New Item in the Marine Radio Collection

Could not stop myself from buying an "Emergency Radio Type 610". I believe it is made by Clifford & Snell, but I am not sure about that.
The radio services the frequencies 500kHz (RX/TX), 2182kHz (RX/TX) and 8364kHz (TX). As in this sort of package, cranks are provided as a power source.

The transmitter seem to be built around two electron tubes (have not checked the types yet), while the receiver seem to employ OC transistors, Germanium that is.
Whilst test TXing into the built-in dummy load, on 2182kHz (A3E), the antenna current meter nicely peaks when the matching variometer (coil with dive-in ferrite rod) is agitated. The two other frequencies would require the operator to have a third arm!?? My radio was supplied with the emergency instructions, which showed one operator only, even the text referred to a single operator doing the cranks and the communications all at once. Who ever wrote this may have never operated a radio himself. While in A3E, a carrier in generated anyway. One hand operating the crank, the other to tune the variometer, no problems here.
It is a different story with 500kHz and 8364kHz. Those are A2A frequencies. No, there is not typoe, A2A it is, AF modulated code. And yes, that makes sense. The signal is received in both, an AM receiver as well as a receiver employing a BFO. However, when tuning the emergency transmitter, one would need one arm/hand operating the crank for energy, a second arm/hand for operating the manual key and a third arm/hand for operating the tuning knob.
The makers of the radio seemed to have spent some thought on this issue, although, maybe not enough. The radio is equipped with a mechanical auto-keyer. Keying the transmitter for tuning can therefore be done, sort of, without three arms. However, the designers seemed to never had the code operator in mind. The built-in manual key is so close to the position of the cranks, that operating both at the same time seems to be a challenge per se. However, if that was your option to survive at sea, that what you would be going for.

Enough about the transmitter, lets have a word on the aerial system provided. A system which managed to impress me. As in all of those sets, the aerial is contained in the box itself. Motto: if your vessel is sinking, throw the emergency radio overboard, get in the life raft and hope for the best. Hence, the floating waterproof box of the emergency radio has to contain everything required to perform emergency communication, including the aerial.
The 610 comes with an antenna base, about 1m long, having a rubber foot (for not damaging the life raft's soft bottom). On this foot, a stainless steel telescopic whip is to be mounted, the whip having an impressive length of estimated 4m (maybe more).

To the downside, and the reason why this radio is not widely available.
In order to keep it smaller, I presume, the designers choose to have a low profile for the cranks. Fair enough... however, they put the cranks so low that they can't be used when the radio laying perfectly flat on the ground. A problem that the very similar TRP1 does not have. Is the TRP1 really as similar? Maybe not... think of it, the TRP1 uses TTL circuits, whilst the 610 employs electron valves and Germanium transistors...

Do I regret having bought on of the 610s? No! Would I buy another one? No!
What is the best thing about the type 610? The aerial provided. I believe, there is no other (convenient) way to get your hands on stuff alike... Think of it!

73!

Skanti Marinetta TRP 1

I got lucky! Ever since I made my GMDSS-GOC, I wanted one of those:

Skanti Marinetta TRP 1 portable survival radio

In the Scheepvaart en Transport College Rotterdam, where I studied for the GMDSS-GOC, those units are on display. You can only guess how happy I am to finally got one into my collection of marine radios. The best thing on this purchase, the set is complete with all standard accessories.
I would like to thank Willy PA0WMR for keeping this rig in near original state. Willy also stated that the transmitter delivers about 5W on 600m.

What is all the fuss about a yellow box anyways you may ask. And the question is well justified. First of all, the box, with the lid closed, swims ;-) It is yellow! (That would be a reference to Douglas Adam's Hitchhiker's Guide to the Galaxy).

OK, lets be serious, why am I so happy to finally posses one?
Having a look at the manual/schematics we see that the rig

• has a modern (digital) design
• operates on 500kHz, 2182kHz and 8364kHz
• is crystal controlled
• allows for CW and AM
• has a built in dummy load
• employs an antenna current meter
• contains an ATU
• can create its own energy (by means of cranks)
• can be energized by an external source

500kHz, 2182kHz and 8364kHz are (former) distress frequencies and must not be use by ham- radio operators! 

Where is the hamradio use of these units? Well, we all hope for the 600m band. The 500kHz signal is created by a  2.000MHz gate-XO and digital dividers. Depending on what band we will finally get, this crystal can simply be replaced by a fitting one. However, since it is a digital XO, on simply could remove the crystal and feed a DDS generated signal into the digital gates.

According to the schematics, the transmitter's 8364kHz crystal can easily be replaced by a 40m crystal. However, the receiver employs some resonant LC-stuff with varactor tuning, which should not pose a major problem to modify to 40m, e.g. 7030kHz.

The receiver uses a 2682kHz crystal oscillator to the 2182kHz emergency frequency. The transmitter employs a 2182kHz digital gate oscillator. We got two options for ham-bands here, 160m or 80m. Both have pros and cons. 2182kHz originally is an A3 frequency. The wiring inside the TRP 1 is providing AM modulation accordingly.
On the 80m band, AM is used in places, hence, that would be a nice possibility to join the action. However, filters will have to be modified.
On the 160m band one may want to aim for A1 operation. A 1.843MHz crystal would do the trick here... However, the wiring will have to be changed to engage the BFO in the "2182kHz" labeled switch position.

What is the prospect for the future use of the rig?
I believe it would provide endless fun during field day operations. In particular when operated from cranks, independently from any power supplies.
The (yellow) box contains everything needed for QRP-ops, including a telescopic vertical antenna and a "long(er) wire" aerial.

I figure it could be reasonable to replace the TBA570 receiver with a NE612 superhet design for side-band use.
The XOs could be replaced by either a DDS or some synthesizers for enhanced flexibility.
Some PIC controls seem obvious, the automatic SOS-TXing is inadequate, obviously.

It all comes down to how much modification is actually wanted. Maybe the greatest fun can be obtained when staying as close as possible to the original functionality, i.e. AM on 80m, CW on 40m and 600m.

Other than that, it is an extremely nice addition to my marine radio collection.

LSB for the IC-M700D

As I wrote before, the Icom IC-M700D, the German version of the famous IC-M700 marine radio, did not come with LSB. What I was reading on the internet lately, there is a French version, the IC-M700F, which also lacks LSB. There is hope, maybe something could be done...

Luckily, my IC-M700D came with a circuit diagram. The schematics of the IC-M700 can be found on the internet.
Studying both circuits, the following can be said (corrections made, due to an error in the Service Manual):

1. the MAIN UNIT pcb of the IC-M700D is the same as the one of the IC-M700
2. both sidebands are using the same oscillator
3. two crystals are switched by means of 1SS53 switching diodes (a 1N4148 will probably do)
4. the LSB crystal's traces are present on the D's pcb, so is the LSB control lead from the MATRIX (ending at Q334's base)
5. the D's LSB crystal and surrounding bits'n pieces (a switching transistor(2SC3402), a varactor (FC51M), an inductor and some resistors) are not populated
6. for LSB a 4.908MHz 4.920MHz crystal is required
7. the mode switch needs to be wired up correctly, there may be a further transistor (Q1210) missing on the MATRIX pcb, further, there could be a jumper somewhere...

Have a look at the IC-M700D PCB

and the corresponding IC-M700 circuit diagram

 The question now would be, if there is any cheap option for the crystal. Well, I figure, we are lucky on that one... there is a cheap crystal for 4.9152MHz. I intend to open one up and pen it down to 4.908MHz grind it up to 4.920MHz. A drop of 7kHz  raise of 4.9kHz should easily be doable, although, this is a little harder than it sounds.

The plan now is to pen down grind up a crystal first and think of the rest of the modification later.

Remark: Never trust a Service Manual!
Reasons: The filter center frequency is 9.0113MHz. The (USB) beat frequency is a mix of 10.24MHz and 4.908MHz divided by four, i.e. 10.24-1.227=9.013.
To get to the other side of the filter, the resulting beat frequency should be higher, i.e. 10.24-(4.92/4)=10.24-1.23=9.010MHz.
I should have seen that before going into penning down crystals, which was a good exercise however.
Now, I need to do both, grinding up, and pen down, when ground away too much crystal material....

YES! (AT-120)

For some reason, life meant it good with me and let me obtain an article I long thought lost. An ICOM AT-120 :-))
The tuner suits my two marine radios, aka SSB radio telephones, IC-M700D and IC-M700TY perfectly. Could well be that the tuner will join one of the radios on board Pandia for /mm operations on 14.313MHz or PSKMAIL frequencies.
Most likely, the AT-120 will match Pandia's backstay, other configurations are thinkable however....

Icom IC-M700D mod

Despite what is told on the internet, there are version of the Icom IC-M700 which actually block out transmission on frequencies outside the marine bands.

Recently, I obtained one of those, the IC-M700D. This radio has got a "Posthörnchen" on it, meaning that the FTZ (Fernmeldetechnisches Zentralamt) gave its blessings. This however means, the radio does not do what it is not supposed to, i.e. transmit outside the marine bands.

Luckily, there is a service manual for the IC-M700 (no D!) available on the internet.

Browsing through the circuit description reveals that LOGIC CIRCUITS holds on control of the receive and transmit frequencies. The manual further recites that IC1006 outputs signals "mute signals for outside the marine bands to P40&P41. Ah! In the schematics diagram, P40 & P41 (pins 7&8 of IC11006) enable a voltage called "TMU" via transistor Q1003. The schematics diagram further shows a wire bridge W1037 shorting the base of Q1003 to ground. Hmmmmm, with W1037 installed, the transistor is never engaged to release the TMU voltage. Could TMU be an acronym for Transmitter MUte?

Let's have a look:

This is how the LOGIC CIRCUITS section looks in its original state:

Note the cut wire, just above the label Q3. That's the cut W37.

W37 aka W1037 reinstalled here. And yes, the radio now switches to transmit on all frequencies. Hard to find, easy to fix.

I hope this will help amateurs since the IC-M700D presently still is very cheaply available, because it does not transmit on amateur radio frequencies... or does it?!

Despite the above success story, the radio by default only is equipped with USB. Yes, the mode switch does have two J3E-positions, however, they both do the same. I will have a closer look into the circuit if there is an easy way to get the BFO to oscillate for LSB too. For the case there is none, the casing provides enough space to add a pulled CB-crystal to add a BFO for the lower side-band. After all, the I.F. is 9MHz ;-)

IC-M700TY qrv

Pandia is out of the water... I wanted her to stay in, but... the anti-fouling paint is essentially gone, the painter forgot to apply primer on top of the gel-shield before rolling on the copper-stuff...
No comment... thus, Pandia is out of the water for winter, giving me the chance of doing some work on the hull and on other part otherwise difficult to reach.

All right, now, what's that to with radio? Well... what about installing some aerials in the rigging?

Hard cut here; the exercise motivated me to wire up the recently obtained Icom IC-M700TY for the first time. The radio is superb! Never before I had the privilege to experience a noise blanker that actually works, well, the radio has got one. The squelch (on SSB!) works well, it's just a switch, I will have a look at the schematics, my impression was, the squelch seems to be dynamic, flip the switch and after a certain while the receiver is silent. The AGC is very effective, it cannot be influenced. Therefore I think, the radio is (w/o mod) not really suited for QRSS. The radio is controlled by a "high precision" TCXO, whatever that means. Said TCXO however is about four times the size of a TCXO in an amateur transceiver.

Downside, one needs to know the frequencies one wants to operate on. We amateurs tend to flip over a range of frequencies and see what's on. Well, spinning a knob in order to scan the band is a no no with the IC-M700TY. Actually, scanning is, compared to more modern professional (marine) radios, not an option to this radio. Thus, know what you want and which qrg to want it on.

I assume, the IC-M700 is ideal for modes such as PSK31, Pactor, etc. and further for nets and similar channelized voice operations.

IC-M700TY

Yes, today it dropped in. The radio is in wonderful condition. I think, it has never seen any ship from the inside.

Yeah!

Yes, luck had it, I found an ICOM IC-M700TY and bought it :-))

The gear is perfect, really. It comprises the two maritime modes USB and F2B, but also A1A, A3E and LSB, which is unusual for maritime radios. This radio is intended for TOR (Teletype Over Radio).

As in all professional radios, there is no main dial (aka VFO-knob). The frequencies, RX and TX are independent, are selected numerically.

This is a no-nonsense professional radio, just like the one I was trained on for the General Operator's Certificate. The only difference here, no DSC. However, DSC could even be run externally, since the radio is prepared for TOR.

update QAM

As announced, the E-probe/HF3/EeeBox-combo was up and running throughout the night. we've got a superb (free) navtex-decoder, check it out http://frisnit.com/ to find out more about navtex, stations, format, etc.

This is what my computer sent to frisnit.com:

Station	Message	Type	Received (GMT+0)	Quality
P	PB76	Met warning	2009-06-03 03:43:00	100	View
T	TA87	Nav warning	2009-06-03 03:20:48	100	View
T	TA06	Nav warning	2009-06-03 03:19:47	100	View
T	TA86	Nav warning	2009-06-03 03:18:37	100	View
T	TA90	Nav warning	2009-06-03 03:15:26	100	View
T	TA91	Nav warning	2009-06-03 03:14:36	100	View
T	TA92	Nav warning	2009-06-03 03:13:36	100	View
T	TA93	Nav warning	2009-06-03 03:12:46	100	View
T	TA95	Nav warning	2009-06-03 03:11:55	100	View
T	TA99	Nav warning	2009-06-03 03:11:15	100	View
P	PA66	Nav warning	2009-06-03 02:37:19	100	View
P	PA59	Nav warning	2009-06-03 02:35:59	100	View
P	PE03	Met forecast	2009-06-03 02:35:28	100	View
M	MA55	Nav warning	2009-06-03 02:05:38	100	View
M	MG06	Decca	2009-06-03 02:04:47	100	View
M	MA62	Nav warning	2009-06-03 02:03:57	100	View
M	MA74	Nav warning	2009-06-03 02:03:27	100	View
M	MA75	Nav warning	2009-06-03 02:02:46	100	View
M	MA76	Nav warning	2009-06-03 02:02:24	100	View
J	JA90	Nav warning	2009-06-03 01:31:43	98	View
J	JB79	Met warning	2009-06-03 01:31:10	98	View
A	AA46	Nav warning	2009-06-03 00:08:17	96	View
A	AH43	Loran	2009-06-03 00:07:07	100	View
A	AA51	Nav warning	2009-06-03 00:06:37	100	View
A	AE10	Met forecast	2009-06-03 00:04:07	92	View
P	PA66	Nav warning	2009-06-02 22:33:08	100	View
P	PA59	Nav warning	2009-06-02 22:31:58	100	View
P	PA33	Nav warning	2009-06-02 22:31:18	100	View

QAM

Received some meteo-charts with the E-probe/HF3/EeeBox-combo....

That not only is interesting to sailors, but also to VHF-dxers... tropo is the name of the game.

This is a part of the fax transmitted by DDH3 (3855kHz). Now, finally, receiving the scheduled navtex from PBK (NCG - Netherlands Coast Guard, Ijmuiden).

Reads like this:

ZCZC PA33

NETHERLANDS COASTGUARD

NAVIGATIONAL WARNING NR. 33 021906 UTC MAY

OFF VLIELAND TSS

HYDROGRAPHIC EQUIPMENT ESTABLISHED

IN 53-18.5N 004-27.3E COVERED BY

YELLOW BUOY FL Y(5) 20S

NNNN

W

ZCZC PA59

NETHERLANDS COASTGUARD

NAVIGATIONAL WARNING NR. 59 260344 UTC MAY

PLATFORM Q8-A

52-35.7N 004-31.8E

REPORTED UNLIT

NNNN

ZCZC PA66

NETHERLANDS COASTGUARD

NAVIGATIONAL WARNING NR. 66 021249 UTC JUN

OFF VLIELAND TSS - VLIELAND NORTH TSS

NORTH GOING LANE

HYDROGRAPHIC SURVEY OPERATIONS BY HRMS LUYMES

IN AN ARE BOUNDED BY

A. 53-36.3N 004-51.8E

B. 53-15.3N 004-38.4E

C. 53-17.0N 004-34.3E

D. 53-36.0N 004-48.0E

WIDE BERTH OF AT LEAST 0.5 NM REQUESTED

VESSEL IS LISTENING ON VHF CH 16 AND 13

NNNN

73!

E-probe experiments

It was an interesting day in the office, I have however not managed to get much work done, shame on me! On the other hand, I had a couple of very inspiring conversations, which will gove work a boost later that month...

Back to electro-magnetic stuff.

Since the E-probe, aka PA0RDT Mini-Whip, proved itself, today it was time see what it can and cannot do.

Thus, wired up the E-probe with the HF3/W and fire up the latter. Location of the E-probe about 2m of my server (which btw also serves as grabber and WSPR-mept) running in full swing. Expecting the worst, I tuned in the following frequencies:

1. 5450kHz RAF Volmet
2. 3866kHz DWD weather fax
3. 7880kHz DWD weather fax
4. 6075kHz DW (BC-AM)
5. 0518kHz international navtex
6. 0198kHz BBC
7. DCF77
8. 0060kHz MFS

Here's the outcome of the tests (performed between 1830z and 1900z):

1. no qrm, 57 / 59
2. no qrm, 59+
3. no qrm, 55
4. no qrm, 59++
5. no qrm, no signal (navtex is scheduled)
6. qrm 3, 26
7. qrm 4, 48
8. qrm 5

Next test, swing the E-probe out of the Farraday-cage I call my house, and here's 'm results:

1. 59+
2. 59+
3. 57
4. 59++
5. no qrm, still no TX scheduled
6. qrm 2, 36
7. qrm 4, 49
8. qrm 5

Concluding, I would like to partially confirm Roelof's experience. What longwave is concerned, and that's what PA0RDT is mainly concerned about, QRM is generated inside my Farraday-cage. Yesterday's test revealed the signals from DCF77 and MSF 60kHz could be received 59 w/o qrm on from my roofdeck.

Speaking shortwave, the story appears to be different... noise generated by my sever appears not to be an issue, signals are down, by the amount one would expect from an indoors aerial anyway.

It's about time now to setup navtex and receive some Netherlands Coast Guard (Den Helder) and some Oostende Radio.

I am confident that this test will prove positive too.

UPDATE:

It's now 2110z, using the E-probe, indoors, the HF3-RX and my EeeBox, all just about 1m apart, capturing forecasts transmitted by DDH7 (7646kHz)... RST: 559

ZCZC 478

WODL45 EDZW 022100 COR

STRONGWIND GALE STORMWARNINGS FOR SEA AREAS:

GERMAN BIGHT, WESTERN AND SOUTHERN BALTIC.

GERMAN BIGHT:

GALES NORTHWEST 17 TO 19 M/S (7 TO 8 BFT).

WESTERN BALTIC:

NEAR-GALES NORTHWEST 14 TO 16 M/S (6 TO 7 BFT).

SOUTHERN BALTIC:

NO WARNING.

COASTAL AREA WARNINGS:

STARKWIND, STURMWARNUNGEN FUER DEUTSCHE KUESTEN.

NR. 246

STURM - WARNUNG DES SEEWETTERDIENSTES HAMBURG

FUER DIE DEUTSCHE NORDSEEKUESTE

HERAUSGEGEBEN AM 02.06.2009 UM 14:00 UHR GZ.

OSTFRIESISCHE KUESTE: NORDWEST 7, DABEI BOEEN VON 9 BEAUFORT.

ELBEMUENDUNG: NORDWEST 7, DABEI BOEEN VON 9 BEAUFORT.

SEEGEBIET HELGOLAND: NORDWEST 7, DABEI BOEEN VON 9 BEAUFORT.

NORDFRIESISCHE KUESTE: NORDWEST 7 BIS 8, DABEI BOEEN VON 9

BEAUFORT.

ELBE VON HAMBURG BIS CUXHAVEN: NORDWEST 5 BIS 6, DABEI BOEEN VON

8 BEAUFORT.

NR. 230

WIND - WARNUNG DES SEEWETTERDIENSTES HAMBURG

FUER DIE DEUTSCHE OSTSEEKUESTE

HERAUSGEGEBEN AM 02.06.2009 UM 22:35 UHR GZ.

FLENSBURG BIS FEHMARN: NORDWEST 6 BIS 7 DABEI BOEEN VON 9

BEAUFORT.

OESTLICH FEHMARN BIS RUEGEN: NORDWEST 6 BIS 7 DABEI BOEEN VON 9

BEAUFORT.

OESTLICH RUEGEN: NORDWEST 6 DABEI BOEEN VON 8 BEAUFORT.

SEEWETTERDIENST HAMBURG

=

NNNN

Thus, concerning my maritime needs, the E-probe does the trick.

Tests on Navtex are still pending... I will leave the setup run through the night, some reports my have tumbled in. FAX also needs to be done. I'll try to catch the 2200z-TX from DDK3 (7880kHz).

73!

The LO for the PSKmail-TRX

First steps first... investigate if I can reach 10148kHz using standard crystals.

The idea, as shown in an earlier post, is, to use a 6144kHz LO and and I.F. of 4000kHz. This short of 4kHz. A lot, one may think.

However, when building my 30m-MEPT, I experienced that oscillators based on 74HC86 generate a frequency much higher than the crystal's nominal. Using a 5068.8kHz XTAL, I thought I was way to low, but then, I had hours of experimentation, before I got the frequency down into the qrss-band.

Thus, today, the idea was, if I can repeat this with 6144kHz crystals to close the 4kHz gap.

Well, the gap is closed, by far exceeding my expectations. The 6144kHz crystal produced a 6154kHz signal. Yes, 10kHz above the nominal frequency. Further experiments revealed, an inductor of 15µH and a capacitor with 47pF both in series with the crystal, brought the frequency down to 6146kHz. Close, but still more room for improvement appeared. The photograph shows the LO with the experimental capacitor (the long legged blue thing).

Two more gates of the 74HC86 will be used to generate an in-phase and an out-off-phase LO signal for use in a 74HC4066-mixer.

The remaining fourth XOR-gate will become the 4000kHz BFO.

Combination found....

Please ignore the question I posed on my previous blog entry, I found my combination. Again SMD, again DigiKey... 6612.813 kHz

Adding a carrier from a 3535kHz QRP crystal gets me to 10147.813kHz.

PSKmail, here we come. Another maritime mobile project in the planning.

http://pskmail.wikispaces.com/

Maritime Mobile USB-TRX

Some thinking occurred in my good old walnut. Being a sailor, designing a designated MM TRX is just that tempting.

For ease of construction, low cost and frequency stability, a superhet using a VXO (super VXO) with a ladder or lattice XTAL-filter.

The arising questions here:

1) Which QRGs are used by the most popular (useful) nets?

2) Which (standard) crystal are available?

3) Is there a chance for regular ham-radio-operations?

4) Any design tricks?

Answers:

1) QRGs

There are a couple of networks, some frequencies are most popular:

1. 14300kHz - Maritime Mobile Service Net, Seafarer's Net, PAC Maritime Net, Intercon Net
2. 14313kHz - Maritime Mobile Service Net, Seafarer's Net, International MM Net, Med. Sea MM et, German MM Net, Intercon Net

2) XTALs

Here, the thinking starts, and that would be y solution. Standars crystals are available for 4194,812kHz and 4194,304kHz. The first idea that pops up would be an intermediate frequency of 4194,812kHz, using a pulled down BFO using a 4194,304kHz-crystal.

Filtering could be done by ladder (the easy choice) or lattice. The latter option would use crystals of both frequencies, this option needs further investigation, i.e. bandwidth.

VXO-frequencies that would mix to the above NET-QRGs (a tiny bit of pulling required):

1. 10106kHz - 30m QRP-crystal
2. 10120kHz - 30m crystal

Pulling a bit further (up) other networks could be reached:

• 14303kHz - UK Maritime Net, Swedish Maritime Net
• 14305kHz - Confusion Net
• 14315kHz - Tony's Net
• 14316kHz - Indian Ocean MM Net, South African MM Net

Other networks will be available with other standard crystals, such as 10115kHz, 10125kHz and 10145kHz.

3) HamRadio

Yes, there are options for regular, non maritime that is, ham-radio-operations. A 9830,4kHz-crystal would result in 14024kHz, thus A1A-operations. For J3E, there are 10000kHz rocks available, well ... add 4194kHz, that's were one ends for USB. For operations at those frequencies, and some better ranges, I will go for a super-VXO for the A1A-part. For the voice, there is choice: super-VXO using crystals or even a greater range using a ceramic resonator.

4) Tricks

Not a trick yet, more a design idea at the present stage.

My 30m MEPT is using the PWM-output of a PICAXE to apply an analogue signal to a varactor (well, the MEPT actually uses a rectifier diode as varactor).

Advantages a suitable (PICAXE-)µ-controller offers:

• channel selection/switching by digital i/o-ports
• RIT/XIT and/or VXO pulling voltages provided by PWM
• VFO/RIT/XIT controls by using on-chip ADCs
• memories by selection of crystals and pulling voltages
• sweeping VXO pulling frequencies
• squelch by use of an on-chip ADC
• channel/memory scanning with halt/stop by squelch

Besides µ-controllers, there's some more to think of, such as power amplifiers, data traffic, maritime aerials.... Not to mention position reporting and distress alerting. For the latter I probably would rather rely on GMDSS-gear/procedures....

Open questions here, with an I.F. of 4194kHz, would there be any obvious choice of standard-xtal to use for PACTOR? Please let me know....

73