Re: Files upload problem.
It appears that after the maintenance the files upload permissions have been set back to moderator only.?? Hans?
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Rob G4NQX
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Anyone else unable to upload a file ?? The option to upload has vanished so I cannot update the Tips n Mods docs in the files section. I've tried logging out and back in but just the same.? I still have folder priviledges but not file upload. Rob G4NQX
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Re: BitX40 Tips and Mods doc
Errrr No.? What's happened ?? I can't upload the files ! I'll attach them here.
Rob G4NQX
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Re: BitX40 Tips and Mods doc
Updated with a few more tips etc. Rob G4NQX
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Re: Bourns 10K 10 turn arrived
I never heard of the brand before.? This is very new to me even though I've been a ham 25 years and been playing with computers and such for 15 more than that.? It looks good and i do know that a finer resolution provides slow moves in tuning.
On Fri, Feb 3, 2017 at 2:11 AM, John Backo via Groups.Io <iam74@...> wrote: FB, Ronnie.
A genuine BOURNS 10k 10-turn pot with all the trimmings for $US8.00. That's a coup!
john
AD5YE
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Re: increase frequency coverage
Oops! You're right, Raj.
The same principles apply...but in reverse.
He still has to experiment, as you suggest, and find out what happens.
john
AD5YE
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Re: Searching the messages
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Re: increase frequency coverage
Hi John,
I see here that you are suggesting what is right for a normal designs but this one is opposite
12Mhz - VFO, so you need to make the VFO go lower for the range to go higher.
Confused the hell out of me in the beginning. Then I programmed my Racal Dana to do math
and subtract VFO - 11.9985 -> giving me a -7.xxxxx display. The reverse is not available
in the 1992 model. Now with the negative frequency I might have a QSO with aliens eh?
Cheers
Raj, vu2zap
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If your C93 is set to minimum capacitance, and the high end of the frequency range is still not enough, then remove a turn or two from the inductor, L4.
If your capacitor C93 is set somewhere above the minimum, then decrease it to raise frequency high end, and increase it to lower it.
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Re: Searching the messages
Hans,
Can we not have SUB GROUPS here like
BITX40 VFO
BITX40 Raduino
BITX40 Box
BITX20 etc..
Just a thought, I have not tried it on my groups but seems worth looking info!
73 Raj
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At 03-02-2017, you wrote: Hi John
At the top of the browser window there are three buttons. One has "Topics View". One has "#HashTags". The rightermost one has a little icon that looks like magnifying glass. This is the SEARCH button. Click it and search away... the difference to Yahoo! is that groups.io search is 30dB faster!
73 Hans G0UPL
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Re: increase frequency coverage
Ricardo,
I can't specifically tell you. You will have to first add the varacters
and then see what range you are getting and
then you can message me for further ideas.
First add parallel varacters and see what range you get.
Changing C96 from 100pf to sat 330 or 470 will improve the range as it
is. Use NP0/C0G for all
caps in the VFO. My board is very stable drifts only 10-20Hz and 50Hz in
the long term.
At the moment I have 3 in parallel with 6uH and 150pf extra and get
200Khz but stabler VFO.
73 Raj
At 03-02-2017, you wrote:
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hi do you mean? to reduce
turn number in L4 by how much turn? what is the inductance value for the
L4 nominal?
- On Fri, 3 Feb, 2017 at 12:27, Raj vu2zap
- <vu2zap@...> wrote:
- Change the varactor to one that has higher capacitance tune ratio
or
- Alternatively, add an MV209 or 2109 in parallel with the one on the
PCB
- The tuning range will increase.
- You may need to tweak the trimmer and maybe change some turns on
- the yellow VFO toroid.
- I was able to do that easily!
- 73 Raj
- At 03-02-2017, you wrote:
- >Hi,
- >
- >??? Kindly help, Is there a way to increase
frequency coverage? of BITX40 v3
- >
- >??? from 7.100 to 7.500 mhz ( a 400khz bandwidth
or more )? By the way? my
- >
- >??? BITX40 V3? is non Raduino? and?
using the? stock? vfo.
- >
- >
- >??? Regards,
- >
- >??? Ricardo Rivera
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Re: Searching the messages
Hi John At the top of the browser window there are three buttons. One has "Topics View". One has "#HashTags". The rightermost one has a little icon that looks like magnifying glass. This is the SEARCH button. Click it and search away... the difference to Yahoo! is that groups.io search is 30dB faster!? 73 Hans G0UPL http://qrp-labs.com
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Hi! ?Just my couple of bucks worth here - if my everdepleting memory serves me right, the MKARS80 is a relative of the BITX in all its iterations. ? The MKARS clicks continuously and I haven't found a way to cure this yet. ?I have a BITX40 ordered, and would be interested in any cures fore the clicking......might even be able to cure my longsuffering MKARS80! Norm vk5gi McLaren Vale South Australia
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Re: Bourns 10K 10 turn arrived
FB, Ronnie.
A genuine BOURNS 10k 10-turn pot with all the trimmings for $US8.00. That's a coup!
john
AD5YE
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Re: increase frequency coverage
I think it was mentioned before that it is ~6-10 uH.
If one is to increase the frequency span, it cannot be done by changing the inductance alone, unless one increases it by adding more turns.
This is not recommended for a VFO. Generally one should increase the capacitance of the tank circuit.
The suggestion to add another varactor in parallel to the one on the board is a good one. Note though, that the minimum capacitance will have to be changed
to increase the upper end of the frequency range -- hence the thought that one MIGHT have to change the inductance by a bit.
Think of it this way: for a resonant circuit F = 25330/LC where f is in megaherz, L is in microhenries, and C is in picofarads. Find this value for the minimum
and maximum frequencies you want, and try to compare them with what you have. You will probably find that it will take only a few pF to achieve your goal.
I easily changed my range by changing the variable capacitor C93 from 22 pF to 33 pF.
If your C93 is set to minimum capacitance, and the high end of the frequency range is still not enough, then remove a turn or two from the inductor, L4.
If your capacitor C93 is set somewhere above the minimum, then decrease it to raise frequency high end, and increase it to lower it.
But to increase the range, the total capacitance has to be increased, most easily by adding another varactor.
As always, experiment and measure to find the right combination. It works.
john
AD5YE
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One of the better features of the Yahoo Group was the ability to search the entire message base by topic, or even by contributor.
I have not found that to be the case here. Is there a general message search function? How it it invoked?
john
AD5YE
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Messages 21347 and 21366 would seem to point to this as being a layout and/or wiring problem. The mcu will produce RF noise. They all do.
The trick is finding the right combination to minimize or eliminate that noise. It might be a particular part, like the tuning pot. It might be in the power supply filtering.
It might be in the routing and shielding of the wiring. It might be in the way one puts together the case. It's probably one of those.
In any event, it looks off-hand like enough fiddling and changing "the way things are" will solve the problem. At least there is little indication that anything major needs to be done.
john
AD5YE
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Re: increase frequency coverage
hi do you mean ?to reduce turn number in L4 by how much turn? what is the inductance value for the L4 nominal?
On Fri, 3 Feb, 2017 at 12:27, Raj vu2zap <vu2zap@...> wrote: Change the varactor to one that has higher capacitance tune ratio or
Alternatively, add an MV209 or 2109 in parallel with the one on the PCB
The tuning range will increase.
You may need to tweak the trimmer and maybe change some turns on
the yellow VFO toroid.
I was able to do that easily!
73 Raj
At 03-02-2017, you wrote:
>Hi,
>
>? ? Kindly help, Is there a way to increase frequency coverage? of BITX40 v3
>
>? ? from 7.100 to 7.500 mhz ( a 400khz bandwidth or more )? By the way? my
>
>? ? BITX40 V3? is non Raduino? and? using the? stock? vfo.
>
>
>? ? Regards,
>
>? ? Ricardo Rivera
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I have the clicks. Very loud. I run straight from a battery. I have not attempted to remedy the problem yet. Too many other things going on right now. Mark K3MRK ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of M Garza
Sent: Thursday, February 02, 2017 9:36 PM
To: [email protected]
Subject: Re: [BITX20] Tuning clicks? Joel, ?What kind of power supply are you using with your radio?? Switching, linear?? What's the voltage?? I am wondering if the radios with higher voltages (>13vdc) are the ones having the issue.? My radio is still in transit, or I would test my theory. ? On Feb 2, 2017 6:36 PM, "Joel Caulkins" <caulktel@...> wrote: I have no clicks from my Raduino at all, even with the vol all the way up and the antenna disconnected I cannot hear any clicks while tuning. Strange that some do. Hi Alf, Had a listen to the radio last night with the antenna connected and if there were clicks they were down at the level of the internal receiver noise.? Cheers, Glenn VK3YY.
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Re: increase frequency coverage
Change the varactor to one that has higher capacitance tune ratio or
Alternatively, add an MV209 or 2109 in parallel with the one on the PCB
The tuning range will increase.
You may need to tweak the trimmer and maybe change some turns on
the yellow VFO toroid.
I was able to do that easily!
73 Raj
toggle quoted message
Show quoted text
At 03-02-2017, you wrote: Hi,
Kindly help, Is there a way to increase frequency coverage of BITX40 v3
from 7.100 to 7.500 mhz ( a 400khz bandwidth or more )? By the way my
BITX40 V3 is non Raduino and using the stock vfo.
Regards,
Ricardo Rivera
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Re: increase frequency coverage
No schema included in my kit but it is the same as posted with ?hfsigs web minus the raduino.
On Fri, 3 Feb, 2017 at 8:34, Ion Petroianu <ion.petroianu@...> wrote: Did you received a schematic with your kit? Can you post it? Is it the same schematic as the version with Raduino only using the coil? I will need the information to calculate new values for capacitors required for your desired frequency coverage.
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Ion VA3NOI
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Raj vu2zap
Ricardo Rivera