HF3

[TaitTait]

I have an HF3 with audio output I use for weatherfax with a 10m wire aerial.Results are not bad but I think the quality of reception of the charts could be improved.Im wondering if the NASA active aerial would be worthwhile.Does anyone have experience of this equipment?

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[mdrifter]

Active antenna might also amplify noise as well as signal...and that's the main problem I've found receiving WxFax. New fangled shore chargers, fridges, coolboxes, inverters and the likes generate so much radio interference that the chart ends up with lines across and blurry overall. Oh for a clean radio environment out at sea and away from noise!

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[Benbow]

I have no experience of this set, but I have recently been playing with several different systems. I found that my major source for noise seems to be RF intereference from the PC connected to the radio. I have tried 2 different laptops, 1 gives crystal clear faxes and other grey muddy ones. This is with the same programme on the same frequency on the same radio. Before changing aerials I would suggest you try it with a different PC. Also note that the noisy laptop is better when running on its own batteries, but still far worse than the good one. There is a message there I presume about noise from power supplies as well as the PC itself.

HTH

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[jerryat]

HI Taittait,

Mdrifter is right, an active antenna, whilst definitely boosting the signal, also boosts the 'noise' you don't want by an equal amount. I ditched my active antenna for this very reason.

As Benbow has indicated, computers make a lot of 'noise' that will effectively destroy the clarity of the signal you need for wefaxes. However, this usually only occurs when the laptop charger is in use at the same time. Moving the computer as far away as possible from the radio will help. We found that charging the battery (if downloading a lot of faxes) beforehand, then using the computer without a charger/inverter etc, produced perfect results every time. The quality did vary sometimes through weather conditions, but virtually no faxes were unusable.

Whilst not a problem on our boat, other electrics can affect things too, notably the 'fridge, which can easily be switched off for the duration of the transmissions. Obviously, non-suppressed fluorescent lights should also be off.

Finally, I think you will have to accept that the HF3 is not a 'top-of-the-line' unit, and that getting crystal clear reception consistently will require a lot of luck, even if you take all the precautions.

Good sailing!

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[ParaHandy]

hmmm .... as told before, the active antennae is perfectly ok. it works for me from navtex up to 10mhz frequencies. use t'other knob below the volume control to tweak the signal. daytime reception when Northwood transmits >8mhz is good but dusk, when they transmit at either 2 or 4mhz, is readable but not that good.

try Frank Singleton site - do google search - for much useful info about picking up wfax, aerial positioning etc .......

as others have said, noise from nearby equipment incl laptop can be a problem.

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[TaitTait]

Guys,thanks for all your inputs.Some useful information there.I may proceed with the active aerial just for ease of installation on board.!0m of wire is a nuisance. I will also try to get a long screened lead for connection between the radio and laptop.The radio will run from the boat's batteries on board which will be a cleaner feed than the 240v converted it has now.I read somewhere that interference decreases with distance so will try to install the radio and PC as far apart as possible
Tait Tait

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[Sunnyseeker]

Before you do that, we used an HF3 and found that around harbours/land/buildings/radars/electrical supplies(shore) etc reception was never very impressive, but once you are 10 miles off shore or better 100 the picture just gets better and better, so it wasn't tha lap top causing the interference noise it was all the other signals flying around once you get near other people. Shore power transformers/chargers on the boats next door seem to be the worst.
We just used the bit of wire the unit comes with attached to the backstay and had lovely pictures of approaching storm systems! lovely

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