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Re: BCI Filter
Joe Puma
¿ªÔÆÌåÓýThis looks good. I don¡¯t have a part inventory worth anything but that will change. Thanks for sharing.?Joe On Oct 2, 2018, at 2:31 AM, Dr. Flywheel <Dr.Flywheel@...> wrote:
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Re: BCI Filter
Evidently it does a very good job removing overload due to some local MW broadcasters. Is the output power the same on all bands or do you experience some lower output power? Il 02/ott/2018 07:18, "Joe Puma" <kd2nfc@...> ha scritto:
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Re: BCI Filter
My BC Interference filter is now permanently installed in my V4 uBitx. The response "Knee" is set to about 2.3 MHz. Most of the Rx birdies are now gone and I am still able to hear WWVH transmissions on 2.5MHz, quite clearly. Considering that it only took a few junk-box parts and about 20 minutes to construct, it was a very worthwhile investment. ? ? ? ? ? ? ? ? ?2000pF? ? ? ? ? ? ? ? ?820pF? ? ? ? ? ? ? ? ? 820pF? ? ? ? ? ? ? ? 2000pF ? ?>-----||-----.-----||-----.-----||-----.-----||-----< ? ? ? ? ? ? ? ? |? ? ? ? ? ? |? ? ? ? ? ? | ? ? ? ? ? ? ? ? E 2.2uH? ? ? E 2.2uH? ? ? E 2.2uH ? ? ? ? ? ? ? ? E? ? ? ? ? ? E? ? ? ? ? ? E ? ? ? ? ? ? ? ? |? ? ? ? ? ? |? ? ? ? ? ? | ? ? ? ? ? ? ? ?GND? ? ? ? ? GND? ? ? ? ? GND ? ?? 73's Ron? ? N7FTZ On Mon, Oct 1, 2018 at 10:18 PM Joe Puma <kd2nfc@...> wrote:
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Re: BCI Filter
Joe Puma
¿ªÔÆÌåÓýThis BCI filter seems to be doing a great job. I took mine out of the housing and took the sma connectors off the board to install it in the ubitx. ? ? ? ? ? ? Sent from for Windows 10 ? From: Jack Purdum via Groups.Io
Sent: Sunday, September 23, 2018 10:38 PM To: [email protected] Subject: Fw: Re: [BITX20] BCI Filter ? Opps...pressed the wrong key. Source listed below: ? ----- Forwarded Message ----- From: Jack Purdum <jjpurdum@...> To: "[email protected]" <[email protected]> Sent: Sunday, September 23, 2018, 10:36:21 PM EDT Subject: Re: [BITX20] BCI Filter ? A similar filter is discussed on the SoftwareControlledHamRadio groups.io Group ?
? site. Just do a? search on "BCI filter". It cost me under a dollar to build but works very well. A "high power" version of the filter appeared in: ? ¡°A Cheap and Easy BCI Filter¡±, CQ Magazine, August, 2016. ? Jack, W8TEE ? ? On Sunday, September 23, 2018, 6:37:43 PM EDT, Nick VK4PP <nickpullen@...> wrote: ? ? Hi.? ? |
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Re: ND6T AGC
Joe Puma
¿ªÔÆÌåÓýMade some progress.... ? I removed the 5V buck regulator, wired back up the 7805 for the Raduino and powered the AGC with that. Something is also wrong with my volume pot, sound cutting out when I wiggle it, ill just replace it. But the spurs that were evenly spaced are gone. I also changed the audio wire I was using to the volume. The AGC is not behaving the way it was before. I get a nice signal and when there¡¯s a loud signal coming in I see the whole waterfall getting attenuated from the strong signal, its looking good to me now. I guess I could fire out if I can move my tap before then AGC. ? Is the antenna connection I¡¯m using for the filter and AGC part of the 45mhz IF?? I¡¯m happy to use it like it is. ? ? Here is the AGC at work. The 5V buck regulator was really causing trouble, signal is much improved overall. ? ? A wider shot of the band. I use the out of band radar on the right as a visual aide for signal strength and propagation, the time server at 3.33 mhz as well. ? ? Closer shot ? ? ? ? ? This is my commercial radio FT-840. For visual reference of the band compared to the ubitx. ? ? ? ? Sent from for Windows 10 ? From: Joe Puma
Sent: Monday, October 1, 2018 7:12 PM To: [email protected] Subject: Re: [BITX20] ND6T AGC ? Yes I was thinking that as well. I¡¯ll see if I can move it. Gonna try to add a power ground as well since the only ground is coming from the pin connector.? ?
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Re: Low Pass filter inductor question.
#filters
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Re: ND6T AGC
I agree with you about getting the 5 volts from the 7805. It only pulls a couple of milliamperes and won't be noticed. That switching power supply, on the other hand, is a known noise source. A great comb generator.
I did not catch your placement like Nick did. Midst the 45 MHz filter? It should be in the receive RF path. Placing it elsewhere will disrupt any filter impedances. Trouble waiting to happen, certainly. This is an RF AGC. It keeps the signal within manageable levels throughout the receiver. All of mine are physically mounted on the rear of the RF gain control up on the front panel. Close to the AF feed from the volume control, the 5 volt source, and the RF path. As a result, they work boringly well. You would not be able to detect the 0.6 dB attenuation without good instruments, certainly not by ear. Movement of the volume control should not change AGC operation at all. Something else is going on. Do you have an oscilloscope? If so, check on the input side of C1. There should only be audio. 73, Don |
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Re: PTT switching for amp
Who said it was PTT but that is what the connection on the amp is called.? In my old HF Packer amp there was a jumper that could be moved for CW. Some have replace the jumper with a switch.? The HF packer amp did not chop syllables.? I am building my 70w amp for 20m? SSB.? I don't care about AM, FM, or CW.? I will go ahead!
-- Lee - N9LO? "I Void Warranties" ? |
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Re: ND6T AGC
Joe Puma
¿ªÔÆÌåÓýHi ND6T, All good questions. The BCI filter was in before the AGC. The waterfall was wonderful. Removed spurs and other emissions. I¡¯ll send a nice screen shot of just the BCI filter. The tap is near the 45mhz crystal for IF out ?so the BCI and agc will effect what tap sees. The AGC is after the BCI so it¡¯s receiving a cleaner signal, I figured that would be the logical thing to do?? ?If I unplug the AGC (see OP pic) and jump in/out I¡¯m back to a clean signal no spurs. Seems like the AGC is adding something back in. I¡¯m powering the AGC and Raduino from a 5v buck regulator. One of those popular ebay items that seems to be used on radio projects.? I thought J1 disables AGC completely. But good to know there is some attenuation as I do have a okay signal but with some added spurs, they are visible In the pics I provided. ?Another odd thing is when I raise the volume the last 15% of the max volume changes the attenuation dramatically? I¡¯ll check voltages. Maybe wire up the 7805.? Joe On Oct 1, 2018, at 4:21 PM, Don, ND6T via Groups.Io <nd6t_6@...> wrote:
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Don, ND6T
Nick VK4PP
Lee