Very nice filter design Harry. Good looking performance. Rob, N4GA

Looking at your filter response I think you may get better harmonic attenuation if you re-designed it for slightly more passband ripple (like say 0.5dB). It looks like you opted for about 0.1dB ripple which gives excellent passband ripple but poorer stopband attenuation which is what's important here.

perfect job.

great work whats the latest?

Hello Harry. Excellent work. I was trying to go to the website where we can purchase some of the products put it seems to off line now for a few days. I will like to take a look at the PC board and the DSP 7. Thanks for all your videos. 73 Juan

@harry4516

6 жыл бұрын

Juan, thank you ! The EU government invented a new regulation regarding personal data protection. It is very complicated and dangerous for small business like me. This is the reason why I had to close the online shop (like many others did). If you need boards, just write me an e-mail (you find my mail adress on my homepage).

@SixDegreesIntellectu

6 жыл бұрын

Thank you Harry. I'll email you. Thank you. Have wonderful weekend. 7 3

Have you ever ran your ldmos without lp filters?

Very good filter. Question - Are the relays sealed? therefore I could use the filter in a liquid immersion cooling housing. I want to reduce the housing size to a minimum, and protect it from weather so that it will be possible to operate the amplifier outdoors directly under the antenna.

@harry4516

4 жыл бұрын

interesting idea! The relais look to be sealed. But what about the other components like SMD capacitors.

@fnordist

4 жыл бұрын

@@harry4516 I think that the heat generated by air cooling affects the filter properties more than a filter that is surrounded by dielectric coolants. The happy little capacitors enjoy relaxing in a cooling bath. I only have to mill a double-walled housing out of an aluminum block, the cooling water flows between the side walls. The filter sits on the inside with aluminum heat sinks attached to the inside. I may have to add a tiny circulation pump for the cooling oil, but I first have to measure whether this is necessary at 1.5KW / SSTV. I want to control the whole thing with the help of Remoterig and a Raspberry pi. Gruss.

Can we run dual LDMOS boards into dual LPF boards, before the combiner? (To allow higher powers/duty cycle)

Hello. Did you measure the filter impedance? I do not have SWR output in the upper ranges better than 1.4. 🙄

@harry4516

4 жыл бұрын

Hello, the silver wire for the upper bands needs some tuning by stretching the coils.

Т98 Amidon core - there is no such. Do you think that FKP1 Wima capacitors are appropriate for this place? They are with polypropylene dielectric, negative temperature coefficient and unknown current rating for this frequencies. Does the capacitor in the first version of your filter not explode because it is inappropriate for this place ?

@harry4516

7 жыл бұрын

Hi, thanks for your comment, T98, should be T94, thanks for the advice. I have very good experience with polypropylene in filter applications up to 10 MHz, but would not use it in filters above the 30m band where it has to handle high frequency and high power harmonics. Thats different in antenna tuners (there are almost no more harmonics). I use FKP1 in an symmetrical 1kW tuner for all bands 160-10m since 2 years, works very well.

Hello, do you sell this type of lpf? Wandering if i can purcashe from you, thanks de yo3abt

Nice filter! Have checked the IMD of your amplifier? Is it linear?

@harry4516

7 жыл бұрын

I have measured IM3 about 30dB. But depends on Band. On 10m its much more, almost 50dB. Maybe my measurement setup is the reason.

hi nice desig i wont pot mor then 1.5 kw in it som componest vont taki it specialy the relays 20 amps or biger ld mos amps and tub amps are similar but difrent hawe a sovit era r140 capable of 500w 1kw 1,5kw 2kw and u to maximum 6 kw evreting is hevy and big ,very big air gaps betwen component main antena filter everything is silver or silver plated the relys are made 4 120amps continus work at 25kv the coils on them are 48v i sugets going wit biger voltage on your caps 3kv or higher 73

They aren't Amidon cores, they are Micrometals cores. Amidon don't make ferrites they only sell them. Everyone seems to think Amidon makes cores.

@harry4516

5 жыл бұрын

thanks a lot for this information. I did'nt know that, like most other people. Found the cores on the micrometal website together with a lot valuable information.

@MrTalaue

3 жыл бұрын

@@harry4516 Indeed, Amidon is just distributor.

@subramanianr7206

2 жыл бұрын

@@harry4516 Fair-rite make ferrites and Micrometals make iron powder cores. The ARRL use to mention Amidon all the time and hence the usage. De VU2RZA