Date   

EURAO Newsletter June 2015

Michael McEwen
 

If you all aren't on this list...it is great for people wanting to operate from or DX EU...
_ _ ...   .. _ _ _

Doc K5OSA - QTH: EM04sr
ARRL  
4SQRP #801 - NAQCC #7625 - SKCC #10098
FISTS #17157 - OMISS #9886
LFSARC (Lawton/Fort Sill Amateur Radio Club)

Michael T McEwen
Lt Col, US Army, Ret

Cellular Phone:  580 919-9205
Residence:  580 529-3412


---------- Forwarded message ----------
From: EURAO <eurao@...>
Date: Tue, Jun 16, 2015 at 11:03 PM
Subject: EURAO Newsletter June 2015
To: k5osa@...


EURAO European Radio Amateurs' Organization open to the world wide amateur radio community
news

Amateur Radio News...

EURAO Newsletter June 2015: contents new

In this issue you will find:

  • European solidarity and Ham spirit in Mediterranean crisis
  • HAM RADIO 2015: Road to Friedrichshafen...
  • Field Day and Flea market of TRGM
  • MHRC Nepal Earthquake Relief Operation
  • EURAO Party - Spring 2015: have fun, go portable
  • AO150ITU: 150th anniversary of ITU
  • New members: MHRC, GARS, ...
  • News in brief
  • ...

EURAO Newsletter comes out quarterly, either in pdf format and as a website. Spread the word!

Unsubscribe: If you do not wish to receive this newsletter any more, just reply to this email stating UNSUBSCRIBE in the subject. If you prefer to receive it in another email, tell us the old and new address, and we will change it.



--


For sale 746 Icom not QRP

Johnny AC0BQ
 

Sorry abt the non QRP post!
I have a very clean Icom 746 for sale if anyone needs a "big rig" for the shack.
It's been my main rig for over 5 years.
It's loaded up with 2 Inrad cw filters, and the origional 2.8 SSB filter.
No display problems.
$700.00 shipped and insured with the cw filters.
600.00 without the 2 cw filters.
Price is firm.
Thanks 
72
Johnny AC0BQ





--
QRP....."More smiles per Watt"
72
JOHNNY AC0BQ  ..




NAQCC Milliwatt Sprint Wednesday night

Larry Makoski <w2lj@...>
 

Tomorrow night, June 17th is the NAQCC June milliwatt sprint.  It will be held from 8:30-10:30PM EDT, 7:30-9:30PM CDT , 6:30-8:30PM MDT, 5:30-7:30PM PDT, which translates as Thursday, June 18th, 0030 to 0230Z in all cases.

For all the "official" information, please go to:

http://naqcc.info/sprint201506mw.html


There you will find all the details as to time, frequencies and other important
information. The details differ a bit from our regular monthly sprints, so check them out beforehand.

See you on the bands with QRPp!

73 de Larry W2LJ on behalf of the NAQCC



Re: 2Ahr

Rick Bennett
 

Michael, another thought is to get a 10 cell AA battery holder and use 10 AA NiMH batteries. This will be somewhat lighter and smaller than the SLAB. Also the NiMH batteries will hold their voltage to a pretty deep discharge and the NiMH batteries don't mind being run low over and over. (One of the disadvantages of SLABs is they don't tolerate a lot of deep discharge cycles). And in a pinch, you can substitute alkaline batteries. I used a similar setup years ago for portable ops with good success.

To go along with Greg's suggestion below, if you can put an ammeter on the power input and an rf power meter on the output at the same time you can look for a good balance of power in to power out. Even 3 watts is a respectable power level if you can get a good increase in battery time.

de KC0PET, Rick

----- Original Message -----
From: "Greg Troxel gdt@... [4sqrp]" <4sqrp@...>
To: "Michael McEwen" <mcewenk5osa@...>
Cc: 4sqrp@...
Sent: Tuesday, June 16, 2015 5:25:39 PM
Subject: Re: [4sqrp] 2Ahr


"Michael McEwen mcewenk5osa@... [4sqrp]" <4sqrp@...>
writes:

I've found a neat little 2AHr SLA (Off road ATV) and it is easily in my PM
weight range. I have an LD5 CW/SSB TXCVR. Would this little batt allow a
couple hours of typical SOTA/PM ops? As I read the LD5 "manual", it should
due to 2A draw on TX...but, I'm an electro-dummy and may be wrong.
A rating of 2 Ah means that it will supply 2Ah/20h = 100 mA for 20h
before reaching 10.5V. As the discharge rate increases, the available
Ah decreases and vice versa, and you get greater voltage drops due to
internal impedance. Generally published curves are available for
multiple charge rates. I would guess that if you were drawing 2A
intermittently with 0 the rest of the time, it might go 30 minutes.
Assuming 0.3A for receive, and 50% keydown while transmitting, the
notion of transmitting for 20 minutes and a few hours of receiving does
not sound crazy.

Hoewver, there's no substitute for actually measuring the current while
in continuous keydown, and in receive, and using an integrating ammeter
to measure total Ah used over some period of operating. I ran a 2m FM
net (at 15W output) as NCS for about 15 minutes total operating time,
and remembered using only about 1 Ah. But this was from a 35 Ah
battery, so my currents were closer to C/20h than our example (0.5A rx,
5A tx, more or less). I'm not sure I would have made it on a 2Ah
battery, and I wouldn't have tried.

The other thing is just to try it; the worst is that you'll break it (if
you discharge too deeply) or that you'll have to stop operating.
Definitely keep an eye on the voltage and just stop if you see anything
below 11.4V on receive.

These days, you are arguably better off with a LiFeP04 battery of about
the same weight and higher capacity, and better ability to cope with
high currents. But it will cost more.

73 de n1dam


Re: 2Ahr

Greg Troxel
 

"Michael McEwen mcewenk5osa@... [4sqrp]" <4sqrp@...>
writes:

I've found a neat little 2AHr SLA (Off road ATV) and it is easily in my PM
weight range. I have an LD5 CW/SSB TXCVR. Would this little batt allow a
couple hours of typical SOTA/PM ops? As I read the LD5 "manual", it should
due to 2A draw on TX...but, I'm an electro-dummy and may be wrong.
A rating of 2 Ah means that it will supply 2Ah/20h = 100 mA for 20h
before reaching 10.5V. As the discharge rate increases, the available
Ah decreases and vice versa, and you get greater voltage drops due to
internal impedance. Generally published curves are available for
multiple charge rates. I would guess that if you were drawing 2A
intermittently with 0 the rest of the time, it might go 30 minutes.
Assuming 0.3A for receive, and 50% keydown while transmitting, the
notion of transmitting for 20 minutes and a few hours of receiving does
not sound crazy.

Hoewver, there's no substitute for actually measuring the current while
in continuous keydown, and in receive, and using an integrating ammeter
to measure total Ah used over some period of operating. I ran a 2m FM
net (at 15W output) as NCS for about 15 minutes total operating time,
and remembered using only about 1 Ah. But this was from a 35 Ah
battery, so my currents were closer to C/20h than our example (0.5A rx,
5A tx, more or less). I'm not sure I would have made it on a 2Ah
battery, and I wouldn't have tried.

The other thing is just to try it; the worst is that you'll break it (if
you discharge too deeply) or that you'll have to stop operating.
Definitely keep an eye on the voltage and just stop if you see anything
below 11.4V on receive.

These days, you are arguably better off with a LiFeP04 battery of about
the same weight and higher capacity, and better ability to cope with
high currents. But it will cost more.

73 de n1dam


RMRc nets today

Dale Putnam
 

NAQCC Rocky Mountain Regional/Continental QRS nets (RMRc)
Tuesday/Thursday at 4:00 PM MDT, which is Tuesday/Thursday 2200 UTC, on 7062.5 kHz
Main NCS - Dale WC7S (Wyoming)

NAQCC Rocky Mountain Regional/Continental QRS nets (RMRc)
Tuesday/Thursday at 4:30 PM MDT, which is Tuesday/Thursday 2230 UTC, on 14062.5 kHz.
Main NCS - Dale WC7S (Wyoming) 


If the T-storms aren't too much today, we could have some fun with a round table after the 20m net
by passing comments from one to another... lots of fun that way.....and lots of practice too.
Stick around after checking in.. I'll come back to call you.


Have a great day,
 
 
--... ...-- Dale - WC7S in Wy
 
 


60M

Michael McEwen
 

Cut/retuned my 80M wire for 60M...wow...few are on it and it is a cool 80-40 compromise for regional HF...haven't tried DX...I'm using an NVIS wire...this ought to become a QRP playground (for SSB)!  No blasters as far as I have heard...I'm monitoring 5370.00...looking for QRP QSOs.

I know not everyone has 60M but most new TXCVRs have it...just aren't many players yet...QRP SSB HF lives!!!
_ _ ...   .. _ _ _

Doc K5OSA - QTH: EM04sr
ARRL  
4SQRP #801 - NAQCC #7625 - SKCC #10098
FISTS #17157 - OMISS #9886
LFSARC (Lawton/Fort Sill Amateur Radio Club)

Michael T McEwen
Lt Col, US Army, Ret

Cellular Phone:  580 919-9205
Residence:  580 529-3412


2Ahr

Michael McEwen
 

I've found a neat little 2AHr SLA (Off road ATV) and it is easily in my PM weight range.  I have an LD5 CW/SSB TXCVR.  Would this  little batt allow a couple hours of typical SOTA/PM ops?  As I read the LD5 "manual", it should due to 2A draw on TX...but, I'm an electro-dummy and may be wrong.
_ _ ...   .. _ _ _

Doc K5OSA - QTH: EM04sr
ARRL  
4SQRP #801 - NAQCC #7625 - SKCC #10098
FISTS #17157 - OMISS #9886
LFSARC (Lawton/Fort Sill Amateur Radio Club)

Michael T McEwen
Lt Col, US Army, Ret

Cellular Phone:  580 919-9205
Residence:  580 529-3412


US 60m CW Frequencies vs Kanga UK 5 MHz Crystals

Chuck Carpenter
 

Don,

Good point, two seem to be the same**

Not as much frequency agility but still could be
useful with two options. Less switching involvement too.

Sounds like a fun project for the educational value... ;-)

Kanga UK 60 m Crystal frequencies

5280 Also known as FB @ £2.00 each
5290 Also known as FC @ £2.00 each
5368 Also known as FK @ £2.00 each
5373 Also known as FL @ £2.00 each**
5400 Also known as FE @ £2.00 each
5405 Also known as FM @ £2.00 each**

US 60 m CW Frequencies via ARRL

Channel 1: 5332.0 kHz
Channel 2: 5348.0 kHz
Channel 3: 5358.5 kHz
Channel 4: 5373.0 kHz **
Channel 5: 5405.0 kHz **



Chuck Carpenter, W5USJ
EM22cv, Rains Co. TX


Re: Kanga UK 5 MHz Crystals

Bill Cromwell
 

Hi Chuck,

My old Kenwood Twins, around about 45 years old now, has five xtal sockets that allow ~5 mc xtals to stand in for the VFO. The rig is dual conversion with the SSB generator and xtal filters at 3.395 mc and the second conversion is a 600 kc wide "bandpass" filter in the 8 mc range. If that 8 mc filter will pass the 60 meter energy from the 75 meter band the xtals could be used that way. The VFO range is from 4.9 to 5.5 mc.

Somebody else mentioned using converters or "transverters" and no reason that can't be used if we watch out for possible spurious signals too close to the operating frequency to filter out. There are useful charts in the ARRL Handbooks (and others) to help choose frequency combinations with fewer problems. Those will be in the receiver discussions but it all applies to heterodyne transmitters, too. A converter or transverter may be viewd as just an addition conversion stage in either a receiver or transmitter. It's all doable.

73,

Bill KU8H

On 06/16/2015 08:31 AM, Chuck Carpenter @W5USJ [4sqrp] wrote:

Now,

This deal from Kanga UK sounds like the easiest way to put a 60 meter
CW rig on the air.

Many of the existing transmitters could be modified to work on 60
with switched crystals for the oscillator.

Even Rockmites could be easily modified for 60 meters for about 1
Watt or so output power. Simplest would be a single frequency and
also use the DC receiver. Switching both crystals has been done but
it's not pretty...

Although I agree with Don, w3fpr, about the use of a better receiver.

I'd want to use some method of temperature control for the oscillator
for stability too.


Re: Kanga UK 5 MHz Crystals

Don Wilhelm <w3fpr@...>
 

Be aware that the 60 meter channels in the UK may be different than in the US.
Check on the specific frequencies.

73,
Don W3FPR

On 6/16/2015 8:31 AM, Chuck Carpenter w5usj@... [4sqrp] wrote:
�

Now,

This deal from Kanga UK sounds like the easiest way to put a 60 meter
CW rig on the air.

Many of the existing transmitters could be modified to work on 60
with switched crystals for the oscillator.

Even Rockmites could be easily modified for 60 meters for about 1
Watt or so output power. Simplest would be a single frequency and
also use the DC receiver. Switching both crystals has been done but
it's not pretty...

Although I agree with Don, w3fpr, about the use of a better receiver.

I'd want to use some method of temperature control for the oscillator
for stability too.

At 05:17 AM 6/16/2015, g6ybc@... [4sqrp] wrote:

>HI All,
>
>Kanga UK, has a number of 5 MHz (60m) Crystals in stock.
>
>If any of you want to do a bulk order, I'll sort a discount
>



Kanga UK 5 MHz Crystals

Chuck Carpenter
 

Now,

This deal from Kanga UK sounds like the easiest way to put a 60 meter CW rig on the air.

Many of the existing transmitters could be modified to work on 60 with switched crystals for the oscillator.

Even Rockmites could be easily modified for 60 meters for about 1 Watt or so output power. Simplest would be a single frequency and also use the DC receiver. Switching both crystals has been done but it's not pretty...

Although I agree with Don, w3fpr, about the use of a better receiver.

I'd want to use some method of temperature control for the oscillator for stability too.




At 05:17 AM 6/16/2015, g6ybc@... [4sqrp] wrote:


HI All,

Kanga UK, has a number of 5 MHz (60m) Crystals in stock.

If any of you want to do a bulk order, I'll sort a discount

Look at <http://www.kanga-products.co.uk>Welcome to Kanga Products
<http://www.kanga-products.co.uk>Welcome to Kanga Products
Welcome to Kanga Products Welcome to the Kanga Products website, home of the famous Foxx-3 Transceiver.

Chuck Carpenter, W5USJ
EM22cv, Rains Co. TX


Re: A simple 60 meter CW transmitter

Bill Cromwell
 

Hi Dennis,

This is useful information but will not help a project like mine. Xtals directly on the operating frequency will be usable in a CW transmitter with a keyed xtal and straight though amplifier chain. It could work in a phasing type SSB transmitter. My project involves a 9 mc xtal filter and thus a ~9 mc carrier oscillator in the SSB generator and either ~4 mc or ~14 mc heterodyne xtals to arrive at an operating frequency on any of the five (actually ten) channels in the 60 meter band.

Xtal oscillators with temperature compensation or outright ovens can provide some of the best frequency stability and phase noise performance. Free running L-C VFOs can also be very good in regard to phase noise performance but will fall behind the xtal oscillators in holding a channelized specification as in the 60 meter band. It can be done. I would prefer xtal control of the five channels since I also anticipate field operation when we are working with those government agencies in emergency situations (if that ever happens). It seems to be the cleanest, most stable way to keep a radio on the button in adverse environments.

For a club project, the CW transmitter with keyed xtal oscillator directly on the operating frequency (center of channel) will be much less complicated and less expensive. Never mind about smaller, too.

Now to look at the ~5 mc xtals for use in my antique (more than 25 years old) heterodyne radios in the xtal socket substitute for the VFO.

73,

Bill KU8H

On 06/16/2015 06:17 AM, g6ybc@... [4sqrp] wrote:

HI All,

Kanga UK, has a number of 5 MHz (60m) Crystals in stock.

If any of you want to do a bulk order, I'll sort a discount

Look at Welcome to Kanga Products <http://www.kanga-products.co.uk>




Welcome to Kanga Products <http://www.kanga-products.co.uk>
Welcome to Kanga Products Welcome to the Kanga Products website, home of the famous Foxx-3 Transceiver.

View on www.kanga-products.co.uk <http://www.kanga-products.co.uk>

Preview by Yahoo

Then click on the 5 MHz Crystals & Links page on the left of the page.

It was also good to meet some of you guys at FDIM, also my thanks to Terry who made me feel very welcome on Club night.

Best regards

Dennis G6YBC
Kanga (UK)


Re: A simple 60 meter CW transmitter

Dennis Anderson
 

HI All,

Kanga UK, has a number of 5 MHz (60m) Crystals in stock.

If any of you want to do a bulk order, I'll sort a discount

Look at Welcome to Kanga Products

 

Then click on the 5 MHz Crystals & Links page on the left of the page.

It was also good to meet some of you guys at FDIM, also my thanks to Terry who made me feel very welcome on Club night.

Best regards

Dennis G6YBC
Kanga (UK)


Re: A simple 60 meter CW transmitter

Todd K7TFC
 

​On Mon, Jun 15, 2015 at 8:23 PM, Bill Cromwell wrcromwell@... [4sqrp] <4sqrp@...> wrote:
I'm not sure of the tolerances in the frequency specs either expect when
I did see them I thought they were tighter than what we have in the ham
bands. 60 meters is shared with gov't services being primary.
​I might be misunderstanding Bill on this point, but according to ARRL, these are the center frequencies for the channels:

​Channel 1: 5330.5 kHz
Channel 2: 5346.5 kHz
Channel 3: 5357.0 kHz
Channel 4: 5371.5 kHz
Channel 5: 5403.5 kHz

Centered on these frequencies is a maximum 2.8KHz. The ARRL doesn't seem concerned in their information about PPMs or specs other than the bandwidth. Are they and I missing something?

73,

Todd
------------------------------------------------------------------------------------
K7TFC / Medford, Oregon, USA / CN82ni / UTC-
7
 (P
​D
T)
------------------------------------------------------------------------------------


Re: A simple 60 meter CW transmitter

yahoomail@...
 

How about we drop back to a SINGLE channel design?  
Pick only one of the five 60 meter channels and have this radio become a 4SQRP intercom?
I'd leave that radio going 24/7 listening for 4SQRP members.  
W25 should be a snap.
72,
-Ed, WG5F-


Re: A simple 60 meter CW transmitter

Bill Cromwell
 

Hi Nick,

I'm not sure of the tolerances in the frequency specs either expect when I did see them I thought they were tighter than what we have in the ham bands. 60 meters is shared with gov't services being primary. The intent is to use 60 meters during emergencies that involve those agencies and us. I have to review those tolerances before I order an xtals for my own proposed project. I am not at all sure that an L-C free running VFO could maintain the tolerances.

FCC gives us tolerances in terms of parts per million or parts per billion. I'll look up the numbers and the specs for the temp compensated oscillator modules I already have and re-evaluate the whole project.

73,

Bill KU8H

On 06/15/2015 09:39 PM, 'Nick Kennedy' nick-wa5bdu@... [4sqrp] wrote:

Yeah, I like that better than crystals anyway. But I wonder if you could get it calibrated well enough that you could set it close enough to the required discrete frequencies? I’m not sure how close you’re expected to get, but I’d think 100 Hz should be OK. But it would be hard to hit that close. The “band” seems to be 73 kHz wide. One solution would be to have an MCU monitor and annunciate the frequency – like a freqmite or equal. OTOH, if you’re going with the original idea of a TX only and using the station receiver (presumably with modern accuracy), you could use it to get on frequency.
For the rest of the transmitter, whether DDS or L/C VFO controlled, I think stealing a bit of the ATS-3 design would be cool. Just three cheap mosfets in parallel and a couple logic gates to interface between the VFO and the finals. Five watts, no heat sink. David Cripe wrote up Class E design in QRP Quarterly some time back. Lots of resources for design of the output networks.
73-
Nick, WA5BDU


Re: A simple 60 meter CW transmitter

Nick-WA5BDU
 

Yeah, I like that better than crystals anyway.  But I wonder if you could get it calibrated well enough that you could set it close enough to the required discrete frequencies?  I’m not sure how close you’re expected to get, but I’d think 100 Hz should be OK.  But it would be hard to hit that close.  The “band” seems to be 73 kHz wide.  One solution would be to have an MCU monitor and annunciate the frequency – like a freqmite or equal.  OTOH, if you’re going with the original idea of a TX only and using the station receiver (presumably with modern accuracy), you could use it to get on frequency.
 
For the rest of the transmitter, whether DDS or L/C VFO controlled, I think stealing a bit of the ATS-3 design would be cool.  Just three cheap mosfets in parallel and a couple logic gates to interface between the VFO and the finals. Five watts, no heat sink.  David Cripe wrote up Class E design in QRP Quarterly some time back.  Lots of resources for design of the output networks.
 
73-
 
Nick, WA5BDU
 

Sent: Monday, June 15, 2015 7:52 PM
Subject: Re: [4sqrp] A simple 60 meter CW transmitter
 
 

This may be heresy in this day of DDS, but how about a good, old fashioned LC VFO for a simple 60M rig? Of course it would need to use NCO/C0G for fixed caps, an air variable, other low TC components, and be thermally insulated. It would also need to be well buffered to eliminate key-down drift, and it would need to be keyed at the driver stage so the VFO can remain free running. Okay, maybe it would need to warm up a little before it goes on the air. But simple it *would* be.
 
73,

Todd
------------------------------------------------------------------------------------
K7TFC / Medford, Oregon, USA / CN82ni / UTC-
7
(P
​D
T)
------------------------------------------------------------------------------------
 
 
On Mon, Jun 15, 2015 at 4:53 PM, Don Wilhelm w3fpr@... [4sqrp] <4sqrp@...> wrote:
 

Nick,

I have built plenty of DC receivers and have been disappointed by each of them.  Apologies to the DC receiver fans, but I like single signal receive and do not like the potential microphonics that some DC receivers produce.  I have tried them, and will trade the DC receiver for a superhet any day.  A good DC receiver may exist, but it takes great care in design and construction.  IMHO, those are "play" receivers and are not for any serious work.

A receiver that makes the top of the Sherwood listing would be 'overkill', but something with decent selectivity, image rejection, and reasonable sensitivity is in order for anything that can properly call itself a receiver in today's bands is a requirement IMHO.  Yes, that includes a receiver that will stand up in contest situations with QRO stations all around (good Dynamic Range), and adequate selectivity to separate stations in a pileup situation.

OK, all of that may not be applicable to operation on channelized 60 meters, but is my bottom-line requirement for a receiver.

73,
Don W3FPR

On 6/15/2015 7:28 PM, 'Nick Kennedy' nick-wa5bdu@... [4sqrp] wrote:
 
I think the output of a typical DDS is reasonably clean.  If the object is to make a receiver that tops Bob Sherwood’s list, some extra pains might be required. 
 
No, phase noise can’t be filtered.  I think with a DDS it’s related to jitter on the reference and with a PLL/VCO, it’s due to “hunting” by the feedback loop which causes a small amount of FMing.  I’m not sure any frequency source can be completely free of phase noise.
 
A DDS can usually be had for less than $10.00 and Arduino Nanos can be gotten 3 for $10 postpaid these days.  It’s hard to justify a bare MCU chip at those prices.
 
As far as channel indication goes,  with enough pins you would have plenty to do an LED per channel, but yeah there are surely better ways.  Looking at my old project, I think I used a piezo beeper to announce the channel in Morse.  But if you want to get fancy, nice backlit white on blue 2x16 LCD displays can be had for $1.89 each, postpaid. Amazing.  You could also use three LEDs in a binary weighted scheme ...
 
There are several other advantages associated with having your LO / VFO under software control.  You could implement RIT – not that the other guy might be off frequency, but so you can adjust his pitch to your liking.  And if you choose to have a superhet receiver instead of direct conversion, it’s easy to do the offset for the IF frequency.  And that’s not all (sounding like a TV pitch man now ...) you could toggle between the right LO frequency to receive CW or switch to the right frequency for decoding USB in the channel.  That would make cross-mode QSOs possible and possibly make it a bit easier to make sure the channel isn’t in use before calling. Or just for monitoring.
 
 

 


Re: A simple 60 meter CW transmitter

Todd K7TFC
 

This may be heresy in this day of DDS, but how about a good, old fashioned LC VFO for a simple 60M rig? Of course it would need to use NCO/C0G for fixed caps, an air variable, other low TC components, and be thermally insulated. It would also need to be well buffered to eliminate key-down drift, and it would need to be keyed at the driver stage so the VFO can remain free running. Okay, maybe it would need to warm up a little before it goes on the air. But simple it *would* be.

73,

Todd
------------------------------------------------------------------------------------
K7TFC / Medford, Oregon, USA / CN82ni / UTC-
7
 (P
​D
T)
------------------------------------------------------------------------------------


On Mon, Jun 15, 2015 at 4:53 PM, Don Wilhelm w3fpr@... [4sqrp] <4sqrp@...> wrote:
 

Nick,

I have built plenty of DC receivers and have been disappointed by each of them.  Apologies to the DC receiver fans, but I like single signal receive and do not like the potential microphonics that some DC receivers produce.  I have tried them, and will trade the DC receiver for a superhet any day.  A good DC receiver may exist, but it takes great care in design and construction.  IMHO, those are "play" receivers and are not for any serious work.

A receiver that makes the top of the Sherwood listing would be 'overkill', but something with decent selectivity, image rejection, and reasonable sensitivity is in order for anything that can properly call itself a receiver in today's bands is a requirement IMHO.  Yes, that includes a receiver that will stand up in contest situations with QRO stations all around (good Dynamic Range), and adequate selectivity to separate stations in a pileup situation.

OK, all of that may not be applicable to operation on channelized 60 meters, but is my bottom-line requirement for a receiver.

73,
Don W3FPR

On 6/15/2015 7:28 PM, 'Nick Kennedy' nick-wa5bdu@... [4sqrp] wrote:
 

I think the output of a typical DDS is reasonably clean.  If the object is to make a receiver that tops Bob Sherwood’s list, some extra pains might be required. 
 
No, phase noise can’t be filtered.  I think with a DDS it’s related to jitter on the reference and with a PLL/VCO, it’s due to “hunting” by the feedback loop which causes a small amount of FMing.  I’m not sure any frequency source can be completely free of phase noise.
 
A DDS can usually be had for less than $10.00 and Arduino Nanos can be gotten 3 for $10 postpaid these days.  It’s hard to justify a bare MCU chip at those prices.
 
As far as channel indication goes,  with enough pins you would have plenty to do an LED per channel, but yeah there are surely better ways.  Looking at my old project, I think I used a piezo beeper to announce the channel in Morse.  But if you want to get fancy, nice backlit white on blue 2x16 LCD displays can be had for $1.89 each, postpaid. Amazing.  You could also use three LEDs in a binary weighted scheme ...
 
There are several other advantages associated with having your LO / VFO under software control.  You could implement RIT – not that the other guy might be off frequency, but so you can adjust his pitch to your liking.  And if you choose to have a superhet receiver instead of direct conversion, it’s easy to do the offset for the IF frequency.  And that’s not all (sounding like a TV pitch man now ...) you could toggle between the right LO frequency to receive CW or switch to the right frequency for decoding USB in the channel.  That would make cross-mode QSOs possible and possibly make it a bit easier to make sure the channel isn’t in use before calling. Or just for monitoring.
 




Re: A simple 60 meter CW transmitter

Don Wilhelm <w3fpr@...>
 

Nick,

I have built plenty of DC receivers and have been disappointed by each of them.  Apologies to the DC receiver fans, but I like single signal receive and do not like the potential microphonics that some DC receivers produce.  I have tried them, and will trade the DC receiver for a superhet any day.  A good DC receiver may exist, but it takes great care in design and construction.  IMHO, those are "play" receivers and are not for any serious work.

A receiver that makes the top of the Sherwood listing would be 'overkill', but something with decent selectivity, image rejection, and reasonable sensitivity is in order for anything that can properly call itself a receiver in today's bands is a requirement IMHO.  Yes, that includes a receiver that will stand up in contest situations with QRO stations all around (good Dynamic Range), and adequate selectivity to separate stations in a pileup situation.

OK, all of that may not be applicable to operation on channelized 60 meters, but is my bottom-line requirement for a receiver.

73,
Don W3FPR

On 6/15/2015 7:28 PM, 'Nick Kennedy' nick-wa5bdu@... [4sqrp] wrote:
 

I think the output of a typical DDS is reasonably clean.  If the object is to make a receiver that tops Bob Sherwood’s list, some extra pains might be required. 
 
No, phase noise can’t be filtered.  I think with a DDS it’s related to jitter on the reference and with a PLL/VCO, it’s due to “hunting” by the feedback loop which causes a small amount of FMing.  I’m not sure any frequency source can be completely free of phase noise.
 
A DDS can usually be had for less than $10.00 and Arduino Nanos can be gotten 3 for $10 postpaid these days.  It’s hard to justify a bare MCU chip at those prices.
 
As far as channel indication goes,  with enough pins you would have plenty to do an LED per channel, but yeah there are surely better ways.  Looking at my old project, I think I used a piezo beeper to announce the channel in Morse.  But if you want to get fancy, nice backlit white on blue 2x16 LCD displays can be had for $1.89 each, postpaid. Amazing.  You could also use three LEDs in a binary weighted scheme ...
 
There are several other advantages associated with having your LO / VFO under software control.  You could implement RIT – not that the other guy might be off frequency, but so you can adjust his pitch to your liking.  And if you choose to have a superhet receiver instead of direct conversion, it’s easy to do the offset for the IF frequency.  And that’s not all (sounding like a TV pitch man now ...) you could toggle between the right LO frequency to receive CW or switch to the right frequency for decoding USB in the channel.  That would make cross-mode QSOs possible and possibly make it a bit easier to make sure the channel isn’t in use before calling. Or just for monitoring.