Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: Prev 1 2 3 4 5 [6] 7 8 9 10 11 12 Next   Go Down
  Print  
Author Topic: Which amp to start with?  (Read 46818 times)
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #75 on: January 20, 2017, 06:16:41 PM »

That said, I would chose an AL-80B (or AL-572) over an SB-200.  Mainly because the AL-80B is in production and full manufacturer support is available.  It is a modern design, and works properly with modern transceivers.

Most SB200's in use today have had a soft key mod to use with modern rigs and if not it is easy to add mod. As far as in production vs not is not as important as quality and if SB200's were not a good quality and reliable unit they would not still be in use 40 years later. I have a stock SB200 that I use as a backup that is still very tight and tunes nicely. I have parts to upgrade power supply and add soft key when I get around to it.

I recommend new amp users buy current production models mainly so that any oppsie moments can be sorted out with the minimum of fuss - there is always the factory to send the amp back to if you can't repair it yourself.

We don't see many Heathkits in VK.  A SB-1000 came up for sale last year but I didn't have the money at the time to buy it.  Really like the look of the SB-1000.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
W8JX
Member

Posts: 13268




Ignore
« Reply #76 on: January 20, 2017, 06:23:39 PM »

I recommend new amp users buy current production models mainly so that any oppsie moments can be sorted out with the minimum of fuss - there is always the factory to send the amp back to if you can't repair it yourself.

Well new and cheaply built (like AL811 series) is more likely to need repair than old and properly built.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #77 on: January 20, 2017, 06:30:16 PM »

I recommend new amp users buy current production models mainly so that any oppsie moments can be sorted out with the minimum of fuss - there is always the factory to send the amp back to if you can't repair it yourself.

Well new and cheaply built (like AL811 series) is more likely to need repair than old and properly built.

Yes, a good second hand AL-80B is likely the best option for a beginner.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
W8JX
Member

Posts: 13268




Ignore
« Reply #78 on: January 20, 2017, 06:34:52 PM »

I recommend new amp users buy current production models mainly so that any oppsie moments can be sorted out with the minimum of fuss - there is always the factory to send the amp back to if you can't repair it yourself.

Well new and cheaply built (like AL811 series) is more likely to need repair than old and properly built.

Yes, a good second hand AL-80B is likely the best option for a beginner.

Maybe not best but close to it.  A SB200 that has been gone throw and freshened is still a good choice for a 500+ watt amp.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #79 on: January 20, 2017, 10:16:51 PM »

Maybe not best but close to it.  A SB200 that has been gone throw and freshened is still a good choice for a 500+ watt amp.

A single 3-500ZG is better than 2x 572Bs though.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
W8JX
Member

Posts: 13268




Ignore
« Reply #80 on: January 21, 2017, 03:39:02 AM »

Maybe not best but close to it.  A SB200 that has been gone throw and freshened is still a good choice for a 500+ watt amp.
A single 3-500ZG is better than 2x 572Bs though.

Not always. Good 572's are just as rugged just less power potenail and a pair is cheaper than a single 3-500 too. A 3-500z is a good tube it is just not really cooled properly in many amps using it to fully exploit its ratings. Strangely Ameritron cools it properly in AL82 but not in AL80
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
KB1SNJ
Member

Posts: 139




Ignore
« Reply #81 on: January 21, 2017, 02:02:30 PM »

UPDATE" re: the choke, didnt do a thing.

Made choke #1 per this chart  http://www.karinya.net/g3txq/chokes/ and keyed up on 80M, jammed my monitor hard as always, knocked it off line. Also had the buzzing in the mixer/headphones.

The picture shown is just outside the window. maybe 8ft away from the actual radio gear.

Not sure what to conclude. maybe the RF is from the antenna itself and there is no CM coming back now? Not sure how to tell the difference.

20170121_164734 by Chris P, on Flickr
Logged
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #82 on: January 21, 2017, 05:35:16 PM »

On the plus side, the choke looks well made Smiley

I'd suggest the 'ground' side of your antenna is woefully inadequate.  You can't use a single thin wire from the antenna ground point to a bunch of radials, you have to connect each and every radial to the antenna (in this case balun) base.

I'd attach another 6-7 wires.  They don't have to be massively long or anything, just as long as you can make them, and rest them on whatever ground you have.

Then try again Smiley

Edit: also what is that loop of grey cable?  Get that sitting on the ground, it is probably acting as an antenna and bringing RF back into the shack.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #83 on: January 21, 2017, 05:40:09 PM »

Not always. Good 572's are just as rugged just less power potenail and a pair is cheaper than a single 3-500 too. A 3-500z is a good tube it is just not really cooled properly in many amps using it to fully exploit its ratings. Strangely Ameritron cools it properly in AL82 but not in AL80

I hope you're right.  I enjoy my AL-572 very much, but if it chews through tubes even half as quick as my AL-811 did I'll be chasing an AL-80B pronto.

Truth be told I don't push the AL-572 anywhere near as hard as I did the AL-811.  Our power limit here is only 400 Watts PEP.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #84 on: January 21, 2017, 05:43:14 PM »

Also thinking about it Chris:

Try this:

1) Bury / place on ground any excess feed line.
2) Connect the feed line to your 1:1 Balun
3) Connect your radials to the "cold" antenna side of the 1:1 balun, making sure the feed line is LOWER than the radials.  Run many radials from the 1:1 balun antenna side.

4) Connect your antenna element to the "hot" side of the 1:1 Balun.


See how the system works like that.
Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
KB1SNJ
Member

Posts: 139




Ignore
« Reply #85 on: January 21, 2017, 06:56:40 PM »

thanks for the words, the coiled gray coax is excess feedline, there's a little more below as well.  The "alley" between the house and fence has a radial on the ground going away from the camera about 20ft, there is about a 10ft radial behind the camera before it stops at the rear fence. I can only go to the left of the camera as a 3rd direction and that goes 40ft. (Theres a diagram of the property and house back a couple pages).

The rear of the property is 40ft wide and I can probably put is support post at each corner sticking up 15ft or so. That would put the broadside toward west which I need.

several have made small lot antenna suggestions. It will be a hassle but putting up some poles and trying different things may be the only answer.

I really thought a 50ft vertical wire would have great potential. It does work, but I guess not so much.
Logged
VK3BL
Member

Posts: 1790


WWW

Ignore
« Reply #86 on: January 22, 2017, 04:05:30 AM »

I really thought a 50ft vertical wire would have great potential. It does work, but I guess not so much.

It might very well do with a bit of tweaking.  50ft might be a bit on the long side - a 43ft element may work a little better depending on frequency etc.  I note 43ft verticals are a popular length.

I would say if you dumped the excess feed line on the ground rather than up near the current maximum of your radiator (the feed point) you'd do a lot better.  Sitting where it is it is just asking to soak up RF, and its AFTER the current choke too so its going to get RF hot.

In fact, I just recently had my audio go terrible because my 2M feed line had been wrapped around my HF feed line a few times, and was bringing RF into the shack.

Feed lines - you have to be careful with them! Smiley

Logged

J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
W8JX
Member

Posts: 13268




Ignore
« Reply #87 on: January 22, 2017, 04:14:11 AM »

Not always. Good 572's are just as rugged just less power potenail and a pair is cheaper than a single 3-500 too. A 3-500z is a good tube it is just not really cooled properly in many amps using it to fully exploit its ratings. Strangely Ameritron cools it properly in AL82 but not in AL80

I hope you're right.  I enjoy my AL-572 very much, but if it chews through tubes even half as quick as my AL-811 did I'll be chasing an AL-80B pronto.

Truth be told I don't push the AL-572 anywhere near as hard as I did the AL-811.  Our power limit here is only 400 Watts PEP.

I think a weakness in AL-572 is cooling. Ameritron tends to focus more on quiet than cooling on its amps in that class. My Dentron has a very aggressive/noisy fan that I reversed to suck air out over 20 years ago and it keeps case cool to touch even after hours of use. (before I reversed it amp got pretty hot to touch after usage)
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
W8JX
Member

Posts: 13268




Ignore
« Reply #88 on: January 22, 2017, 04:18:15 AM »

It might very well do with a bit of tweaking.  50ft might be a bit on the long side - a 43ft element may work a little better depending on frequency etc.  I note 43ft verticals are a popular length.

If you run 80 and 160 the extra length can help a bit but if you run mostly 40 and higher, a 33 footer will play better.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
AC2RY
Member

Posts: 755




Ignore
« Reply #89 on: January 22, 2017, 01:33:36 PM »

UPDATE" re: the choke, didnt do a thing.

Made choke #1 per this chart  http://www.karinya.net/g3txq/chokes/ and keyed up on 80M, jammed my monitor hard as always, knocked it off line. Also had the buzzing in the mixer/headphones.

The picture shown is just outside the window. maybe 8ft away from the actual radio gear.

Not sure what to conclude. maybe the RF is from the antenna itself and there is no CM coming back now? Not sure how to tell the difference.

20170121_164734 by Chris P, on Flickr

You didn't mention is you have any tuner. With non-resonant antennas like yours you must have a wide band tuner. Do you have antenna analyzer? What is your SWR range on bands you plan to use? Considering that you cannot have enough radials, it is almost a must to have tuner at antenna feed point. Another problem is that antenna is too close to house. This is not only problem on transmit, but receive too. What is your average noise level on 20 and 40m? As was mentioned above, amplifier is the last thing to put in. Even if you get an amplifier, you will need a wide band tuner to use it with most multiband antennas. And this tuner can be expensive for 1000W power.

Logged
Pages: Prev 1 2 3 4 5 [6] 7 8 9 10 11 12 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!