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RD15HVF1 source #5wPA
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HF
I wish to make an amplifier for WSPR on 8m (40 MHz). RD15HVF1s are likely to outperform IRF510s in the 5, 10, and 50W QRP-Labs amplifiers. These cost $20 each at RF Parts, and Amazon no longer offers them 2/$8 as they did in 2019. There are many sellers on ebay and also many negative comments on some of the sellers reporting that parts received are fake. Has anyone here bought these in the last few months from ebay, Amazon, or aliexpress and received devices that worked? Which seller? Thanks!
Halden VE7UTS |
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Hans Summers
Hello Halden The idea that substituting an RD15HVF1 will automatically result in an easy improvement in performance is a bit of a myth in my opinion. Particulalry in the 10W Linear. Other than the 5W PA I suspect you're going to be disappointed... But please do report back! And unfortunately I don't know where to get them. Anything on eBay would be a bit of a gamble probably. -------- Original message -------- From: "HF via groups.io" <incorridge@...> Date: Fri, Nov 19, 2021, 7:32 AM To: QRPLabs@groups.io Subject: [QRPLabs] RD15HVF1 source #5wPA I wish to make an amplifier for WSPR on 8m (40 MHz). RD15HVF1s are likely to outperform IRF510s in the 5, 10, and 50W QRP-Labs amplifiers. These cost $20 each at RF Parts, and Amazon no longer offers them 2/$8 as they did in 2019. There are many sellers on ebay and also many negative comments on some of the sellers reporting that parts received are fake. Has anyone here bought these in the last few months from ebay, Amazon, or aliexpress and received devices that worked? Which seller? Thanks! |
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Jim Mcilroy
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On 19 Nov 2021, at 07:03, Hans Summers <hans.summers@...> wrote:
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HF
Hi Hans,
Thanks for your comments. I'm not sure I understand your "Other than the 5W PA..." comment. If I try to use one of the QRP-Labs amplifiers with the original IRF510s on 40 MHz, which of the products (5W, 10W, 50W) do you think will work closest to its HF performance? Cheers Halden VE7UTS |
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Hans Summers
Hello Halden The 10W Linear. I don't think there is much, if any, advantage substituting a RD15HVF1. The 5W PA output power drops off quickly after 10m. The 50W Amp, I have not tested beyond 20m. The 10W Linear was tested to 6m and will work well at 40 MHz other than losing a dB or two of gain. 73 Hans G0UPL http://qrp-labs.com -------- Original message -------- From: "HF via groups.io" <incorridge@...> Date: Fri, Nov 19, 2021, 1:54 PM To: QRPLabs@groups.io Subject: Re: [QRPLabs] RD15HVF1 source #5wPA Hi Hans, |
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ajparent1/kb1gmx
The RD15HVF1 is nice part for 144mhz otherwise no advantage and bring limits.
First he specified gain of the device is not higher than IRF510 and can be lower. The power dissipation is not higher. The usable upper frequency range is greater at the cost of other specs (power and votage). Many poor designs it will make a bit more power but that's more because the design didn't like the IRF510 and the RD part was closer to the design misconceptions. That its a better device is mostly lore, wishful thinking, and not fact. For example the RD15HVF1 in the 10W linear limits it to 12V ONLY as the device max is 16V! it is not a higher power device than the IRF510. It also has no more gain as the amp stages have feedback to limit gain, improve stability and flatten bandwidth, so a higher gain (which it is not) device buys nothing. For the 50W amp its likely to fail at more than 16V as that its design max for the part. It does not have a higher power dissipation. It does not offer more gain though it doe work at 2M. For the 5++$ price each you can get a lot of IRF510s. It is also a single vendor and if Mitsubishi decides its done then only new old stock will be the source and at higher prices. There are many MOSFET (Vmos and LDmos) devices that get more power and gain but most all want 28 or 50V and are more expensive. Allison ------------------------------- Please reply on list so we can share. No private email, it goes to a bit bucket due to address harvesting |
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ajparent1/kb1gmx
Halden,
At 50mhz I use IRF510s, a pair get me about 35W, a 4x4 push pull at 28V does a nice 200W. The idea tha the RD device at 40M is better is myth. I have a pair or irf510 at 28V that doe about 55W with 2W drive linear. The RD is incapable of that. Allison ------------------------------- Please reply on list so we can share. No private email, it goes to a bit bucket due to address harvesting |
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There are people selling these as pulls on Alibaba. I have no idea why they are pulls but they are very cheap as they obviously have to be. I'll send you a PM on this. Another poss is Mini Kits in Adelaide, Australia. he used to sell them and they were bought directly from major suppliers so they are sure to be original mafr. Perhaps he has a few knocking around still for use as spares for his kits. You can find him on the internet. He lists the RD16HH but not the RD15 as available for purchase under semi conductors. It's worth a go. The SDR Radio outfit in the UK that someone suggested - no dice - out of stock . Because this part has such specialised uses It's hardly surprising that they are a bit hard to find. Every 15 to 20W SSB commercial tcvr in production at the moment seems to use the RD16 or similar but VHF handhelds generally want to use a 7.2 V device so the RD15Vhf1 is a a bad fit.
TEF |
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