Bitcoin donations to: 1CE9UfWJcHBYkWPns7iqBqZgKhd5xfqEaM thanks!
Buy Bitcoins easily by clicking HERE!


Use coupon radiopreppers for 20% off on the above site.

Recent Posts

Pages: 1 2 3 [4] 5 6 ... 10
31
Hi Stan,

I am aware about insulating the IRF510's from ground, I have done this on all 5 of my Bitx builds.

 As far as the harmonic/spur problems of the uBitx are concerned, its far too complicated for me to explain, and due to the fact that no two people can agree to anything on that group, it muddys  the water even further. Suffice it to say, something needs to be done and I'm waiting to see what Farhan comes up with, he always seem to find a simple solution to problems as opposed to these people that want to start from scratch and completely redesign the radio.

Joel
N6ALT
32
Don't know if any of you have been following the debacle going on over at the bitx20.io group regarding the uBitx, but those few fortunate people who have quality Spectrum Analyzers and know how to use them, have found that the uBitx 'mostly' does not pass FCC specs, (US), for spectral purity, (some nasty spurs). Some are advising not to use them on the air until some kind of fix is figured out. Funny I have been using mine every since they came out and nobody has knocked at my door yet, but I don't want them to either. All of the EE's on the group are seeking to redesign the uBitx to meet specs. I find this whole thing to be rather disheartening after all the time and effort I put into my two radios. They are talking about cutting the traces going to the LPF section and adding a daughter board with a new LPF design to fixed the existing boards. Not quite sure what to do but wait and see what everybody comes up with. :( :-[ :-\

Joel
N6ALT

I own a µBitX but I'am not a subscriber of this group. Did they say anything about the frequencies of those spurs ? Are they over 30 MHz  ? In this case, an external third order LPF (at the cost of a few dB of power loss) might do the job...

73's, Stan.
33
I ordered another uBitx, it should be here in a few days. It will be the V4 board with some improvements incorporated into the new PCB. I will be using a 3.2 inch Nextion touch screen display on this one.
I'm going to make numerous case improvements to this one, like bolting the finals to the case for better heat dispersion. Gil, you wont like this one because it's going to have a higher idle current draw than the previous one, but it isn't intended for portable use.
I look forward to starting work on it. Ill post my progress.

Joel
N6ALT

Be careful with the finals. If I recall well, the IRF510's back is connected to the drain, which is not "groundable". If you want to bolt them to the case, don't forget to use TO220 insulation kits  ;)


73's, Stan.
34
Military Radios / Re: Czech Military RF-10 Radio.
« Last post by W5IJH-Jeff on August 28, 2018, 07:41:27 AM »
The battery was shot when I received the radio (no surprise) Bought a Duracell Ultra SLAB 6vdc 3.3Ah. Unsoldered the positive and negative wires to battery holder and gutted the battery box. As a note, there are 2 little C-clips holding the positive and negative terminals in place. Remove those and push the terminals up through the plastic cell holder. I just crimped and soldered on F1 spade lugs. I centered the SLAB in the battery box and used 2 pieces of foam to hold the battery in place. I carefully connected the battery lid onto the battery box and installed the unit onto the radio. It powered on and I ran through a functional check before trying to make a contact. Set frequency to 52.025MHz and made contact with a friend who was waiting. Audio was surprisingly good. Distance was about 1 mile.  I have a fondness for "Greenies" even though modern stuff is better and more compact. I've been pretty impressed with this little radio despite it's limitations and functionality. In fact, I bought a PRC-351 which will arrive next week. This should be fun!
35
Morse Code / Re: Learn How To Increase Your Morse Code Copy Speed.
« Last post by gil on August 28, 2018, 04:34:52 AM »
Excellent Chris, just keep doing it, it does take a long time...

Gil.
36
Morse Code / Re: Learn How To Increase Your Morse Code Copy Speed.
« Last post by cthompson01 on August 27, 2018, 09:47:19 PM »
I followed your advice and I'm slowly getting there.  I passed my 5 wpm test many years ago to get my tech license and then did nothing cw wise.  After watching your video I downloaded the app "Morse Machine" by IU4APC, set it to 25 wpm and subjected myself to 30 minute practice sessions.  It gets frustrating.  But, I'm realizing I'm starting to pick up morse characters more by sound rather than counting dits and dahs.

Chris
37
Morse Code / Re: Can Morse Code Still Save You?
« Last post by gil on August 27, 2018, 05:27:00 PM »
38
Don't know if any of you have been following the debacle going on over at the bitx20.io group regarding the uBitx, but those few fortunate people who have quality Spectrum Analyzers and know how to use them, have found that the uBitx 'mostly' does not pass FCC specs, (US), for spectral purity, (some nasty spurs). Some are advising not to use them on the air until some kind of fix is figured out. Funny I have been using mine every since they came out and nobody has knocked at my door yet, but I don't want them to either. All of the EE's on the group are seeking to redesign the uBitx to meet specs. I find this whole thing to be rather disheartening after all the time and effort I put into my two radios. They are talking about cutting the traces going to the LPF section and adding a daughter board with a new LPF design to fixed the existing boards. Not quite sure what to do but wait and see what everybody comes up with. :( :-[ :-\

Joel
N6ALT

Well I just read through all that..... What a let down!! Although I have had mine checked over for harmonics by an electronics specialist and it was passed  good. Nice to know mine at least isnt typical of the rest.


39
Military Radios / Re: Czech Military RF-10 Radio.
« Last post by gil on August 25, 2018, 08:58:01 AM »
Let us know!

Gil

Sent from my SM-G928F using Tapatalk

40
CB / Re: CB as a SHTF option, in my opinion
« Last post by gil on August 20, 2018, 06:28:01 AM »
Definitely a good band for local communications. Looking back at my CB days, the one thing I lacked the most back then was a good understanding of antennas. I had no idea about the different kinds of antennas I could have used to extend range, beams, Moxon, wire antennas, etc. The standard was the quarter-wave vertical with radials, or the 5/8 like the excellent Solarcon Imax 2000. Mobile antennas ranged from the very good to ridiculous.

Bottom line is, had I studied antennas, I could have gotten much more from CB. That would be my best advise to CBers, study and try many types of antennas!

Gil.
Pages: 1 2 3 [4] 5 6 ... 10