Amps for 1500 from ebay

Marty Bluhm

I am looking at adding an amp to my 1500 for when going gets rough. I've seen a lot of amps on ebay for the kx3,703, etc. Has anyone used one of these with the 1500 and what was the outcome?
Thanks and 73
Marty
W8AKS

Richard McClelland, AA5S

I'm using an RM Italy amp with my 1500.  It's ok but an Elecraft KPXA100 would be much nicer (possibility of a built in tuner & covers 6 meters).  There are a lot of people using a 50 watt kit, I've forgotten the name at the moment, but the reports are good.  The now defunct Tokyo Hi-Power company used to produce a 45 watt amp but they are out of business and some have reported that they've inadvertently destroyed theirs when paired with a 1500.  I'd check on that before pursuing the Tokyo Hi-Power. 

Daphne g7ena

I use a Chinese MX-P50M from eBay. I get good signal reports and the output is fairly clean, you just have to remember to change bands manually. To key the amp I use a home brew interface using a relay, plugged into the Flexwire socket.

73

Daphne G7ENA

John

depends what power you want to run. There are some good solid state amps out there which will give you 50w + output. If you want to run full legal limit, then you would have to choose a amp with tubes which has high gain, but 5w to 1500w is HIGH GAIN.

James Whiteway

http://www.w8ji.com/rm_hla-150_test.htm
Read this article before you purchase a RM Italy amp.
It has known, proven, IMD issues. Couple that with the 1500 that also has IMD problems at 5 watts, and you'll have more problems. There are cleaner amps and SDR radios out there. The issue with the 1500 can be controlled by running less power.(3 watts or less)
Better to get a good amp like a TenTec or get a Flex 3000. 100 clean watts. Good signal reports don't tell you if you're radiating spurious signals up and down the band from your signal. Only a spectrum analyzer will show that. Be a good neighbor and try to transmit as clean a signal as you can.
James
WD5GWY

Daphne g7ena

A couple of links to a review and some test results:

https://vk2qr.wordpress.com/2014/11/25/mx-p50m-hf-amplifier-review/

http://gm4slv-geek.blogspot.co.uk/2015/03/mx-p50m-amplifier-for-ft817.html

73
Daphne

Jim Veatch

Hi,

The 50W kit is the Hardrock-50. more info here:

http://www.hobbypcb.com/products/hardrock-50-hf-power-amp

160-6m, 50W with less than 5W drive, built-in tuner available, FCC Type Accepted, USB connection supported in PowerSDR for automatic band switching. Responsive USA support team.

It's also a good physical match for the 1500 since it's the same width and if the rubber feet are in the right places it'll sit nicely atop the Flex.

I'll be happy to answer any questions that you might have.

73,
Jim WA2EUJ

Richard McClelland, AA5S

Regarding the IMD issues, these can largely be alleviated by running on the lower power setting of the amplifier.  I believe this topic is outlined in the document James refers to above.  This provides about 40 to 50 watts out which I've found to be quite adequate.  Perhaps the best point about the RM Italy amplifiers is that they are quite inexpensive on eBay.  Clearly there are other 100 watt amplifiers of better quality available; most notably, the Ten Tec and the Elecraft units.

Richard McClelland, AA5S

This might be an interesting amplifier.  $229 is more than a used RM Italy HLA-150 but perhaps the IMD performance is better.   On the other hand, an Elecraft KPA500 would put out 175 watts with 5 watts in and that would be a rather significant boost.  The comments made elsewhere about the 1500's lackluster IMD performance might make one consider whether such a choice would lead to QRM on the bands.  But expanding one's horizons like this leads to a consideration of the possibility of a very clean 12 watt Flex 6100 which might or might not be introduced. Personally, I would wait a few months to see if such a device is forthcoming then make an amplifier choice after seeing what's up next on the Flex stage.

Richard McClelland, AA5S

12 watts into a KPA500 would produce something on the order of 250 to 300 watts out.  For simple people, such as myself, this would be quite a suitable arrangement.  

Richard McClelland, AA5S

While I'm advocating for 12 watts output, I would like to mention that 5 watts, which the 1500 produces, is not enough to tune the KAT500 auto tuner.  12 watts is certainly enough to tune the KAT500.  A worthy benchmark, if I might say so.

James Whiteway

The Hardrock 50 would be cheaper, and a much cleaner solution than the RM Italy HLA series of amps. And the cost would be cheaper too. More so, if all you wanted was 40-50 watts out. Besides, the temptation to drive the HLA amp might not be so easy to pass up! That's why I passed up several deals on HLA 150's and 350's, when I gave serious thought to the same thing for my 1500 when I had it. But, reading closely everything I could find regarding that combination, convinced me that it was not money well spent. And inconsiderant of other Amateur operators. So, I used the 1500 at 3 watts both SSB & CW and had a blast with it. So much so, that I bought a 6300 and sold the 1500. james WD5GWY

Manuel - W4SSB

Marty,

I just sold my 1500 and bought a 6300.  I have an as new RM Italy HLA-350 Plus available if your interested.

Marty Bluhm

Yes, interested, email w8aks55@gmail.com with the particulars. Thanks & 73 Marty

Tim - W4TME

https://helpdesk.flexradio.com/hc/en-us/articles/205165475-Amplifier-Options-for-the-FLEX-1500

James Whiteway

Tim, if you look up the number posted for the RM Italy amp you posted you will find it is an application number, not a FCC Certification number. It has not been approved yet. They (RM Italy) are being deceptive using that number saying it has been approved when the FCC database says it has not.

Tim - W4TME

Ahhhhh.  Thanks for the info.

Richard McClelland, AA5S

A KPA500 is looking better every day (or the Flex kilowatt amp that is rumored to be forthcoming.)

James Whiteway

The KPA500 is a very good amp with good IMD numbers. Well made too. james WD5GWY

Tim - W4TME

Yes, Elecraft makes quality products.

Mike NA5U/K5D/K1N

In the for what it's worth category, I saw an earlier comment that said it depends on what you want to output . At HamCom this past weekend, I saw a Expert Linear 1.3KFA output 1.5K with 5watts (1.2K @ 2-3 watts). Granted, this is another price range but as stated, it depends what you want to output. I would like to see them do a 500W version in a corresponding package size. This would be a perfect DXpedition size.
73,
Mike, NA5U

Barry N1EU

I believe someone posted one of those 50W portable amps on QTH.COM yesterday.  I just tried to search their site to get the details to post here but there seems to be intermittent access/browser issues with QTH.COM currently (keeps throwing 403 errors).

Paul Christensen, W9AC

Mike, was that 25 dB of RF gain accomplished with an internal modification to the SPE 1.3KFA (e.g., bypassing a resistive RF input pad?) 

In the U.S., Part 97.317(a)(2) limits gain from a commercially-manufactured external RF amplifier to no more than 15 dB. 

Paul, W9AC

Mike NA5U/K5D/K1N

Paul,
I don't know. Glenn, W0GJ and I were being shown this by Bob Hardie, W5UQ. We what it would output with a 2 to 3 and 5watt drive and that what we saw. You might contact Bob for the details. It was an impressive amp but pricey.
73,
Mike, NA5U

Ken - NM9P

I have heard a couple of HLA-150s on the air with 1500's in my rag 80/40 rag chew group.  In practical use, they seem to be fairly clean up to about 80-90 watts out, but after that they get nasty-dirty pretty quickly, just as W8JI has reported in his article.  By "fairly clean" I mean that there were no visible spurious sidebands generated on my 6500 screen.  Yet when over the limit, the "trash" started to rise on either side of the transmit passband pretty quickly.  Coupled with a second amp to reach 800-1200 Watts, it could get bad really quickly, so it was essential that the user implemented an automatic power output control such as the utility on DDUtil in order to "keep the neighbors happy!"

Ken - NM9P

W9OY

look at this

http://www.eham.net/ehamforum/smf/index.php/topic,100501.msg808246.html#msg808246