Re: No RF Power Output From Bitx40
Possibly. If your final is fine then the bias pot would work.
Check if U3 has 5V out.
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At 08/07/2017, you wrote: So this radio that has never transmitted before and has had a dummy load on it or an antenna every time the mic button has been pressed has a blown final?
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Re: No RF Power Output From Bitx40
So this radio that has never transmitted before and has had a dummy load on it or an antenna every time the mic button has been pressed has a blown final?
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Re: No RF Power Output From Bitx40
At 08/07/2017, you wrote: - set PA bios pot makes no difference in current reading with mic keyed (audio/no audio) Means final is blown. - mic element 0.877k ohms in one direction and 1.101k ohms in other direction I have not checked but I would expect a condensor mic to be open circuit when not connected to board. Unplug and check. - same mic ohm values on the mic connector and board connector
- 12vdc between the Gate and Drain of the PA. No voltage between the Gate and Source when mic is keyed
Any ideas?
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Thanks Raj,
I¡¯ll try that tomorrow.
At the moment the antenna ground is connected to the case - and the power negative is also connected to the case.
I¡¯ll try isolating the antenna ground,
John
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On 8 Jul 2017, at 11:25 pm, Raj vu2zap <rajendrakumargg@...> wrote:
Thats good John,
Now unplug the antenna and just touch the antenna ground to rig rear connector ground.
Nothing should be heard on RX.
If you hear AM signals or noise - probably the socket to board may be an issue or a ground loop.
I have had a similar problem when my jumper cable from rig to SWR meter was frayed and ground
was open.
The antenna ground should be isolated from ground of other rear inputs/outputs. They are all connected
internally on the board.
Raj
At 08/07/2017, you wrote:
Hi Raj,
yes, I understood. From the board to the antenna connector is correct.
I???ve checked for continuity and for any shorts in the connection, but all seems ok.
I'll keep trying - and double checking the connections!
John
On 8 Jul 2017, at 11:11 pm, Raj vu2zap <rajendrakumargg@...> wrote:
Hi John,
Sorry I meant from the board to the antenna connector.
Check with a multimeter on beep continuity if the connections are proper to the connector.
At 08/07/2017, you wrote:
Hi Raj,
I??????ve double checked and just now checked again. Centre pin to antenna and shield to ground - all correct.
John
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No RF Power Output From Bitx40
Hi guys, I finally got around to finishing my Bitx40 project. Everything works but it will not transmit. This has me scratching my head. Here are some details.? - when I press the PTT on the mic I can hear the relay pull in and receive audio goes away as it should.? - I've verified that I have 12vdc on the PA connection and it's wired in the right direction.? - mic element ohms out properly and it's wired in the right direction according to instructions
- 152mA on receive
- 260mA on transmit with no audio
- current may change by .001mA when yelling into the mic
- set PA bios pot makes no difference in current reading with mic keyed (audio/no audio)
- mic element 0.877k ohms in one direction and 1.101k ohms in other direction
- same mic ohm values on the mic connector and board connector
- 12vdc between the Gate and Drain of the PA. No voltage between the Gate and Source when mic is keyed
Any ideas?
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Thats good John,
Now unplug the antenna and just touch the antenna ground to rig rear connector ground.
Nothing should be heard on RX.
If you hear AM signals or noise - probably the socket to board may be an issue or a ground loop.
I have had a similar problem when my jumper cable from rig to SWR meter was frayed and ground
was open.
The antenna ground should be isolated from ground of other rear inputs/outputs. They are all connected
internally on the board.
Raj
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At 08/07/2017, you wrote: Hi Raj,
yes, I understood. From the board to the antenna connector is correct.
I?€?ve checked for continuity and for any shorts in the connection, but all seems ok.
I'll keep trying - and double checking the connections!
John
On 8 Jul 2017, at 11:11 pm, Raj vu2zap <rajendrakumargg@...> wrote:
Hi John,
Sorry I meant from the board to the antenna connector.
Check with a multimeter on beep continuity if the connections are proper to the connector.
At 08/07/2017, you wrote:
Hi Raj,
I???€??ve double checked and just now checked again. Centre pin to antenna and shield to ground - all correct.
John
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Hi Raj,
yes, I understood. From the board to the antenna connector is correct.
I¡¯ve checked for continuity and for any shorts in the connection, but all seems ok.
I'll keep trying - and double checking the connections!
John
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On 8 Jul 2017, at 11:11 pm, Raj vu2zap <rajendrakumargg@...> wrote:
Hi John,
Sorry I meant from the board to the antenna connector.
Check with a multimeter on beep continuity if the connections are proper to the connector.
At 08/07/2017, you wrote:
Hi Raj,
I???ve double checked and just now checked again. Centre pin to antenna and shield to ground - all correct.
John
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Hi John,
Sorry I meant from the board to the antenna connector.
Check with a multimeter on beep continuity if the connections are proper to the connector.
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At 08/07/2017, you wrote: Hi Raj,
I?€?ve double checked and just now checked again. Centre pin to antenna and shield to ground - all correct.
John
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Re: Oops..I did it this time....
I did something similar. ?If you hold the pushbutton in while powering up, it will reset the Radinuo to original "factory" settings.?
Greg
KD4VV
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Hi Raj,
I¡¯ve ?double checked and just now checked again. Centre pin to antenna and shield to ground - all correct.
John
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Looks like you have interchanged the ground and antenna wires!
Black is ground everywhere in BITX40. Brown is the center pin of BNC or
SO239.
Let us know!
Good luck
Raj
At 07/07/2017, you wrote:
Hi all,
I moved my Bitx40 board to a smaller enclosure and somewhere along the
line I ended up with massive breakthrough from AM stations.
This happened even with the VFO unplugged from the board.
The breakthrough stopped (surprisingly) when I grounded the centre
contact of the antenna input. 7mhz? SSB signals came through
fine!
I experimented with a couple of capacitors across the antenna input
instead of the grounding, and finally used a 100pf capacitor.
Now the receive is great, no AM breakthrough at all and a reduction in
noise. Signals still getting through fine.
Transmit seems ok (on a nearby receiver), but I haven???t tested power
output.
I???m not sure how that all worked. I have Peter parker???s improved
audio transmit mod. Also removed the 1uf capacitor between pins 1 and 8
of the LM386
and replaced with resistor/capacitor.
Any thoughts?
John
VK2VOL
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Hello, I realized this problem of delaying cw during a qso. When I transmit for example the letter "P" the bitx40 sends a letter "G". I noticed that the delay appears from 10 PPM up. I really have to send a DIT before any initial transmission. But I am very satisfied with Bitx40 and waiting for the new update.
?
73 from Junior
PY2ADA
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Looks like you have interchanged the ground and antenna wires!
Black is ground everywhere in BITX40. Brown is the center pin of BNC or
SO239.
Let us know!
Good luck
Raj
At 07/07/2017, you wrote:
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Hi all,
I moved my Bitx40 board to a smaller enclosure and somewhere along the
line I ended up with massive breakthrough from AM stations.
This happened even with the VFO unplugged from the board.
The breakthrough stopped (surprisingly) when I grounded the centre
contact of the antenna input. 7mhz? SSB signals came through
fine!
I experimented with a couple of capacitors across the antenna input
instead of the grounding, and finally used a 100pf capacitor.
Now the receive is great, no AM breakthrough at all and a reduction in
noise. Signals still getting through fine.
Transmit seems ok (on a nearby receiver), but I haven?€?t tested power
output.
I?€?m not sure how that all worked. I have Peter parker?€?s improved
audio transmit mod. Also removed the 1uf capacitor between pins 1 and 8
of the LM386
and replaced with resistor/capacitor.
Any thoughts?
John
VK2VOL
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Drill very slowly i.e. don't be in a hurry. Acrylic melts and the bit will grab the sheet and spin it and you could get hurt.
I have built many projects with it and even built paddles. I used water to cool the bit and end mills.
I used to save the shavings and dissolve then is a small glass bottle with chloroform and use that as glue.
I learnt this from a local sign board maker in the old days.
Raj
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At 08/07/2017, you wrote: Do you have to be careful when drilling the acrylic to avoid cracking?
Phil, W1PJE
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Do you have to be careful when drilling the acrylic to avoid cracking?
Phil, W1PJE
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I'm just getting started with my BITX40 kit, without Raduino (at present). First power-up was *incredibly* noisy. with audio seemingly OK. I've since ratted a 1000uF/16V electro cap and 27 ohm (2W?) resistor from a defunct PC power supply and used them to filter the power supply (a junk-sale purchase never since used). Whoopee (I don't Yahoo)! Clean audio - minimal hiss at full volume, indicating healthy rig. No antenna yet, so the rest still unknown, but I've now verified the purchase was worth it! Thanks, Farhan and crew, and folks and hints from here ...
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Hi, Jerry,
very weird is a good description.
As you suspected, the rig did not want to transmit with the 10 nf capacitor across the antenna.
I moved the capacitor to C1 - added it parallel to C1 - and it fixed the receive audio, but again did not want to transmit with any power.
(I thought C1 would be out of circuit during transmit, but I¡¯m not great at reading the schematics!)
Back to square 1, I removed the capacitor and I can transmit ok, but back to noisy receive.
I checked C1 and it reads as 1200 pf instead of the 470 pf on the schematic. That might be my inaccurate capacitance meter.
The Bitx has had a big burst of RF from a nearby transmitter, maybe that upset something.
I¡¯ll keep experimenting. I do have a good antenna (ZS6BKW) so plenty of signal going into the Bitx.
John, VK2VOL
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On 8 Jul 2017, at 12:32 am, Jerry Gaffke via Groups.Io < jgaffke@...> wrote:
My thought is that this is very weird. I'd be checking all those connections around the antenna with an ohmmeter. Make sure everything you think is connected is really connected. If you want to try transmitting with the rig in such a questionable state,? maybe start out with a 10v power supply into the IRF510 and increase it to 12v? only if a watt or so is getting through to the dummy load. ?If you do have a bad connection at the antenna BNC, the high SWR could blow the IRF510. Especially if you are feeding the IRF510 more than 12v. Jerry On Fri, Jul 7, 2017 at 07:21 am, John Sharpe wrote:
The breakthrough stopped (surprisingly) when I grounded the centre contact of the antenna input. 7mhz ?SSB signals came through fine!
?
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This with a proper bezel can give the Bitx40 a great look!
73
--
Raj, vu2zap
Bengaluru, South India.
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I had a low level buzzing sound in my Bitx40 when the volume was at a low level.
I disconnected the center brown lead of the volume control and added a 10K
resistor from the pot to the wire and problem solved.
Cheers
--
Raj, vu2zap
Bengaluru, South India.
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Re: BITX40 Microphone options
On my analog VFO board #66, I measured across C107 - a level of 500+ mV
pp gives full power with the level control
R136 midway.
With the supplied mic I can't get the power while speaking in a normal
level. With a normal voice I should be able to
see 3-4 watts!
Raj, vu2zap
At 08/07/2017, you wrote:
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On Thu, Jul 6, 2017 at 07:24 am,
Raj vu2zap wrote:
- With my lung capacity down I can't do "haaaaloo" level of
yelling anymore so I am using an amped motorola mic.
What voltage (Vpp) do you look for going into the bitx's mic in?
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Raj vu2zap
J¨²nior PY2ADA