RX1 bands coverage

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RX1 bands coverage

Postby ok1rp » 22 Mar 2012 22:38

Hello,

is there somebody who tried to extend the bands coverage of RX1 please?

73 - Petr, OK1RP
ok1rp
 
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Re: RX1 bands coverage

Postby KH2BR » 15 Feb 2013 21:39

Hi petr,

I am in the process of doing that right now. I know your post is one year old, but others may be interested.
I found the N3ZI dds vfo and the mpu/ dds board is the same size of the receiver board, a perfect match.
It works just great. Now, I need to figure how to make band pass filter switching work. The dds vfo only provides two bits for band pass filter switching so I was thinking of a up down counter with b.c.d. output to switch in the various filter banks.
There are two memory up down buttons that I think I can use to step a up down counter. It will take some playing around
With it to see how it will work. I saw a chip that does frequency to voltage output that would be nice, but those I saw went up to 1 MHz, didn't see any that went higher but there could be some out there.

There is lots of room remaining and I think I can also include the TX-1 inside. I am a cw only op and I want 30, 40, 20, and 15 meters. This will do it. There are lots of band pass filter applications on the Internet, just look for them.
Texas Instruments has a nice one that I am playing with to build the cw filter.

73', Bob. KH2BR
DSC00034 (640x480).jpg
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Re: RX1 bands coverage

Postby KH2BR » 23 Feb 2013 23:21

I found a nice band pass filter kit ffrom K5BCQ web site. It is designed by WB6DHW. The kit is only US $ 40 and very small. Measures 38cm x 90 cm
http://www.qsl.net/k5bcq/Kits/Kits.html
I decided to change the VFO again but this time to a SI570 that has full 3.5 mhz to 30 mhz coverage plus it has bcd output to switch the band pass filter.
It is also fromK5BCQ
I also found a narrow cw filter about 200 hz HyperMite CW filter for US $ 20 http://www.4sqrp.com/HiPerMite.php

Robert KH2BR
Attachments
cwfilterdarpic2sm.jpg
BPF1[1].jpg
Last edited by KH2BR on 01 Aug 2013 23:02, edited 1 time in total.
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Re: RX1 bands coverage

Postby ok1rp » 03 May 2013 06:47

Hi Robert
Thank You for very useful info.
You are doing great job i think.
I am cw only op also so i like the
Cw filters in the kits.
You can also try the Nescaf filter
available on New England Club.
It works like champ.
Ok so it seems that easiest way to
extend the range is to use new dds
module instead of re-programming
the origin one.
Good luck and will be great to see
Your progress...
73 - Petr, OK1RP
ok1rp
 
Posts: 55
Joined: 27 Feb 2012 23:20
Location: Czech Republic

Re: RX1 bands coverage

Postby KH2BR » 01 Aug 2013 22:58

The modification to the RX-1 is finished and I am very pleased with the way it works. All I have remaining is to install the cw filter which will fit into the remaining space behind the controls. The receiver will tune all of the ham bands.
Here is what I did. Installed a 5 volt regulator.
Installed a K5BCQ si570 controller 2 kit. This kit has user programmable band pass filter selection output.
Added a low pass filter to the output of the SI570 which you can see in the middle of the controller.
The controller will only operate down to 3500 kHz with out using a frequency divider chip. If 160 meters is needed, then a divider chip must be installed.
The SI570 controller 2 will switch the band pass filters of the WB6DHW band pass filter kit which is also available from K5BCQ.
The band pass filter kit is mounted above the RX-1 Receiver board.
The RX-1 band pass filter was removed and the WB6DHW band pass filter kit was installed into its place.
The little green leds are cut off and glued to push buttons. only one is functional for the mem button of the VFO
The SI570 controller kit consists of only the pc board and programed micro chip. You will have to order the other components.
I will have to install small shielded cable for the BPF I/O and also RF output from the SI570 VFO. Wire position of those wires results in hum if not shielded.
This was a fun project, Now, I have to find some thing else to do.
Robert KH2BR
rx1.JPG
Attachments
rx3.JPG
rx2.JPG
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Re: RX1 bands coverage

Postby ok1rp » 25 Jul 2014 08:59

Dear Robert,

many thank for sharing all of details. Its really amazing job!

If You are thinking what to do next > then what about the similar bands coverage upgrade implementation for TRX-1 please?

It should not be so different I guess...

best regards,

73 - Petr, OK1RP
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Posts: 55
Joined: 27 Feb 2012 23:20
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