UPDATE -

I placed the set into a prototype cabinet so that I do not unnecessarily drill several holes into my 'new' case which is it's intended destination.

1.  Thank you ALL for excellent advice.  Tough I am a very experienced builder and moderately successful amateur designer,  is my first high powered amplifier, so it's good learning experience.

2.  Reading through some of the less exciting text in the application notes, there was a little gem about keeping the input and output coax cables as far apart as possible.  This made a terrific difference in stability, allowing a few successful tests at full power. I have a VERY small ham 'nook' and keeping wires apart at QRP levels in unnecessary - at 140Watts, with maybe a little stray RF... problem.

3.  to: WB8VLC:  All ver useful information - thank you. The transistors are Motorola and I've been VERY careful with the through hole leads on the bottom side near the heatsink and actually lightly sanded them before final assembly all for JUST THE REASON YOU MENTIONED - potential for arcing from pointed leads. I am leery of so much gain in a single stage... but I'm a very conservative old school guy when it comes to design and we used to sat 10dB or maybe 13dB max in a single stage RF amp for fear of feedback, but I was third-string in such things  - at best! ha ha

The power is good, the amp is quite usable except for these spurious signals on my SDR up and down the band when I use the amp into the dummy load.  I did hat it on the air, but the SWR meter indicated multiple peaks, which told me that I had multi-frequency emissions wide enough to dull my normally sharp tuning peak! Dummy load testing revealed the spurs.  Suspecting my switching PS might have super imposed these waveforms into  the am at load, I swapped to a large analog PS: no change...

It appears that the amp itself is generating spurs.

We're close to being able to put this puppy on the air once these spurs are eliminated and when I have time, I'll do some experiments to determine whether a resistive input might help.  The negative feedback is very much on my mind //tnx ZS4L//

I'll CONFIRM and if necessary retrofit more through board ground plane through wires, especially on the emitter pads.

Now all that I need it time and a little more application of these excellent insights. I am also considering an in-box separation plate, to try to give a good path for srtay RF/currents back to ground, rather than finding entrance (line of sight) back into the input.



73 de Ray
W7asa ..._ ._

KD8GTP blethered: "As you defend the wacker we can only assume you are one."[/b]

Hmmmm, not much for rational thought - are you?   Practice: you'll eventually get the hang of it.

There ARE widely differing views here and though the participants in most of this discussion use humor at times or hyperbole, in general their points are well presented & defended.  It's OK to disagree, in fact it's great fuel for thought and personal growth. We can't help but notice that you've not even attempted to answer or introduce any factual aspects for this discussion: not a single one.  You add nothing, yet spew tripe. What an abysmal waste of life. What your poor wife must have to endure can only be imagined.

de Ray
W7ASA ..._ ._

K8GTP Says:  "  I was ashamed to have a 2m antenna on my car ..."   

Give the entire car to charity.  How can you stand the shame of driving a car, when whackers also drive them?

-...-

Perhaps the well spoken point of KF7CG needs to be restated:

He said that the State of Tennessee had issued ham callsign plates with the word "EMERGENCY" in place of county.  It is not something which the ham put on the plate.  The request was made to the State office for vehicle registration for  callsign plates; a perfectly normal thing which many hams request. The State put the word EMERGENCY there. Perhaps you should protest to the State of Tennessee - assuming that you are willing to actually take personal action on anything. 

Creating a strawman argument of 'whackers' (I've seen one in over 40 years of ham) as grounds to avoid community service is silly.  You're illusory 'whackers' drive cars - so will you refuse to drive a car?  They probably had dental filing too -- shall you go to the garage, get out the Vice-Grip pliers and remove your fillings?  You choose.  All ham radio operators are under a body of regulations called: "Part 97 The Amateur Radio Service." I wonder why they have STILL not caught their mistake of calling it a 'service'? That fact that we can enjoy it as a hobby is a perk, which I am grateful for.  Additionally ham radio is also a powerful tool if needed, which it often is in many parts of the world.


de Ray
W7ASA ..._ ._

KO3D says: " The EMCOMM push is a marketing scheme to increase ARRL membership rolls."

Naturally - there could be no other conclusion.

 " ...repeaters in my area sit silent for most of the day. I surmise that most of these new "hams" are people who were signed up by their employers. "

Naturally - there could be no other conclusion. Your evidence for this statement is that you do not hear them on your area repeaters, therefore they must be hams on the pay-roll of some company.  Hmmmm , there must be a lot of these new/company paid hams in my area too, because I don't hear them either, or perhaps they're penguins or lions, because I have not heard any of those either.
 I did hear a kookaburra once on the radio, but that was in California - and you know Californians.   


It's a shame for you that there is no Olympic gold medal for 'jumping to conclusions'.  This is gold medal material       



>de Ray

This amp was completed last week.  I am STRONGLY suspecting RF feedback at this point.  I can often hold an entire sked with no RF hash.  Because it's still my prototype, it's not fully enclosed and the cables are often in different positions. Bias checks before the 'smoke test' were uniform and well within spec.  The power transistors -when operating normally- are not hot, even after long skeds (no hash). Warm - as normal.

I'm a big fan of resistive input networks for this reason. I'd rather have a little less gain, but better stability.  I'll do some calcs on a good resistive pad and likely add that as well.  

I do NOT see this as a design or other fault from CCI.  Their materials, board and etc. have been quite good.

I do believe that it's RF feedback, occasionally causing the amp to oscillate. I have power off as soon as I hear it in the RX (and believe me I hear it and the SWR meters show it). so it's only done this for a few 1 second bursts since I built it.

I wanted to pass this idea by the fellows here for a 'sanity check'.

I do agree, better enclosure, bonding the entire station and accessories together and GROUNDING the station more effectively.  All things I should have done anyway.

I'll take it from here and post my findings in a week or two after testing.


Thanks!

73 de Ray
W7ASA ..._ ._


Ps.  Sssssh! I'm a QRP'er, so DON'T let this get around about me building a 140 Watt AMPLIFIER!!!    

Yes - it is generating high power, broad spectrum RF hash.  Mean power output is roughly the same as when it's operating properly.  However, when the RF hash begins, the SWR goes through the roof. 


Thank You for Asking,


Ray

Oh man!  It sounds like an RF version of "The People of WalMart". Evidently, I'm just fortunate in not having to deal with that sort of thing.


73 de Ray
W7ASA ..._ ._

This is a great discussion. I've learned much from K8VUL's postings as well as K1CJS and the others.  Because the ideas here are often different & the concerns  which some hams / pros have had direct contact with in their regions seem almost 'foreign' here in my rural location, that makes it very good food for thought. While we in this discussion may disagree with each other's conclusions, the discussion itself is very good. Our volunteer communications team here enjoys a very close relationship with county emergency services, so VUL's posting about the union angle / volunteers -v- union wage never (and I mean NEVER) entered my mind. I am SO glad that we don't have that problem. That must be a very tough impediment to planning.

OTOH - I'm grateful that I've never seen those wanna-be guys with light bars and tactical vests, spare batteries in magazine pouches and maybe some face paint.     ( I take that back - I once saw a 19 year old in Colorado during Y2K, who had "ARES" magnetic signs and orange lights on his mother's car... :^)  but that was only one young zealot in 13 years.

Seriously:  Are you fellows out there seeing many hams like this?  //Maybe a new topic can be generated "Whacker Sightings"  ??    



73 de Ray
W7ASA ..._ ._

 

GTP DE ASA

BT

You're probably just a lonely guy looking for attention.  OK - you had it.
 
Words mean things.  Most people believe that if they can genuinely help someone in a disaster, that they should.  Evidently, so does the FCC, though they do not force us to do so.   They call it: Part 97 - The Amateur Radio Service .  Just because we enjoy it, does not mean that it's not a powerful tool when used properly.

BT
AR SK  

Hajime Maste, Tanaka-san,

I will take a look at the bypass capacitors as you pointed-out and also likely upgrade the ferrites I have on the DC power leads.

>>> I like the CCI amplifier and at some future date, might build another one of different power.




>Ray

A question for those you who might have some experience with this problem.  I just built my EB63A from Communications Concepts Inc (CCI).  It's a good experience building from their kitted materials. this amplifier takes my signal from QRP levels to over 100 Watts easily. I am operating using the standard CCI output filter for 20 meters and really having a good time with my -now- high powered home brew CW station. 

Here is the 'difficulty':  Occasionally, the amplifier begins to generate RF 'hash' - that is white noise. I hear is between dits while sending, and immediately kill power (no harm to the amp so far). 

Here is my best thought:  The RF HASH is bale to continue (until I hit the power switch - as fast as I can) after the exciter signal stops.  Because it continues after keu UP (no signal) from teh exciter, it is not the 'exciter'.  The occurrance of RF haSH increases with drive level/output power. The input to this amplifier has NO resistive pad, but only an L/C formed by the input to the first binocular transformer at the input. 

I believe that this is caused by RF feedback. What are your thoughts?



73 de Ray ..._ ._
W7ASA 

I've done decades of QRP comms, often over long paths and for personal as well as professional 'occasions'.  I'm quite familiar with military manpacks, though unlike Mr Z,  I virtually always used efficient antennas, such as the dipole for NVIS through medium range and -yes- a wire halfsquare for long range.

For this transceiver, the math of system gain -v- power show that an increase from this rig's designed output of 5 watts to 20 Watts is only one s-unit at the receiving station, but would significantly change it's size, weight and power consumption for only one s-unit - at best.  That's basically nada for all that increased consumption, size and weight. Personally, I can't see a reason to complain that this is not a 20 Watt rig. If they DO indeed build a different rig at 20 Watts, well then that's GREAT! What's not to like about more cool rigs to choose from?

Small, lite & portable are great attributes for a rig like this. The niche market needs more - this I agree with.  I do DISagree with Z in his recurring idea that 20-25 Watts is necessary for fieldable ham QRP rigs such as this one and the KX-3, which he also has strange issues with. I would highly recommend re-reading his posts re: the KX-3 and then compare that with his statements here, to see the same feelings at work. Interestingly, the math remains constant and still DISagrees with his feelings.

Let's do a little math here:

For a rise from 5 to 20 Watts, we can expect at least the following increase:

 
+Size of the rig due to slightly more circuitry, larger batteries and especially a larger heat sink.
+Weight (see above)
+Power consumption (4 times more power consumed & DISSIPATED on transmit)
+Likely also a change of battery type, due to the need for much higher instantaneous current for voice peaks and etc.
+A much larger heat sink to dissipate the 4x power.
+Higher cost
+Larger recharging system, or 4x longer recharging time.

And reduce the:

Portability
Length of transmit time using batteries.

- and much more.

All this to gain just one S-unit on the receiving end: basically nada.

We had similar discussions on the KX-3 postings.  The math never changed. dB are still dB and four times higher power output in the same class of amplifier operation requires at least 4x more heat sink and battery, as a rule of thumb.  


As for manpack radios - they're FUN for hams, heavy as a box of lead for soldiers and I like them! Carrying one along with a normal backpacking load of shelter, food, water and spare knickers on a camping trip as a civilian is not my idea of fun.  Been there & done that back when I was younger, stronger and thought that a mil rig was the coolest thing since sliced bread.


Feelings vary.  Math does not.


My 2 cents worth. Please adjust for hyper-inflation.


73 de Ray
W7ASA ..._ ._

CJS - That was well stated.

I'll keep this brief (rather than my USUAL manner - ha ha)

As you pointed out, the matter of whether or not what hams can do is needful, is absolutely the key point.  If we are not needed, then let's keep out of the way. 

If we are needed, but the bureaucrats will not admit or simply don't know it, that's a bit more difficult, but we hams cannot win a political decision like that. We'd better get used to that fact and either work through an NGO's or local neighbors . We have no 'throw weight' in political decisions.

I am fortunate to live in an area that is not badge heavy; the county and NGO's are pleased to have communications volunteers in place BEFORE needed. 

I appreciated your thoughtful post.


73 de Ray
W7ASA ..._ ._

This is a global forum.  Your blanket statements from your very narrow slice of Ohio (or wherever) where you pontificate about how ham is not useful for EMCOMM for the rest of the real world is short-sighted at best.  

Opinions are common, thoughts from a reasonable person are food for thought.   However, actual events clearly demonstrate that your most recent all-or-nothing / blanket statement that ham radio and ham radio operators can bring nothing to pubic service which is not already there is not really supportable.  You clearly know that hams around the globe routinely serve when the standard communications service sector employees and their appliances (good or bad) are overwhelmed and/or prove to be insufficient for the needs & etc.  This happens regularly in hurricanes, floods, tsunamis, earthquakes and more around the world for both governments and major NGOs. Hams assist and oftimes are the ONLY information source into and out of ravaged regions until government and NGO resources can be mobilized, inserted and activated in the troubled areas. Their (govt & NGO) deployments are often initially coordinated with ham radio operators in the region of the disturbance. As you know, the more widespread the damage, the longer that any governmental asistance will require to help anyone. // Thus reinforcing my experience that politicians are generally slow to serve, but quick to steal.  ;^)  //

Those of us who do help are growing weary of hearing those who won't even try, telling us that we can't.


73 de Ray
W7ASA ..._ ._

The lack of domestic shortwave was because of the terrible policy of forbidding American broadcasters to use shortwave to reach a domestic audience - by regulation.  This was done waaaaay back in the beginning of US domestic broadcasting for profit, to give the networks a defacto monopoly.  What a shame.  This is such a large continent that continental broadcasting on shortwave a la Europe and Asia would have been a tremendous boon for the people - rather than for the few short range AM/FM stations in the network matrix. At present, many domestic shortwave stations are -cough cough- 'international', and in fact this is true, in that they can be heard internationally.  However, even for these stations, shortwave radio listeners are still pretty rare in the USA, compared to those who know no better than to listen to the usual rubbish on the AM/FM dial.

When I had shortwave in the car, I used to listen to it.  Now that I have a different car - I rarely have the radio on at all. It's a puppet show - and I get the feeling that WE'RE the puppets.  IMHO


73 de Ray
W7ASA ..._ ._

Very very fortunate here. Our local team of communications volunteers have been very well received through the years.  The reasons are probably manifold, beginning with Southern hospitality, but the basics here are that we live in a remote area, do not have the big city budgets, manners are important and we hams assist primarily with 'back-channel' communications, so that the main fire/rescue/police channels are not over-run with shelter, lower level admin and other communications when normal infrastructure is impaired or overwhelmed. Though we do occasionally pass a piece of official 'gummit' traffic, that is rare enough to be appreciated.  When internet dies, we really shine because of our WINLINK HF capability.  We hams have been able to supply storm track information & official forecasts during hurricanes and other useful information, of which our local friends in uniform who are planning their response have only the single source: internet. We've also been able to keep our remote counties in touch with each other & their higher eschelon people in Richmond & etc. during loss of infractructure, which is common during hurricanes. In general - we can take some of the load off of those very busy people.

I do disagree with the assertion that a guy who is provided with an HT,  a mobile and an MDT somehow makes is a 'EMCOMM professional'.  They would be an 'end user' and it's not even remotely reasonable to expect them to improvise power, antennas, mics, or modify their comms gear to send/receive data and imagery, because they are generally busy doing the things which we pay them do to - not fiddle with radios.  Their radios and data terminal are tools in the box, used hard and the goal is to have them understand these tools at the operator's level - which is how it should be. I know how to use a hammer to drive nails, but am not required to be a metalurgist or a blacksmith. The rub occurs when things are not working and/or overwhelmed by unusual & widespread circumstances.   Buddies of mine who are badged AND are skilled hams see this first hand all the time.  (you know who you are...). In my past, I routinely had to correct some otherwise talented people who hold an HT upside down, with the rubber duckie running down the inside of their forearm because they saw it on TV and they want to look 'professional', not realizing that the flesh in their forearm is absorbing RF energy and the antenna works much better when vertical and in the clear: some were PhD's other's were in uniforms of various countries.

We volunteers who provide surge communications capabilty in this rural area don't pretend to kick in doors and point weapons. Perhaps that is common behavior in other areas of the country, but I don't keep-up with what's fashionable elsewhere.   ;^)    A team - by definition is a coordination of effort among people with various talents.  Communication makes beneficial coordination all the more likely. That's what we're here to do for our neighbors.



73 de Ray
W7ASA  ..._ ._