I bit the bullet and ordered one myself but am going ot have to wait to get it up utility company is moving equipment through the back of my property to relocate some underground cables that has had several issues through the time I have lived here....Will let all of you know how it works .
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Bought Sigma Venom 5/8 Silver Rod, Performance Review To Follow
- Thread starter Wire Weasel
- Start date
I've been using one for about 3 years now. Seems to do the job very well. They are extremely light and durable as hell. We've had some 65 to 70 mph winds and mine has a little bow in her, but she's up there in one piece.
i just bought a signa venom 5/8 wave with no instructions. Is it a mark on each pole to set it for best swr.. Haven't had time to look in over but i noticed bottom rod had 3 marks about 1/8 inch apart. any comments that can help me since i dont want to take it up and down.
In any event your specific installation will dictate what the precise length needs to be for the lowest SWR on your range of frequencies of greatest interest.
I am not sure what those 3 marks are as I have never seen them on these antennas myself. (low /mid /high band is a good possibility, but not certain)
To get the best SWR you really do need to put it up and down in position and adjust.
To set optimum SWR for the middle of the band of interest (or range of frequencies - say 27 - 28MHz) by taking SWR reading at channel 40 (or 28MHz) and channel 1 (or 27MHz) and and then adjust length as necessary.
As an example if you plan to use around 27.500 as your most used frequency and your SWR is higher at 28MHz and lower at 27MHz you will probably need to shorten the antenna slightly (and vice versa if the opposite is the case) but measure the SWR at the centre of the band also. (i.e. the place where you like to hang out most.)
The SWR will of course be different between 2 frequencies on this type of antenna although what you do length wise.. does depend on the amount of difference in the readings you see between your 2 chosen band ends. It can take a little while to really get the SWR spot on for the frequency of greatest use.
I usually change the length by a couple of cms at a time before taking the SWR again.
I had to think this through as I almost forgot all this stuff as I put my antenna up and never even think about it as the one I use is so wide banded for 11m anyway.
I am not sure what those 3 marks are as I have never seen them on these antennas myself. (low /mid /high band is a good possibility, but not certain)
To get the best SWR you really do need to put it up and down in position and adjust.
To set optimum SWR for the middle of the band of interest (or range of frequencies - say 27 - 28MHz) by taking SWR reading at channel 40 (or 28MHz) and channel 1 (or 27MHz) and and then adjust length as necessary.
As an example if you plan to use around 27.500 as your most used frequency and your SWR is higher at 28MHz and lower at 27MHz you will probably need to shorten the antenna slightly (and vice versa if the opposite is the case) but measure the SWR at the centre of the band also. (i.e. the place where you like to hang out most.)
The SWR will of course be different between 2 frequencies on this type of antenna although what you do length wise.. does depend on the amount of difference in the readings you see between your 2 chosen band ends. It can take a little while to really get the SWR spot on for the frequency of greatest use.
I usually change the length by a couple of cms at a time before taking the SWR again.
I had to think this through as I almost forgot all this stuff as I put my antenna up and never even think about it as the one I use is so wide banded for 11m anyway.
Comments about the sigma eurocomm venom 1/2 & 5/8 antennas. They are made in Birmingham England, around 20 miles from where I live. I've used them along with other far more expensive antennas such as the antron a99. They are all much of a muchness really. However, the halfwave will ALWAYS give a good swr, regardless of mounting, the 5/8 will if you follow certain rules. As has already been mentioned choke the coax at the feedpoint!! Otherwise cmc and odd swr behaviour in relation to power can occur. It will then use the mast as a counterpoise, lowest swr is usually achieved on 5-10 ft mast, or 25-30 ft mast. The 5/8 is quieter than the halfwave, and is quieter at my location than antron ect. For maximum reliability of these antennas, they do last quite well if: you remove the screw that connects the radiator to the coil at the bottom/ front and grease it, and out it back in, so it doesent corrode and fail, open the slots slightly with a hacksaw or tinsnips can be used, then the supplies hoseclamps actually grip the section inside, rather than squash the sides together, then strip the clamp!!!, Finally take all the joints well with whatever you see fit, or amalgamating tape, or just insulation tape to stop water ingress. Also equalise the sections so as none of them are just hanging on by the slot!!!. You can expect 8-10 years before it needs therapy. Then you can mend it if it breaks. Here in the U.K. We have 80 channels, the same ones as usa, plus the FM only channels (27.601.25-27.991.25) . The marks on them are normally for the higher frequencies in the uk. I set mine to around 17'6" for the 1 /2 wave and 19'6" for the 5 /8. You may find the 5/8 has a lump in the swr curve of around 1.5 at around 27.500 dropping off either side. The halfwave is always conventional set curve lowest in the middle. Just a final thing, radios and amplifiers ALWAYS run cooler on the 5/8 wave, even if the swr is higher. No idea why. I know this is long, but I hope it helps in some way. The antennas are matched with a transformer of sorts it the bottom cap, from memory it's ten and a half turns of around 1&1/4" former tapped at 1&3/4 turns for halfwave, and 8 turns on the same former tapped around the same point for the 5/8. Best regards all, Tim HT England.
J
jacquelyn S cortes
Guest
Nice write up and welcome aboard.
I recently got the half wave venom but it's still in the box as of now. I'll use your tips whenever it goes up in the air.
I've heard about the matching coil inside, maybe it can be waterproofed with some marine heat shrink to keep it dry. I've read that a weak point on the antenna is the paper coil former but I don't know that as fact.
J
jacquelyn S cortes
Guest
Yes their junk!! Go with a mobile antenna like the browing Br-28 mount it to a 10ft pole use rg8u your SWR.will be a flat one on all channels I use one on usb&lsb.on my Robyn from southbrige mass to North Carolina and South Carolina well 73,
Thank you for the warm welcome folks. R regarding the coil former, it is a sort of compressed card, the sigma eurocomm ones have a sort of lacquer on them, and they don't normally act up in the rain, normally very stable, although residual snow around the mounting does cause it to rise a little. I did 're wind one on an electrical tape reel for someone, still working now. I am very familiar with these products, and they represent good vslue, fair life good performance here in the uk. The starduster as mentioned previously is also a fine antenna. I generally find them much of a muchness too, maybe quieter than end fed halfwave??? If course there are bigger better antennas out there, such as Imax2000 although that likes cmc badly, avant sigma 4 and some of the big 5/8 groundplanes of course. Here in England a very popular antenna is the sirio 827, but up to about 15 miles it's really not that good, after that however, it's very good. Also many of our properties ar'nt big enough for18 ft of radial spread! Our rear garden is 14ft wide by about 90 ft long. Final note, sigma eurocomm also make fibreglass antennas with the same bracket at the bottom, don't bother. The feruls corrode and crack in under two years. You could tape them I suppose, but still very poor quality aluminium feruls. Regards Tim HT 325 England.
I had a Sigma 5/8 Silver rod up for a few years. Worked really well. BUT, I installed the Sirio 2008 and my skip shooting and receive went way the hell up. Much better ears than the Sigma.
I just purchase a Sigma Venom 5/8 wave with the radials. It will replace a fiberglass antenna I’ve been using that is working but has a high noise level. After reading the reviews on aluminum antennas, I purchased a Sirio Tornado 27 for my northern Ohio QTH and found it works very well. Set it up at 18.5 ft off the ground and had a perfect swr. The issue with the Tornado is the very long radials. I purchased the Sigma for my winter QTH in southwest Florida, where I have to deal with an HOA. The fiberglass antenna wasn’t as noticeable behind the house. The long radials would be more appt to catch the HOA Nazi’s eye. I will post how the installation goes with my findings on improvements made and SWR.
My little Mudduck Station and I look forward to being part of the group.