Backstay radar mount and SSB antenna

[Warren Stringer]

Greetings to all:

"Eendracht" will be receiving radar this spring as a belated Christms present. The unit will be a 10-15 lb. radome. We are looking at a fixed mast mount vs. a self-levelling backstay mount. Problem is, our backstay is also the SSB antenna. Can anyone help with the following issues (plus any others I've overlooked). Thanks in advance for your input.

1) Torque from the weight of the radome and mount on the antenna isolators.

2) Interference with SSB transmission and reception, with the radar either on or off.

3) Potential damage to the antenna, couplings, or SSB transceiver, either on or off, when the radar is transmitting.

Two other questions:

How much will a LCD display unit mounted on the pedestal guard affect compass deviation?

Is it necessary or desirable to update the ship's radio license to operate radar in US waters?


Warren Stringer
s/v "Eendracht"
Cape Dory 36 cutter, 1981



watringer@aristotle.net

[John]

Greetings to all:

"Eendracht" will be receiving radar this spring as a belated Christms present. The unit will be a 10-15 lb. radome. We are looking at a fixed mast mount vs. a self-levelling backstay mount. Problem is, our backstay is also the SSB antenna. Can anyone help with the following issues (plus any others I've overlooked). Thanks in advance for your input.

1) Torque from the weight of the radome and mount on the antenna isolators.

2) Interference with SSB transmission and reception, with the radar either on or off.

3) Potential damage to the antenna, couplings, or SSB transceiver, either on or off, when the radar is transmitting.

Two other questions:

How much will a LCD display unit mounted on the pedestal guard affect compass deviation?

Is it necessary or desirable to update the ship's radio license to operate radar in US waters?


Warren Stringer
s/v "Eendracht"
Cape Dory 36 cutter, 1981

Warren;
I don't have exact answers for all of your questions but I can tell you we have a LCD radar on our CD30. We mounted the radome on the mast as we also have a SSB with a insulated backstay and didn't have a good source for dependable answers as to whether or not it would have any effect on the strength of the insulators or on the performance of the radio. We simply opted for the mast setup for the simplicity of installation, dependability of installation and radome height. We also liked the idea of the radome in front of the main mast for less chance of interference in the radars forward transmission signal. It also made it easy to run the large radome cable down the inside of the mast to the main cabin. A side benefit of the cable inside the mast was protection from damage. We have never experienced interference from one unit to the other. Our LCD display at the pedestal guard caused a 5 or 7 degree deviation that was adjusted out. You do have to have the radar listed on your ships radio liscense, just like your VHF and SSB, EPIRB etc.,.

[chuck yahrling]

Greetings to all:

"Eendracht" will be receiving radar this spring as a belated Christms present. The unit will be a 10-15 lb. radome. We are looking at a fixed mast mount vs. a self-levelling backstay mount. Problem is, our backstay is also the SSB antenna. Can anyone help with the following issues (plus any others I've overlooked). Thanks in advance for your input.

1) Torque from the weight of the radome and mount on the antenna isolators.

2) Interference with SSB transmission and reception, with the radar either on or off.

3) Potential damage to the antenna, couplings, or SSB transceiver, either on or off, when the radar is transmitting.

Two other questions:

How much will a LCD display unit mounted on the pedestal guard affect compass deviation?

Is it necessary or desirable to update the ship's radio license to operate radar in US waters?


Warren Stringer
s/v "Eendracht"
Cape Dory 36 cutter, 1981

Warren:

Practical Sailor did a review of various radar mounting strategies in the current issue. Your library may subscribe to this if you can't find a copy elsewhere.



yahrling@cybertours.com

[D. Stump, Hanalei]

Warren,
If you are operating as a "Voluntary" vessel per USCG definition, you do not need a license to operate RADAR aboard your vessel in Coastal US waters. If you have a current ships radio station license, RADAR is included under that license, as is LORAN, SSB, VHF, etc. Look at FCC.com or FCC.org under ships radio licenses, it gives all the info. As I understand the regs., you do not need to notify the FCC if you add or replace one of the "radio" systems covered by the license. Hope this helps...

Dave Stump
Captain commanding
s/v Hanalei (CD-30)

[Chris]

Greetings to all:

"Eendracht" will be receiving radar this spring as a belated Christms present. The unit will be a 10-15 lb. radome. We are looking at a fixed mast mount vs. a self-levelling backstay mount. Problem is, our backstay is also the SSB antenna. Can anyone help with the following issues (plus any others I've overlooked). Thanks in advance for your input.

1) Torque from the weight of the radome and mount on the antenna isolators.

2) Interference with SSB transmission and reception, with the radar either on or off.

3) Potential damage to the antenna, couplings, or SSB transceiver, either on or off, when the radar is transmitting.

Two other questions:

How much will a LCD display unit mounted on the pedestal guard affect compass deviation?

Is it necessary or desirable to update the ship's radio license to operate radar in US waters?


Warren Stringer
s/v "Eendracht"
Cape Dory 36 cutter, 1981

Warren - I have recently installed a Raytheon SL72 radar on my CD330. I can not provide the answers to all of your questions, but can provide my findings and suggestions. Raytheon technicians advised against a gimbaled raydome mast or aft pole mounting bracket They indicated that excessive movement of the dome can cause cable fatigue / failure. Raytheon also indicated that mast mounts increase the forward range of the radar. They also indicated that the increased height can cause reduced sensitivity to close range low level objects ("a blind spot develops just off the bow") like rowboats or channel markers. I opted for the aft pole mount to avoid wear on the staysail and clarity of close objects.

I also wished to have the flexibility of operating the radar screen at the navigation station or at the helm. I purchased a 5 meter antenna extension cable and second power/data cable. I have two mounting brackets, one at the helm and one at the navigation station. I avoided the additional cost of the two monitor system which I did not need as I would be operating at only one station at a time (usually the helm). One disadvantage to this set-up is that the radar needs to be recalibrated when the location is changed due to the different antenna cable lengths (a 3-5 minute process).

[Warren Stringer]

Warren - I have recently installed a Raytheon SL72 radar on my CD330. I can not provide the answers to all of your questions, but can provide my findings and suggestions. Raytheon technicians advised against a gimbaled raydome mast or aft pole mounting bracket They indicated that excessive movement of the dome can cause cable fatigue / failure. Raytheon also indicated that mast mounts increase the forward range of the radar. They also indicated that the increased height can cause reduced sensitivity to close range low level objects ("a blind spot develops just off the bow") like rowboats or channel markers. I opted for the aft pole mount to avoid wear on the staysail and clarity of close objects.

I also wished to have the flexibility of operating the radar screen at the navigation station or at the helm. I purchased a 5 meter antenna extension cable and second power/data cable. I have two mounting brackets, one at the helm and one at the navigation station. I avoided the additional cost of the two monitor system which I did not need as I would be operating at only one station at a time (usually the helm). One disadvantage to this set-up is that the radar needs to be recalibrated when the location is changed due to the different antenna cable lengths (a 3-5 minute process).

How close is your helm mount to the compass? Do you find any difference in deviation between the two locations?

Warren



wstringer@aristotle.net

[Warren Stringer]

Warren;
I don't have exact answers for all of your questions but I can tell you we have a LCD radar on our CD30. We mounted the radome on the mast as we also have a SSB with a insulated backstay and didn't have a good source for dependable answers as to whether or not it would have any effect on the strength of the insulators or on the performance of the radio. We simply opted for the mast setup for the simplicity of installation, dependability of installation and radome height. We also liked the idea of the radome in front of the main mast for less chance of interference in the radars forward transmission signal. It also made it easy to run the large radome cable down the inside of the mast to the main cabin. A side benefit of the cable inside the mast was protection from damage. We have never experienced interference from one unit to the other. Our LCD display at the pedestal guard caused a 5 or 7 degree deviation that was adjusted out. You do have to have the radar listed on your ships radio liscense, just like your VHF and SSB, EPIRB etc.,.

John, thanks for the response. Do you notice any difference in deviation when the unit is on or off?

Warren



wstringer@aristotle.net

[John]

Warren;
I don't have exact answers for all of your questions but I can tell you we have a LCD radar on our CD30. We mounted the radome on the mast as we also have a SSB with a insulated backstay and didn't have a good source for dependable answers as to whether or not it would have any effect on the strength of the insulators or on the performance of the radio. We simply opted for the mast setup for the simplicity of installation, dependability of installation and radome height. We also liked the idea of the radome in front of the main mast for less chance of interference in the radars forward transmission signal. It also made it easy to run the large radome cable down the inside of the mast to the main cabin. A side benefit of the cable inside the mast was protection from damage. We have never experienced interference from one unit to the other. Our LCD display at the pedestal guard caused a 5 or 7 degree deviation that was adjusted out. You do have to have the radar listed on your ships radio liscense, just like your VHF and SSB, EPIRB etc.,.

John, thanks for the response. Do you notice any difference in deviation when the unit is on or off?

Warren

Warren, the answer is no.