Hi Baruch, I did the same thing for my microphone, and I'm glad you received a good report on your transmit audio. I was using my SW receiver (with SSB capability) to monitor my transmit audio. Just like you said, it sounded horrible. I haven't made any contacts yet, but your experience gives me hope that I will have the same result as you did.
73
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Re: LOW tx output1.4 volt
Dear farhan
After replacing Mic i am able to get? 1.5 at 100 preset.
But still power out put is below 4 watt.
Driver transistor DC voltage
ground to emitter 440 mv
Ground to base 1.2 volt
Emitter to base 646 mv
pk to pk 7mhz voltage is
Driver base 1.5 volt
Driver collector 1.4 volt
PA gate 1 volt
Checked for short in toroids .
Shall i replace driver transistor.
I have 2N2218A. Shall i use instead of 2N2219A?.
Any it good experience get more exposure in Bitx.
I am enjoying the experience.
Full joy is ,when come on AIr with 8 watt power.
73s
Soundar
Vu2rjw
On Nov 23, 2016 9:30 PM, "Soundararajan Ra." < vu2rjw@...> wrote: Dear mr farhan
Realy unble to solve my problem
removed predriver transformer and rewound .
Ground to collector 1.1 v
collector to centret tap .5 volt (both supposed to be added and to get 1.5 v)
But CT to ground is .5 volt (c134).
At 100R preset getting .5 v so insufficient drive voltage .
Getting 2 watt out put at antenna.
I am blinking ,what next 7 do.
One more option for me? is to order one more kit.
Soundar
Vu2rjw.
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The Circuit Description page has a broken link.
Instead of:
It should be without the 20:
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Hi Ashhar
What is the centre frequency and bandwidth of the BPF?
73
Ken VA3ABN
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Hi Ashhar
What is the centre frequency and bandwidth of the BPF?
73
Ken VA3ABN
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I am happy to report that I have successfully completed my BITX 40 v3 project.? The board is securely installed in a nice enclosure.? I used a commercial enclosure, $20, steel and aluminum.? I "splurged" and bought a new set of drill bits from Home Depot for $10 to drill the holes (instead of using my rag-tag bunch of second hand tools.) I used the Mic from a surplus old RS CB.? The mic handset includes a push to talk switch.? The jack from the CB is installed in the BITX.? I removed the original mic and installed the BITX supplied microphone in the handset. ?
During testing, I was dismayed that the transmit audio was horrible, when listening on my big rig.? But when I arranged a QSO with a nearby ham friend, he gave me a good report.? Success!
There are two issues remaining.? Number one is the loud snap in the earphones when I key the microphone.? Is there anyway to solve that?? Number two is the frequency drift.? The frequency drift seems to settle down after a half hour.? I would like to leave most of the original circuit as is, if I can.? I am thinking of replacing the frequency determining capacitors with mica or polystyrene.? Would that help with the drift?? Has anyone tried this?
Thanks to Ashar for his hard work, made my work easier! ?
73, Joe W3TTT
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Thank you. It was me. From the photo it seems like 10 turns yes. But the output transformer close to the IRF510 and the LP filter, is it also 10 turns (usually it is 3, I think).
Thanks.
Roy
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Re: Toroids Loose on Arrival
yep, that's pretty much what mine looked like, a bit loose and a bit scramble wound jerry aa1of/6
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Show quoted text
From: BITX20@... [mailto:BITX20@...]
Sent: Tuesday, November 29, 2016 1:26 AM
To: BITX20@...
Subject: RE: [BITX20] Bitx 40 board.? ? Mark, This is the official bitx40 hack blog:
73 Giuseppe, ik8yfw
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Re: Toroids Loose on Arrival
Hi Joel,
Thanks a lot for that. I've seen that others have had issues, wasn't sure though. I'll try the nail polish trick since I don't have anything else handy. Looks like I have an antenna to erect and some soldering to do!
Thanks,
Ryan Flowers KC7RYS
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I just updated my blog with the progress I have made on building my BITX 40 board. Except for a little drift that I am still working on, the receiver portion is working quite well. Next to check the transmitter portion. | | | | | | A couple of things came up and I was delayed in building Farhan's SMD BITX 40.? With the availability and price point on the board, I decid... | | | | Preview by Yahoo | | | ? DuWayne KV4QB
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I just wanted to thank everyone for the help.? My problem turned out to be the 9 volt regulator.? I probably dragged a screwdriver across it while dinking around.
Bill
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From: Bill Robbins
Sent: Monday, November 28, 2016 6:27 PM
To: BITX20@... for the help.? My problem turned out to b e a
Subject: Re: [BITX20] Bitx 40 Problem
?
I have another, just arrived, Bitx 40.? Hooked it up and works as it should, at least for receive.?
#67, the first, cannot hear a signal generator putting out 0 dBm? signal.? Running it on a 12 volt battery eliminated a lot of hash.
So I at least know the signal is not making it very far.
From: BITX20@... on behalf of Jeff Glass kg6sgx@... [BITX20]
Sent: Monday, November 28, 2016 5:51 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 Problem
?
?
Do you have a nice strong power source? Like all high-gain LM386 circuits, the audio amp is prone to becoming an oscillator when starved of sufficient power.
Best,
Jeff
KK9JEF
Sent from my iPhone
?
You may also be able to drape it over the antenna connector. Try that first without the antenna connected.
73 Ken
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Re: Toroids Loose on Arrival
As long as none of the wires are broken on the toroids, all you need to do is straighten them. They pretty much all came with toroids crunched, mine did. For glue, I use hot glue, but you can use silicon or contact cement or anything really. I used to use clear finger nail polish. Don't glue L4 down until you get it on frequency by compressing the turns or loosening them until you get the band coverage you want. You should be on the air soon. Joel Caulkins KB6QVI
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On Nov 29, 2016, at 4:18 PM, geocrasher@... [BITX20] < BITX20@...> wrote:
?
Howdy all,
I've just received #697 in the mail today, and I sure am excited to get on the air! I did notice a couple of toroids were loose on it, and before I power it up and start playing with it, I want to be sure that they just came unglued and need to be glued back down. Here are pictures of what I see:
L2:?
L4: ??(at least, I think this is L4 according to the schematic- it's not visible on the board)
Both of these were oriented incorrectly as seen here:
I straightened them out, but am not sure what to glue them down with. Any assistance would be most appreciated. Thanks!
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Howdy all,
I've just received #697 in the mail today, and I sure am excited to get on the air! I did notice a couple of toroids were loose on it, and before I power it up and start playing with it, I want to be sure that they just came unglued and need to be glued back down. Here are pictures of what I see:
L2:?
L4: ??(at least, I think this is L4 according to the schematic- it's not visible on the board)
Both of these were oriented incorrectly as seen here:
I straightened them out, but am not sure what to glue them down with. Any assistance would be most appreciated. Thanks!
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BITX40 v3 #697 ?arrived in Washington State today. Very excited to get on the air with this radio! A couple of toroids are loose however so I'll be posting about that separately.?
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I hooked up the speaker and it sounds a million times better with the new cap. Thanks Joel.
73 Ken
On Tue, Nov 29, 2016 at 1:48 PM, caulktel@... [BITX20] <BITX20@...> wrote:
?
Ken,
I changed mine this morning and the receive audio is just about perfect now on a mobile speaker mounted up on my shelve.
Joel
KB6QVI
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Re: Ebay Store Kits Out Of Stock?
I just want to say thanks guys for the clarifications. I think for the fun of it I'll be building mine with a through-hole kit. I just feel like I'll have more fun modding it, and it'll look older and cooler. :)
Also planning to add a CW tone generator to it.
THX, KC9DZT Mark
On Mon, Nov 28, 2016 at 5:03 PM, r j rjinspace@... [BITX20] <BITX20@...> wrote:
?
I have a BITX 20m v.3 PA PCB from the ebay shop of Sunil VU3SUA. It has two amplifier stages and two transformers. The description says it can be modified for 40m. But it does not say how.
How many bifilar turns on FT37-43 should I use for the driver and final transformers when I build for 40 meter / 7mHz?
Thank you. Roy
-- Mark Baldridge 608.561.3853
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Nice job John, looks great!
I also plan on a PCB case.
73
Ken VA3ABN
On Tue, Nov 29, 2016 at 3:39 PM, johnbaggott@... [BITX20] <BITX20@...> wrote:
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I have mine built now photos in the link below, next job is DDS and hook up the audio through my mixer, this has and is so much fun.?
| | | | | | 5 new photos added to shared album | | | | Preview by Yahoo | | |
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I have mine built now photos in the link below, next job is DDS and hook up the audio through my mixer, this has and is so much fun.?
| | | | | | 5 new photos added to shared album | | | | Preview by Yahoo | | |
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Soundararajan Ra.
DuWayne Schmidlkofer
Joel Caulkins/N6ALT