How To Adapt The 'New' 2.4gHz Gear To R/C Submarines

[He Who Shall Not Be Named]

2.4-gigga-Hertz (2.4gHz) radio frequency -- the band at which all of today's commonly available radio control (r/c) systems operate -- does not penetrate water. In the past we r/c sub drivers enjoyed r/c systems that operated in the 27-75mHz bands -- radio frequencies (RF) well below the resonate frequency of fresh water. With that old gear we had the ability to operate the model submarine to considerable depths yet still maintaining complete control of the model -- the radio link between topside transmitter and submerged receiver was little atenuated by fresh water.

However, with the almost over-night switch within the r/c system industry from the lower frequency bands to the relatively high 2.4gHz band we r/c submarine drivers are now screwed! Using this new gear we denizens of the deep can no longer plunge our model submarines to great depths. Today, we are married to the surface, and if we are to be in control of our model submarine via radio control the receiver antenna must project up into the air. The goal of this instructional pamphlet is to demonstrate how to get the r/c system antenna off the receiver and up high atop the sail, resulting in the ability to at least operate your model submarine at 'periscope depth'. Not as good as it was with the old gear, but better than being a total surface-runner.

The objectives of this instructional pamphlet:

• establishment of how much coaxial cable is needed between receiver and topside antenna
• make up of coaxial cable conductor and shield to the receiver
• use of a packing gland to make a watertight passage of coax cable through the Sub-driver
• forming the 2.4gHz receiver antenna at the upper end of the coaxial cable
• working out a means of hiding the receiver antenna within a 'periscope'
• setting the receiver channel fail-safes to drive the model back up once the antenna dunks beneath the surface

Before doing anything else you need to establish that the r/c system is working fine before proceeding with the receiver antenna modification.
Read and understand your r/c system set-up and receiver-transmitter binding instructions! First task is to get your transmitter talking to your receiver -- this is the initialization of receiver to transmitter.

2.4GHz RECEIVER AND THE 'ANTENNA PROBLEM' Unlike the lower frequency r/c systems, the exceptionally high frequency of 2.4gHz demands strict adherence of receiver antenna length and the need to maintain an unobstructed line-of-site orientation of the receivers antenna to that of the transmitters antenna. The very short wave form of the 2.4gHz signal demands the use of a very short, full-wave antenna -- this is why it is so easy to block the signal between transmitter and receiver: should not a sizable fraction of the wave impinge the antenna, very little signal gets to the receiver and drop-out will occur. Hence the need to get the antenna out of the WTC/Sub-driver and positioned up high atop the sail. The agent of receiver antenna relocation is the thin gauge RG-178 coaxial cable provided.

I would be negligent not to credit the early pioneers of r/c submarining. Guys like Mike Dorey. Guys who, forced by location, where only salt water was available to them, had to devise means to run their receiver antennas up high into the sail of the model submarine. To sail in salt water, which blocks even the 27-75mHz RF signal. These guys showed how to extend the antenna out from the watertight enclosure and up where at least some fraction of the antenna projected above or even with the raised periscope. This was a relatively easy task with the 27-75mHz r/c systems as those receiver antennas were of fractional lengths of the systems full wave form, so there was a lot of latitude as to how much signal got to the antenna, i.e. even a 1/4" of such an antenna above salt water was enough to ensure detection by the receiver even out to a two-hundred foot cross-range.

However, the critical operating perimeter of the 2.4gHz system is the fact that the 1.25" long antenna is a full-wave antenna -- it either gets the full wave form or the signal is not likely to be detected by the receiver. Extending the antenna length by anything other than a shielded cable will result in de-tuning of the receiver detector circuit and the system won't work.

So, to get the 2.4gHz r/c system to work with the model submerged we have to get the antenna off the receiver printed circuit board, and place it to a point atop the sail. And doing so while keeping the antenna geometry to the critical 1.25" length. And insuring an unobstructed (by water or other RF blocking structure) line-of-sight between transmitter and receiver antenna. This repositioning is done by splicing in a length of coaxial cable between receiver and receiver antenna.

Coax is a special type of conductor designed to carry high frequency signals without outside EMF getting to the conductor or permitting RF within the conductor from getting out. Coax typically has a single conductor at its center which is wrapped in a thin insulation; surrounding this insulated conductor is a braded metal shield -- This shield, at ground (typically electrical negative) potential, prevents induction to or from the inner conductor, such induction would change the effective length of the antenna. The short length (1.25") of coaxial cable with the shield pulled away becoming the receivers antenna.

ESTABLISHING LENGTH OF COAX CABLE The length of coaxial cable needed between the Sub-driver/WTC and antenna is of course driven by the scale and model submarine subject. Two-feet of RG-187, .071" diameter coaxial cable has been provided -- more than enough for most model submarine subjects. You will determine the length of coaxial cable you need by a dry-fit of the cable -- one end (dry side) runs into the SD to a position where the receiver will go, and the other (wet side) end of coax sized to run up into the models sail and up into a suitably modified scope tube or mast to place the antenna, atop the coaxial cable, as high as possible. You also must account for the slack in the coaxial cable required to permit easy access the models interior as you lift its upper hull off and set it aside next to the lower hull.
Once the length is established, the excess coaxial cable is cut away and you can proceed with make-up of the dry-side of coaxial cable to the models receiver.

The gland is made up to the coaxial cable after you have soldered the shield and conductor to the receiver pads and mounted the receiver within the SD. Run the bare end of the coax through the dry side open hole in the motor-bulkhead, then install the motor-bulkhead onto the after end of the SD's cylinder. Lightly coat the coax cable with Vaseline, then slide the gland down on it till the gland is about an inch away from the motor-bulkhead hole. Mount the system into the lower hull of the model submarine.

You have already worked out where the antenna atop the coax will reside within or atop the sail and have made provision to pass the coax through the upper hull and sail. Pass the coax up through the upper hull and sail as you place them atop the lower hull. Pull out the slack (easily, this is not a tug-of-war contest!). Push about two-inches of coax down and into the model. The end of the coax is standing vertical where is will sit during operation. Cut off the excess coax. The next step will outline how you strip back the insulation and shield to convert that last inch-and-a-half into the required 2.4gHz antenna

MAKING UP THE COAXIAL CABLE TO THE RECEIVER Once you cut the coaxial cable to the required length, the next step is to remove the receivers factory installed antenna/coaxial cable and make up the dry-side of your coaxial cable.

2.4gHz receivers, for the sake of this discussion, are of two types: those with one antenna, and those with two antenna. Why two antennas on some of these receivers? Well, that's because such receivers have two detector circuits on a common board, each with its own antenna -- this two-in-one packaging permits selection of the detector possessing the 'cleanest' data stream; should detector circuit not generate the proper pulse chain, then it's output is shunted, and the detector with the best signal has its output sent on for decoding and use by the models on-board devices. The two-detector receiver is expensive and usually has at least eight-channels. The cheapie four-channel receiver usually has only one detector, hence one antenna

Some receivers have the 1.25" long antenna directly soldered to a pad on the receiver printed circuit board (PCB). Other type receivers, extend their antenna a few inches clear of the PCB through a length of very small gauge coaxial cable. The type receiver with the antenna directly attached to the PCB present a special problem -- the lack of a dedicated grounded solder-pad for our coax cables shield; we are compelled to run a jumper wire from the coax cable shield to the nearest grounded point we can find on the receiver board (or, as illustrated the negative side of the pin-connector bus).

Caution: after exposing the receiver PCB, make sure you hold the receiver by the edges of the PCB and don't touch any of the exposed conductors on the face of the PCB -- the microprocessors are sensitive to electro-static current, and you can cream the entire receiver if you're not careful. Once work is done either protect the conductors with heat-shrink tubing or insert the receiver back into its original case.

Regardless of receiver type, the objective here is to move the receiver antenna (or one of the two receiver antennas) off the receiver board and move it a considerable distance from the SD housed receiver, to a position up high in the model submarines sail, were it will be in the air as the model cruises submerged at 'periscope depth'. Placed between the receiver and the relocated antenna is a length of small-gauge coaxial cable (coax).

OK, enough background -- now, on to how to solder the receiver end of the coax to the antenna and ground pads:



1. De-solder the existing receiver antenna or coaxial cable unions at the receiver PCB. This is done by heating the solder and either wicking it away through capillary action or use of a molten 'slurp gun. One the binding solder has been removed from between the receiver antenna and shield pad, the antenna/coax is pulled away. At this point the crystallized rosin (an artifact of the original soldering job) has made a mess on the face of the PCB -- this is easily removed with a stiff lacquer thinner drenched acid-brush and a low pressure air blow-down.

2. At the dry-side of your coaxial cable remove 1/4" of outer insulation, pull back the shield and roll it between your fingers for form a lug you can solder too. 1/16 from the shield, strip the insulation away from the conductor. Tin (pre solder) the shield lug and conductor. It's vital to keep the distance between conductor and shield as short as possible -- if you can remove more conductor and insulation after the tinning and still achieve a good solder joint at the receiver antenna pad, do so! Solder the coaxial cables conductor to the receivers antenna pad. If the receiver has a ground pad, then make use of it and solder the coaxial cables shield to it. If there is no defined shield ground pad on the receivers PCB, then run a jumper from the coaxial cables shield and make it up to a clearly defined portion of the receivers negative bus. Strive to make the jumper wire as short as possible. Where possible provide some form of strain-relief -- this to immobilize the coaxial cable from flexing at the receiver PCB solder pads.

3. The coaxial cable watertight glad is prepared within the motor bulkhead, and the receiver installed to its assigned position within the Sub-driver. The wet end of the coaxial cable is lightly greased and run through the gland, leaving about 1/2" of slack between the forward face of the motor-bulkhead and receiver

4. The receiver is either returned to its factory case or wrapped in heat-shrink tubing to protect the exposed conductors from shorting out against the Sub-driver device shelf

THE COAXIAL CABLE SUB-DRIVER WATERTIGHT GLAND Looking very much like our standard 1/16" (.062") pushrod seal, the coaxial cable gland is in fact the same device, bored out to receive the .071" diameter of the coaxial cable. It's the function of the gland to make watertight the passage of the coax into the SD. The provided coaxial cable watertight gland is inserted into an unused 1/4" pushrod seal body hole in the motor bulkhead.

An alternative -- if you are presented with the situation where you have more 1/16" pushrod seals set into the motor-bulkhead than your model requires pushrods: Identify the 'unused' pushrod seal and enlarge the bore by drilling through it with a 3/32" bit. This will not damage the rubber sealing element within. However, the larger bore of the converted pushrod seal will now permit passage of the coaxial cable.

FORMING THE ANTENNA FROM THE COAXIAL CABLE CONDUCTOR OK, you've made up the dry side of the coaxial cable to the receiver; you've run the wet side of the coaxial cable through the motor-bulkhead watertight gland; and you've worked out where the eventual receiver antenna will be situated up atop the sail -- either sitting up high or hidden within an RF transparent structure such as a periscope tube, periscope head, or mast fairing.

Right now there is no antenna, just coaxial cable -- the grounded shield prevents any RF energy from inducing a signal to the internal conductor. However, if you strip away the outer insulation and shield to expose the correct length of center conductor, now you have an antenna. An antenna of the correct length for the frequency, and well removed from the receiver, safe within its watertight Sub-driver.

The photo shows the steps taken to produce the antenna. Note that once the antenna is exposed a short length of heat-shrink tube, which will form a protective sheath, is placed over the antenna; this sheath extending down 1/4" over the un-stripped coaxial cable. Heat is applied to tighten up this protective sheath and once cool the tip if filled with RTV sealant and the bottom of the sheath rubbed with the RTV -- this step to insure no water gets at the antenna conductor or shield. The last thing you want is water working its way down to the receiver PCB ... ain't that right, Gene!?

The completed antenna can be situated atop the model submarines sail alone or hidden within any mast, scope head, or shear large enough to accommodate the diameter of the sheaths bulge at the base of the antenna.

HIDING THE ANTENNA ATOP THE MODELS SAIL Most of us drive scale model submarines, and want to hide the receiver antenna as best we can. A sometimes difficult task on model submarines representing subjects in scales smaller than 1/96. The obvious answer is to run the coaxial cable, topped by the receiver antenna up a hollow tube -- that tube representing either a periscope tube or other retractable mast unique to the submarine in question. Metal tubes would attenuate the signal to the antenna, so that portion of scope or mast must be of an RF transparent material (no metal, no carbon) which is pretty much transparent to RF energy in this band.

As illustrated here, you can employ a metal scope tube, to run the coaxial cable, but provide the upper portion (scope head) within which the antenna resides, as a plastic, RF transparent material. This arrangement puts the scope head above water -- and coincidently, the antenna -- when operating the model submerged, at 'periscope depth'.

Your average real-world periscope tube is between seven and ten inches in diameter, that scales out to around 5/64" diameter for a 1/72 scale model submarine. Study the photo of this 1/72 Revell Type-7C model and how I replaced the number-2 scope provided in the kit with an aluminum tube topped with a hollowed out scope head: the coaxial cable running up the tube, terminating in the antenna that sits within the RF transparent plastic scope head. Obviously, the larger the scale, the easier the task of hiding the receiver antenna.

If you are operating smaller scale model submarines, then the periscope option is not viable -- you will have to hide your antenna within a mast of thicker proportions, such as the snorkel induction mast, or radar mast. Whatever mast you chose, it must be plastic and robust enough to survive handling and minor collisions.

SETTING-UP YOUR RECEIVER FAIL-SAFE POINTS The receiver fail-safe settings work to direct your submerged submarine upward when the antenna dunks under the water's surface. Almost all of the new r/c gear has the fail-safe feature -- the ability of the receiver to generate commands to position the devices it controls to pre-set positions upon loss-of-signal. Positions that will, in our case, work to raise the model in the water. As a loss-of-signal condition would most likely be the result of the antenna dipping beneath the water's surface, it's desirable to have the model submarine seek the surface once loss-of-signal occures ... we want that antenna back up into the air ASAP! These autonomous commands, along with the slightly buoyant submarine (submerged trim will place the waterline an inch or so below the top of the conning tower/sail) should broach the antenna in short order and you can sail along, in control, as before.

When the receiver antenna goes underwater, the receiver looses the signal and, switching to fail-safe mode (the loss-of-signal settings you programmed into the receiver) commands the ESC, control surface servos, and ballast sub-system servo/solenoid/pump controller to work to reduce the depth of your model submarine.

During the set-up of your r/c system you not only 'bind' your receiver to your transmitter, you also configured the receiver fail-safe signals (originating from the receivers memory, not the transmitter) to the devices it controls. When properly set, the receiver, when it loses the transmitted signal, directs the devices to push the model to the surface, to broach the antenna so it can once again deliver the transmitted signals to the receiver, putting you back into the control loop.

channel type control device action fail-safe action

1 servo rudder position center rudder(s)
2 servo bow plane or stern plane full rise
3 electronic speed controller propulsion all-stop
4 servo/pump/solenoid manage ballast water blow/pump out water
5 servo bow plane retract n/a
6 servo stern plane full rise



David Douglass Merriman lll
Caswell-Merriman

[zhuravlik]

How about fundraising a synthesized dual conversion 8 ch RX with integrated programmable failsafes a couple of switches built in?

[He Who Shall Not Be Named]

How about fundraising a synthesized dual conversion 8 ch RX with integrated programmable failsafes a couple of switches built in?

To what end?

M

[Slats]

David an excellent and timely essay, however can you tell us what the story is in the US with availability of traditional lower frequency radios. Mike I know you were doing W-FLY radios.

Have these dried up? I can still (for now) buy Radios that are legal here in Australia via Engel subs in Germany.

No matter what the current supply issue, the article is timely that the end of these ideal lower legal frequencies appears to be here. BUT also maybe this is an opportunity. David's article as per usual is excellent, but I think if we are to keep the hobby open to the new guy the conversion (albeit not overtly difficult if one follows the article above) is an extra layer of complexity and might be for the newcomer a bridge too far. Furthermore, I think I'd rather not sail at all, if the rest of my hobby is spent restricted to PD.

Surely a cheap Chinese supplier could be found for a dedicated FM / PPM Submarine radio. Pick maybe three - four bands that could cover Legal frequencies almost everywhere. 75MHZ -US, 40MHZ / 35MHz UK / Germany / Australia + another

Chuck in China might be a good point man for manufacturer. In terms of minimum start up volumes - I'm quite sure with the right International marketing and price, the small sub community which is all in the same boat could order enough. David / Mike how about it? - A dedicated Subdriver radio set?
Keep the manufacture out of David's hair. You don't need another product line to clog up the works.

I'm noticing that there seems to still be an endless supply of RXs on channels that are legal in Australia and Europe. Is this the case in the US?

Best

John

[Slats]

How about fundraising a synthesized dual conversion 8 ch RX with integrated programmable failsafes a couple of switches built in?

Yes what David said, why?

Our current FS equipment is fine. You can buy RXs. The whole point of the article is that Radio units (specifically TXs) on legal frequencies are facing extinction. Hence why we need to consider a 2.4GHZ conversion that we can mount in our subs.

[Von Hilde]

Great tutorial Dave. I prity much had the general idea of the concept, electronicly, but not sure of the perameters of the box. I was wondering a couple things. The exposed wire at the end of the coax is waterproofed by the heat shrink, is the antenna, itself. Is that liength criticle? or is the total overall liength, the factor? Can I solder a brass periscope to the tip of the wire and waterproof the connection and scope with the sprey on waterproof vinal coating for marine switches? I have brass tubing in my scope housings instead of the revell plastic, which may come in contact with the metal scope. Will that have any bearing onthe preformance? I would think there would be no direct interfearance with any of the extra metal in the boat, such as decks ect. I suppose I should get a better soldering iron than the antiques I have, or at least some new, finer, tips. Now if I ever get the Wfly8 I ordered......priority mail?....with another ez....hmmmmmm? somebody fell asleep on watch on watch up at the con, sir. I see the falls have frozen up in the great white north in kazzland, think that stuff is comming down to me in a slow boat? Maybe the sled dogs just dont want to go out. Annyway, I dont know why peope think the low freek transmitters are illeagle, there just old concept. Same as an old car with a distributer and carburator and no emmission equipment. They dont make em anymore because the became extinct and have new laws governing viehicles being produced, now. You still can operate them if you can buy the fuel that they were designed for. A case in point is my hot rod. It wont run on the new ethinol pump gas. It has many modern up graded preformance parts, such as disc brakes which were adapted to fit the car, and a nice digital instrument package and sterio, but The engine is a total "Old School" high preformance, hi compression 400+ HP V8 that requires hi octain leaded fuel to operate at its optimim leavel. However I ocasionaly drive the monster on the street and cant just pull up to the pump at the airport or boat ramp and put it in the tank. That is illeagle to put in an over the road viehicle, acoarding to the US DOT laws, reguarding fuel in viehicles. However there are options to make the available fuel work, by adding addatives to boost octain. That stuff has lables that say,"Not for street use" but.....I drank from the water hose, back in the day, so I'm "Grandfathered in" as they say. ******t Jannett!! Im puttin a hemi on that skate board, I dont care what they say. I grew up with E J Potter and Art Arfrons [oops I said a bad word]

[He Who Shall Not Be Named]

David an excellent and timely essay, however can you tell us what the story is in the US with availability of traditional lower frequency radios. Mike I know you were doing W-FLY radios.

Have these dried up? I can still (for now) buy Radios that are legal here in Australia via Engel subs in Germany.

No matter what the current supply issue, the article is timely that the end of these ideal lower legal frequencies appears to be here. BUT also maybe this is an opportunity. David's article as per usual is excellent, but I think if we are to keep the hobby open to the new guy the conversion (albeit not overtly difficult if one follows the article above) is an extra layer of complexity and might be for the newcomer a bridge too far. Furthermore, I think I'd rather not sail at all, if the rest of my hobby is spent restricted to PD.

Surely a cheap Chinese supplier could be found for a dedicated FM / PPM Submarine radio. Pick maybe three - four bands that could cover Legal frequencies almost everywhere. 75MHZ -US, 40MHZ / 35MHz UK / Germany / Australia + another

Chuck in China might be a good point man for manufacturer. In terms of minimum start up volumes - I'm quite sure with the right International marketing and price, the small sub community which is all in the same boat could order enough. David / Mike how about it? - A dedicated Subdriver radio set?
Keep the manufacture out of David's hair. You don't need another product line to clog up the works.

I'm noticing that there seems to still be an endless supply of RXs on channels that are legal in Australia and Europe. Is this the case in the US?

Best

John

The availability of American r/c systems on the lower frequencies is at club raffles, on Ebay, and at yard and estate sales. The last of the 75mHz WFly r/c systems were sold months ago. No more. Only r/c systems Mike can get out of China now are the 2.4gHz ones.

I failed to mention that my article is a copy of an instructional pamphlet I prepared. This pamphlet will accompany the coaxial cable and watertight gland that will be provided with all subsequent SD systems. This 'enhancement' of the product line acknowledging the fact that future customers will likely be using 2.4gHz gear.

Mike has worked long and hard to maintain a source of the 75mHz gear -- up until very recently he had been assured by our primary source of r/c systems, WFly, that they would continue production of that gear. Last year they dropped the bomb with a simple, no nonsense notice that all future systems would be on the 2.4gHz band. No warning. Nothing. Mike has looked for other sources of r/c systems we can use, but to no avail. So far, if you want a lower frequency r/c system that does not require an FCC license, you are out of luck -- I, of course, speak from the American perspective. I can't speak for the r/c system situation in other countries.

Tim Senecal (a tinkerer of the first-order) has done excellent work identifying producers and applications of the little known 433mHz r/c systems. Seems this band is being exploited by the virtual goggle flyers out there in r/c vehicle land. A spin off of that gear -- that is of interest to us -- has been the availability of transmitter RF modules and receivers that permit conversion of our old transmitters (those that accept removable RF modules) to the 433mHz band. Tim has written extensively about his experiences with this alternative gear, and he reports that it works fine with the deep running r/c submarine. So, in the absence of the 27-75mHz gear we all have become accustomed to, Tim may have found us an alternative. The fly in the ointment is the need to pass an FCC operators exam before you can transmit on this band ... that added layer of complexity you talked about, John.

As to Mr. Caswell financing his own line of 75mHz transmitter-receiver systems. He's already looked into it with WFly and other manufacturers. Not going to happen. Too much money to start it up with way, way too little market to justify the expense. And here's a thought: in the absence of AMA and other organizations lobbying efforts, I fear Congress will soon permit the FCC to auction off the lower bands to other RF product interests -- the 27-75mHz bands may become illegal to us toy drivers in the future.

From a selfish perspective: The added complexity and difficulty presented to those wishing to get into r/c submarining is a fine way to keep the 'Sunday-driver' RTR r/c submarine idiots away from the pond. 'Drone' flying idiots are one step away from getting the government to further restrict ALL r/c aircraft flying. It can happen to us too. How many of you have had to share the lake/pool with idiots recklessly driving their RTR speed-boat over your submerged submarine with little regard as to courtesy or rules-of-the-road? Government has an easy answer to the 'safety' issue when it's raised about r/c vehicles. That answer will be a law to prohibit ALL of us from enjoying the hobby.

But, from a business point of view, John, I see your point. As this game gets ever harder to get into, there will be fewer customers to support the manufacturing end of the game.

M

[He Who Shall Not Be Named]

Great tutorial Dave. I prity much had the general idea of the concept, electronicly, but not sure of the perameters of the box. I was wondering a couple things. The exposed wire at the end of the coax is waterproofed by the heat shrink, is the antenna. Is that liength criticle? Can I solder a brass periscope to the tip of the wire and waterproof the connection and scope with the sprey on waterproof vinal? I have brass tubing in my scope housings instead of the revell plastic. I would think there would be no direct interfearance with any of the extra metal in the boat, such as decks ect. I suppose I should get a better soldering iron than the antiques I have. Now if I ever get the Wfly I ordered......priority mail?....with another ez....hmmmmmm? somebody fell asleep on watch on watch up at the con, sir. I see the falls have frozen up in the great white north in kazzland, think that stuff is comming down to me in a slow boat? Maybe the sled dogs just dont want to go out.

2.4gHz receiver antenna length is VERY critical!

Yes, the exposed conductor with its insulation is the antenna. The heat-shrink and RTV serve to keep water out of the conductor and shield. You can substitute any conducting metal for the antenna, but it must be 1.25" long -- the wave-form of the 2.4gHz signal. And you have to keep this antenna from grounding out when it hits the water.

Don't over-think this, Dave. Just RTFI and follow 'em.

Your SD's are sitting on my work table -- I differed sending them till I had the 2.4gHz antenna instructions and alteration kits were ready. They are, and they go out to Caswell today. Sorry for the delay. Product enhancement is the delay issue this time.

This is a one-horse shop, and I'm dancing as fast as I can, guys.

M

[Kazzer]

David

You haven't addressed the 2 antenna receivers? Are you suggesting we only run on 4 channels?

[Von Hilde]

No problems on the delay, Im kinda swamped with bizzy work here at the rock, and dont have much playtime. I was wondering about the Wfly8 75mhz situation tho. I thought they were still some available thru Mike, and one had been sent. Im not to concerned about it's arrival yet, I can wait a few days more. Ive got plenty to do on the hull to keep me going for a while. Its a might brisk this morning and the arthritis and old broken bones are kickin my ancient alien bedonkeydonk

[Slats]

David

You haven't addressed the 2 antenna receivers? Are you suggesting we only run on 4 channels?

Hi Mike,
there are some 2.4 GHZ Rx that have more than 4 channels that have a single antenna. The Planet RC range has these. http://www.cornwallmodelboats.co.uk/...receivers.html
Scroll down - they do 6 and 7 channel RXs. BUT these RC systems state they are for limited ranges. I use these in Targets, as I typically don't sail more than 80m away direct line of site. I use both the 6 ch and 7 ch units in surface boats with no range problems.

That said - I too want to understand how the 2 antenna RXs could be converted.

John

[He Who Shall Not Be Named]

Hi Mike,
there are some 2.4 GHZ Rx that have more than 4 channels that have a single antenna. The Planet RC range has these. http://www.cornwallmodelboats.co.uk/...receivers.html
Scroll down - they do 6 and 7 channel RXs. BUT these RC systems state they are for limited ranges. I use these in Targets, as I typically don't sail more than 80m away direct line of site. I use both the 6 ch and 7 ch units in surface boats with no range problems.

That said - I too want to understand how the 2 antenna RXs could be converted.

John

Replace one of the factory installed antenna/coax with the kit we now provide in every SD, and you're good to go.

M

[Slats]

Replace one of the factory installed antenna/coax with the kit we now provide in every SD, and you're good to go.

M

So we just leave the other one in place and in the SD.

Ok

[He Who Shall Not Be Named]

So we just leave the other one in place and in the SD.

Ok

Yup. As simple as that.

As the two detectors are sampled many times per second, the one with the antenna in the SD will go dark as soon as LOS is lost between it and the transmitting antenna. Where as the one up in the sail will still be in LOS and that's the detector that will be feeding the decoder and the commands from there sent to the devices aboard the SD.

M

[Jocurran]

From an Australian perspective I also thought that I was going to be having to use 2.4 gig and queried wether there was value in getting the full SAS Sub Driver or just using the lower cost Easy Sub Driver if only being able to go to periscope depth, but now I have a brand new 40mhz Robbe FC16 from Alexander Engel so am getting on with outfitting the SAS Sub Driver.
as an aside David did you manage to post me those parts I pm'd you about