Topics

Experiments with #Progrock Follow-up #progrock

Mike
 

Well, its been a few days and I hav'nt seen any significant drift !.
Here's an Argo capture of the SI5351 output at 56Mhz received on a well known amateur tranciever.
Interesting ?. Its not the SI5351 thats drifting ! Can you guess the tranciever model ?

ajparent1/KB1GMX
 

If I had to guess it would be an ICOM.
Curious which one though.

Allison

Mike
 

Yes Allison, its an Icom, IC706mk2g, the sawtooth is caused by the fan cooling
the circuitry every time it thinks its too hot. You should see what its like
at 2m, mine swings by about 100hz. good for wspr eh?.

On 20 May 2019 at 14:22, ajparent1/KB1GMX wrote:

If I had to guess it would be an ICOM.
Curious which one though.

Allison



ajparent1/KB1GMX
 

Its why I picked on Icom as I've worked people using them on 6 and 2 and they drift.
Chasing them up and down the band is no fun.  The FT817 has issues too as well 
but adding a TCXO helps.  there are many other that wander about on 2M.

The IC706 series is notable for many things including phase noise so bad that banning it from
any multi radio event is considered required.  However the fan can be modded to run slowly
all the time and its a good mod to help with cooling.

Allison

Mike
 

Yeh, its pretty nasty. And I loathe he Menus. My radio of choice is my
TS-130V.
I only use the IC-706 as a shack monitor receiver, I doubt its had much more
than 30 minutes transmit time since new.
I tried the 10mhz clocked SI5351 on 2m today, but the converter I grabbed from
the junk box turned out to be unstable, need to build a 'proper' 2m front-end
to try it out... later. Mike

On 20 May 2019 at 15:42, ajparent1/KB1GMX wrote:

Its why I picked on Icom as I've worked people using them on 6 and 2 and they
drift.
Chasing them up and down the band is no fun.  The FT817 has issues too as
well
but adding a TCXO helps.  there are many other that wander about on 2M.

The IC706 series is notable for many things including phase noise so bad that
banning it from
any multi radio event is considered required.  However the fan can be modded
to run slowly
all the time and its a good mod to help with cooling.

Allison



ajparent1/KB1GMX
 

Mike,
Understood.

I use a Tentec 6n2 with amps for most of the 6 and 2M activity also a FT817
for the 432 with amp.  For contesting a HB trx I call Crunchproof a very high
dynamic range transceiver for 6m, uses analog phasing in a hybrid superhet
framework and all analog.  Another flier ring also HB in the truck for 6M SSB
action. The backup radios included IC245, and  a KLM linerII (based on a
SBE CB chassis with transverter) and that's a decent 5W radio for 2m
(covers .100 to .340) though people tend to look at it oddly it has a
decent RX and clean TX.

HF includes a Argonaut 505 (QRP!) for 80 through 10, a Triton and a an
Eagle.  Also other like Atlas 210 and a moded one.

All odd gear finds me.

Allison

Peter Mulhare
 

Hello Mike and Allison,

 

I am also a member of the QRSS fraternity, and run a Grabber Station in Northern New Zealand.  I have in the past looked for a solution to keep off the shelf receivers (in particular) from drifting too much.  My Station receiver is an Icom IC-R75, and I wanted to be able to dial set the receive frequency to better than 1e-9 (+1 part in 10-9), and for it to remain there over extended periods of time..   Like you Mike, I have a home brewed VE2ZAZ GPSDO, which outputs a 10MHz signal with an accuracy of a further 2 orders of 10 better than what I wanted.  I had noted that the IC R75 (plus the IC706, and a number of other rigs), source all their internal frequencies like, BFO/IF Mixer LO’s/etc, from the Rig’s own onboard Reference Oscillator.

 

I already knew that it is possible to phase lock crystal oscillators relatively easily, by injecting a suitable stable signal into an oscillator appropriately, usually in series with the crystal current.  I did this using the 10.0MHz output from my ‘ZAZ GPSDO, injecting it in series with the crystal current of the IC-R75’s Reference Oscillator which runs at 30.0MHz, to my amazement the IC-R75 locked up immediately to the GPSDO!  I simply wound 5 turns of small insulated hookup wire (from ground) over an RF Choke in the Reference Oscillator’s circuit, which was in series with the Reference Crystal, and took this out via small diameter coax to an SMA connector on the rear apron of the receiver, then connected it via a coax fly-lead directly to the GPSDO output.  The RF Choke looked like a small 1/8th watt resistor, and was through hole soldered to the PC board in a vertical orientation. 

 

This worked because the ‘R75 receiver’s Reference Oscillator runs at 30.0MHz (the 3rd Harmonic of the GPSDO output), so the reference oscillator gets a kick every third cycle to keep it in phase step with the GPSDO.  I have had this arrangement working now for around 4 years with the R75 remaining locked, 24/7 over that period.  This method can absolutely tame the rogue ICOM rigs that drift too much, simply and effectively!  There is no need to do fan modifications, as in the case of the IC706 or IC756 series, or even to go to using fancy TCXO’s.  The next one I do, will be my IC756 Pro3, however I will need to use a phased locked ProgRock (already purchased) for this, as the IC756’s Reference oscillator runs at 33.16666MHz (from memory).  What I like is that immediately from switch on the rig is exactly on frequency (as long as the GPSDO is never switched off!) and will never drift from its intended frequency, over time.

 

This will work with other manufacturers Rigs too, however the given is that all frequencies within the rig must be derived from the set’s internal Reference Oscillator.

 

73's

 

Pete Mulhare

ZL2iK/ZL4Ei

 

RF74ci

Northland

New Zealand

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Tuesday, 21 May 2019 10:43
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Experiments with #Progrock Follow-up

 

Its why I picked on Icom as I've worked people using them on 6 and 2 and they drift.
Chasing them up and down the band is no fun.  The FT817 has issues too as well 
but adding a TCXO helps.  there are many other that wander about on 2M.

The IC706 series is notable for many things including phase noise so bad that banning it from
any multi radio event is considered required.  However the fan can be modded to run slowly
all the time and its a good mod to help with cooling.

Allison

Mike
 

Thankyou for that Peter. I was aware of the phase locking possibilities but
I've not attempted it. Its certainly worth a try using the SI5351 and 10mhz
reference to lock 'cleaner' oscillators.
Can you provide details, or a URL decribing the basic method?.
73, Mike

ps. I have a ve2zaz query off list. OK with you?

On 21 May 2019 at 13:53, Peter Mulhare wrote:

Hello Mike and Allison,



I am also a member of the QRSS fraternity, and run a Grabber Station in
Northern New Zealand. I have in the past looked for a solution to keep off
the shelf receivers (in particular) from drifting too much. My Station
receiver is an Icom IC-R75, and I wanted to be able to dial set the receive
frequency to better than 1e-9 (+1 part in 10-9), and for it to remain there
over extended periods of time.. Like you Mike, I have a home brewed VE2ZAZ
GPSDO, which outputs a 10MHz signal with an accuracy of a further 2 orders of
10 better than what I wanted. I had noted that the IC R75 (plus the IC706,
and a number of other rigs), source all their internal frequencies like,
BFO/IF Mixer LO´s/etc, from the Rig´s own onboard Reference Oscillator.



I already knew that it is possible to phase lock crystal oscillators
relatively easily, by injecting a suitable stable signal into an oscillator
appropriately, usually in series with the crystal current. I did this using
the 10.0MHz output from my `ZAZ GPSDO, injecting it in series with the
crystal current of the IC-R75´s Reference Oscillator which runs at 30.0MHz,
to my amazement the IC-R75 locked up immediately to the GPSDO! I simply
wound 5 turns of small insulated hookup wire (from ground) over an RF Choke
in the Reference Oscillator´s circuit, which was in series with the
Reference Crystal, and took this out via small diameter coax to an SMA
connector on the rear apron of the receiver, then connected it via a coax
fly-lead directly to the GPSDO output. The RF Choke looked like a small
1/8th watt resistor, and was through hole soldered to the PC board in a
vertical orientation.



This worked because the `R75 receiver´s Reference Oscillator runs at
30.0MHz (the 3rd Harmonic of the GPSDO output), so the reference oscillator
gets a kick every third cycle to keep it in phase step with the GPSDO. I
have had this arrangement working now for around 4 years with the R75
remaining locked, 24/7 over that period. This method can absolutely tame the
rogue ICOM rigs that drift too much, simply and effectively! There is no
need to do fan modifications, as in the case of the IC706 or IC756 series, or
even to go to using fancy TCXO´s. The next one I do, will be my IC756
Pro3, however I will need to use a phased locked ProgRock (already purchased)
for this, as the IC756´s Reference oscillator runs at 33.16666MHz (from
memory). What I like is that immediately from switch on the rig is exactly
on frequency (as long as the GPSDO is never switched off!) and will never
drift from its intended frequency, over time.



This will work with other manufacturers Rigs too, however the given is that
all frequencies within the rig must be derived from the set´s internal
Reference Oscillator.



73's



Pete Mulhare

ZL2iK/ZL4Ei



RF74ci

Northland

New Zealand





From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of
ajparent1/KB1GMX
Sent: Tuesday, 21 May 2019 10:43
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Experiments with #Progrock Follow-up



Its why I picked on Icom as I've worked people using them on 6 and 2 and they
drift.
Chasing them up and down the band is no fun. The FT817 has issues too as
well
but adding a TCXO helps. there are many other that wander about on 2M.

The IC706 series is notable for many things including phase noise so bad that
banning it from
any multi radio event is considered required. However the fan can be modded
to run slowly
all the time and its a good mod to help with cooling.

Allison