Land based ICOM 802/Pactor

[ess105]

With two radials I am jammed up on my lug on the tuner. I need to do something different to add a third. If I create a connector block how do I factor in the line to the connector? Let's say my connector is 4 inches long. Should I reduce my radials by 4 inches or keep them the length they are?

[btrayfors]

Two options:

1. use a healthy-sized ring terminal and crimp all your radials into it; or

2. use a bus bar with, e.g., 1/4" lugs; connect one lug to the tuner with a short strap or heavy wire; connect radials to the other lugs.

Figure distance as total distance from the ground lug on the tuner.

Don't forget: when you're making radials use insulated wire and be sure to cover/insulate the ends, and don't let them near anything important. They are very hot when transmitting.

Bill

[ess105]

Got it. Forgot I had a bunch of rings to crimp on so this will be the first choice for now. How important are the radials for receiving? Much of what I have read about grounds / counterpoises suggests that they are used to 'push off' when transmitting.

[btrayfors]

Definitely more important when transmitting. However, with that tuner in line there's a Catch-22: if the tuner isn't tuned to the frequency you're listening to, then signals will be attenuated. And, as previously mentioned, you don't want to force a tuneup unless you have an appropriate RF ground system in place (meaning, in your case, a 1/4-wave radial for that band).

B.

[Wotname]

RF theory and especially antenna theory is a complex (and to some, facsinating) subject; however a good rule of thumb is: an efficient transmitting antenna is also an efficient receiving antenna. An antenna with a poor SWR will have standing waves when transmitting as well as when receiving; it is just the effects are not as noticeable - IMHO.

[btrayfors]

Wotname,

Well, here we've gotta agree to disagree.

A good antenna for receiving on a given frequency at a given time is NOT always an antenna which is tuned to that frequency. VSWR has little to do with it.

Recognizing this fact, some high-end radios are actually built with a separate connection for the receiving antenna, in addition to the connection for the transmitting antenna.

A single wire stuck into the SO-239 connector on a radio will receive pretty well. Many times, if you have an antenna farm -- as I do -- you will find that the antenna which is NOT matched to the listening frequency is actually better on receive....for many different reasons, including horizontal and vertical angles of the incoming signal, local RFI, etc.

What you do NOT want is to try to listen to a signal thru a tuner/coupler which isn't tuned to the receiving frequency or has a direct pass-through. Almost certainly, there will be some attenuation of the received signal.

How do I know this? About a god-zillion hours of operating and listening on all HF frequency bands, day in and day out, for more than four decades.

Of course, who knows what the signals do "down under"? Sometimes reception of signals from your neck of the woods is best over the North Pole :-)

Bill

[Wotname]

BT
Gotta disagree to your "Well, here we've gotta agree to disagree." 'cause I AGREE with your post entirely which is why I qualified my antenna view as " a good rule of thumb". This was aimed as primer for "non RF" folk rather than an absolute truth. Not sure if this is helpful to ess105 or not

Must PM you sometime and talk antennas.....

[MidLandOne]

If you are not able to transmit safely to tune the antenna tuner, in case not realised the IC-M802 coupled with the AT-140, which is what I believe you have ess105, has a THRU function for the tuner. Push the F key and the THRU/TUNE key together and the tuner will be bypassed for receive.

It will still be a mismatched situation in most instances but much better than trying to receive through the mistuned tuner for when just receiving.

[ess105]

This is all helpful. I am progressing. I have my outdoor antenna up now. I actually sent my 17 year old son up the tree - very Victorian. Reception seems to be better now. I also have made up a six strand counterpoise covering the bands allowing voice from 40m down to 10m. Once it's taped up it's no more mess than a single strand. So now I can hear a bit of chatter. Tuned into some bloke in Norway on 14.2MHz which I suppose is not bad from NJ. I'd like to try and contact someone but this is where I'm now coming unstuck. I've tried CQ'ing at 7.290 (AM & LSB) and also on 14.286 (AM & USB). Not sure if I'm doing the right thing but I've not managed to get in contact with anyone yet. Also - practically every station / channel I listen to, all I get is static. Normal I suppose.

[ess105]

Originally Posted by MidLandOne

If you are not able to transmit safely to tune the antenna tuner, in case not realised the IC-M802 coupled with the AT-140, which is what I believe you have ess105, has a THRU function for the tuner. Push the F key and the THRU/TUNE key together and the tuner will be bypassed for receive.

It will still be a mismatched situation in most instances but much better than trying to receive through the mistuned tuner for when just receiving.

Thx - I'm aware of the button but didn't realize it would help in the way you suggested.

[btrayfors]

Easiest way to make contacts is not to call CQ, but to listen in on nets and when they call for checkins give your call sign.

The maritime mobile net is on most of the day on 14300USB. The Waterway Net is on 7268LSB beginning at 0800 or so (after about 15 minutes of weather reporting) until 0830. They even stop and call for new checkins.

Many other nets...EastCars on 7255LSB, SouthCars on 7251LSB, MidCars on 7258LSB. Late in the afternoon the '68 group from the midwest holds forth on 7268LSB.

Also, to check propagation -- remember, you cannot transmit here -- you can listen to nets on the marine bands (like Cruizheimer's net beginning at 0830 on 6227USB), the USCG WX reports on several HF bands several times a day, etc. A good list of nets of interest can be found here: East Coast Cruising Nets

Remember also that propagation changes from day-to-day and from hour-to-hour (and, sometimes, minute-to-minute). Don't be discouraged. Try later and next day. After a few days, you'll begin to see some patterns.

Oh yes, I heartily endorse what MidLandOne said about the THRU tune function. I hadn't mentioned it because until you're familiar with the radio it's all too easy to hit the TUNEthru button without hitting the "F" button first, which would make the radio try to tune. When you're just listening, by all means use the THRU function...then you can just change bands and frequencies at will without worrying about tuneup.

But, before you transmit, you do need to put it back into the TUNE mode and have the tuner activate. I assume you've tried this on the bands which you have cut radials for and assume that it tuned up just fine. Please confirm.

Bill

[ess105]

If tuning up correctly is identified by the sound of (what seems to me) a wheel turning inside the AT-140 followed by the display showing TUNE solidly then it is working ok.

[btrayfors]

Yes, those are latching relays. Sounds like it's working OK.

But, you don't have to guess. Do yourself a favor, get out your wallet and purchase a good cross-needle power/swr meter. When you transmit, one needle shows power, the other SWR...simultaneously. That way, you'll know for sure that everything is working as it should.

Daiwa's are a good brand. Here's a sample of one of their discontinued oldies but goodies. It's showing about 115 watts power output and the needle at rest on the right indicates that SWR is just about 1:1....right where you want it to be.



A new Daiwa 101L costs about $99. You can also find used ones on eBay from time to time.



IMHO, every boat with a transceiver aboard should have and use a power/swr meter as an essential tool for reporting the status of onboard radios and antenna systems.

Bill

[ess105]

Presumably this would be placed between the transceiver and the tuner. Meant to thank you for the reference to the list of nets. Turns out many of these map to preset frequencies on the 802. I just have to try them at the right time.

I'm surprised you're saying the sounds from inside the tuner are relays. I would have expected that explanation for the sounds from the transceiver (click, click). The tuner gives more of a whirring sound.

[btrayfors]

Yes, you want to place the meter between the radio and the tuner and as close to the radio as practicable.

Re: the noise, most marine couplers/tuners use what are called "latching relays" to switch in series inductance and input or output capacitance to find a "match" to the antenna system.

It's kind of a trial and error process. When you choose a frequency for the first time, the microprocessor will begin switching in inductance and capacitance little by little, trying to find a match. There are thousands of potential combinations. When it does find one, the settings of the relays are recorded in memory so that the next time you tune to that frequency -- or one nearby -- those settings are recalled from memory almost instantaneously. The tuner will in that instance click once or twice while the relays are being set, and the "tune" light will come on.

But if you choose a frequency the tuner doesn't already "know", it will begin the process all over again. Ditto if you change the antenna or RF ground system significantly...this, to the tuner, is the same as a new band.

Anyway, sounds like you're on your way. Let us know how you get along in a few days.

73,

Bill