Keyboard Shortcuts
Likes
- BITX20
- Messages
Search
|
Re: Strong stations too loud even at lowest volume
Using a pot between antenna and ground, center wiper into the receiver, seems the most obvious thing. ?The ideal place for such an RF gain control would be in the wire between K2-14 and K1-12, an attenuator there will only affect the receiver. ?Pot should have short wires to it, or use coax. Should also work fine to put a 1k pot in front of C11, as output of the transmit amp at Q4 would then only see 1k to ground regardless of the position of the RF gain control. ?Also, that node is free floating with DC blocking caps in all directions. ?But can't be on the Q1 side of C11, as that would muck with the DC bias into the base of Q1. ? ? What's the best way to do AGC here, such that it affects the RF gain and not AF gain? Does Don's trick of cutting power to Q1 make that first RX amp go non-linear, and introduce crud into the received signal? On Mon, Jan 23, 2017 at 05:42 am, Lawrence Galea wrote:
The simplest way. ? |
|
Re: Strong stations too loud even at lowest volume
Jack Purdum
I bread boarded Peter's set up and it works great. The only variation I had was I put the LED and LDR in a sleeve of shrink tubing. (I bought a bag of the stuff at Dayton for next-to-nothing and I'm going to have to live to be 150 to use it all up. If it doesn't move and I can't eat it, it ends up in shrink tubing...) Jack, W8TEE From: Peter Parker <parkerp@...> To: [email protected] Sent: Monday, January 23, 2017 4:06 AM Subject: Re: [BITX20] Strong stations too loud even at lowest volume Another AGC idea. ? Uses an LED & LDR. ?Louder signals brighten the LED which reduces the LDR's value which reduces the volume, so compressing the audio.?
https://www.youtube.com/watch?v=IQ5JEPRiPoM |
|
Re: Strong stations too loud even at lowest volume
The simplest way. A pot at the aerial input to the receiver side. 50¦¸, 100¦¸, 1k¦¸, 10k¦¸ whatever you have. Aerial input to the top, centre to receiver, other contact to earth. Used it way way back and it works.? Low values are better.? Just try it. V I ? ? ? ?Potentiometer? I ------- Antenna < > < ><---------Receiver input < > I ------- earth |
|
Re: Second tuning pot in analog
Thank you
toggle quoted message
Show quoted text
72, Bob KI0G On Jan 23, 2017, at 7:19 AM, Rajendra Kumar G G <vu2zap@...> wrote: |
|
Re: Second tuning pot in analog
Bob,
toggle quoted message
Show quoted text
A bourns 100K 10 turn pot will do a great job. Alternatively use a pot of 10% of the value of the main tuning and connect the center and end pin in series to the tuning pot. Disconnect the earth end of original tuning pot. Connect the end of fine tune pot to ground. Connect the center of fine tune pot to the main pot disconnected earth end. If the tuning works reverse of what you expect then use the other end of fine tune pot to ground. That should do it! At 23/01/2017, you wrote: How do you wire the second pot in series? |
|
Re: Strong stations too loud even at lowest volume
R15 serves as part of the stage supply filtering. I would leave it. If you want to remove R16 then be sure to install a 220 ohm resistor in series with the switch or control. That will limit the current. A switch works very well, don't discount the simplicity and utility. I would recommend that you only do this at this one stage. The others need to provide the proper terminations to the crystal filter. -ND6T |
|
Re: Battery recommendation...with external amp
Sounds like I would be well off going LIPO, I don't want to go with an automotive or RV battery - I have to lug one of those when I go camping anyway, as I run a CPAP on an inverter when I am sleeping (if I start out fully charged it lasts a full weekend), but I really don't want to run my radio equipment off the same battery, for obvious reasons. If I can charge my radio battery packs off my car's battery overnight, then run the car engine for a bit to charge the car battery back up, or run a SMALL solar charger during the day to charge spare packs (big panels get expensive...), that would be fine as well. I live in northern Michigan so we don't get as much sun (or wind, most of the time) as the fellow in Texas does... Rich KC8MWG On Monday, January 23, 2017 1:12 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
|
|
Re: Question about power to raduino
¿ªÔÆÌåÓýMine hasn't arrived here either yet but in addition to Steve's advice, I would also check that you have a ground connection to the Raduino board. Bill, VK7MX On 23/01/2017 4:38 PM, Steve Robertson
wrote:
|
|
Re: Battery recommendation...with external amp
If I had the motorcycle battery handy, I'd certainly use it. ?Check water levels occasionally if it has vent caps, especially if it's on the charger much. ?I even suggested somebody try a motorcycle battery here a few weeks ago when I thought they might be having trouble with their switching power supply. ?But they aren't built to give a lot of discharge cycles, and lithium is far better than lead if you are going to be lugging it around in a backpack. ?
|
|
Re: Battery recommendation...with external amp
M Garza
Thanks for the info, Jack.? The battery is a sealed lead acid from a game feeder.? I had it & the solar panel, so I though I would use them.? I want to be able to hike out to the shore (3 miles or so) with everything. Since I will be playing with arduino now, I should pickup that book. Thank you everyone, for the direction and suggestions. Sorry Rich, I did not mean to hijack the thread. Marco - KG5PRT On Jan 22, 2017 11:24 PM, "Jack Purdum via Groups.Io" <econjack=[email protected]> wrote:
|
|
Re: Question about power to raduino
Yup. ?So power goes into one terminal of the switch on the volume control from that outside connector, and power goes from the other terminal of that switch to the three places where power is needed: Raduino, PA-Power, Main-Power. ? And all three of those places have ground returns to outside connector. ?(And I don't have mine yet either) That wire-up page needs a proof-reader. |
|
Re: Question about power to raduino
My unit hasn't arrived yet, but the instructions on the BITX site say: Solder the orange wire to the DC power switch on the volume control Sooo, there's a switch on the volume control, one side of that switch has to have the power input and the other side is the switched power, use a meter and to find the switched terminal, then hook your orange wire there. |
|
Re: Battery recommendation...with external amp
Jack Purdum
Marco: I don't know how "portable" you need to be, but I've used a 10W panel with my Forty-9er and it worked well. I was given a 7AH motorcycle battery, so that's what I used. I don't use it a lot, but when I have, it worked fine. As I recall, the panel is about 17"x10" and weighed about 3.5lbs. I also used a cheap ($10) solar panel charge regulator with the setup. I kept all of the electronics and battery in a toolbox. (I had an Arduino controlled stepper motor that adjusted the panel throughout the day so it always faced the sun. You can see it in the Arduino Projects for Amateur Radio book.) Jerry's suggestion for a different battery makes sense and may be cheaper in the long run. Jack, W8TEE From: M Garza <mgarza896@...> To: [email protected] Sent: Sunday, January 22, 2017 10:38 PM Subject: Re: [BITX20] Battery recommendation...with external amp Jerry,
WOW.? Completely off grid.? Nice. I guess I need to investigate better batteries (NI-MH maybe?) and solar/wind power.? I live near the coast, in S. Texas.? Plenty of sun and wind. ? Marco - KG5PRT On Jan 22, 2017 9:28 PM, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote:
|
|
Question about power to raduino
James Gardner
Hi. This is my first attempt at trying a kit of any kind and I have a question that is probably extremely simple to those who are used to kit building. I ordered and received this Bitx40. The other day I finally got some free time and tried my hand at putting it all together. I've got everything together except the power for the raduino. Instructions say to wire the orange wire to the the power/volume control but this is not giving me power to the raduino. Both rig and pa power is wired to the power input connector and the rig itself turns on and off as it should. Wiring orange wire straight to power input connector does not allow the raduino to turn off by turning rig off. I have tried attaching the orange wire to different pins on the power/volume control with no luck. What am I missing? |
|
Re: I was able to compile the BITX40 code
Andy -
Since I'm waiting on my BITX40, I decided to play with the raduino sketch. I installed the most recent Si5351 library (Etherkit_Si5351-2.0.1). I followed your advice and searched for the instances of set_freq and deleted the middle term (there were four instances), however when I compiled I still got an error. I referenced the library change log and found this: "The init() method now has three parameters: the crystal load capacitance, the reference frequency, and the frequency correction value (with this last parameter being a new addition). You'll need to add that third parameter to your old init() calls, but then you can delete any set_correction() calls after that (unless you explicitly are changing the frequency correction after the initialization)." And the init call was indeed the compile error.? I added a 0 as the third parameter and now the code compiles with the new library, though I'm as of yet unable to test it. I have uploaded the sketch to the KA0NEB File Folder, along with a compiled hex for those who wish to forgo library installation and compiling and would rather just load it with XLoader. Steve, KA0NEB |
|
New file uploaded to [email protected]
[email protected] Notification
Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group. File: Raduino_V1_1.zip Uploaded By: Steve Robertson Description: You can access this file at the URL: Cheers, |
|
Re: Battery recommendation...with external amp
M Garza
Jerry, WOW.? Completely off grid.? Nice. I guess I need to investigate better batteries (NI-MH maybe?) and solar/wind power.? I live near the coast, in S. Texas.? Plenty of sun and wind. ? Marco - KG5PRT On Jan 22, 2017 9:28 PM, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote:
|
Raj vu2zap
Don, ND6T