Antenna tuner/ground plate

[osprey877]

I have a Target SSB Receiver (NOT a transceiver). Do I need an antenna tuner and ground plate, or are they only needed for transmitting, not receiving?

[Jim Cate]

No, you do not need either for reception. Attaching the radio's gruond terminal to a through hull or other underwater metal may help reduce noise in your reception but is not necessary. Another thing to try is attaching a wire between the radio's antenna terminal (if it has one) and a shroud or stay. They make a pretty good antenna all on their own.

Jim

[Seeking Solace]

Although it may RX well without a proper antenna, a resonant antenna will be far superior. You can find nice manual tuners on ebay for pennies on the dollar. I've picked them up for under $40 for a $300 tuner (new price). Since you're not going to be TXing power limitations isn't important.

Something you might want to keep in mind is future purchases. If you plan to someday in the future upgrade to a transceiver the economic impact is much less when buying things in stages. Keep in mind that many automatic tuners require a transmitter to function. Some even want a specific model or line of transmitter, but can be worked manually.

If you never intend to upgrade it would be a huge waste of money in most cases unless trying to listen to very weak signals. There are lots of SWL (short wave listeners) who go the extra mile and are able to copy stations they wouldn't otherwise be capable because they have quality receivers and resonant antennas.

Did you know that getting a ham radio license is easier than it's ever been? The license is good for 10 years and can be renewed free of costs. The initial expense is usually around $15 for testing (charged by the group giving the test to cover expenses associated with giving the test, not the FCC) if you're in the US. They did away with the code nearly a decade ago and to work HF you only need a General Class ticket. I know some teenagers who passed both the Technician and the General only reading the question pool in a weekend. The knowledge you gain from just studying for the test is pretty useful.

TLDR: No you don't need a fancy grounding system or a tuner. Yes it would make a huge difference to have resonant antennas. If you enjoy listening check out ham radio.

[osprey877]

okay, thanks. I asked the question because I have a 10' co-ax antenna cable hooked up to the radio and run aft inside the boat to the transom. No ground. I don't seem to be able to get any reception and thought maybe I needed the tuner. I will try again now that I know it should work. Can you recommend a couple of stations that any radio in Vancouver Canada should be able to easily receive if it is working at all. Thanks.

[a64pilot]

Coax is shielded, if it's not hooked to something like a stay, it is not an antenna

[Seeking Solace]

You can make an antenna from coax, but it isn't as simple as running it to the transom. My suggestion would be to google radio antenna basics. Maybe even go as far as making one for the bandwidth you wish to monitor. Many boats use a backstay, but without a proper ground plane and resonant lengths it won't be effective without a tuner except for very strong received signals nearby. A proper antenna is worth the effort.

[Seeking Solace]

Could you possibly give the make and model of the receiver you're trying to use? Knowing what types of connections it has and what bands it covers could be a real big help it getting you a nice RX antenna set up on your vessel.

[osprey877]

Originally Posted by Seeking Solace

Could you possibly give the make and model of the receiver you're trying to use? Knowing what types of connections it has and what bands it covers could be a real big help it getting you a nice RX antenna set up on your vessel.

Here are pics of the front and back of the receiver. The white antenna cable is marked as "Digital Satellite Cable" . Thanks again.

[Seeking Solace]

Originally Posted by osprey877

Here are pics of the front and back of the receiver. The white antenna cable is marked as "Digital Satellite Cable" . Thanks again.

Alrighty. Let's start with the fact that all cable is not the same. It appears you have put an adapter on the connector to go from phono to and F connector. You're going to average about 3db of loss right there. Not a huge deal. then you've got what appears to be rg6 coax that is 75 ohms. I'm not sure what the receiver requires, but I'm guessing closer to 52 ohms. Still not a huge deal, but whenever you start mismatching impedances you're going to have loss.


So back to what you can do with what you've already got. Go to the other end of your coax and remove any connector it has. Take the center conductor and affix it to the backstay so you'll at least have an areal for RX. You'll want to try to get the shield to a ground, preferably not to one connected to a noise source such as the engine or electrical system. If it's too much trouble, just about any ground to the water will work.

That should get you hearing stations. It's not ideal and it's going to be far from perfect, but depending on what you're trying to accomplish it may be more than adequate. You should probably still take the time to learn about antennas and resonance. The knowledge will serve you well.

[osprey877]

my main purpose in getting the radio is so that I can receive weather broadcasts and faxes. The NOAA Pt Reyes station seems to broadcast on 4.3 to 22mhz range. What would you recommend as an Rx antenna for these signals?

[osprey877]

Originally Posted by osprey877

my main purpose in getting the radio is so that I can receive weather broadcasts and faxes. The NOAA Pt Reyes station seems to broadcast on 4.3 to 22mhz range. What would you recommend as an Rx antenna for these signals?

I meant to say "getting the radio operating", as it came with the boat. My plan is to get familiar with the Rx side of SSB before deciding whether or not to spend the money on a full Tx set, such as the Icom M802. At the moment, all I get is white noise and snow!!

[ka4wja]

Osprey877,
Please go no further....
Go, back and read Jim Cate's posting again!!!

Originally Posted by Jim Cate

No, you do not need either for reception. Attaching the radio's gruond terminal to a through hull or other underwater metal may help reduce noise in your reception but is not necessary. Another thing to try is attaching a wire between the radio's antenna terminal (if it has one) and a shroud or stay. They make a pretty good antenna all on their own.

And, then read it again!!!
It is the definitive answer to your original question!!

Do NOT worry about any of the other answers right now...




As for what you write now...
You will be well served by some honest, accurate info and advice....which I will give you!!
But, please forgive me if some of it sounds harsh....I mean no offense!!

Originally Posted by osprey877

I meant to say "getting the radio operating", as it came with the boat. My plan is to get familiar with the Rx side of SSB before deciding whether or not to spend the money on a full Tx set, such as the Icom M802. At the moment, all I get is white noise and snow!!

You have the typical "can't hear anything - itis"....

Those that are new to HF radio communications ("SSB", "weFax", etc.), are surprised by the "noises" and "static" they hear...
Some of these are "natural", but many are "man-made" (RFI)...

If you are at a dock, marina, boat yard, yacht club, etc....or your boat is near shore (within 1/4 mile to 1/2 mile of civilization), you are almost certainly picking-up significant RFI (Radio Frequency Interference)...

Probably receiving lots of RFI, as well as getting a good deal of natural noise due to using the wrong freq, for specific time-of-day and distance of communications....

PLEASE do not worry....this stuff DOES work....it will just take you some time to get the hang of it...



Now, here is the "harsh" part....
The Sitex receiver is a pretty bad piece of kit....it was made by Nasa Marine in the UK, and is a rather poor receiver, no matter what the cost no matter what the specs....it's not a great unit to try and make work for someone new at HF comms....
Actually it might even be worse than trying to use a small portable SW receiver....but, whether worse or not, you WILL need to learn about HF communications no matter what receiver you have...


Remember the "sticky" at the top of the Marine Electronics page has just about all the links to all the info you'd ever need...including "SSB receive only" info, "WeFax" info, etc...
http://www.cruisersforum.com/forums/...tc-133496.html



Osprey, you don't say where you are at, nor where you'll be sailing....but, you mention USCG out of Pt- Reyes.....so, I assume west coast USA???
So, aside from you using NMC out of Pt. Reyes, ALL the answers you need are right here in this recent thread!!
In addition to you taking Jim Cate's answer as definitive, AND realizing that you trying to use that Sitex receiver is going to be a real pain...Please have a look at this recent thread, where you will find ALL the answers to your questions...
http://www.cruisersforum.com/forums/...ml#post2233025

http://www.cruisersforum.com/forums/...ml#post2233086


Please read this discussion and watch the videos, before you go any further!!!

And, then come back here, tell us where you are at, where you're planning on sailing/cruising, whether you've tried the radio in marina, etc. or at sea????
And, of course what you are trying to receive and at what time of day...

And, we will get you going!!!
Seriously....please read the above discussion and watch the videos, before you do anything else!!


Fair winds..

John

[Seeking Solace]

Originally Posted by osprey877

I meant to say "getting the radio operating", as it came with the boat. My plan is to get familiar with the Rx side of SSB before deciding whether or not to spend the money on a full Tx set, such as the Icom M802. At the moment, all I get is white noise and snow!!

Here is your dilemma, You've got a receiver but no antenna system. If you want a temporary antenna that will give you some idea of what the receiver is capable of the suggestions I gave you earlier will get you there.

If you want to know the full potential of the receiver you would need a tuned or resonant antenna. You can't usually use an automatic antenna tuner without sampling the RF output from a transmitter. It puts out a low power signal that is used to measure VSWR and find the best match for the frequency you're trying to match the antenna to the transmitter. Even an antenna analyzer has an oscillator that it uses to measure resonance.

The only option you really have for matching a non resonant antenna without a transmitter is by a manual tuner. There are many different kinds and a typical arrangement is a CLC tuner (Capacitor, inductor, capacitor). This allows you to closely match the impedance of the antenna and the receiver. Impedance = resistance, the less resistance you have to the flow of energy the more of the received signal you will end up with. When you are manually tuning , unless you use an analyzer each time for each frequency it is a matter of best guess. You listen for the best perceived signal trying different combinations of adjustment on the tuner.

All of that being said, it is different than having an antenna designed for the purpose of being an antenna. You can very often use a very poor antenna for reception that would be unacceptable to use as a transmitting antenna. The selectivity and sensitivity of the receiver will determine how good of an antenna will be needed to hear your desired station. I've been able to copy the weather faxes with a piece of electric doggy fence aluminium wire cut to a random length. The images were very clear and the reception was nearly perfect. I've also copied them with my $300 vertical and there was little difference in the images (other than being from different transmissions).

If you intended to install an HF station you should learn as much as you can before taking that step. If you plan to go more than 25 miles offshore you need to have it. If you plan to do international travel it is highly recommended. The HF station will require a properly installed antenna to work properly. You would want to do a good backstay antenna installation. It uses your existing backstay, but has isolators that keep the mast and other rigging from becoming part of your antenna system. It will still interact with it, but will usually not energize it in such a way that touching it will deliver a nice shock or RF burn. The stay should be insulated if possible to prevent passengers from coming into contact with an energized antenna. I've touched one while transmitting and it is no joke very painful. Even the VHF at low power hurts (never tighten connectors while keyed down, yeah I know it was stupid).

So you've got to make a decision. If you want to have an HF installation that is going to serve you well, do it right the first time. Make sure you also have all the appropriate licenses for an HF/MF station as well. There are 2, station license and at the minimum a restricted operators license. This station license is going to be renewed periodically and the operators is for life. If you change vessels you'd need a new ships license for each vessel. Also, the installation of the isolators and antenna system. It's a big expense to do things right. Once it's done it will need very little maintenance.

Were you using it on shore I would say just put up an inverted vee 478/Freq in Mhz, cut that in half and put the coax in between the two pieces. Support in the center and pull the ends down at 45 degree angles. Looks like an upside down letter V. You could do that for a specific frequency and it would be resonant for that frequency (may require minor adjustment for transmitting).

Ultimately your cost is inverse to your abilities and your effort is going to be linear to your desire. I can tell you that I'm into radio. I got interested in it when I was about 12 and I've got an Extra Class ham radio license. The time and effort I put into it was fun for me. I have spent thousands of dollars on equipment and activities related to using it. It has been worth every penny. I would have gladly paid 100 times as much knowing how much enjoyment I've gotten out of it. I've talked to kings, senators, astronauts, and all walks of life from every corner of the world. There is something for everybody there. I can't say marine radio is nearly as much fun, but it serves a purpose. If it only saved your life once, could you justify the investment? I'm guessing there has never been one person plucked from the sea who said they paid too much for their HF station that brought help to them.

[ka4wja]

Oh goodness, there is so much bad info here!
I'm sorry...
I've read this and tried to figure out a way to correct this, without coming off as rude....but, don't know how..


So, "Seeking Solace", please forgive me!!

Originally Posted by Seeking Solace

You can make an antenna from coax, but it isn't as simple as running it to the transom.
Yes....
But, if he just connects the center conductor of the coax to the stay (or stay chainplate), he will be fine!!
Seeking Solace, please read Jim Cate's posting above...he is 100% correct!!


My suggestion would be to google radio antenna basics. Maybe even go as far as making one for the bandwidth you wish to monitor. Many boats use a backstay, but without a proper ground plane and resonant lengths it won't be effective without a tuner except for very strong received signals nearby.
Again, forgive me....but, this is pure bunk!!
For HF receiving systems a non-resonant antenna is fine....there is NO advantage to using a resonant antenna for HF receiving (as long as it's long enough....at least a 1/10-wave at your lowest operating freq....preferably longer....but there is NO advantage to having a resonant antenna for HF receiving (and for many HF transmitting applications, no advantage there either)

Hf reception is all about S/N....as long as your antenna is picking up noise it is big enough and does not need to be resonant!!

I've been studying and teaching radiowave propagation and antenna system design since the early 1970's....
And, this is an old red herring that seems to pop up every few years....that somehow you need a resonant antenna for receiving!! A complete 100% myth!!


A proper antenna is worth the effort.
A proper understanding of HF radiowaves and antenna systems is worth the effort....but...
But, even more worth the effort is understanding the issue of HF noise (natural and man-made) and an understanding of received signal-to-noise ratios (S/N) and how to improve them...

Have a look at what professional / commercial HF comm networks use....and what most serious low-freqs HF hams use, for HF receiving antennas....and, you'll see it's all about S/N, and nothing to do with resonance nor tuners, etc.!!

On our boats the antennas we have are almost always going to be verticals or sloping verticals....whether end-fed or center-fed....and mostly will be non-resonant verticals....

Osprey, simply needs to accept the limitations of the Sitex receiver, connect the center conductor of the coax to his stay, and gain an understanding of HF radiowave propagation and HF noise both natural band noise and man-made (RFI)....
And, he'll be fine!!!

All this talk about "proper antennas" is just bunk!

Originally Posted by Seeking Solace

Alrighty. Let's start with the fact that all cable is not the same.
Yes....all cable is not the same...
But, in an HF receiving system it is almost a moot point...
(and, in actuality, use of a higher-impedance cable can actually have a very slight, a few tenths of a db, advantage...)


It appears you have put an adapter on the connector to go from phono to and F connector. You're going to average about 3db of loss right there.
Again, sorry to sound harsh, but this too is complete hog wash!!!
3db loss from a "F to RCA adapater", why not try 0.03db!!
Seriously....

Have a look at the photo showing 23 different adapters and a short piece of coax, all connected in series, with 100 watts RF @ 28mhz into it...showing a total loss of 0.5db!!!



Not a huge deal. then you've got what appears to be rg6 coax that is 75 ohms. I'm not sure what the receiver requires, but I'm guessing closer to 52 ohms. Still not a huge deal, but whenever you start mismatching impedances you're going to have loss.
While there might be a slight mismatch, this will not cause any measurable loss....but even if it did, it would be moot as the key to HF reception is S/N not raw signal....
(every HF receiver made in the past 40 - 50 years has more than enough sensitivity....if you plug in any antenna at all and the noise / static increases, your radio is sensitive enough and any loss is not only tolerable, but many times desirable!!!)
But, even so....use of a slightly higher-imped cable can actually improve things a bit...


So back to what you can do with what you've already got. Go to the other end of your coax and remove any connector it has. Take the center conductor and affix it to the backstay so you'll at least have an areal for RX.
Seeking Solace this is good advice....and is what Jim Cate recommended above!!!
If you believe this, why propagate the myths that are contradictory??


You'll want to try to get the shield to a ground, preferably not to one connected to a noise source such as the engine or electrical system. If it's too much trouble, just about any ground to the water will work.
Again, not bad advice....but again, just what Jim Cate wrote above....and contradictory to the myths that you mention....
(and, in reality, it isn't necessary at all)


That should get you hearing stations. It's not ideal and it's going to be far from perfect,
Actually it will be fairly good....and again, why contradict what you write in the sentences above???



but depending on what you're trying to accomplish it may be more than adequate.
It's obvious what he's trying to accomplish....reception of NWS/NOAA WeFax charts, from NMC, USCG out of Pt. Reyes, CA (and possibly the Voice weather broadcasts, as well)....
And, what he needs to do is learn about HF radiowave propagation and HF radio noise (both natural band noise and man-made noise/RFI)


You should probably still take the time to learn about antennas and resonance.
Nothing wrong with knowledge, and learning about antennas is good....
But, I just hope he takes Jim's and my advice here....


The knowledge will serve you well.

Here's the photo...



Again, I'm truly sorry to sound so harsh, but so much of this is complete hog wash, and will have him chasing his tail until he gives up...
HF RFI is a serious issue in marinas, etc....and on many boats as well...
And, being new to HF comms, and trying to learn while using a compromise receiver, is going to present some issues....
I just don't want him ham-strung by lots of false info!!

Fair winds..

John

[ka4wja]

Osprey,
Please read Jim Cate's posting....
And, please read the recent discussion I referenced...
And, please forget the BS about needing a resonant antenna or antenna tuner to receive HF signals...

Do, all of those.
Tell us exactly where you are at, what you wish to receive, and at what time of day....and we'll get you going...

fair winds...

John