View Full Version : New to HF
Maybe one of you can tell me why these things happened.
When communicating with HF on a PRC 150 radio I had some issues which threw me for a curveball.
At times I could hear the NCS but they could not hear me. They could hear me and I could not hear them. The PSC 5D was up and running so I was able to confirm that we were heard by the NCS on HF.
Also at times we had perfect voice commo but data would not send over those same freqs.
What I am trying to figure out is why these happened? Does the Ionoshpere come into play or is HF just a general PITA? Some days it took no time to get a decent commo shot other times it took hours (all day once shooting from St Mere to Son Tay road)
This was done mostly with the NIVIS antenna but a slant wire was also used.
We eventually worked these out by setting up our antennas differently or trying a differnt one til it worked. LAter in the day freqs were the problem and once or twice the NCS was jacked up.
Does it get easier to make commo the further you are from the base station?
CommoGeek
06-01-2004, 09:58
The NVIS has some limitations in that certain freqs can't be used/ used with minimal effectiveness. I don't recall those off the top of my head. Your NVIS may have transmitted over the NCS but their's did not (I'm assuming that have an RF-5000 on a fanlite antenna). Regardless, your RF pattern may have placed the NCS in a dead zone so that they could not hear you, but you could hear them.
For your data problem it sounds like (and I'm no data over HF guru, most of mine was SATCOM) you have a COMSEC setting off a notch or two. KY-57's were bad about this and the KY-99 may be as well (I'm not sure about the -99).
Were you using ALE?
For close in commo, I always had a good ground on the radio and antenna to pick up a ground wave. If a NVIS doesn't work you can also place a 1/2 wavelength dipole about 6 inches off of the ground and get a "bounce" from the earth. An Inverted V with a counterpoise works well also.
Close-in commo isn't any harder or easier to me than long range commo. If your freqs are propped out, then most of it from there is antenna theory and construction.
Originally posted by CommoGeek
The NVIS has some limitations in that certain freqs can't be used/ used with minimal effectiveness. I don't recall those off the top of my head. Your NVIS may have transmitted over the NCS but their's did not (I'm assuming that have an RF-5000 on a fanlite antenna). Regardless, your RF pattern may have placed the NCS in a dead zone so that they could not hear you, but you could hear them.
thats what we figured happened. the NCS was using a NVIS as well.
For your data problem it sounds like (and I'm no data over HF guru, most of mine was SATCOM) you have a COMSEC setting off a notch or two. KY-57's were bad about this and the KY-99 may be as well (I'm not sure about the -99).
I dont know. We were using TEK 01 in ALE mode. They tried a broadcast SYNC but something in the net was screwed up and we had to go from 3G to ALE mode.
Data over SATCOM was easy. The PSC 5D made it easy. Either you hit the bird or you dont.
Were you using ALE?
yes
For close in commo, I always had a good ground on the radio and antenna to pick up a ground wave. If a NVIS doesn't work you can also place a 1/2 wavelength dipole about 6 inches off of the ground and get a "bounce" from the earth. An Inverted V with a counterpoise works well also.
Going back later in the week. I will have to try that. We talked about using the counterpoises but havent used one yet.
Close-in commo isn't any harder or easier to me than long range commo. If your freqs are propped out, then most of it from there is antenna theory and construction.
Going to try some long wire shots and other antennas when I go back. Class wasnt long enough to get as deep into HF as I would have liked so I worked a deal with the instructors to come back and learn some more while they teach BN Level commo to others.
Sinister
06-01-2004, 19:50
St. Mere to Son Tay using a NVIS? Jeez, you guys are close. If the NCS' antenna was set up for a NVIS you might have been matched.
Why not just use a ground wave? Get a copy of the ARRL antenna book and try to get an idea of the shape of your radiating lobes.
Antennae like the I-ring are SUPPOSED to radiate up and then lobe down so you can be in a valley or low ground (say you're in a hide site below a ridge line between you and NCS and want/need a high take-off angle to radiate over to get out a burst or packet shot).
Push-to-talk SATCOM is great until you have a whole battalion's worth of teams on one net and they put you on comm skeds and enforced "Quiet Time" to get all traffic thru.
Originally posted by Sinister
St. Mere to Son Tay using a NVIS? Jeez, you guys are close. If the NCS' antenna was set up for a NVIS you might have been matched.
Why not just use a ground wave? Get a copy of the ARRL antenna book and try to get an idea of the shape of your radiating lobes.
Antennae like the I-ring are SUPPOSED to radiate up and then lobe down so you can be in a valley or low ground (say you're in a hide site below a ridge line between you and NCS and want/need a high take-off angle to radiate over to get out a burst or packet shot).
Push-to-talk SATCOM is great until you have a whole battalion's worth of teams on one net and they put you on comm skeds and enforced "Quiet Time" to get all traffic thru.
At that range, I would have used a whip antenna with a counterpoise.and just kept adjusting the angle of the whip until I received a good signal.
I always carried a SWR meter also to measure the output power as compared to my reflective power.