Topics

Receive only version?


Gerald Bramwell
 

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Bill Cromwell
 

Hi Gerald,

Your idea really is practical. To assure your radio does not transmit you can disconnect the CW key line and the Push to talk. You could go so far as removing the finals but just turning the bias and drive pots all the way down should be good - just in case it does get put into transmit. Some day you may want to sell it to a licensed ham (or get your own ham license). All you have to do is connect those CW and PTT lines and set up the bias and drive.

The fact is - I do a lot more listening than transmitting even though I am licensed. I already have a general coverage receiver but I also use my V3 for SWL. I also use it as a signal tracer and heterodyne frequency meter on my bench. You do not have to transmit to get some work out the uBitX.

73,

Bill KU8H

bark less - wag more

On 9/2/20 7:46 AM, Gerald Bramwell wrote:
Hi all,
As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


iz oos
 

Indeed, It could be. But consider that a Tecsun PL660 costa less than 100usd, is sensitive, sounds good, forse have synch detection, AGC. A ubitx receiver would be interesting but the ubitx is very convenient as a transceiver as a multiband QRP can cost 1000usd or even more.


Il mer 2 set 2020 01:46 PM Gerald Bramwell <gerald.bramwell@...> ha scritto:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Bob, N1KPR
 

I have not actually spec'd out the receiver yet, but can tell you that it is very sensitive and the MDS is excellent...guessing about -130dB. The one (of many) receiver controls missing is AGC for general SWLing. If I was going to build one for receive-only, I'd cut the 12V T/R relay rail and add an audio leveler to act as AGC (link below). Another definite addition would be a real RF Gain control. I'm using a 5K pot as an attenuator in the front end. And, of course, all receivers need an S-Meter. It would be a fun project for an SWLer who has some tech skills. Half the fun is building this stuff.

Go to the 3-minute mark to see the leveler

and the complete system here:

Gud signals to all,
Bob, N1KPR







NOTE Pls add backup address to your phone book: rwbetts@...

http://www.bobsamerica.com  http://www.youtube.com/n1kpr

Engineering: Where Enigma meets Paradox


On Wednesday, September 2, 2020, 8:08:08 AM EDT, Bill Cromwell <wrcromwell@...> wrote:


Hi Gerald,

Your idea really is practical. To assure your radio does not transmit
you can disconnect the CW key line and the Push to talk. You could go so
far as removing the finals but just turning the bias and drive pots all
the way down should be good - just in case it does get put into
transmit. Some day you may want to sell it to a licensed ham (or get
your own ham license). All you have to do is connect those CW and PTT
lines and set up the bias and drive.

The fact is - I do a lot more listening than transmitting even though I
am licensed. I already have a general coverage receiver but I also use
my V3 for SWL. I also use it as a signal tracer and heterodyne frequency
meter on my bench. You do not have to transmit to get some work out the
uBitX.

73,

Bill  KU8H

bark less - wag more

On 9/2/20 7:46 AM, Gerald Bramwell wrote:
> Hi all,
>
> As a SWL for a number of years and haveing found this group, I was
> wondering if a receive only version could be built as it looks like a
> very interesting project.
> 73s
> Gerald Bramwell (RS49875)
>




Scott McDonald
 

Hi Gerald,

It’s a very doable project if you have a bit of building experience or friends that build.

I got some good receiver building advice from a clever lady named Allison suggesting to break the radio into its parts and build them as 50 ohm blocks that could be built, tested and put together.  They can later be easily swapped out for ones that you like better, like different band pass filters or a decent AM detector.

My receiver is based on Version 3 and has been hot rodded a bit since I first built it, but the basic great Farhan topology remains, and other than adding an IF amplifier with AGC and a cw filter, none of the improvements made a dramatic difference in performance.  The basic design is very good.

If you’re pretty new to this you might consider picking up on old or new uBITX and studying it for a while first, I found that really helpful.  If you just want a good SWL radio for a nice price then the folks that suggest just picking up a stock uBITX have it right.  It would be hard to scratch build one for any less.

If you decide to build one in sections, there are inexpensive boards for things like the mixers (totally homebrew or using a commercial mixer) and post mixer amps (same as the UBITX but easy SMT) available on Osh Park.  And using an inexpensive EBay TDA2050 audio amp kit would provide lots of clean cheap power for only a few quid.

There are a couple pics of my V3 receiver on my QRZ page if interested.

Scott ka9p


On Sep 2, 2020, at 6:46 AM, Gerald Bramwell <gerald.bramwell@...> wrote:

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Jack, W8TEE
 

Neat stuff, Scott! Especially like the hex beam installation. You're either single or I want to know where you met your XYL!

Jack, W8TEE


On Wednesday, September 2, 2020, 9:26:30 AM EDT, Scott McDonald via groups.io <ka9p@...> wrote:


Hi Gerald,

It’s a very doable project if you have a bit of building experience or friends that build.

I got some good receiver building advice from a clever lady named Allison suggesting to break the radio into its parts and build them as 50 ohm blocks that could be built, tested and put together.  They can later be easily swapped out for ones that you like better, like different band pass filters or a decent AM detector.

My receiver is based on Version 3 and has been hot rodded a bit since I first built it, but the basic great Farhan topology remains, and other than adding an IF amplifier with AGC and a cw filter, none of the improvements made a dramatic difference in performance.  The basic design is very good.

If you’re pretty new to this you might consider picking up on old or new uBITX and studying it for a while first, I found that really helpful.  If you just want a good SWL radio for a nice price then the folks that suggest just picking up a stock uBITX have it right.  It would be hard to scratch build one for any less.

If you decide to build one in sections, there are inexpensive boards for things like the mixers (totally homebrew or using a commercial mixer) and post mixer amps (same as the UBITX but easy SMT) available on Osh Park.  And using an inexpensive EBay TDA2050 audio amp kit would provide lots of clean cheap power for only a few quid.

There are a couple pics of my V3 receiver on my QRZ page if interested.

Scott ka9p


On Sep 2, 2020, at 6:46 AM, Gerald Bramwell <gerald.bramwell@...> wrote:

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)

--
Jack, W8TEE


Scott McDonald
 

Jack, you always make me laugh!  E-Harmony - really!  I just asked for a geek.  She even made me put the skylight in the garage roof so minor antenna maintenance could be done without climbing on the roof.  Probably because she helped me drop it off the roof twice.  A keeper, and she even does FDIM banquets!  Cheers, Scott


-----Original Message-----
From: Jack, W8TEE via groups.io <jjpurdum@...>
To: BITX20@groups.io <BITX20@groups.io>
Sent: Wed, Sep 2, 2020 8:32 am
Subject: Re: [BITX20] Receive only version?

Neat stuff, Scott! Especially like the hex beam installation. You're either single or I want to know where you met your XYL!

Jack, W8TEE


On Wednesday, September 2, 2020, 9:26:30 AM EDT, Scott McDonald via groups.io <ka9p@...> wrote:


Hi Gerald,

It’s a very doable project if you have a bit of building experience or friends that build.

I got some good receiver building advice from a clever lady named Allison suggesting to break the radio into its parts and build them as 50 ohm blocks that could be built, tested and put together.  They can later be easily swapped out for ones that you like better, like different band pass filters or a decent AM detector.

My receiver is based on Version 3 and has been hot rodded a bit since I first built it, but the basic great Farhan topology remains, and other than adding an IF amplifier with AGC and a cw filter, none of the improvements made a dramatic difference in performance.  The basic design is very good.

If you’re pretty new to this you might consider picking up on old or new uBITX and studying it for a while first, I found that really helpful.  If you just want a good SWL radio for a nice price then the folks that suggest just picking up a stock uBITX have it right.  It would be hard to scratch build one for any less.

If you decide to build one in sections, there are inexpensive boards for things like the mixers (totally homebrew or using a commercial mixer) and post mixer amps (same as the UBITX but easy SMT) available on Osh Park.  And using an inexpensive EBay TDA2050 audio amp kit would provide lots of clean cheap power for only a few quid.

There are a couple pics of my V3 receiver on my QRZ page if interested.

Scott ka9p


On Sep 2, 2020, at 6:46 AM, Gerald Bramwell <gerald.bramwell@...> wrote:

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)

--
Jack, W8TEE


Jack, W8TEE
 

Wow...that's a winner! The only way my XYL would be at FDIM would be in a hearse.

Jack, W8TEE

On Wednesday, September 2, 2020, 9:40:39 AM EDT, Scott McDonald via groups.io <ka9p@...> wrote:


Jack, you always make me laugh!  E-Harmony - really!  I just asked for a geek.  She even made me put the skylight in the garage roof so minor antenna maintenance could be done without climbing on the roof.  Probably because she helped me drop it off the roof twice.  A keeper, and she even does FDIM banquets!  Cheers, Scott


-----Original Message-----
From: Jack, W8TEE via groups.io <jjpurdum@...>
To: BITX20@groups.io <BITX20@groups.io>
Sent: Wed, Sep 2, 2020 8:32 am
Subject: Re: [BITX20] Receive only version?

Neat stuff, Scott! Especially like the hex beam installation. You're either single or I want to know where you met your XYL!

Jack, W8TEE


On Wednesday, September 2, 2020, 9:26:30 AM EDT, Scott McDonald via groups.io <ka9p@...> wrote:


Hi Gerald,

It’s a very doable project if you have a bit of building experience or friends that build.

I got some good receiver building advice from a clever lady named Allison suggesting to break the radio into its parts and build them as 50 ohm blocks that could be built, tested and put together.  They can later be easily swapped out for ones that you like better, like different band pass filters or a decent AM detector.

My receiver is based on Version 3 and has been hot rodded a bit since I first built it, but the basic great Farhan topology remains, and other than adding an IF amplifier with AGC and a cw filter, none of the improvements made a dramatic difference in performance.  The basic design is very good.

If you’re pretty new to this you might consider picking up on old or new uBITX and studying it for a while first, I found that really helpful.  If you just want a good SWL radio for a nice price then the folks that suggest just picking up a stock uBITX have it right.  It would be hard to scratch build one for any less.

If you decide to build one in sections, there are inexpensive boards for things like the mixers (totally homebrew or using a commercial mixer) and post mixer amps (same as the UBITX but easy SMT) available on Osh Park.  And using an inexpensive EBay TDA2050 audio amp kit would provide lots of clean cheap power for only a few quid.

There are a couple pics of my V3 receiver on my QRZ page if interested.

Scott ka9p


On Sep 2, 2020, at 6:46 AM, Gerald Bramwell <gerald.bramwell@...> wrote:

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)

--
Jack, W8TEE

--
Jack, W8TEE


Gerard
 

Hello,
That’s exactly what I’m doing.

Look, the emission part is not cabled. By default it is in reception. Of course, you have to analyze the diagram and plug in what is needed. See my PCB (Homemade)


Gerald Bramwell
 

I have some building experience. I'm 73 and built my first crystal set when I was 6, it used a homemade crystal from putting a piece of rock sulphur into a tin of molten lead (caused a bit of smoke). It was tuned by running a slider along the wound coil, received quite a few stations with it. My grandfather got me interested with the radios he had built, all done on wooden boards with blueprints stuck to them, (the blueprints really were blue), the connecting wire was square and all the components had screw terminals. They needed two batteries. Once, a good few years ago I designed and built a TTL digital clock using Nixie tubes, I designed and etched the PCBs for it.
Gerald


On Wed, 2 Sep 2020 at 14:26, Scott McDonald via groups.io <ka9p=aol.com@groups.io> wrote:
Hi Gerald,

It’s a very doable project if you have a bit of building experience or friends that build.

I got some good receiver building advice from a clever lady named Allison suggesting to break the radio into its parts and build them as 50 ohm blocks that could be built, tested and put together.  They can later be easily swapped out for ones that you like better, like different band pass filters or a decent AM detector.

My receiver is based on Version 3 and has been hot rodded a bit since I first built it, but the basic great Farhan topology remains, and other than adding an IF amplifier with AGC and a cw filter, none of the improvements made a dramatic difference in performance.  The basic design is very good.

If you’re pretty new to this you might consider picking up on old or new uBITX and studying it for a while first, I found that really helpful.  If you just want a good SWL radio for a nice price then the folks that suggest just picking up a stock uBITX have it right.  It would be hard to scratch build one for any less.

If you decide to build one in sections, there are inexpensive boards for things like the mixers (totally homebrew or using a commercial mixer) and post mixer amps (same as the UBITX but easy SMT) available on Osh Park.  And using an inexpensive EBay TDA2050 audio amp kit would provide lots of clean cheap power for only a few quid.

There are a couple pics of my V3 receiver on my QRZ page if interested.

Scott ka9p


On Sep 2, 2020, at 6:46 AM, Gerald Bramwell <gerald.bramwell@...> wrote:

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Arv Evans
 

Gerald

In some countries there are laws or rules that do not allow SWL's to 
own transmit capable apparatus, but in other places it might be less 
expensive and quicker to just build a BITX transceiver and never use 
the transmit side of things.  If you have enough technical expertise to 
design a receive-only BITX it would also be possible to modify a regular 
BITX transceiver by omitting the transmit components.  This would 
involve change some impedances and changing the bias for some of 
the dual-use stages.

Arv
_._

On Wed, Sep 2, 2020 at 5:46 AM Gerald Bramwell <gerald.bramwell@...> wrote:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Gregory Stearman
 

Gerald, 

I use a V4 as a receive only rig and definitely recommend KD8CEC's firmware (http://www.hamskey.com/2019/04/release-cec-firmware-v1200-for-ubitx.html). It is easy to use stand-alone and it supports FT817 style USB CAT control so you can tune the radio from FLRIG, WSJTX or FLDIGI on a PC and use it to save frequencies or tune the radio from the mouse wheel.  I built an "Easy Digi" audio interface (probably overkill for RX only) and leave the uBitx on decoding FT8 sometimes using my house rain-gutters as an antenna. The uBITx pulls in reports from across the world on the pskreporter map. Not bad for a very small investment. Be careful not to key the radio from these PC apps if you haven't made the hardware mods to disable the TX, of course. 

GregS
KG5VVV 

On Wed, Sep 2, 2020 at 10:37 AM Arv Evans <arvid.evans@...> wrote:
Gerald

In some countries there are laws or rules that do not allow SWL's to 
own transmit capable apparatus, but in other places it might be less 
expensive and quicker to just build a BITX transceiver and never use 
the transmit side of things.  If you have enough technical expertise to 
design a receive-only BITX it would also be possible to modify a regular 
BITX transceiver by omitting the transmit components.  This would 
involve change some impedances and changing the bias for some of 
the dual-use stages.

Arv
_._

On Wed, Sep 2, 2020 at 5:46 AM Gerald Bramwell <gerald.bramwell@...> wrote:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Gerald Bramwell
 

Next question then is where can I get hold of the kits? I'm in the UK.
Gerald


On Wed, 2 Sep 2020 at 17:16, Gregory Stearman <greg.stearman@...> wrote:
Gerald, 

I use a V4 as a receive only rig and definitely recommend KD8CEC's firmware (http://www.hamskey.com/2019/04/release-cec-firmware-v1200-for-ubitx.html). It is easy to use stand-alone and it supports FT817 style USB CAT control so you can tune the radio from FLRIG, WSJTX or FLDIGI on a PC and use it to save frequencies or tune the radio from the mouse wheel.  I built an "Easy Digi" audio interface (probably overkill for RX only) and leave the uBitx on decoding FT8 sometimes using my house rain-gutters as an antenna. The uBITx pulls in reports from across the world on the pskreporter map. Not bad for a very small investment. Be careful not to key the radio from these PC apps if you haven't made the hardware mods to disable the TX, of course. 

GregS
KG5VVV 

On Wed, Sep 2, 2020 at 10:37 AM Arv Evans <arvid.evans@...> wrote:
Gerald

In some countries there are laws or rules that do not allow SWL's to 
own transmit capable apparatus, but in other places it might be less 
expensive and quicker to just build a BITX transceiver and never use 
the transmit side of things.  If you have enough technical expertise to 
design a receive-only BITX it would also be possible to modify a regular 
BITX transceiver by omitting the transmit components.  This would 
involve change some impedances and changing the bias for some of 
the dual-use stages.

Arv
_._

On Wed, Sep 2, 2020 at 5:46 AM Gerald Bramwell <gerald.bramwell@...> wrote:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Jonas Sanamon
 

Hi Gerald,

I have 3 :-)

Based on several bad experiences with India Post lately (the last 6 months) I would go for the DHL shipping option.

Regards
Jonas - SM4VEY

Den ons 2 sep. 2020 kl 18:30 skrev Gerald Bramwell <gerald.bramwell@...>:

Next question then is where can I get hold of the kits? I'm in the UK.
Gerald
_._,_._,


Ashhar Farhan
 

There is just a bit of bureaucratic hassle with this. HF Signals, confirms the callsign of the buyer and the shipping address from the callbooks. This is just to be sure. you will have to have a ham purchase it and disable the tx for you.
- f

On Wed, Sep 2, 2020 at 10:25 PM Jonas Sanamon <sanamon@...> wrote:
Hi Gerald,

I have 3 :-)

Based on several bad experiences with India Post lately (the last 6 months) I would go for the DHL shipping option.

Regards
Jonas - SM4VEY

Den ons 2 sep. 2020 kl 18:30 skrev Gerald Bramwell <gerald.bramwell@...>:
Next question then is where can I get hold of the kits? I'm in the UK.
Gerald
_._,_._,


Shirley Dulcey KE1L
 

An alternative to hardware mods would be to take transmit capability out of the software. That shouldn't be too difficult; no need to remove all the code, just change the point where it actually gets turned on.


On Wed, Sep 2, 2020 at 12:16 PM Gregory Stearman <greg.stearman@...> wrote:
Gerald, 

I use a V4 as a receive only rig and definitely recommend KD8CEC's firmware (http://www.hamskey.com/2019/04/release-cec-firmware-v1200-for-ubitx.html). It is easy to use stand-alone and it supports FT817 style USB CAT control so you can tune the radio from FLRIG, WSJTX or FLDIGI on a PC and use it to save frequencies or tune the radio from the mouse wheel.  I built an "Easy Digi" audio interface (probably overkill for RX only) and leave the uBitx on decoding FT8 sometimes using my house rain-gutters as an antenna. The uBITx pulls in reports from across the world on the pskreporter map. Not bad for a very small investment. Be careful not to key the radio from these PC apps if you haven't made the hardware mods to disable the TX, of course. 

GregS
KG5VVV 

On Wed, Sep 2, 2020 at 10:37 AM Arv Evans <arvid.evans@...> wrote:
Gerald

In some countries there are laws or rules that do not allow SWL's to 
own transmit capable apparatus, but in other places it might be less 
expensive and quicker to just build a BITX transceiver and never use 
the transmit side of things.  If you have enough technical expertise to 
design a receive-only BITX it would also be possible to modify a regular 
BITX transceiver by omitting the transmit components.  This would 
involve change some impedances and changing the bias for some of 
the dual-use stages.

Arv
_._

On Wed, Sep 2, 2020 at 5:46 AM Gerald Bramwell <gerald.bramwell@...> wrote:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)