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Re: Harmonic performance - SSB vs CW
mcHF Boards:- he does sell the bare 0.6 boards as? pair i think.? See order page, bottom.
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On Tue, Aug 7, 2018 at 12:24 PM, RCBoatGuy wrote:
Actually, the more I look a the mcHF RF board schmatics, the more i think its a good solution for the BPF, PA, and LPF issues. The mcHF RF board has both the BPFs and LPFs, PA with 16HVF1 push-pull PA, RX-TX switching via diodes plus an SWR bridge.? Not sure of the board layout, but he does have separate relays for the LPF inputs and outputs. |
Re: ND6T AGC and Click kit wiring notes
One more question, folks:
I have one of later run V3 kits with socket mounted 2822M chipset.? It works fine, and is SOCKET mounted.? Wonder if anyone has played with a substitute that pops in and might offer some (audio level albeit) AGC?? Just a thought.? I dunno what's out there, and what has been tinkered with. Eddie |
Re: Harmonic performance - SSB vs CW
An interesting exercise is to take the values for the Lo Band 80m LPF and compare the data between Farhan's LPF, Hans' LPF and the W3NQN LPF they are basically the same design, except the W3NQN LPF has 1 extra capacitor. Use a program like "Elsie" the student version is free and look at the results ......quite a difference. Hans has the best Return Loss numbers and W3NQN has by far the best rolloff and should readily meet FCC specs.?
I'll see if I can upload the results. The actual capacitor/inductor values are readily available on the ARRL website .....just look up "Second Harmonic Optimized Low-Pass Filters" by W3NQN.? Should be easy to rework if you are interested but it needs testing with Farhan's relay scheme. T37 or T44 toroids are fine for 10W or less and so are 100V rated Ceramic MLCs. 73 Kees K5BCQ |
Re: Harmonic performance - SSB vs CW
Actually, the more I look a the mcHF RF board schmatics, the more i think its a good solution for the BPF, PA, and LPF issues. The mcHF RF board has both the BPFs and LPFs, PA with 16HVF1 push-pull PA, RX-TX switching via diodes plus an SWR bridge.? Not sure of the board layout, but he does have separate relays for the LPF inputs and outputs.
I wonder if M0NKA would consider selling the RF board as a stand-alone kit... |
Re: Harmonic performance - SSB vs CW
Timothy Fidler
Kiss principle is good minimum changes? because you don't know how many V4 version boards A Farhan has on the shelf. .? Give away 15 m as a concept.? One reason being that $35 USD transverter boards for? 144Mhz exist.? The only work for 10 mtr? IO.? Thus 15m gets the chop.
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NB the -38 Db noted on that specific? 30m filter is no so much of a worry. The Japanese guy was driving 2x2 RDHH16 in parallel to get 50W out (so he said).? He should have expected 35W maximum for reasonable harmonics level. Hence harmonic production would have been much worse than a safe design. What his test set up was and calib. aspects I have no idea. regards, Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2?
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Re: Harmonic performance - SSB vs CW
Overkill maybe, I have a 3 band version PCB of the G4TZR version used in Picastar, rated 100+ watts.?? Made for a personal HF rig project where 3 bands is all i need although the board can be stacked for 6 bands.? Schematic is on G6ALU's web pages, but cut down for 3 bands.? Layout identical.
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glenn vk3pe On Tue, Aug 7, 2018 at 11:31 AM, Gordon Gibby wrote: Sure seems like it would be fairly simple and inexpensive, to make a small additional board to which you would route the transmitter signal, and relay ?control voltages, buffered if necessary ¡ª-as Nik is working on.? |
Re: Harmonic performance - SSB vs CW
Timothy Fidler
Nick have a look at the "Jap"? 5 bands with three outputs and diode OR LPF suggestion that I just posted before you go too much further.. just a heads up.? THe design needs rework for lower power ,? but it is not too bad.? It can be just std double Pi design without all the magic bypass cappies - there must be books that cover that but I don't have one.
Remember too that a BPF board looks as if? required to cut right into the cct . thought it may be with a well designed LPF board that latter may be dispensed with.? That may affect your layout to produce a one size suits all. |
Re: Harmonic performance - SSB vs CW
On the subject of adding BPFs in place of the 30MHz LPF between T2 and the PA, has anyone considered using M0NKA's mcHF transceiver's solution for BPFs using multiplexer I/Cs?? The IC's are pretty cheap, only 48 cents in quantities of 10.
His schematics can be downloaded here:?.? The first page of the RF schematics shows the BPF and multiplexers. Not sure what kind of impedance matching would be required to use these, but thought I'd mention it. 73, Carl, K0MWC |
Re: Harmonic performance - SSB vs CW
Timothy Fidler
Proposed filter switching fr the rework.
BEfore everyone rushes off into filter relay config as in electrical this one can do 80m,? 40 (10 with changes) and 20-30m. And all on three outputs because of the cunning diode "Or.? Moreover it shorts the unused filter to GND (except for the 20-30 one) as per AJP suggestions . This of course is a LPF design and the power level at 50W and therefore input Z is not correct for uBit X use.?? Not beyond the wit of man /or women ! to fix that. What is really cunning is that the design is zero load when used on the 20m daylight service,? ie out and about on a battery.? "It's got a Cop motor before unleaded so it runs good on regular gas ....".? Perhaps worthy of consideration though all the relay select firmware has to change.? You lose 15 m tx but still need only three o/p as before . what the heck...I kept this on file for a rainy day.? ?Allison .. am I forgiven..? please. No metric fishing...from now on. Personally I dislike the the idea of zero means a valid state from an electrical Pof View.. ie wire falls off . no fault occurs but a logic state changes . But on a PCB it seems acceptable. |
Re: Harmonic performance - SSB vs CW
Gordon Gibby
¿ªÔÆÌåÓýSure seems like it would be fairly simple and inexpensive, to make a small additional board to which you would route the transmitter signal, and relay ?control voltages, buffered if necessary ¡ª-as Nik is working on.?With the relays at opposite ends, even in expensive one should work. ?
Reuse ?as many components as reasonable from the existing filters. ? The inductors at least!
Fairly simple upgrade! ?If someone builds it , I¡¯ll buy several boards, if not, I¡¯ll lay out my own! You guys are busy explaining exactly how it needs to be done! ?And I mainly care for just a few bands?
Cheers
Gordon
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Re: Harmonic performance - SSB vs CW
Warren Allgyer
Kees
The capacitors were new from my stock in the case of the 80 meter trial filter because I did not want to bother with pulling them from the uBitx until I was sure it was going to work. I do plan to use the on-board caps for the other three filters. WA8TOD |
Re: BitX40 Sketch still needed....
Paul Mateer, AA9GG Is this what you are looking for? Arv? K7HKL _._ On Mon, Aug 6, 2018 at 7:04 PM AA9GG <paul.aa9gg@...> wrote:
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