Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- BITX20
- Messages
Search
Re: Volume not working and high pitch squeal on bitx40
Put a resistor of any value between 1-10K in series with center lead of volume control
toggle quoted message
Show quoted text
and see if that stops it. Raj At 29-12-18, you wrote:
Hello, I am having problems with my bitx40, whenever I listen in there is a very high pitch squeal, and you can't hear actual radio, and if you touch the potentiometer, other sounds can be heard. I have tried to resolve the connection, but I still have the problem. |
Re: Antuino - the antenna analyzer
Must be following this group!
toggle quoted message
Show quoted text
Raj At 29-12-18, you wrote: The SMD AD8307 was selling for two dollars on mouser, then suddenly upped the price.? |
Volume not working and high pitch squeal on bitx40
Hello,? I am having problems with my bitx40, whenever I listen in there is a very high pitch squeal,? and you can't hear actual radio,? and if you touch the potentiometer, other sounds can be heard.? I have tried to resolve the connection,? but I still have the problem.?
Any help would be appreciated. |
Re: Antuino - the antenna analyzer
The SMD AD8307 was selling for two dollars on mouser, then suddenly upped the price.? - f On Sat, Dec 29, 2018 at 11:54 AM Jerry Gaffke via Groups.Io <jgaffke=[email protected]> wrote: Tacking an AD8307 into a uBitx between the 12mhz crystal filter and the demodulator |
Re: Antuino - the antenna analyzer
Tacking an AD8307 into a uBitx between the 12mhz crystal filter and the demodulator
toggle quoted message
Show quoted text
could make it useful as a spectrum analyzer.?? Given the better crystal filter and the higher first IF of the uBitx, should be a better choice than an Antuino. Though may not fit into a cubesat. The AD8307 is $13 each up on Mouser. Ebay sellers have them at about $0.30 each. The ebay parts reportedly work well enough, but may be a bit out of spec with regard to calibration. ?? Jerry On Fri, Dec 28, 2018 at 09:46 PM, Jerry Gaffke wrote: I was assuming the Antuino would have a set of front end filters for each region of interest. |
Re: Antuino - the antenna analyzer
jerry,? we need 80 db dynamic range for useful work with specans. at 6db per bit, this pushes for a 14 bit dac or better. these, including thr rtl-sdr family are hardly useful. for a radio amateur, a double conversion specan can easily be buily for less than $100?providing as good a performance as thr professional ones with limited range and bandwidth selection. with 110 mhz as the first IF and 12 mhz as the second, onr can span 0-70 mhz easily? - f On Sat, 29 Dec 2018, 11:16 Jerry Gaffke via Groups.Io <jgaffke=[email protected] wrote: I was assuming the Antuino would have a set of front end filters for each region of interest. |
Re: Antuino - the antenna analyzer
I was assuming the Antuino would have a set of front end filters for each region of interest.
toggle quoted message
Show quoted text
Though the 25mhz IF is kind of low for this to be convenient. Arv's DC receiver as a spectrum analyzer is also worth considering.? I've had parts here for a year or so to build a 0-55mhz spectrum analyzer? around two of the PX1002 86.85mhz SAW filters.?? Seeing the Antuino, I'm inspired enough to have parts splayed out?on my workbench, an enclosure selected, am about to cut the bare PC board to fit.? Will build ugly style, use 3/4" copper pipe cut into 1/4" high cylinders to provide a shield for each section, bolt a plate over the top once it works. Signals going off to the next shielded section will have a wire through a hole in the board to to where it's held down to the back groundplane using copper tape.? So almost coax, the one inch runs short enough that impedance won't be an issue. But by selecting appropriate wire diameter and insulation thickness, might hit 50 ohms. And if it works, maybe add another stage up front using a 915mhz SAW filter. That first VFO would have to do something like 915 to 1500mhz. Either a clock doubler on the 1000mhz si5340, or perhaps the si549. But of course, I'll have a hard time looking at that stuff when it doesn't work. Anybody have a feel for how well the cheap $200 laptop based spectrum analyzers are doing?? Is there much reason to homebrew other than as a hobby? How do those $200 units compare to a Rigol SA? Jerry, KE7ER On Fri, Dec 28, 2018 at 08:05 PM, Ashhar Farhan wrote:
the challenge would be to eliminate the if image. this could be done when you sweep to both sides and eliminate the image reading in software. here is an example : |
Re: uBITXv4 for sale
#ubitx
And if it were to become by possibly various way a radio museum
toggle quoted message
Show quoted text
or the items were to be a radio museum? I wonder too if there is not someone who would want to be the owner of such a collection in its entirety and had the wherewithal to make it happen. It seems somehow undesirable that there would be a break-up of such a collection. In many ways, it IS amateur radio history. My imagination working here and I do not mean to be morbid about it. Bob ¡ª KK5R -------------------------------------------- On Fri, 12/28/18, K5ESS <k5ess.nothdurft@...> wrote:
I apologize if this is a bit morbid, but the mother of all estate sales on Ebay looms in the future. Mike K5ESS From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io Sent: Friday, December 28, 2018 9:22 PM To: [email protected] Subject: Re: [BITX20] uBITXv4 for sale #ubitx But wait... There's more! He's an equal opportunity collector. I saw my long lost piece-o-crap Hallicrafters S120 in there, about 10 down from Jack's photo, top left. Also the ARC-5 receiver I used while in college. Look hard enough at those photos and you will find every piece of store-bought communications gear you ever touched. Jerry |
Re: uBITXv4 for sale
#ubitx
¿ªÔÆÌåÓýI apologize if this is a bit morbid, but the mother of all estate sales on Ebay looms in the future. Mike K5ESS ? From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io ? But wait...? There's more! Naw. This is too many radios... |
Re: Antuino - the antenna analyzer
the challenge would be to eliminate the if image. this could be done when you sweep to both sides and eliminate the image reading in software. here is an example : 1. lets imagine that there is a signal at 10 mhz. for this, we set the local oscillator at 35 mhz (as the IF is at 25 mhz). how can we be certain that the signal we are resolving is not at 60mhz (60mhz - 35 mhz = 25 mhz)? 2. we can take a second reading by setting the local oscillator at 85 mhz. in this csse, thr 60 mhz response (if any) should show up. else we can confirm that the signal we resolved in step 1 is indeed a 10 mhz signal. one has to be aware that such a system will be slow. lets imagine that you have to sweep 30 mhz. the crystal filter is 10 khz wide. hence, we will need 30,000/5 = 6000 readings. if we can get, 100 readings a second, this will take a minute to complete the scan. an alternative would be to have two filters, a crystal filter and a 4 or even 5 section LC filter at around 12 mhz. we could switch to the lc filter for large sweeps. my specan circuit has a suitable design. you are aking what happens if there was signal at 110 mhz in step two? aaaah, you tell me! - f On Sat, 29 Dec 2018, 00:48 Jerry Gaffke via Groups.Io <jgaffke=[email protected] wrote: It already is a simple SA. |
Re: uBITXv4 for sale
#ubitx
Jack Purdum
Bob: That's not my shack. It belongs to George Ulm, W9EVT. Everyone I show the picture to says it's a remarkable collection. No, what's remarkable is his wife and that he's still married! Jack, W8TEE
On Friday, December 28, 2018, 7:08:03 PM EST, Bob Lunsford via Groups.Io <nocrud222@...> wrote:
RE: This is too many radios... Inline image Jack W8TEE Now, that is worthy of a feature article in QST. I have to wonder how you find the time to spread around the operating table/s for keeping those radios in shape... The Radio Museum in Huntington, WV would love to have a pic of your station to post on one of their walls. Bob ¡ª KK5R -------------------------------------------- On Fri, 12/28/18, Jack Purdum via Groups.Io <jjpurdum=[email protected]> wrote: Subject: Re: [BITX20] uBITXv4 for sale #ubitx Date: Friday, December 28, 2018, 9:57 AM ? ? ? ? ? ? ? ? ? ? ? ? I have too many radios! Naw. This is too many radios... Jack W8TEE ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? On Friday, December 28, 2018, 8:46:12 AM EST, Jim Reagan <jimreagans@...> wrote: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? I have too many radios! (like 6 transceivers, including another uBITX)? This is a version 4 uBITX in a nice case (Fry's).? It has a 2.8" Nextion display, AGC/S meter, Axicom relays, and an LM386 audio amp. (The original audio is all there, just not loud enough for me) Includes power cord and mike. I used it on FT8 and SSB.? Asking $199, which includes USPS Priority shipping CONUS only.? Thanks, Jim W0CHL ? ? ? ? ? ? ? ? ? ? |
Re: uBITXv4 for sale
#ubitx
But wait...? There's more!
toggle quoted message
Show quoted text
? ?? He's an equal opportunity collector. I saw my long lost piece-o-crap Hallicrafters S120 in there, about 10 down from Jack's photo, top left. Also the ARC-5 receiver I used while in college. Look hard enough at those photos and you will find every piece of store-bought communications gear you ever touched. Jerry On Fri, Dec 28, 2018 at 06:57 AM, Jack Purdum wrote:
Naw. This is too many radios... |
Re: uBITXv4 for sale
#ubitx
Mike Short
I ship all over the world and have not had any issues? On Fri, Dec 28, 2018 at 7:08 PM Bob Lunsford via Groups.Io <nocrud222=[email protected]> wrote: RE: |
Re: uBITXv4 for sale
#ubitx
RE:
toggle quoted message
Show quoted text
This is too many radios... Inline image Jack W8TEE Now, that is worthy of a feature article in QST. I have to wonder how you find the time to spread around the operating table/s for keeping those radios in shape... The Radio Museum in Huntington, WV would love to have a pic of your station to post on one of their walls. Bob ¡ª KK5R -------------------------------------------- On Fri, 12/28/18, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
Subject: Re: [BITX20] uBITXv4 for sale #ubitx To: [email protected] Date: Friday, December 28, 2018, 9:57 AM I have too many radios! Naw. This is too many radios... Jack W8TEE On Friday, December 28, 2018, 8:46:12 AM EST, Jim Reagan <jimreagans@...> wrote: I have too many radios! (like 6 transceivers, including another uBITX)? This is a version 4 uBITX in a nice case (Fry's).? It has a 2.8" Nextion display, AGC/S meter, Axicom relays, and an LM386 audio amp. (The original audio is all there, just not loud enough for me) Includes power cord and mike. I used it on FT8 and SSB.? Asking $199, which includes USPS Priority shipping CONUS only.? Thanks, Jim W0CHL |
Re: BitX40 low power output
#bitx40
The audio chain is just the mike pre-amp at Q12.
toggle quoted message
Show quoted text
A good start would be to check for the DC voltages that Randy gave us. Key the mike, but no need for audio into the mike. Next step is to do Allard's mods (either version), and see if you get full power as a CW transmitter. If it works for CW, then (on the Bitx40) it all comes back to trouble around the mike and Q12. If you can figure out a way to feed 50mv of 1khz audio into the mike amp, maybe try that. But mostly just inspect those parts for bad solder joins, bad wiring to the mike, bad mike, perhaps probe around as much as you can with an ohmmeter to verify that things are still soldered together ok. Jerry, KE7E On Fri, Dec 28, 2018 at 07:07 AM, David Arthur wrote: Jerry, thanks for the tips. I was able to adjust RV1 and see 100mA with the key down and no audio input. However, I do not see the 1A current when shouting/whistling into the mic. My "power meter" is a QRP Labs dummy load with pinouts for the voltage across the resistors (and a formula for calculating watts). I still only see 3V peak across the load which is very low (should be like 20V or more I think). |
to navigate to use esc to dismiss