Topics

mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

freefuel@...
 

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

Ken Hansen
 

I understand the motivation, but the Chinese are mass-producing dual band HTs for less than $30 delivered to your door, and the Japanese are producing higher-quality units starting at about $120, how much of a premium over these off-the-shelf solutions are you willing to pay to build your own VHF radio? Are you hoping for SSB operation or FM?

Personally, I'd love to see an extremely simple version of the old Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters for under $40 all-in, as a fun club build, but I suspect I'm alone on that desire...

I think it would be fun to have a local net based on low-cost radios and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

Steve Black
 

You are not alone. I would be glad to see a 6 meter or 2 meter or even dual band radio for AM or SSB or both. It would be easy to conceal from the HOA people. A  small self contained unit would be awesome. Steve kb1chu


On 04/26/2018 05:00 PM, Ken Hansen wrote:
I understand the motivation, but the Chinese are mass-producing dual band HTs for less than $30 delivered to your door, and the Japanese are producing higher-quality units starting at about $120, how much of a premium over these off-the-shelf solutions are you willing to pay to build your own VHF radio? Are you hoping for SSB operation or FM?

Personally, I'd love to see an extremely simple version of the old Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters for under $40 all-in, as a fun club build, but I suspect I'm alone on that desire...

I think it would be fun to have a local net based on low-cost radios and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

freefuel@...
 

Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 

Tim Gorman
 

I wouldn't even care about AM. AM operation greatly increases the
complexity of thermal design. SSB would be all I would want -
especially with a good receiver!

tim ab0wr

On Thu, 26 Apr 2018 16:00:38 -0500
"Ken Hansen" <ken@...> wrote:

I understand the motivation, but the Chinese are mass-producing dual
band HTs for less than $30 delivered to your door, and the Japanese
are producing higher-quality units starting at about $120, how much
of a premium over these off-the-shelf solutions are you willing to
pay to build your own VHF radio? Are you hoping for SSB operation or
FM?

Personally, I'd love to see an extremely simple version of the old
Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters
for under $40 all-in, as a fun club build, but I suspect I'm alone on
that desire...

I think it would be fun to have a local net based on low-cost radios
and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters
and I am curious who might also be interested in such a device. my
initial plan is to build the main circuit board the identical size
of the uBITX and later reduce it to within the confines of the
common 20 by 4 line LCD character display. in an attempt to build
this as a Handi Talkie rig.

-Justin N2TOH

freefuel@...
 

for Ken and Steve, if you want compact antenni you really need to look into loop antenni, it's amazing what you can accomplish with some old Cable TV coax and an adjustable vacuum capacitor.  or soft copper tubing for that matter, some people have even managed to pass them off as "Lawn Art". I've even seen at least one example of a loop hidden under the table top of a plastic outdoor set.  with limited success there is the old standby of the rail gutters, and even the holiday lights for the creative! 

-Justin N2TOH 

John P
 

The (expensive) vacuum capacitor isn't really necessary at reasonable power levels. My 40 meter loop has a regular variable capacitor and I have no problem running 100W on SSB or FT-8.

The design for the loop and controller are in the "files" section on here. 
--
John - WA2FZW

Steve Black
 

I just buried 32 radials for a flagpole antenna I am installing for HF. I have an MFJ loop antenna in my attic as well as several vhf and uhf antennas. I have a camo tri-band for 2 meter 1.25 and 70 cm soon to be installed in an oak tree. If I place it 30 feet above ground in the 65 foot tree my outdoor antennas will be 130-135 ASL. My previous location was 30 feet ASL with a 50 foot tower so with the HOA I am still 50 feet higher. I had to sell the crossed Yagi antennas I used for space stuff but I'll get over it. Oh I'm still planning to hide a wire dipole or two. If you can't see it its not there! Steve kb1chu


On 04/26/2018 09:37 PM, freefuel@... wrote:
for Ken and Steve, if you want compact antenni you really need to look into loop antenni, it's amazing what you can accomplish with some old Cable TV coax and an adjustable vacuum capacitor.  or soft copper tubing for that matter, some people have even managed to pass them off as "Lawn Art". I've even seen at least one example of a loop hidden under the table top of a plastic outdoor set.  with limited success there is the old standby of the rail gutters, and even the holiday lights for the creative! 

-Justin N2TOH 

iz oos
 

I agree, only ssb/cw is all is needed. Keep the quality of TX of Ubitx increasing the average output like the MFJ ssb transceivers.


Il 27/apr/2018 03:14, "Tim Gorman" <tgorman2@...> ha scritto:
I wouldn't even care about AM. AM operation greatly increases the
complexity of thermal design. SSB would be all I would want -
especially with a good receiver!

tim ab0wr

On Thu, 26 Apr 2018 16:00:38 -0500
"Ken Hansen" <ken@...> wrote:

> I understand the motivation, but the Chinese are mass-producing dual
> band HTs for less than $30 delivered to your door, and the Japanese
> are producing higher-quality units starting at about $120, how much
> of a premium over these off-the-shelf solutions are you willing to
> pay to build your own VHF radio? Are you hoping for SSB operation or
> FM?
>
> Personally, I'd love to see an extremely simple version of the old
> Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters
> for under $40 all-in, as a fun club build, but I suspect I'm alone on
> that desire...
>
> I think it would be fun to have a local net based on low-cost radios
> and antennas so small no HOA could object to.
>
> Ken, N2VIP
>
> > On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:
> >
> > my attention has turned to building a single band rig for 2 meters
> > and I am curious who might also be interested in such a device.  my
> > initial plan is to build the main circuit board the identical size
> > of the uBITX and later reduce it to within the confines of the
> > common 20 by 4 line LCD character display.  in an attempt to build
> > this as a Handi Talkie rig.
> >
> > -Justin N2TOH
> >   




Lawrence Galea
 

A very thin copper wire supported by fishing line would be invisible.
I had a 160M dipole supported at the centre like this for ages way back.
I had actually used a length of very thin intercom cable and it was practically invisible. 
So a very thin copper wire supported by a fishing line will be invisible.

On Fri, Apr 27, 2018 at 5:34 AM, Steve Black via Groups.Io <kb1chu@...> wrote:

I just buried 32 radials for a flagpole antenna I am installing for HF. I have an MFJ loop antenna in my attic as well as several vhf and uhf antennas. I have a camo tri-band for 2 meter 1.25 and 70 cm soon to be installed in an oak tree. If I place it 30 feet above ground in the 65 foot tree my outdoor antennas will be 130-135 ASL. My previous location was 30 feet ASL with a 50 foot tower so with the HOA I am still 50 feet higher. I had to sell the crossed Yagi antennas I used for space stuff but I'll get over it. Oh I'm still planning to hide a wire dipole or two. If you can't see it its not there! Steve kb1chu


On 04/26/2018 09:37 PM, freefuel@... wrote:
for Ken and Steve, if you want compact antenni you really need to look into loop antenni, it's amazing what you can accomplish with some old Cable TV coax and an adjustable vacuum capacitor.  or soft copper tubing for that matter, some people have even managed to pass them off as "Lawn Art". I've even seen at least one example of a loop hidden under the table top of a plastic outdoor set.  with limited success there is the old standby of the rail gutters, and even the holiday lights for the creative! 

-Justin N2TOH 


Scott Bridges
 

I haven't ordered my uBITX yet, but I am very excited about the idea of a 2m SSB radio. I could probably only use it while in the States(summers), because I just don't think there'll be any activity where I'm at during the school year, but I would still love the idea of using it while traveling during the summers.

Scott N0SAB

Dave Bottom <ars.kd6az@...>
 

I think it would be a great project. In the ‘60s I built a solid state 2M transverter and it only had 100mW output but I worked 500 miles regularly with my little Skelton slot antenna. A sad story that another Ham stole my 100W Motorola rig I was going to turn into a linear amplifier but a couple of hand held 2M SSB rigs would be a blast.

I did build two 2M AM handhelds using the basic concept of the CQ Ham Tip rig (Superregen IF) and common audio for both RX/TX but with transistors (6 if I remember correctly). They were great for playing with VHF/UHF antennas while I waited for the opportunity to take the train to Customs House in San Francisco to take my General exam.

Dave WI6R ex-WB6BDA

On Apr 26, 2018, at 6:13 PM, Tim Gorman <tgorman2@...> wrote:

I wouldn't even care about AM. AM operation greatly increases the
complexity of thermal design. SSB would be all I would want -
especially with a good receiver!

tim ab0wr

On Thu, 26 Apr 2018 16:00:38 -0500
"Ken Hansen" <ken@...> wrote:

I understand the motivation, but the Chinese are mass-producing dual
band HTs for less than $30 delivered to your door, and the Japanese
are producing higher-quality units starting at about $120, how much
of a premium over these off-the-shelf solutions are you willing to
pay to build your own VHF radio? Are you hoping for SSB operation or
FM?

Personally, I'd love to see an extremely simple version of the old
Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters
for under $40 all-in, as a fun club build, but I suspect I'm alone on
that desire...

I think it would be fun to have a local net based on low-cost radios
and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters
and I am curious who might also be interested in such a device. my
initial plan is to build the main circuit board the identical size
of the uBITX and later reduce it to within the confines of the
common 20 by 4 line LCD character display. in an attempt to build
this as a Handi Talkie rig.

-Justin N2TOH

ajparent1/kb1gmx
 

For 6 and 2m SSB use it is a great staring point.  The power amp stages are not up to it for 2
at all but for 6 with work it can be made to work.    For the RX side you need a good LNA
on 6 and 2.  For 6 a gain of 10-17 db is enough. For 2M the gain will need to be closer to
20Db and the noise figure under 1 db.

To do dual band you need two front ends (LNAs) and switching from those to the 1st mixer.  Same for
the power out stages as wide band in that range is tougher to do than a per band stages.    A target
power of 10W is adequate 20 would be better.

For 4M we don't have that band here but that is about the same story as 6M however its going to
need a better power amp.  The IRF510 can pump power thee but everything before it has hit the
wall at 10M and needs better devices to go higher. 

UHF with ubitx its better to use it as an IF with a transverter.

As to VHF loop antennas, forget the Vacuum variable. its not needed.  For 6M the loop is about 30 inches
across and the end gap tunes it.  For 2M about 11inches and the end gap tunes that.  For VHF height is valuable
but also makes it hard to hide.  Gama fed in both cases.  Use good coax (quality RG8X minimum for short
(under 25ft) runs as losses are painful.  For longer runs RG8 .400 cable (RG213 or LMR400) are the usual.
However if you can do a beam (easy on 2M due to small size for a 4 element) it really helps.  Staced loops
also help but the stacking distance for 6m is around 12Ft and for 2M 4ft so its not stealth.

NOTES:
Around here in Eastern MA USA getting higher than the trees is the trick as they absorb a lot.   That is rarely
stealth.  Second best is higher than buildings.   Dead last is in the attic, roofing material especially wet are
absorbers.  Indoors works for local to a few miles at best.  I run 6M ssb from the mobile with a square loop
onthe truck using a HB rig at 4W or I add in the 6M brick I built to pump that up to about 70W.  The home
station the usual rig is HB contest radio for 6M (about 7W),  Tentec 6n2 (20W), and FT817 for  432mhz. 
Matching HB amps to get to 160W on 6,  160W on 2, and 60W on 432.  Antennas see QRZ, I have
5 elements on 6M, 11 elements for 2M and 15 for 432.  All are my design or highly modified commercial.
I also have antennas for Field Day (last full weekend in June) for 6/2/432 that are somewhat portable. 
Mountain (or high local hills) topping works using simple beams or loops.  Be aware unlike HF
polarisation counts, for SSB (VHF AND UHF) its generally horizontal here, the islands, and from
all accounts in Europe. cross polarization of direct local links incur great losses ( sometimes
more than 20DB).

I've been on VHF and up for a long time and built for all of the bands including 432 (transverter to 10M).
It is more home to me than HF.

Allison

Tim - M0THM
 

4 and 2m ssb would certainly grab my eye.

 


On 2018-04-26 22:33, freefuel@... wrote:

Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 

Thomas Sharka
 

I haven't really been following all the details of the conversation, but how about a front end mixer to convert VHF to HF? You'd still need to work out something for FM but most other modes would be covered.
 


Sent from Yahoo Mail. Get the app


On Friday, April 27, 2018 5:11 PM, Tim - M0THM <tim@...> wrote:


4 and 2m ssb would certainly grab my eye.
 

On 2018-04-26 22:33, freefuel@... wrote:
Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 


K9HZ <bill@...>
 

If this new 2 meter radio would be used on FM… it’s time to start over.  Most of the IF chain will have to be modified to work including the crystal filters and addition of a discriminator…. And a way to frequency modulate the oscillator on transmit.  Way too much work to perform on a uBITx.  Start over from scratch.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

Moderator – North American QRO Group at Groups.IO.

 

email:  bill@...

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Thomas Sharka via Groups.Io
Sent: Friday, April 27, 2018 4:50 PM
To: BITX20@groups.io
Subject: Re: [BITX20] mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

 

I haven't really been following all the details of the conversation, but how about a front end mixer to convert VHF to HF? You'd still need to work out something for FM but most other modes would be covered.

 

 

 

Sent from Yahoo Mail. Get the app

 

On Friday, April 27, 2018 5:11 PM, Tim - M0THM <tim@...> wrote:

 

4 and 2m ssb would certainly grab my eye.

 

 

On 2018-04-26 22:33, freefuel@... wrote:

Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 

 


Virus-free. www.avg.com

iz oos
 

Makes sense the transverter approach. Not sure whether the ones from Ukraine could match well. But is a different approach. You need both hf and transverter. This may give some advantages  but is not very handy for sota or portable operation.


Il 27/apr/2018 23:49, "Thomas Sharka via Groups.Io" <sharkatw=yahoo.com@groups.io> ha scritto:
I haven't really been following all the details of the conversation, but how about a front end mixer to convert VHF to HF? You'd still need to work out something for FM but most other modes would be covered.
 


Sent from Yahoo Mail. Get the app


On Friday, April 27, 2018 5:11 PM, Tim - M0THM <tim@...> wrote:


4 and 2m ssb would certainly grab my eye.
 

On 2018-04-26 22:33, freefuel@... wrote:
Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 



ajparent1/kb1gmx
 

Several things, like others have repeatedly pointed out the uBITX is very unsuited for FM or AM.
FM needs wider filter and far more gain to get the needed limiting action.  Its not drop in its full
replacement.  A Baofeng UV5R goes for 30 bucks and does 2M and 70CM.    AM there are
issues with drive level and sustained power out, that and its sparsely used.  My opinion is
that if you want all that get a FT817, its a do all and has a noise blanker.

To get the front end to cover VHF the LO system deliver a VHF LO (95mhz for 6M, about 99 or 189mhz for 2m)
and the input filter needs to pass the VHF band and not a low pass.  IF memory sers the 5351 can go to 220Mhz
A LNA before the mixer would be required for reasonable performance.    For UHF if you had a version of the
5351 or maybe used a si570 flavor to generate the LO and an improved mixer 432 is possible but its more
effort and would likely need a board redesign.

UHF is better done with a competent converter/transverter with a 404mhz LO and run that into a uBitx at 28mhz.

In all cases 6 though 70cm the tx power chain would need work as the drivers are all 300mhz FT devices 
just will not do it.   The IRF510 I've used at 50mhz as a monoband linear and its respectable
(40+W for push pull @ 28V properly done for 6M only) but I think maybe 70mhz is a stretch without
first trying.  In all cases the TX chain is mono band only as VHF impedance matching from stage
to stage is required. Just dropping in higher FT devices will not help its a across the board redesign
for a specific band.

Receiving is easy enough, transmit above 50mhz is going to be harder.


Allison


Ashhar Farhan
 

Allison,
For a power chain of about 5 watts that goes from 50 mhz to 500 mhz, what would be your recommendations? The RD15HVF1 seems to be used frequently at 435 Mhz. Are there any broadband alternatives? What kind of cores can we use at UHF? 
- f

On Sat, 28 Apr 2018, 06:37 ajparent1/KB1GMX, <kb1gmx@...> wrote:
Several things, like others have repeatedly pointed out the uBITX is very unsuited for FM or AM.
FM needs wider filter and far more gain to get the needed limiting action.  Its not drop in its full
replacement.  A Baofeng UV5R goes for 30 bucks and does 2M and 70CM.    AM there are
issues with drive level and sustained power out, that and its sparsely used.  My opinion is
that if you want all that get a FT817, its a do all and has a noise blanker.

To get the front end to cover VHF the LO system deliver a VHF LO (95mhz for 6M, about 99 or 189mhz for 2m)
and the input filter needs to pass the VHF band and not a low pass.  IF memory sers the 5351 can go to 220Mhz
A LNA before the mixer would be required for reasonable performance.    For UHF if you had a version of the
5351 or maybe used a si570 flavor to generate the LO and an improved mixer 432 is possible but its more
effort and would likely need a board redesign.

UHF is better done with a competent converter/transverter with a 404mhz LO and run that into a uBitx at 28mhz.

In all cases 6 though 70cm the tx power chain would need work as the drivers are all 300mhz FT devices 
just will not do it.   The IRF510 I've used at 50mhz as a monoband linear and its respectable
(40+W for push pull @ 28V properly done for 6M only) but I think maybe 70mhz is a stretch without
first trying.  In all cases the TX chain is mono band only as VHF impedance matching from stage
to stage is required. Just dropping in higher FT devices will not help its a across the board redesign
for a specific band.

Receiving is easy enough, transmit above 50mhz is going to be harder.


Allison


Tim Gorman
 

Respectfully, as Allison points out, it's not just the PA active element
that will be the problem. When your frequency width is an order of
magnitude, e.g. 14Mhz to 144Mhz, you begin to run into all kinds of
issues with components. Lead lengths and circuit trace lengths/widths
at 2m cause many more problems than at 14Mhz. It gets even worse at
432Mhz.

I agree with others on here. It would be a lot more feasible to do one
band modules, e.g. one for 2m and another one for 432Mhz, that are
small enough they could be placed in one case along with a ubitx
being used as an IF amplifier.

tim ab0wr

On Sat, 28 Apr 2018 01:12:16 +0000
"Ashhar Farhan" <farhanbox@...> wrote:

Allison,
For a power chain of about 5 watts that goes from 50 mhz to 500 mhz,
what would be your recommendations? The RD15HVF1 seems to be used
frequently at 435 Mhz. Are there any broadband alternatives? What
kind of cores can we use at UHF?
- f

On Sat, 28 Apr 2018, 06:37 ajparent1/KB1GMX, <kb1gmx@...> wrote:

Several things, like others have repeatedly pointed out the uBITX
is very unsuited for FM or AM.
FM needs wider filter and far more gain to get the needed limiting
action. Its not drop in its full
replacement. A Baofeng UV5R goes for 30 bucks and does 2M and
70CM. AM there are
issues with drive level and sustained power out, that and its
sparsely used. My opinion is
that if you want all that get a FT817, its a do all and has a noise
blanker.

To get the front end to cover VHF the LO system deliver a VHF LO
(95mhz for 6M, about 99 or 189mhz for 2m)
and the input filter needs to pass the VHF band and not a low
pass. IF memory sers the 5351 can go to 220Mhz
A LNA before the mixer would be required for reasonable performance.
For UHF if you had a version of the
5351 or maybe used a si570 flavor to generate the LO and an
improved mixer 432 is possible but its more
effort and would likely need a board redesign.

UHF is better done with a competent converter/transverter with a
404mhz LO and run that into a uBitx at 28mhz.

In all cases 6 though 70cm the tx power chain would need work as the
drivers are all 300mhz FT devices
just will not do it. The IRF510 I've used at 50mhz as a monoband
linear and its respectable
(40+W for push pull @ 28V properly done for 6M only) but I think
maybe 70mhz is a stretch without
first trying. In all cases the TX chain is mono band only as VHF
impedance matching from stage
to stage is required. Just dropping in higher FT devices will not
help its a across the board redesign
for a specific band.

Receiving is easy enough, transmit above 50mhz is going to be
harder.


Allison