Topics

AM Broadcast interferance #filters #v6


Aaron K5ATG
 

Ok, I got the Nextion up and running on my uBITX and now I am getting swamped by what I am assuming is AM broadcast stations. It sounds like several stations at once on receive on every band from 15-80 meters. I know that this is kind of a common problem with amateur radio rigs, I have been searching through my books and online trying to find some sort of filter that could work. 

PS- I know that I have been having a lot of problems here. Due to medical issues, I am on a pretty powerful pain reliever that is screwing up my mind and I can't remember and understand as well as I could a year ago. I am trying as best that I can. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080


Curt
 

Aaron

yes front end overload.  not everyone has a large AM broadcast station nearby, but this matter has been reported in India and USA. 

type these words into your search engine:

ubitx broadcast band filter

I see several solutions, including a few videos.  It may not take a huge amount of rejection - try one of the easier filters using what stuff you may have in hand.  there is somewhat purposely no low frequency rejection in the ubitx - on my to do list to try it as a 630m receiver (I have been using my ft817 which does pretty good down there).  email me (see qrz) as you need anything further to create this BCB filter (but I don't have the issue here to test anything directly). 

73 curt wb8yyy


AndyH
 

Aaron,

   Sorry to hear about pain meds - pain's no fun.  I hope it's temporary.

   W0EB has a BCB filter, for one example:  http://www.w0eb.com/

    72/73, Andy, KG5RKP


On Tue, Oct 13, 2020 at 04:50 PM, Aaron K5ATG wrote:
Ok, I got the Nextion up and running on my uBITX and now I am getting swamped by what I am assuming is AM broadcast stations. It sounds like several stations at once on receive on every band from 15-80 meters. I know that this is kind of a common problem with amateur radio rigs, I have been searching through my books and online trying to find some sort of filter that could work. 

PS- I know that I have been having a lot of problems here. Due to medical issues, I am on a pretty powerful pain reliever that is screwing up my mind and I can't remember and understand as well as I could a year ago. I am trying as best that I can. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080


iz oos
 

If you have a tuner, use It! It's likely act as a highpass filter. Try It!


Il mer 14 ott 2020 01:05 AM Curt via groups.io <wb8yyy=yahoo.com@groups.io> ha scritto:
Aaron

yes front end overload.  not everyone has a large AM broadcast station nearby, but this matter has been reported in India and USA. 

type these words into your search engine:

ubitx broadcast band filter

I see several solutions, including a few videos.  It may not take a huge amount of rejection - try one of the easier filters using what stuff you may have in hand.  there is somewhat purposely no low frequency rejection in the ubitx - on my to do list to try it as a 630m receiver (I have been using my ft817 which does pretty good down there).  email me (see qrz) as you need anything further to create this BCB filter (but I don't have the issue here to test anything directly). 

73 curt wb8yyy


_Dave_ AD0B
 

We have mfj versa manual tuners and they definitely have a high pass filter in them. I can't hear any 1.8-2mhz or lower frequencies when running them. To communicate on 160,  I bypass the mfj and add in a 2mhz high pass. of my own design. The uBITX will definitely go that low. Of course Broadcast band AM is lower than 160. 


--
73
Dave
ADOB
Raduino bracket and Ham_Made_Keys


Aaron K5ATG
 

Thanks for the suggestions. 
I have an N7DDC tuner that I am about to finish putting together. 
I have a kit in the mail and I will see how that goes. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080


Jack, W8TEE
 

Hi Aaron:

I realize I'm too late to help, but I've attached an article on a BCI filter I build that can easily handle 100W. This version I put in my Forth-9er at a cost of $0.87. It has almost the same characteristics as the one in the article.

Inline image

Sorry I missed the earlier posts.

Jack, W8TEE


On Wednesday, October 14, 2020, 8:35:12 PM EDT, Aaron K5ATG via groups.io <k5atg@...> wrote:


Thanks for the suggestions. 
I have an N7DDC tuner that I am about to finish putting together. 
I have a kit in the mail and I will see how that goes. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080

--
Jack, W8TEE


Aaron K5ATG
 

Thanks,
I love the transparent case
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080


Jack, W8TEE
 

Aaron:

You may or may not have heard why I chose that case. At Field Day, 2015, a youngster about 13 was on our GOTA station for almost 2 hours. His mom came to pick him up and he rushed over to her, eyes the size of hubcaps, and started telling her about talking to someone in CA and FL...he could hardly contain himself. His mother listened and then said: "I sure it's a wonderful hobby, but where are you going to get the thousands of dollars it costs for the radio?" She may as well have shot him.

I built the Forth-9er, added a VFO and LCD display, put it in a clear case, with a big sign that the 2016 FD saying: "Build this ham radio station for less that $50!" I used a clear case to show how simple it was inside. (The article was published in the March, 2016, issue of QST.)

Inline image

We need to do a better job of telling the public that ham radio is not just for the rich, but can be available to those on a lawn-mowing budget.

Jack, W8TEE

On Thursday, October 15, 2020, 8:49:42 AM EDT, Aaron K5ATG via groups.io <k5atg@...> wrote:


Thanks,
I love the transparent case
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080

--
Jack, W8TEE


Aaron K5ATG
 

Great story and idea. I will be looking up the QST Article
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080


Ashhar Farhan
 

You should figure out where in the circuit the station is breaking-in from.
If you are hearing all the stations at once, it cant be breaking from the front end (it has two narrow filters). The other possible routes are the audio (volume control) and the DC power source.
1. Disconnect the antenna, can you still hear the interference?
2. Use a battery, does it go away?
3. Does it vary with the volume? What happens if you short the two ends of the volume control?

On Fri 16 Oct, 2020, 4:41 AM Aaron K5ATG via groups.io, <k5atg=yahoo.com@groups.io> wrote:
Great story and idea. I will be looking up the QST Article
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080