Re: Harmonics and Relay Replacement
Kees
Will this pcb for sale? ?Got your refund on the other one
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On Oct 20, 2018, at 7:34 PM, Kees T < windy10605@...> wrote: This is another pass on the LPF board....being tested.? 1) this one is meant to install under the covers of the uBITX, Board is 68mm x 48.4mm. 2) uses the existing uBITX LPF components moved over to small plug-in LPFs (can also use the QRP Labs ? ? LPFs or your own LPF design), 3) uses basically the physical layout of the LPF board as outlined by Allison in the Wiki section, the high band ? ? LPF?is ALWAYS in the circuit Rx or Tx. 4) if Tx voltage is present, the LPF board is routed to T11 and removed from the Rx section which is grounded. 5) if one of the bands, other than the high band, is selected by the TxA, TxB, or TxC, it inserts that LPF AND the ? ? high band LPF in series for Tx. Really reduces high frequency harmonics.? 6) has a 1 mH inductor in series with each relay coil for further isolation, 7) uses the smaller NAiS TQ2-H-12V relays. Good relay I have used before.? 8) extensive use of flood-fill ground and ground stitching 9) interfaces provided are: T11 (near the PA, happens to have a SMA installed for test), Ant (happens to have ? ? a SMA installed for test), Rx (near the line to Rx), TxA, TxB, TxC, Tx Voltage, and Ground 73 Kees K5BCQ  ? <MVC_020S.JPG>
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
My experience in QRP contesting is that trying to compete at the outset is difficult at best. However, trying again towards the end of the contest makes a lot of difference as the "big guns" seem to be more willing to dig us out of the noise than at the beginning of the contest.
Jack, W8TEE
On Sunday, October 21, 2018, 10:56:21 AM EDT, taycheel@... <taycheel@...> wrote:
But that's physics, not psychology.
I did not call QRP when I was calling and I did not get one, not one, reply. Yet I QSO'ed many stations. I think many contesters don't bother with weak stations until things get very slow. It's more points faster to contact the strong stations. I heard many stations just a bit over the noise that I didn't bother answering either. Shame on me. I guess that shows my inexperience as a single-op QRP . My experience contesting is with multi-op "big" stations.?
So here's where I think the psychology come in: When I'm on the loud end and I? hear QRP, I assume the station will be hearing *me* very clearly and half the battle is won. I can help the other end give me the information I need, if any. Well, that's how I did it, but its been 20 years since I was an avid contester.
Another mistake I think I made was choosing "single mode." I'll run mixed mode next contest so I can slide my CW call into a pile-up. I'v often got "the CW station" as an answer in the past... this stuff is coming back to me but slowly!
73, Ed aa2mz
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
But that's physics, not psychology.
I did not call QRP when I was calling and I did not get one, not one, reply. Yet I QSO'ed many stations. I think many contesters don't bother with weak stations until things get very slow. It's more points faster to contact the strong stations. I heard many stations just a bit over the noise that I didn't bother answering either. Shame on me. I guess that shows my inexperience as a single-op QRP . My experience contesting is with multi-op "big" stations.?
So here's where I think the psychology come in: When I'm on the loud end and I? hear QRP, I assume the station will be hearing *me* very clearly and half the battle is won. I can help the other end give me the information I need, if any. Well, that's how I did it, but its been 20 years since I was an avid contester.
Another mistake I think I made was choosing "single mode." I'll run mixed mode next contest so I can slide my CW call into a pile-up. I'v often got "the CW station" as an answer in the past... this stuff is coming back to me but slowly!
73, Ed aa2mz
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
Thank you! ,,,, it wasn't as much fun as I thought it would be: me sitting on a frequency and the world piling up to QSO ... it didn't happen.
It was about the same as last week.I worked just about everyone I called in the East Cost Maine to Virginia and west to Illinois. But no one, not one station answered when I called CQ.?
Since I build the x40, i've heard out to California (I'm in western NY) , south to north South America and a lot of Europe. I think the receiver is doing its job.?
So thanks for looking Ian!?
I've got a MiniPA 70? (eBay 70 maybe 50 watt linear amp for $16 USD) on the bench almost ready to go, but that's a different thread.
- Ed.T aa2mz
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
I find saying qrp does sharpen those kind hearted stations to get back to you as opposed to the big boys.You often hear,the qrp station only.... Ian M0IDR
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I looked for you yesterday.
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
I looked for you yesterday.
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Michael,
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At 21-10-18, you wrote: 1: I tried going down to 10pF in C102 and then put a trimmer in C103 but it still was too narrow. This changes the BFO frequency NOT the bandwidth. It will change the tone.. 2: May try changing those caps tomorrow and see what happens. This will change the filter bandwidth! Will sound better, then use the first mod above to get the audio to sound right. Raj Michael
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Until the link is fixed, here is a copy of the uBitx v3 schematic.? At least it will be archived.
Marco - KG5PRT
On Oct 20, 2018 8:36 PM, < micah@...> wrote: Ashhar,
Nudge. I'm sure you're incredibly busy, and the v3 boards are ancient history at this point. But they're important history for those of us with that hardware.
(Or perhaps the latest files are out there, and only the link on the page needs to be updated)
:)
Cheers et 73, -m
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Laurence = Firstly both the CIA and Russkies in Moscow head office? read this site looking to improve battlefield communications,? so Laurence most likely has altered the balance of world power.? ?..? I knew something like this would happen.
Secondly if you get xtals of no name brand ...mm.. they might be all on same nom freq but certainly they are likely to be? near enough design for micro controllers and such and not formal communication xtals. If they work for you,? then you have the deal of the century. Others like? Alltronics in Calif? sell microprocessor spec xtals for? up to one USdollar each.? ?If they all come with same mafr brand on side then you are in with a good chance - like ECE or Fox.?
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Thanks Raj.....sounds like a good idea!
Michael
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I tried going down to 10pF in C102 and then put a trimmer in C103 but it still was too narrow.
May try changing those caps tomorrow and see what happens.
Michael
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Re: Loud sound on first power-up
#ubitx
Howdy friends,
Still haven't licked this. I made a short video to demonstrate the problem and show what I've tried so far--which involves stripping away almost everything but the main board.
Kindly have a look and let me know what you think I should try next.
I appreciate your applied expertise. :)
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Ashhar,
Nudge. I'm sure you're incredibly busy, and the v3 boards are ancient history at this point. But they're important history for those of us with that hardware.
(Or perhaps the latest files are out there, and only the link on the page needs to be updated)
:)
Cheers et 73, -m
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Re: Harmonics and Relay Replacement
This is another pass on the LPF board....being tested.? 1) this one is meant to install under the covers of the uBITX, Board is 68mm x 48.4mm. 2) uses the existing uBITX LPF components moved over to small plug-in LPFs (can also use the QRP Labs ? ? LPFs or your own LPF design), 3) uses basically the physical layout of the LPF board as outlined by Allison in the Wiki section, the high band ? ? LPF?is ALWAYS in the circuit Rx or Tx. 4) if Tx voltage is present, the LPF board is routed to T11 and removed from the Rx section which is grounded. 5) if one of the bands, other than the high band, is selected by the TxA, TxB, or TxC, it inserts that LPF AND the ? ? high band LPF in series for Tx. Really reduces high frequency harmonics.? 6) has a 1 mH inductor in series with each relay coil for further isolation, 7) uses the smaller NAiS TQ2-H-12V relays. Good relay I have used before.? 8) extensive use of flood-fill ground and ground stitching 9) interfaces provided are: T11 (near the PA, happens to have a SMA installed for test), Ant (happens to have ? ? a SMA installed for test), Rx (near the line to Rx), TxA, TxB, TxC, Tx Voltage, and Ground 73 Kees K5BCQ  ? 
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Jim,
That's exactly how the K2 handles it, its one of the first kit QRP rigs to use microprocessors
(more than one) for ore than a digital dial.
The software puts out Via PWM or DAC controll voltages for the BFO and the filter.
Allison
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Indeed ..certainly the K2 ...Seems the bfo could be controlled by software ..One setting for ssb .another for cw but I am no software guy
Jim
On Sat, Oct 20, 2018 at 8:41 AM ajparent1/KB1GMX < kb1gmx@...> wrote: Its known as a Jones filter and was used by TenTec? many years backand the Elecraft K2
for a more recent example.
With matched or at least close to each in capacitance for a given voltage it can work well.
Another is to use dies with less capacitance range and parallel caps like 82pf and a?
varicap diode that can do 30pf.
The problem is the BFO has to be close to the edge of the filter and the edge is variable.
Keep them in sync may be a handful.
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SSSSSSShhhhh!!!!!!? THIS IS MY **SECRET** U.S.A. SOURCE...
between YOU and I ONLY!!!!!
12Mhz Crystals 5 for a $1.00? or 15 cents each in lot 100 quanities...
Right! 5 for a DOLLAR.!!!.... over $75 free shipping, under $75 flat $7 shipping.. They have 1/8" uBITX volume knobs too..
Also read my review on 50ft. RG58/u cables with BNC's both ends (GO KIT SPECIAL) ... and adjustable 6.8uH inductors..
I usually get my order Calif. to Kansas in 2 days...
de W8LM
PS... they have small pf trimmers dirt cheep...65 cents..10 for $6.00
?????
.
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Re: AGC AND POP FIX KITS.FOR SALE.
thje agc kit has been sold just 2 pop fix kits left.dave G0AYD
Hi, ???? I have 1 agc kit by N6 DT and the 2 pop fix kits by K5 CBQ all with circuit diagrams and all componants..$15.00 plus post to your country the weight is 6 grammes and will be in a jiffy bag..paypal as gift please....contact me off site to wylyeguy2@... ? Dave G0AYD QTHR ??
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Re: Low IMD MMIC replacement for TIA
Gary,
Good catch on the current... next time wear glasses...? THat was the max current not operating.
There is a table in the datasheet for the resistor needed.
Allison
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Re: Low IMD MMIC replacement for TIA
A good reference app note on MMIC biasing from minicircuits:?
I've done 2 VHF amps, and good results with running 12V, bias resistor and choke also.
(Also had access to a top tier spectrum analyzer at that time :-)
(Recommended Device Operating Current for ERA-3SM+?is 35mA)
Regards,
Gary
AG5TX
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_Dave_ AD0B
Raj vu2zap