don't have buyers remorse on my THP HL-2.5Kfx (second hand), Palstar HF-Auto (second hand) or Icom IC-7610, the truth is there isn't really much in the way of shack equipment for me to lust after these days. 

I put the knowledge I had gained from owning 'starter amps' (which I sold for more than I paid originally after gaining the knowledge to fully service them), to find killer deals on last decade's flagship equipment.  The fact of the matter is even today the THP HL-2.5Kfx is one of the most powerful solid state amps ever made and I paid well less than half what any current production amp in its class would cost new.  The newer designs - although packed with more features - are arguably less repairable in the future due to relying on switch mode power supplies for example.

Same with the Palstar HF-Auto.  Having owned a cheaper Palstar AT2K and learnt to service it, I knew what to look for to ensure the tuner I bought second hand was in pristine condition, and I saved a bucket load there too.

The state of the art new path is not for a Ham on a budget, and definitely not for one who states they can't afford an amp.  After all, as Ferrari salesmen say, if you ask the miles per gallon or servicing costs, you can't afford the car.  And QRO gear running at high voltage (tube) or high current (solid state) putting out a truck load of heat DOES need servicing from time to time.

I hope my words inspire realistic goals and encourage you to pursue the path needed to reach your dreams.

73, Jarrad VK3BL

PS, you can see my shack on youtube, look up 'Rate My Radio'.  It took me many years of sustained dedication, saving and bargain hunting to build up that shack, as all good shacks are built.
« Last Edit: May 07, 2019, 06:37:15 AM by VK3BL » Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
KX2T
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« Reply #20 on: May 07, 2019, 01:25:15 PM »

I agree with BL on the good multi band antenna, forget the garbage you see on the net about end fed antennas, its like playing lotto, a dollar and a dream on working DX on a regular basis. The key thing in your station is the antenna and its efficiency, next is the receivers ability along with a decent power amp. Do some research and you will find a modified ZS6BKW antenna in which you do a small modification on the input side of a 1:1 balun with some added capacitance in series with the center conductor of the balun which will bring up the match and efficiency of this antenna on 80/75m, this info can be found on Cicil's W5DXP site and this antenna will do a more than decent job on 40,20,17,12&10 meters providing a more than decent match but you may want another simple antenna on 15&30 meters cause it does not do or play well on those bands. It a shame but there is no free lunch when it comes to antenna and SWR is one things , efficiency of what power actually gets radiated is another.
As far as an amp goes something like an Ameritron AL80B  is kind of the gold standard but if its solid state you want then the cost of wattage and performance does bring the price up then again not knowing how deep your pockets are depends cause you mention SPE but they are one of the higher cost SS amp's out today. The AL80B uses a tried and true very rugged tube the 3-500ZG and will give you a solid 800W on CW with about 1KW PEP on SSB plus there always seems to be ones for sale used in decent shape.
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WG8Z
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« Reply #21 on: May 07, 2019, 08:40:55 PM »

Taylor
Working toward your extra very prudent. Hats off to you.
Certainly looking forward to nice gear, amp ect. a reasonable goal.
Hope it all plays out in a timely fashion.

Look forward to you returning asking questions in the RFI section.
"When I try to operate on 40M at over 300w into my short endfed the toaster reboots and the neighbors washing machine smokes."
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KD8MJR
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« Reply #22 on: May 07, 2019, 10:19:25 PM »

Jarrad gave some solid advice Smiley
Most of us started off with pretty much crap equipment and bought more equipment as we gained knowledge.  Its pretty easy in this hobby to reduce a $3000 amplifier into a pile of smoking garbage if you don't know what your doing or don't have the rest of equipment to run it safely.

One thing you hear often is Antenna Antenna Antenna!  Yep it's really true, it's best to put your first stash of cash and hard labor into buying and installing the best possible antenna that you can.  Once you have a good antenna the rest of the pieces will come gradually and are easy to install.

73s
Rob
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W1VT
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« Reply #23 on: May 08, 2019, 06:43:17 AM »

The antenna really makes a difference.  I put up a 42' top loaded wire vertical for 80M and got my 80M DXCC in just 3 months running 100 watts.  It only cost my $60 to build and worked just fine without an antenna tuner.  I used the big maple tree in the center of the back yard to support it.  With a 600W amp I'm now up to 224 countries on 80M.

Zak W1VT
« Last Edit: May 08, 2019, 06:46:14 AM by W1VT » Logged
K6BRN
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« Reply #24 on: May 11, 2019, 11:49:05 AM »

Quote
forget the garbage you see on the net about end fed antennas, its like playing lotto, a dollar and a dream on working DX on a regular basis.

Oddly enough, users of end fed antennas seem to like them, even if they already have, say, a Yagi.  And MANY use then as a "first antenna" because they go up so easily and with so little impact.  Wish the EFHW-8010 or -4010 were around whe I first started.  "Look, Ma!  Got the radio!  Now what?"

No need to listen to me, listen to other USERS, not "Armchair Skeptics"...

https://www.eham.net/reviews/detail/12423

https://www.eham.net/reviews/detail/13169

https://www.eham.net/reviews/detail/12714

End-feds like the EFHW-8010 are NOT meant to compete with a big Yagi - but they can certainly complement one to add band coverage, which is what I do at QTH#1.  And as a first antenna, thy simply work.  At a condo, they are nearly invisible.  Working mobile, they fold up into a book-sized package.  Andy they are inexpensive.  So... where is the downside, exactly?

Always use the right tool for the right job, in the right context.  In MANY contexts, an EFHW is the way to go.

I'ved worked plenty of "DX" with mine, too, including on 80M (I guess this is supposed to be hard?)  And so did the PV ARC at the recent Catalina Island IOTA expedition.  I'm in the ARC meeting right now and have just been going over the results that the team yielded - I did NOT go (was at QTH#2 on the East Coast).  And this was a group of operators interested in RESULTS, not brands.  And they got them.  Technically speaking:  100% pure fun.  Hard to model, evidently.

So, people who bash products they've never used?  Sometimes 100% pure "garbage"

You be the judge.

Brian - K6BRN
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W9IQ
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« Reply #25 on: May 11, 2019, 12:40:58 PM »

End fed antennas and a legal limit amp are a bad combination. Most of the impedance transformers used on the end feds will go belly up with legal limit power. That event may also burn up the amp - a 2 for 1 deal.

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
K6BRN
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« Reply #26 on: May 11, 2019, 03:47:18 PM »

Glenn: (W9IQ):

Quote
End fed antennas and a legal limit amp are a bad combination. Most of the impedance transformers used on the end feds will go belly up with legal limit power.

For average power, you are quite correct.  I limit average power (on 80M, its better on 40M) into my EFHW-8010 to 300 watts and have no problem it at these levels, on FT-8, JT-65, etc.  On SSB I run 1 KW with no problem, either.  And I run RTTY at 500W for a limited time, too.  The antenna matching transformer tends to heat up as more power is fed into it.  If too much average power is applied for too long a period, the magnetics overheat and the SWR changes slowely at first, then rapidly.

Oddly enough, all the trap Mosley antennas (and really the MFJ/Cushcraft/Hygain antennas with traps, too, verticl or horizaontal) are limited to 600W average power under the same circumstances.  And for the Mosleys, 2.5 KW on SSB  When the traps DO fail due to too much power, they usualy arc or burn in a bad sort of way with little warning.  Then troubleshooting and repair can be a real pain.

With ANY antenna, you've GOT to know its limitations.  Same with your amplifier.

For full legal limit at AVERAGE power, an operator will need a pretty special amplifier, like a modern (solid-state)  KPA-1500 or equivalent tube amp to generate the output and sustain it without melting down (only a few will be able to do this) and an antenna rated at 1500 watts average power - usually something without a trap or magnetics based balun (not talking about a common mode choke, BTW), like a SteppIR antenna.

My SB-200 tube amplifier can put out (on 20M) about 680W SSB PEP, 500W CW (brief QSOs) and only about... 250-300 Watts average power.  My Yaesu Quadra amp is rated at 1000 watts output in any mode, but at only 500 watts sustained average power.  My little KPA-500 will sustain 500 watts average power for quite some time.  An AL-80B tube amp will do  about the same - 500W average power, in a much bigger size.  Really have to hand it to Elecraft - they design very nice products.

So, its not like the EFHW is a real problem with an amp.  Just get the highest power version you can (-2K matching transformer) and watch the SWR for changes if you are running more than 300 watts continuous.

But... if you feel the need to run the full legal limit... maybe you should upgrade the antenna first, to something that's built to handle it and also provide gain.  And the coax feedline, too.  I find the Mosley TA-33-MW/40M more than adequate.  My neighbor runs a KPA-1500 full-bore on all modes and prefers a SteppIR.  It's a personal choice.

Brian - K6BRN

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N3DT
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« Reply #27 on: May 11, 2019, 03:53:33 PM »

I would also add, that with end fed antennas and legal power, you are most likely going to have large issues with common mode junk and RF hot stuff in your shack, the closer the antenna the worse the issue. If I were you, I'd look into some sort of horizontal antenna to start, you may find you have a favorite band or two, especially in this atmosphere that we are experiencing. The AL80B is a great amp for the loot, especially used. And you can still use reasonable coax without breaking the bank. The difference between an 80B and full legal limit is a few dB, not worth the effort in my book. Just my 2 cents. Good luck with your dreams, I started with a DX40 and S38E with a 40M dipole if you can even imagine that. But the bands were good in the 60's.

Dave
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W9IQ
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« Reply #28 on: May 11, 2019, 03:53:43 PM »

Most of the claimed power specs by end fed antenna manufacturers are dubious to say the least.

The reason is they don't use a balun. The use an autotransformer - commonly called an unun in antenna parlance. If it were an effective current balun, the antenna performance would suffer greatly. I find it interesting that Danny didn't know the difference.

- Glenn W9IQ
« Last Edit: May 11, 2019, 04:03:11 PM by W9IQ » Logged

- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
AH7I
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« Reply #29 on: May 11, 2019, 04:40:11 PM »



The most important item not mentioned is what is your local noise floor. If the local noise floor is high your radio experience will be quiet frustrating. If you have a high noise floor this need to be address first. It will do you no good to have a great signal if you cannot hear the contact.

Good advice. Here at my in town Atlanta QTH, the noise level is pretty high. High enough that it is the rare station that I can hear who can't hear me.
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