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Author Topic: RM Italy Amplifiers  (Read 91031 times)
WY7CHY
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Posts: 953




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« Reply #150 on: July 03, 2019, 08:12:59 PM »

I recently bought one of their linear HF amps and much of what is said on this thread is true - they do not deliver what they claim. However, my 300W (claimed) RM amp is giving me up to 180W on most HF bands on data, and it only cost a couple of hundred pounds new. It has performed faultlessly so far, so even though I'm not too happy with the output, I've gained 6dB on my signal for very low cost, and my more expensive transceiver is likely last much longer now it is only asked to deliver 5-10W. For what I paid I'm happy with the result as I could never afford the several thousand pound price tag of a good quality linear.

Update. A few weeks ago I accidentally drove my RM Amp with the full 100W output from my rig for 2-3 seconds before realising what I'd done. I assumed the linear would have been cooked, but when I reset the drive to 10W all was working perfectly, and now several weeks later all is still fine. This RM amp appears to be idiot proof, or at least able to cope with this particular idiot. I now have a big red warning sticker on my rig so hopefully I won't repeat my mistake.

It is pretty much idiot proof when it comes to normal users and power. If you put more than 15-20 watts Continuous, or 25-30 watts PEP into it, it will protect itself. I have multiple amps, multiple radios, multiple antennas, and multiple meters. My bench is made up of multiple switches. So I can combine any radio with any amp and any antenna and any meter. I have accidentally put in 50-100 watts into the HLA-300v a number of times. It protects itself. Do I recommend doing it? No. But accidents happen. Especially if you have a complex setup. My biggest problem is the opposite. I have my transceiver set for 20-30 watts PEP and I connect it to one of my other amps and can't figure out why I'm only putting out 200-300 watts. Then I realize I have to crank up the transceiver output power.

Again; for a NEW PRICE, the HLA-300v and HLA-305 are NOT worth the money. If you have a low power transceiver that you'd like to get a good bump for normal operation, the HLA-300v is an excellent amp if you can find a used one for $400 or less. If you have a standard 100w transceiver, the MOST you'll get out of this amp is 400 watts PEP on certain bands. That's a 6db (2 S-unit) increase. Most times, you'll probably get around 350 watts out. That's about a 5.45db gain. I don't think paying $400+ for this amp is worth that. You'd be better off paying another $100 and getting a decent 500-800 watt amp. Yes, it would be a tube amp, but definitely better bang for the buck.

There is one caveat however. MOBILE USE. We all know that the biggest gain most people can get, is with their antenna. In a mobile environment, ALL antennas are a compromise. The best (In my opinion) would be like a Tarheel screwdriver antenna; e.g. 200HP. But even that's a compromise. So, adding 5-6db gain with a 300-400 watt amp, that works GREAT in a mobile environment. (That's what it was made for; that's why it's set up for 12vdc). This amp is actually a very good addition to a mobile rig. It's very small. Doesn't weigh much. Most current alternators have no problem handling it. But for a base rig; you're better off spending a little more for a good used tube amp like an AL-811(H), SB-200, FL-2100b, etc. Any of which you can get for $400-$600.
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Born Wild - Raised Proud: 73
Cheyenne, Wyoming
G0OQX
Member

Posts: 20




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« Reply #151 on: July 04, 2019, 12:42:14 AM »



It is pretty much idiot proof when it comes to normal users and power. If you put more than 15-20 watts Continuous, or 25-30 watts PEP into it, it will protect itself. I have multiple amps, multiple radios, multiple antennas, and multiple meters. My bench is made up of multiple switches. So I can combine any radio with any amp and any antenna and any meter. I have accidentally put in 50-100 watts into the HLA-300v a number of times. It protects itself. Do I recommend doing it? No. But accidents happen. Especially if you have a complex setup. My biggest problem is the opposite. I have my transceiver set for 20-30 watts PEP and I connect it to one of my other amps and can't figure out why I'm only putting out 200-300 watts. Then I realize I have to crank up the transceiver output power.

Again; for a NEW PRICE, the HLA-300v and HLA-305 are NOT worth the money. If you have a low power transceiver that you'd like to get a good bump for normal operation, the HLA-300v is an excellent amp if you can find a used one for $400 or less. If you have a standard 100w transceiver, the MOST you'll get out of this amp is 400 watts PEP on certain bands. That's a 6db (2 S-unit) increase. Most times, you'll probably get around 350 watts out. That's about a 5.45db gain. I don't think paying $400+ for this amp is worth that. You'd be better off paying another $100 and getting a decent 500-800 watt amp. Yes, it would be a tube amp, but definitely better bang for the buck.

There is one caveat however. MOBILE USE. We all know that the biggest gain most people can get, is with their antenna. In a mobile environment, ALL antennas are a compromise. The best (In my opinion) would be like a Tarheel screwdriver antenna; e.g. 200HP. But even that's a compromise. So, adding 5-6db gain with a 300-400 watt amp, that works GREAT in a mobile environment. (That's what it was made for; that's why it's set up for 12vdc). This amp is actually a very good addition to a mobile rig. It's very small. Doesn't weigh much. Most current alternators have no problem handling it. But for a base rig; you're better off spending a little more for a good used tube amp like an AL-811(H), SB-200, FL-2100b, etc. Any of which you can get for $400-$600.


Some wise words so I cannot take issue with this advice. When funding permits I will probably take the steps you suggest, but in my particular situation I'm happy with my current set up. My operation is almost exclusively FT8 so I'm not sure another 100W is desirable, and living in the centre of town I'm always worried about too much power causing problems with neighbours. My current power levels with the RM linear suit me just fine. The signal reports I used to receive running 50W averaged 2-3dB lower than the reports I was giving, now my average received report 2-3 dB higher. A quality valve amp would be appreciated, but I'm in no rush to get one straight away.
« Last Edit: July 04, 2019, 12:45:09 AM by G0OQX » Logged
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