HF Amplifier


Rodney Tanner
 

I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.


Dave Kjellquist, WB5NHL
 

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.


On 6/29/2021 9:09 AM, Rodney Tanner wrote:
I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.


-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555

--
Dave,  WB5NHL
Treasurer,  NABRC


KENT HUFFORD
 

The KPA500 COMBO is great, but$$..

A working A811 will work on 120vdc and do 500 watts.

Kent


From: WB5NHL <dave@...>
Sent: Tuesday, June 29, 2021, 11:24
To: nabrc@groups.io
Subject: Re: [nabrc] HF Amplifier

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.


On 6/29/2021 9:09 AM, Rodney Tanner wrote:
I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.


-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555

--
Dave,  WB5NHL
Treasurer,  NABRC


Rodney Tanner
 

Your right that a lot $$$$

On Tue, Jun 29, 2021 at 11:28 AM KENT HUFFORD <khufford@...> wrote:
The KPA500 COMBO is great, but$$..

A working A811 will work on 120vdc and do 500 watts.

Kent


From: WB5NHL <dave@...>
Sent: Tuesday, June 29, 2021, 11:24
To: nabrc@groups.io
Subject: Re: [nabrc] HF Amplifier

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.


On 6/29/2021 9:09 AM, Rodney Tanner wrote:
I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.


-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555

--
Dave,  WB5NHL
Treasurer,  NABRC



--
Rodney
WM4RT


James F. Boehner, MD
 

As an interesting story, while I was Director, I made two trips to ARRL/W1AW each year for the board meetings.  W1AW has multiple operating positions, but also has a small workshop.  The door was open, and I saw an Ameritron amp on the workbench. I asked Joe Carcia (caretaker of W1AW) what was going on.  He told me that the amp was inoperative, and that he couldn’t get a reply from Ameritron Tech Support.  I asked if they knew he was calling from W1AW.  He said they did.  I told him, “Joe, PUT IT IN QST!”  He did, and as soon as the issue was published, he was called by the CEO of Ameritron immediately, and they had a new amp sent out to him the next day.

 

I reminded him about this on my next visit, and he told me “good advice!”

 

I wish the rest of us could count on that degree of customer service.

 

’73 de JIM N2ZZ

 

 

 

From: nabrc@groups.io <nabrc@groups.io> On Behalf Of WB5NHL
Sent: Tuesday, June 29, 2021 11:24 AM
To: nabrc@groups.io
Subject: Re: [nabrc] HF Amplifier

 

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.

 

 

On 6/29/2021 9:09 AM, Rodney Tanner wrote:

I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.

 

-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555


--
Dave,  WB5NHL
Treasurer,  NABRC


Dave Kjellquist, WB5NHL
 

My final straw experience was trying to get a schematic for their power supply. The schematic on their web site clearly did NOT match my 10 year old ps. I was told they did NOT have a schematic or any documentation. I wasn't looking for spare parts just a schematic!

On Jun 29, 2021 2:53 PM, "James F. Boehner, MD via groups.io" <jboehner01@...> wrote:

As an interesting story, while I was Director, I made two trips to ARRL/W1AW each year for the board meetings.  W1AW has multiple operating positions, but also has a small workshop.  The door was open, and I saw an Ameritron amp on the workbench. I asked Joe Carcia (caretaker of W1AW) what was going on.  He told me that the amp was inoperative, and that he couldn’t get a reply from Ameritron Tech Support.  I asked if they knew he was calling from W1AW.  He said they did.  I told him, “Joe, PUT IT IN QST!”  He did, and as soon as the issue was published, he was called by the CEO of Ameritron immediately, and they had a new amp sent out to him the next day.

 

I reminded him about this on my next visit, and he told me “good advice!”

 

I wish the rest of us could count on that degree of customer service.

 

’73 de JIM N2ZZ

 

 

 

From: nabrc@groups.io <nabrc@groups.io> On Behalf Of WB5NHL
Sent: Tuesday, June 29, 2021 11:24 AM
To: nabrc@groups.io
Subject: Re: [nabrc] HF Amplifier

 

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.

 

 

On 6/29/2021 9:09 AM, Rodney Tanner wrote:

I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.

 

-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555


--
Dave,  WB5NHL
Treasurer,  NABRC



--
Dave,  WB5NHL
Treasurer,  NABRC


Carl Juvrud KP2L
 

Rodney,
Aren't you using a vertical antenna???  It might be better to buy the beam first.  Like a hexbeam that you could turn with a light duty rotor.
carl

On Tue, Jun 29, 2021 at 3:03 PM WB5NHL <dave@...> wrote:
My final straw experience was trying to get a schematic for their power supply. The schematic on their web site clearly did NOT match my 10 year old ps. I was told they did NOT have a schematic or any documentation. I wasn't looking for spare parts just a schematic!

On Jun 29, 2021 2:53 PM, "James F. Boehner, MD via groups.io" <jboehner01=yahoo.com@groups.io> wrote:

As an interesting story, while I was Director, I made two trips to ARRL/W1AW each year for the board meetings.  W1AW has multiple operating positions, but also has a small workshop.  The door was open, and I saw an Ameritron amp on the workbench. I asked Joe Carcia (caretaker of W1AW) what was going on.  He told me that the amp was inoperative, and that he couldn’t get a reply from Ameritron Tech Support.  I asked if they knew he was calling from W1AW.  He said they did.  I told him, “Joe, PUT IT IN QST!”  He did, and as soon as the issue was published, he was called by the CEO of Ameritron immediately, and they had a new amp sent out to him the next day.

 

I reminded him about this on my next visit, and he told me “good advice!”

 

I wish the rest of us could count on that degree of customer service.

 

’73 de JIM N2ZZ

 

 

 

From: nabrc@groups.io <nabrc@groups.io> On Behalf Of WB5NHL
Sent: Tuesday, June 29, 2021 11:24 AM
To: nabrc@groups.io
Subject: Re: [nabrc] HF Amplifier

 

One of the best is Elecraft KPA500 with KAT500 tuner    capable of 500 watts, loafing at 250.  Only drawback is $$$   My opinion is to stay away from Ameritron amps  I have had multiple bad experiences.

 

 

On 6/29/2021 9:09 AM, Rodney Tanner wrote:

I am looking for an amplifier to use with Icom 7300.
Need one that put out 250 watts. Any suggestion.

 

-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555


--
Dave,  WB5NHL
Treasurer,  NABRC



--
Dave,  WB5NHL
Treasurer,  NABRC


Kevan Nason
 

You likely have a good reason for wanting 250 watts maximum, but I'm having a hard time understanding why you are willing to spend so much money for such little power increase.  That is assuming you are using 100 watts now. Carl's suggestion of improving your antena seems a much better route -- whether it is to get a hex beam OR improving your vertical's performance. Especially since a hex beam would give you improvements on both transmit AND receive.

At the risk of stating the obvious... Going from 100 watts to 250 watts is basically a 3 dB improvement in your transmitted signal. That helps, but mostly only if you are chasing weaker signals like the DXers and Contesters do. Many newer rigs have S meter calibrations of 3 dB per S unit. Older rigs have 6 dB per S unit. Your desired amp will only give a 1/2 to 1 S unit increase in signal for the other guy. You won't make a lot more contacts with that little of an increase. Think of how little difference you see when someone calls you with an S5 signal and while they are talking you see the meter "jump" all the way up to S6. It just doesn't make much of a difference. Is that worth the money?  Not for me. And it's my experience from attending dozens of Field Days that most people just skip over those very weak signals where that one S unit improvement would make the difference. They just don't want to make the effort to dig the other station out of the noise. I'm not an FT8 guy, but I doubt it will mean a ton more contacts in that mode either.  You'd likely get much better performance from a Hex due to its directionality. True, a Hex doesn't do 40 or 80 meters, but the high bands are rapidly coming back. If you're looking at 40/80 then I would focus more on better low band antennas. In fact, that is the route I took here at my own station. By improving my 40/80/160 meter antennas I've seen a dramatic improvement in my ability to work stations -- without buying an amplifier.

Kevan N4XL



Dave Kjellquist, WB5NHL
 

Rodney;

Are you still using the Comet CHA-250B    Carl and Kevan are absolutely right as to where to spent your efforts.  An antenna other than the CHA-250B aka "antenna dummy load" would do wonders.  Even Comet, in there advertise, recognizes the CHA as mostly a radiating dummy load.

"Yes, some of the RF that enters the power feeding section is turned into heat rather than transmitted as RF, but that is one of the compromises needed to create a broad-band, low SWR, multi-band HF antenna with minimal visual impact."


The way they are able to create a broadband vertical is with a lossy transformer. In their "matching transformer" a very wide range impedance on the secondary is NOT accurately transformed to the primary thus maintaining the 50 ohm load.

One possible solution would be a Hustler 6BTV vertical. At Schofield middle school for SCR we used a Huster 6BTV with good success. Even with a very modest temporary ground system it did well. As a single aluminum pole the visual impact is minimal.  If necessary the Hustler can tilt mounted to hide it when not operating.  DX Engineering sells the 6BTV for $242.   



On 6/30/2021 7:19 AM, Kevan Nason wrote:
You likely have a good reason for wanting 250 watts maximum, but I'm having a hard time understanding why you are willing to spend so much money for such little power increase.  That is assuming you are using 100 watts now. Carl's suggestion of improving your antena seems a much better route -- whether it is to get a hex beam OR improving your vertical's performance. Especially since a hex beam would give you improvements on both transmit AND receive.

At the risk of stating the obvious... Going from 100 watts to 250 watts is basically a 3 dB improvement in your transmitted signal. That helps, but mostly only if you are chasing weaker signals like the DXers and Contesters do. Many newer rigs have S meter calibrations of 3 dB per S unit. Older rigs have 6 dB per S unit. Your desired amp will only give a 1/2 to 1 S unit increase in signal for the other guy. You won't make a lot more contacts with that little of an increase. Think of how little difference you see when someone calls you with an S5 signal and while they are talking you see the meter "jump" all the way up to S6. It just doesn't make much of a difference. Is that worth the money?  Not for me. And it's my experience from attending dozens of Field Days that most people just skip over those very weak signals where that one S unit improvement would make the difference. They just don't want to make the effort to dig the other station out of the noise. I'm not an FT8 guy, but I doubt it will mean a ton more contacts in that mode either.  You'd likely get much better performance from a Hex due to its directionality. True, a Hex doesn't do 40 or 80 meters, but the high bands are rapidly coming back. If you're looking at 40/80 then I would focus more on better low band antennas. In fact, that is the route I took here at my own station. By improving my 40/80/160 meter antennas I've seen a dramatic improvement in my ability to work stations -- without buying an amplifier.

Kevan N4XL



-- 
Dave, WB5NHL
8BDXCC, 314 countries confirmed (mixed current)
Hamshack Hotline x5555

--
Dave,  WB5NHL
Treasurer,  NABRC


Rodney Tanner
 

I have a Comet CHA-250B limited yard space. Antenna max power is 250 SSB.
Wish I had 40 foot tower that way I could my antenna above the 35 foot in the instructions
See attached instruction sheet.


On Wed, Jun 30, 2021 at 7:20 AM Kevan Nason <knason00@...> wrote:
You likely have a good reason for wanting 250 watts maximum, but I'm having a hard time understanding why you are willing to spend so much money for such little power increase.  That is assuming you are using 100 watts now. Carl's suggestion of improving your antena seems a much better route -- whether it is to get a hex beam OR improving your vertical's performance. Especially since a hex beam would give you improvements on both transmit AND receive.

At the risk of stating the obvious... Going from 100 watts to 250 watts is basically a 3 dB improvement in your transmitted signal. That helps, but mostly only if you are chasing weaker signals like the DXers and Contesters do. Many newer rigs have S meter calibrations of 3 dB per S unit. Older rigs have 6 dB per S unit. Your desired amp will only give a 1/2 to 1 S unit increase in signal for the other guy. You won't make a lot more contacts with that little of an increase. Think of how little difference you see when someone calls you with an S5 signal and while they are talking you see the meter "jump" all the way up to S6. It just doesn't make much of a difference. Is that worth the money?  Not for me. And it's my experience from attending dozens of Field Days that most people just skip over those very weak signals where that one S unit improvement would make the difference. They just don't want to make the effort to dig the other station out of the noise. I'm not an FT8 guy, but I doubt it will mean a ton more contacts in that mode either.  You'd likely get much better performance from a Hex due to its directionality. True, a Hex doesn't do 40 or 80 meters, but the high bands are rapidly coming back. If you're looking at 40/80 then I would focus more on better low band antennas. In fact, that is the route I took here at my own station. By improving my 40/80/160 meter antennas I've seen a dramatic improvement in my ability to work stations -- without buying an amplifier.

Kevan N4XL




--
Rodney
WM4RT


Rodney Tanner
 

Nice antenna. I do not believe I have room for ground radials in my backyard.
If I got one I would need help getting it assembled and put up.
I am on oxygen 24/7 plus I had joint replacement on my shoulder probably be in therapy
to the end of the year.
I have made 8327 QSO and 7231 QSL on my antenna I am using


On Wed, Jun 30, 2021 at 8:45 AM Rodney Tanner via groups.io <wm4rt.hamradio=gmail.com@groups.io> wrote:
I have a Comet CHA-250B limited yard space. Antenna max power is 250 SSB.
Wish I had 40 foot tower that way I could my antenna above the 35 foot in the instructions
See attached instruction sheet.


On Wed, Jun 30, 2021 at 7:20 AM Kevan Nason <knason00@...> wrote:
You likely have a good reason for wanting 250 watts maximum, but I'm having a hard time understanding why you are willing to spend so much money for such little power increase.  That is assuming you are using 100 watts now. Carl's suggestion of improving your antena seems a much better route -- whether it is to get a hex beam OR improving your vertical's performance. Especially since a hex beam would give you improvements on both transmit AND receive.

At the risk of stating the obvious... Going from 100 watts to 250 watts is basically a 3 dB improvement in your transmitted signal. That helps, but mostly only if you are chasing weaker signals like the DXers and Contesters do. Many newer rigs have S meter calibrations of 3 dB per S unit. Older rigs have 6 dB per S unit. Your desired amp will only give a 1/2 to 1 S unit increase in signal for the other guy. You won't make a lot more contacts with that little of an increase. Think of how little difference you see when someone calls you with an S5 signal and while they are talking you see the meter "jump" all the way up to S6. It just doesn't make much of a difference. Is that worth the money?  Not for me. And it's my experience from attending dozens of Field Days that most people just skip over those very weak signals where that one S unit improvement would make the difference. They just don't want to make the effort to dig the other station out of the noise. I'm not an FT8 guy, but I doubt it will mean a ton more contacts in that mode either.  You'd likely get much better performance from a Hex due to its directionality. True, a Hex doesn't do 40 or 80 meters, but the high bands are rapidly coming back. If you're looking at 40/80 then I would focus more on better low band antennas. In fact, that is the route I took here at my own station. By improving my 40/80/160 meter antennas I've seen a dramatic improvement in my ability to work stations -- without buying an amplifier.

Kevan N4XL




--
Rodney
WM4RT


Kevan Nason
 

On Wed, Jun 30, 2021, 9:42 AM Rodney Tanner <wm4rt.hamradio@...> wrote:
Nice antenna. I do not believe I have room for ground radials in my backyard.
If I got one I would need help getting it assembled and put up.
I am on oxygen 24/7 plus I had joint replacement on my shoulder probably be in therapy
to the end of the year.
I have made 8327 QSO and 7231 QSL on my antenna I am using

Many people like the antenna you have, Rodney. I've used one not too different from yours, an R5, and was happy with it. I was in Rhode Island next to a salt marsh. However, it seems to me that since you are thinking of an amplifier you must be somewhat unhappy with its performance. It's your station and your money, I just don't think an amplifier is going to make you happy. Every antenna is a compromise to some degree. I've got fairly decent antennas now, but am unhappy with some aspects of their performance too. There is no doubt in my R5 experienced mind that the people who designed the Comet made some compromises that aren't serving you as well as you would like. 

I've given a presentation of my low band antenna journey to several groups, including one in England. The Deep Dixie Contest Club recorded it. A link is below. It sounds like you don't have the room I do. Fine. The presentation is really about understanding how verticals work and understanding how your choices affect its performance. Maybe you won't find a lot of it interesting. If you don't want to watch the whole thing, but you might find some points interesting in regards to your current situation. Of particular note is minute 42 which shows you might very well have room in your backyard for a 6BTV with radials.
- Minute 20 talks about measured comparisons of a 6BTV vertical to several other verticals. Although the Comet 250b isn’t shown, it is in the same category as a couple radial less verticals that are shown.
- Minute 42 talks about how ground radials do not need to be ¼ wave length long and gives guidance on how many to use.
- Minute 27 talks about how SWR doesn’t mean much in regards to antenna efficiency. It gives an example of how one antenna showing an SWR of 1.4:1 still puts 96 out of 100 watts into the dirt instead of into the air.
- Minute 16 discusses losses in antenna tuners.

I've put that same R5 up when inland away from the ocean. Up at 30 ft like they say. As compared to the better designed antennas I now use it doesn't work very well there either. I did buy another one, but I'll only use it for portable and/or emergency operations now.

Hope that helps to get you thinking. 

Kevan N4XL