Newbie HF Antenna / Radio setup help

[km6zeb]

Hi!

I need help!

I live in enough of a VHF/UHF deadspot / the repeater tax news that I only just learned about from a few years ago have convinced me to start using HF. I've had my eye on the Icom-IC705 basically since it came out, so I figured I'd take the plunge soon.

I want to be able to operate from my house, so that means installing an HF antenna for the first time. I understand the need to ground it, so I'm getting 10AWG grounding wires and I plan to attach one of these: Moonraker UK Limited 11-252 Moonraker Ltd GPA-80F Fiberglass HF Vertical 80-6M Antenna | DX Engineering ("Moonraker Ltd GPA-80F Fiberglass HF Vertical 80-6M Antenna") to a pole on my roof, add one of these: ICOM AH-705 Icom AH-705 Compact Antenna Tuners | DX Engineering ("Icom AH-705 Compact Antenna Tuners") to the base of it and then into one of these: PolyPhaser IS-50UX-C0 PolyPhaser Coaxial Lightning Protectors | DX Engineering ("PolyPhaser IS-50UX-C0 - PolyPhaser Coaxial Lightning Protectors"), with the grounding connection going via a clamp into 10AWG grounding wire to then be clamped to the roofjack that my mains electricity goes through - which I hope is grounded, I mean my god.

My question is: is this likely to be effective for HF, and is this sufficient lightning protection in the event of a direct strike?

Ben
km6zeb

 

[popnokick]

If you read the entire product description you'll see the words, "REQUIRES EXTERNAL TUNER". They are NOT kidding about that. First off is the fact that vertical antennas without an RF counterpoise (ground radials) are sketchy on HF. And made even worse by elevating them above ground... such as installing on a rooftop or other elevated surface. Metal roofs work quite well however since they provide the RF ground counterpoise. So especially without a metal roof you will need a tuner... don't skimp on that part. You will not be happy with that antenna unless you have a tuner. And even then it will only come close to "happy" if mounted rooftop with a counterpoise. An autotuner such as the ICOM AH-4 or LDG Electronics AT-200PROII would be good choices. PS - If your rig has an internal automatic tuner it is probably not going to cut it. Most of them fail to tune a match that is greater than 3:1. You'll be seeing mismatches of 10:1 on some bands.

 

[km6zeb]

If you read the entire product description you'll see the words, "REQUIRES EXTERNAL TUNER". They are NOT kidding about that. First off is the fact that vertical antennas without an RF counterpoise (ground radials) are sketchy on HF. And made even worse by elevating them above ground... such as installing on a rooftop or other elevated surface. Metal roofs work quite well however since they provide the RF ground counterpoise. So especially without a metal roof you will need a tuner... don't skimp on that part. You will not be happy with that antenna unless you have a tuner. And even then it will only come close to "happy" if mounted rooftop with a counterpoise. An autotuner such as the ICOM AH-4 or LDG Electronics AT-200PROII would be good choices. PS - If your rig has an internal automatic tuner it is probably not going to cut it. Most of them fail to tune a match that is greater than 3:1. You'll be seeing mismatches of 10:1 on some bands.

Thanks so much for replying! Would the ICOM AH-4 be suitable? Thanks for the tips on the counterpoising, I'll see if I can get an antenna that has those. Maybe this would be a better choice?: Hustler Antenna 5BTV Hustler 5BTV 5-Band HF Vertical Antenna and DXE Installation Guide Packages | DX Engineering

 

[footage]

Where are you located? You might be able to get some good neighborhood-specific advice from your local amateur radio club -- mine, SF Radio Club, has a great Slack (sfarc.slack.com) with many hams who are very generous answering questions, and I don't think you need to be a member to join.

 

[km6zeb]

Where are you located? You might be able to get some good neighborhood-specific advice from your local amateur radio club -- mine, SF Radio Club, has a great Slack (sfarc.slack.com) with many hams who are very generous answering questions, and I don't think you need to be a member to join.

I am in San Rafael. Thanks for the tip, I will check that out now.

Update: There is a domain restriction on signups to that slack workspace, you must be coming from emails that are @undef.org, or @arrl.net or @sfgov.org, that means I won't be able to join it.

 

[KK2DOG]

Also, keep in mind the IC-705 only has a 10 watt output. For the money you'll spend you may as well get a 100 watt rig.

 

[popnokick]

Thanks so much for replying! Would the ICOM AH-4 be suitable? Thanks for the tips on the counterpoising, I'll see if I can get an antenna that has those. Maybe this would be a better choice?: Hustler Antenna 5BTV Hustler 5BTV 5-Band HF Vertical Antenna and DXE Installation Guide Packages | DX Engineering

The ICOM AH-4 is a solid tuner that will handle large SWR ratios. And the Hustler "BTV" series has been around as a mainstay ham vertical for many years. Get the DXE Installation Guide and you are likely to see "For peak performance, a field of radial wires should be used." If you are mounting on a non-metal rooftop you are going to need a number of radial wires a minimum of a 1/4 wavelength long stretching out in a radial pattern from the base of the antenna. When I was in military housing in Japan I had a flat concrete roof and was able to mount a vertical in the center of the flat rooftop and put four radial wires that were that long. Worked great... but do you have that much room for radials on your roof? Actually, they advise a radial field even if you mount it in the preferred manner for HF verticals (on the ground).

 

[prcguy]

With a 10w radio you need a really good antenna to make up for the miniscule power and the Moonraker antenna you mention is a super duper inefficient dummy load of an antenna. I think you will be really disappointed with that setup and would recommend a much better antenna.

Do you have room for about 64ft of wire going horizontal? A cheap 40-10m end fed will run circles around the Moonraker or its cousins made by Comet and others and it doesn't need a tuner. Unfortunately most vertical antennas require an extensive ground radial system to work well and there are a few that work ok but they get really get expensive.

The Icom tuner for the 705 is a ridiculously expensive tuner for what it is and I would look for something like the Elecraft T1 tuner which is smaller than a pack of cigarettes and will handle twice the power. I have a 705 with T1 tuner and its a winning combination for portable use.

 

[km6zeb]

I should have given some context on my planned use a bit more and my building layout: Yes I own my own home and it's a single story house with a flat roof, so I can do 64ft of wire no problem at all. So what I'm hearing is that end-fed >> moonraker, but what's better than end-fed? Like, if I'm going as all-out as a noob with lots of space can do, what should I be using?

I plan to get an amp to plug the icom-ic705 into, which is why I need the extra current handling capacity, but then I also want to take it to the top of the various mountains we have here (without the amp!) for some SOTA action (and of course with a more portable antenna).

Great tip on the Elecraft T1 - looks amazing and will save my back on bigger hikes

 

[alcahuete]

The thing to remember is that all a tuner does is make the radio happy. It does nothing for the efficiency (or lack thereof) of the antenna. Of course any antenna is better than none, but going with a more resonant antenna is going to make a world of difference. This is especially true if you are only using 10W. 10W into a non-resonant antenna is not going to turn out well.

 

[prcguy]

I got my T1 tuner off eBay for around $170 slightly used but that was before the 705 came out which caused a lot of people to look for small tuners.

What's better than an end fed??? Depends on what bands you want and how much space you have. A 40-10m end fed works about the same as a full size 65ft 40m dipole fed with balanced line on 40, 20, 15 and 10m. Its also about equal to a good 40m OCFD and in all cases your exciting a 40m antenna on different resonant bands, just with different methods of feeding the wire.

If you have room for 133ft of wire then the 80-10m version will get you 80m plus many WARC bands and all without a tuner. Or at least the MyAntennas version will. I've used so many wire antennas I can't even remember them all but so far the best for my house and space is the MyAntennas 80-10m OCFD. I would have used the end fed version but that would have placed the transformer and feedline out in my alley so I opted for the OCFD which puts the transformer over my house but one end of the wire still ends up in my alley.

I supplement that with an NA4RR Hex Beam on 20 through 6m since I cant rotate my house with the wire antenna attached. For me its a great combination since I typically use 80 and 40m for local/regional comms out to maybe 1k miles then the Hex Beam for the higher bands. When I'm running two radios at the same time one will have access to all bands with the 80-10m OCFD while the other can do 20-6m on the Hex.

When I mentioned using the OCFD out to about 1k mi, that's usually during daytime hours, at night I can work coast to coast on 80 and 40m.

I should have given some context on my planned use a bit more and my building layout: Yes I own my own home and it's a single story house with a flat roof, so I can do 64ft of wire no problem at all. So what I'm hearing is that end-fed >> moonraker, but what's better than end-fed? Like, if I'm going as all-out as a noob with lots of space can do, what should I be using?

I plan to get an amp to plug the icom-ic705 into, which is why I need the extra current handling capacity, but then I also want to take it to the top of the various mountains we have here (without the amp!) for some SOTA action (and of course with a more portable antenna).

Great tip on the Elecraft T1 - looks amazing and will save my back on bigger hikes

 

[km6zeb]

This is all great stuff! My property is about 140ft diagonally. How far off the ground does the MyAntennas 80-10m OCFD need to be ideally? My roof, diagonally, is more like 85ft, so I'd be arranging an overhang, assuming it's okay over the roof somewhere. I think I'd have to check my local code if there's an overhand beyond 85ft.

I'm looking to get into HF, presumably either voice or ft8 as I don't know morse code, but it also needs to coexist with a 2m/70cm antenna on the same roof (also pending).

Edit: the EFHW-4010 looks similar, has similar resonance and will fit handily on my roof, I think I'll plumb for that.

I got my T1 tuner off eBay for around $170 slightly used but that was before the 705 came out which caused a lot of people to look for small tuners.

What's better than an end fed??? Depends on what bands you want and how much space you have. A 40-10m end fed works about the same as a full size 65ft 40m dipole fed with balanced line on 40, 20, 15 and 10m. Its also about equal to a good 40m OCFD and in all cases your exciting a 40m antenna on different resonant bands, just with different methods of feeding the wire.

If you have room for 133ft of wire then the 80-10m version will get you 80m plus many WARC bands and all without a tuner. Or at least the MyAntennas version will. I've used so many wire antennas I can't even remember them all but so far the best for my house and space is the MyAntennas 80-10m OCFD. I would have used the end fed version but that would have placed the transformer and feedline out in my alley so I opted for the OCFD which puts the transformer over my house but one end of the wire still ends up in my alley.

I supplement that with an NA4RR Hex Beam on 20 through 6m since I cant rotate my house with the wire antenna attached. For me its a great combination since I typically use 80 and 40m for local/regional comms out to maybe 1k miles then the Hex Beam for the higher bands. When I'm running two radios at the same time one will have access to all bands with the 80-10m OCFD while the other can do 20-6m on the Hex.

When I mentioned using the OCFD out to about 1k mi, that's usually during daytime hours, at night I can work coast to coast on 80 and 40m.

 

[prcguy]

This depends on how you want the antenna to behave and how much height you have available. For the best DX you want the antenna at 1/2 wavelength or multiples of 1/2 wavelength above ground and that would be about 65ft high for 40m and 133ft high on 80m. 133ft is not practical for most people but 65ft could be and that would also work great for DX on higher bands like 20 and 10m.

For the best regional comms like zero to a couple hundred miles out in NVIS mode, getting the antenna horizontal about 33ft off the ground would place it 1/4 wavelength high on 40m and 1/8 wavelength high on 80m which is an ideal compromise for those bands. This also places the antenna at 1/2 wavelength above ground on 20m for good DX there and on higher harmonically related bands. I put all my wire antennas at about 32-33ft off the ground for this reason.

If you put the antenna lower than 33ft it will continue to operate in the NVIS mode on 40/80m but the lower you go the less efficient it gets and the quieter your receiver will be on 40 and 80m. 20m and higher bands will start to suffer as they are mostly DX bands and when the antenna gets below 1/2 wavelength it starts to have upward and unfavorable takeoff angles for good DX.

How far off the ground does the MyAntennas 80-10m OCFD need to be ideally?

 

[w2xq]

Build a multiband counterpoise out of inexpensive rotor cable. Back in the day before the WARC bands, I made a 5-band counterpoise out of a length of 5-conductor. Cut a length to a quarter wave length for 40m.

On one end strip each of the 5 strands, twist them together and solder a lug to attach to the antenna ground.

Starting at the other end, peel off one strand to a quarter wave length for 10m. Repeat with the next strand for 15m. Ibid, for 20m.

With the three excess pieces, solder them end to end. Attach/solder the new length to the 5th stand. Measure off a quarter wave length for 80m, and cut off the excess.

The result? A single wire bundle/package covering 5 bands. If you operate the WARC bands and 60m, just wash-rinse-repeat with the required quarter wave lengths.

Given your flat roof, you can probably lay out two or three counterpoise bundles snaked around as space permits. Anchor these with dabs of roof tar or equivalent, so as not to damage the roof itself. (I had two on the roof, and a third tied off to a fence post in the back yard. Given the lot size, I too had to use a multi-band vertical above the roof line. )

There is more than one way to skin the skunk... 😀

Good luck. HTH.