FT-817 with the RM K300P
Lately I’m trying to improve my portable HAM Radio setup because I want to do some activations for Castles On The Air (COTA) and WorldWide Flora & Fauna (WFF).
The idea for the activations is that you take all the HAM radio gear you need to make your contacts and carry them to the end location which can be in my case a castle or a nature park. From there you will then make your contacts.
You can imagine, if you need to carry everything to your transmitting location, you want to carry as little as possible! And so started my search for the best and lightest HAM setup possible. 🙂
My Setup
At the moment I’m using the Yaesu FT-817nd plus a manual tuner with built in 1:4 balun so I can use a random length wire antenna with that. I’m using a lot of different antenna’s by the way, depending on my mood and the circumstances.
I’m also a fan of the Hy End Fed which is an end fed antenna made by some guys here in the Netherlands. It works on the 10m, 20m and 40m band and doesn’t need any tuning. Plain, old home brew monoband dipoles are also great in a lot of circumstances. I made a lot of them, using them in all kinds of situations.
Although I also have a Yaesu FT-857D I prefer the FT-817nd because it works also just on batteries. With that you have the lightest setup possible! Just the FT-817nd, a tuner and an antenna wire will already do the trick! 🙂 And the FT-817 is just a nice little rig, almost a toy, so I anyway like it.
For my battery power I just bought a Tracer 12 volt, 14Ah Lithium Polymer Battery Pack. Although not very cheap, it is small and light and should give me enough juice to use the FT-817nd together with the KL300P. I replaces the connection on the Tracer with some Anderson Power Poles to make connecting things to it a bit safer and easier.
Tracer 12v 14Ah Lithium Polymer Battery Pack
More Power!
Because the FT-817nd has a maximum of 5 watts I was looking for some more power. When you go through all the trouble of walking to the activation location you want to be able to talk to people in the end, also if propagation isn’t so great!
I know there are some nice HAM linears available but they either are to big, to expensive or both! The Tokyo HighPower HL-45B is one of those and I do also like the RM HLA 150 linear from Italy. They both have all the band filters built in and give a pretty clean signal for this type of amplifier.
The RM KL300P Linear Amplifier
I decided in the end to go for the RM KL300P linear. It’s a small (!) HF linear with max 300w output on SSB when driven by max 10w input. The bad thing about it is that it doesn’t have any filters built in. The good thing though is the size (!) and the value for money.
(Small) Size Matters!
The price of the KL300P is around 135 euro (185 USD) and will give you 300 watt, so it’s very affordable! The Tokyo HighPower (THP) linear in comparison costs 670 euro (925 USD) and will give you 45 watt(!)
A quick calculation shows me that the THP gives me 1 watt per 20.5 USD, the KL300P gives me 1 watt per 0.61 USD! The THP will give you bandpass filters though, that are missing in the KL300P but still, the price difference is just to much! Especially as, in my case, you are not using it very often. Next to this the THP is just to bulky to carry around with you and is in all aspects not an option for me.
I know the Italian RM linears are not allowed in the USA but in most other countries they are. In the Netherlands, where I live, you’re allowed to use any equipment if you have a HAM license as long as you keep to the rules of your license. I have a full HAREC license (comparable to the Extra license in the USA) so I’m allowed to use any and all HAM radio equipment.
Filtering
I would not use these RM linears from home without adding good filters, for sure a low pass filter to keep the neighbors happy! My base setup is a Yaesu FT-1000mp Mark V plus an Ameritron AL-811HD linear amplifier so at home I anyway don’t need the KL300P.
As long as you don’t over drive the RM linear the disturbance to other HAM operators can be kept to a minimum, I think. The FT-817 anyway doesn’t have more than 5w which is halve of what you can use to drive the linear on SSB. And of course, when you use the RM linear close to buildings or places where people live, you should at least use a low pass filter. One that cuts off all harmonics above 30 mHz that could otherwise show up in some electronic equipment.
The low pass filter still doesn’t remove all interference but it’s a minimum addition when using the linear at home I think.
To get the same power the Tokyo High Power gives you (45w) you only need to drive the KL300P with 1 watt. In the specifications it says this is not possible on SSB but in practice it is and this will give you about 40w output.
Conclusion
I did some quick tests using the KL300P with the FT-817nd, driving it with maximum 5 watt and found that the values in the following table were reached. The amount of amperes needed is also very important to me because this shows me what battery to take.
| FT-817 input | KL300P output | Linear Setting | Amperes |
|---|---|---|---|
| 5 w | 170 w | HI | 17 A |
| 5 w | 90 w | LO | 13 A |
| 2.5 w | 110 w | HI | 15 A |
| 2.5 w | 40 w | LO | 8 A |
| 1 w | 50 w | HI | 10 A |
| 1 w | – | LO | – |
The tests that I did were very basic, using the KL-300P, a 13.8V power supply, a 1:1.2 20m dipole and an FT-817nd. I tested around 14.200mHz and used an MFJ tuner and an Ameritron AWM-30 (analog) watt meter.
One, for me not so positive point about the KL300P (next to the no filtering) is that when you turn on the linear, you also get the pre-amp “for free”. You cannot turn the pre-amp off when you’re using the linear. Especially in situations when there are some strong stations around you don’t always want a pre-amp.
Another point to think about is that the linear works with a SWR of maximum 1:1.5 (!) So you should have a good antenna and / or a good tuner to get the SWR as low as possible.
All in all, if you look at what you get for the money it’s a great little amp that makes my portable configuration perfect….. for now…. 😉
Maybe you’re right but for home use get the ft857d instead. Cheaper and no filters required. It’s also more tolerant of VSWR
So
Hi Ian, thanks for your comment!
Yes, for home use I wouldn’t quickly use the KL300P. Of course the FT857D is an excellent choice! I have one myself. I started out in the beginning with an FT-897 which is also great for home use.
What I like about the above setup is that you can use the FT-817nd everywhere (with the battery pack) where you want to transmit or just listen. Then when you find out that QRP is not possible in your location you just throw in the KL300P and it’s a whole different story!
90% of the time though the KL300P stays in the bag when I’m out in the field, just for those 10% times that you climbed up the mountain and you want to talk to people, not just listen, its very much worth having!
Hoi, Werkt de kl300p van 80 tot 10 meter??
Ik heb hem uitgeprobeerd van 40m tot 10m. Ik heb geen goede 80m antenne dus ik heb hem daar niet gebruikt.
Maar van 40m tm 10m doet hij het prima!
Officieel werkt hij op HF. De banden staan jammer genoeg niet aangegeven in de specificaties.
Hallo Cees,
Dankzij dit artikel heb ik ook een “dirty”amp aangeschaft, de BJ300.
Ik mag graag portable werken en ben onlangs begonnen met activaties voor PAFF, COTA etc. Met mijn geliefde FT817 ging dat prima, maar af en toe wat meer vermogen is wel prettig, zeker bij tijdgebrek.
De FT897 in de auto werd niets en betekende nog een extra tas/koffer erbij dus wilde ik op de FT817 verder. Jouw artikel was voor mij de tip.
Afgelopen week binnengekomen (409shop) en uiteraard getest. Een prachtig apparaat wat in de natuurparken weinig storing kan geven.Toevallig staat in de Veron Electron van november een schema voor het bouwen van HF-bandfilters. Dus dat komt mooi uit. 73 Hans, PE1BVQ
Hi Hans,
Leuk dat je wat aan mijn blogje gehad hebt! Ik ben ook zeer tevreden met mijn KL-300p en heb hem al op een aantal vakanties gebruikt. Het extra vermogen scheelt een stuk, als de omstandigheden niet optimaal zijn. Het is het verschil tussen geen contacten maken en in ieder geval wat contacten maken!
Ik wil zelf ook PAFF en COTA gaan doen maar ben er nog niet aan toe gekomen om dit ook echt te doen. Ik moet mezelf even een zetje in de rug geven denk ik. Ik weet niet wat me tegenhoudt. Jij hebt wel al activaties gedaan?
Ik had het Veron artikel over HF-bandfilters nog niet gezien. Ik zal er ook eens naar kijken. Altijd leuk als projectje denk ik; om die filters te maken.
Veel plezier met je BJ300 en laat me weten wat de ervaringen zijn!
73 de Cees, PA1CA
Hello Cees, using the same setup sometimes over here (817 and KL-300), but the KL-300 is heavily modified so it is usable. There is something is wrong with your measurements, 14A at 12V is 168W, it can’t output more than ~90W at that power draw. Plus the transistors inside are rated at 70W each (therefore 140W max. in total) at 10dB nominal gain, wich would make 50W output of the 5W input. Indeed, as you go lower in frequency the gain increases, but even on the lower bands 5W barely pushes it over 100W. Remeber that for 200W output you need at least 30A of current draw at 12-14V (at 50% efficiency) and the fuses on the KL-300 are limiting the current at 24A max.
It is impossible to get useful SSB output since the KL-300 is working in Class-C, wich is severely non-linear, heavily distorts modulation and generates alot of intermodulation and harmonic products unless it’s used in continous carrier mode (CW, FM etc). To get it working in Class AB you need to add a biasing circuit that provides about a 300mA standby current.
To get reasonably clean output from a pair of SD1446 transistors (like in the KL-300) you need to keep the output around 100-120W depending on the supply line (very strong and steady 14V supply => 120W). With higher drive (and with all improvements done, in best conditions), it can be forced to output about 140-150W, but the output gets really dirty.
The level of the odd harmonics is high and it needs low-pass filtering even in portable operations. The first issue you’re going to see is that the automatic tuner won’t tune properly, as there will always be a reflected signal from the antenna (match the funadamental, the harmonics aren’t matched etc). If you plan on working only on one band when portable, you can make just a filter for that band; some filters can help with multiple bands (10m filter is good for 12m too, 15m also works on 17m etc).
Let me know if you need help regarding the KL-300, it can be the base of a useful amplifier. Please also look at the HLA-150 review by W8JI, that has the same power transistors but has many improvements over the KL-300 (and still doesn’t meet the specs). PA0FRI has a review of the HLA-300, wich uses 4x SD1446, that can also give you an idea on what to expect in terms of input, output and current draw (but not on distorsions and IMD products, for wich PA0FRI doesn’t seem to care).
Cheers,
Razvan.
Hello Razvan,
Thanks for your comment and your analyzes. The tests that I did were very basic, using the KL-300P, a 13.8V power supply, a 1:1.2 20m dipole and an FT-817nd. I don’t know, by the way, if the KL-300 (like you have) and my KL-300p have the same characteristics but I guess they come close(?)
I tested around 14.200mHz and used an MFJ tuner and an Ameritron AWM-30 (analog) watt meter. So the test situation wasn’t great but as I say in my blog it was just a quick test. You wrote “14A at 12V is 168W” but because of the 13.8V I used it is 14A at 13.8V is 193W. For writing down the amperes I used the ampere meter on my power supply which isn’t all that accurate. Since I wrote the blog, I bought a small watt meter that you can put in between your rig and the power supply and that one is more accurate.
I did the quick test again and got a bit different amperes out of this on the new meter. The number of watts I got this time doing the tests was more or less the same by the way, only the 200w is now more in the direction of 160w / 170w. I changed the numbers in the table now with the numbers I got from the new test.
I agree that the KL-300p isn’t a great amplifier but for the purpose I wanted it, it works great. I wanted just a little more power in certain (portable) situations and the KL-300p is giving me this. When I bought the KL-300p I wanted such a linear with a high (claimed) power because I knew that then, if the input is low (2.5 watt), the signal will be less dirty and I will not overdrive the linear.
As I wrote in my blog, I am using it now and then in portable situations, and then only in the 20% of the times that the 5 watt of the FT-817nd isn’t getting me anywhere. I found that if I drive the amp with 1 or 2.5 watt I can get around 40 / 50 watt out of it which is enough for my portable operations. I do know the HLA-150 (I have one) but that linear is even bigger than my FT-857d so I would never take the HLA-150 with me in the field.
At home I am using an FT-1000 mark V which gives me enough power (200w). Very occasionally I am using my Ameritron AL-811hd so I wouldn’t use the KL-300p at home (of course).
Any info on the mods that you did to the KL-300p would be appreciated by the way! I am interested to know what you did.
I’m especially interested in how the distortions can be made less.
73, Cees