Amateur Radio

[mtnbkr]

A new FT-891 and a MAT-30 tuner arrived today, and I have the EFHW that I’m going to try and string in the attic before surgery next month - I don’t think I’ll bother with my earlier Hamstick idea. I’m trying to decide whether I should do it when the wife isn’t here or not - she will be worried about me being up there, my balance kinda sucks.

Is that EFHW with a 49:1 unun or 9:1? If the former, you shouldn't need a tuner as EFHWs are resonant. If it's a "random wire" with 9:1 unun, then you need a tuner.

I use both types, so wasn't sure which one you are deploying.

Chris

[HeavyDuty]

Is that EFHW with a 49:1 unun or 9:1? If the former, you shouldn't need a tuner as EFHWs are resonant. If it's a "random wire" with 9:1 unun, then you need a tuner.

I use both types, so wasn't sure which one you are deploying.

Chris

You’re right - I wasn’t describing it correctly. It’s an end fed random wire with a 9:1, I went with a commercial product for speed since my soldering box is still missing since the move. I wish I had the space for a proper EFHW, but this will be a compromise antenna in the attic.

Radio, tuner and power supply arrived, I just need to get into the attic. I may do it tomorrow while the plumber is here working up there so I have a safety fallback.

[mtnbkr]

You’re right - I wasn’t describing it correctly. It’s an end fed random wire with a 9:1, I went with a commercial product for speed since my soldering box is still missing since the move. I wish I had the space for a proper EFHW, but this will be a compromise antenna in the attic.

Radio, tuner and power supply arrived, I just need to get into the attic. I may do it tomorrow while the plumber is here working up there so I have a safety fallback.

Gotcha. Random wires can be surprisingly effective. One of my portable antennas for SOTA is effectively a "random wire" using a 16' vertical "whip" with top hat and an LDG 9:1 unun. The KX2's tuner can get me a match on 40-10 and performance from mountaintops has been impressive. Because it doesn't need supports, it's quick and easy to set up.

I'll be interested to hear how yours performs.

Chris

[RoyGBiv]

You guys make my head hurt with the HF stuff.... lol..

I just finished responding to an email about where best to temporarily mount a random wire 132' (80M half wave, I assume) 49:1 balun for the upcoming field day we are hosting ("we" = other people using "our" facility.). Trying to utilize an existing through-the-roof coax for this temporary setup... I have to go walk off 132' to see if maybe a parking lot light pole can be used to support the other end.... with proper insulation, of course..

Our installed HF uses an ~82' random wire and 49:1, after failing to be tunable using a shorter wire and 9:1...

[mtnbkr]

You guys make my head hurt with the HF stuff.... lol..

I just finished responding to an email about where best to temporarily mount a random wire 132' (80M half wave, I assume) 49:1 balun for the upcoming field day we are hosting ("we" = other people using "our" facility.). Trying to utilize an existing through-the-roof coax for this temporary setup... I have to go walk off 132' to see if maybe a parking lot light pole can be used to support the other end.... with proper insulation, of course..

Our installed HF uses an ~82' random wire and 49:1, after failing to be tunable using a shorter wire and 9:1...

https://hamuniverse.com/randomwireantennalengths.html

82' "should" have worked with a 9:1, but another 2' of wire would have put it in the sweet zone for a random antenna. Also, it might have been tunable with the 49:1 due to changes in losses and such. Often a tuner will work with a given antenna not because it found a match, but because system losses were such that it didn't see as much reflected RF. Match doesn't mean good, it just means safe(r). Also, the tuner may not have had sufficient range. A 9:1-based random wire antenna needs a wide-range tuner.

Rather than putting the 132' wire straight across the lot, why not set it up as an inverted V or inverted L. That'll reduce the linear length somewhat.

BTW, 132' is a tad long for 80m. Depending on where you want to operate in the 80m band, you may need to shorten it a bit. You could shorten it considerably by introducing a loading coil, but the straight wire would probably perform better and be easier to build. Are you going for strictly 80m or an 80-10m multi-band?

Chris

[HeavyDuty]

https://hamuniverse.com/randomwireantennalengths.html

That’s a great link - thank you!

[RoyGBiv]

https://hamuniverse.com/randomwireantennalengths.html

82' "should" have worked with a 9:1, but another 2' of wire would have put it in the sweet zone for a random antenna. Also, it might have been tunable with the 49:1 due to changes in losses and such. Often a tuner will work with a given antenna not because it found a match, but because system losses were such that it didn't see as much reflected RF. Match doesn't mean good, it just means safe(r). Also, the tuner may not have had sufficient range. A 9:1-based random wire antenna needs a wide-range tuner.

Rather than putting the 132' wire straight across the lot, why not set it up as an inverted V or inverted L. That'll reduce the linear length somewhat.

BTW, 132' is a tad long for 80m. Depending on where you want to operate in the 80m band, you may need to shorten it a bit. You could shorten it considerably by introducing a loading coil, but the straight wire would probably perform better and be easier to build. Are you going for strictly 80m or an 80-10m multi-band?

Chris

When it comes to HF, I'm strictly Hero Support. Climb on roof, execute plan, climb down. IIRC, we measured 82.5 feet for our permanent install, but, could have been 84... I recall the discussion of should we leave the 9:1 on the longer wire and my contribution was, "You have the 49:1 in hand, unless you have some other purpose for it, why not use it here?"... Limit of my HF expertise .... I expect the guys making that decision know what they're doing... A pair of Korea and Vietnam-era Air Force radio guys... The tuner they tried on the shorter wire with 9:1 did not have enough range... my understanding.

Our available mounting points for the temporary wire are 3 masts on top of a building, where an inverted V between them is only about 60 feet if we want the endpoints to stay above the metal-clad roof line. Current thinking is to pick one mast as the balun end and see how far 132' reaches across the lot. Have to stay above 20 feet or so to avoid delivery trucks.... If that doesn't work out, we'll need to get clever about using some other anchor locations on the roof...

Looking at the notes for the temp wire... I'm seeing 136-feet, for 80 (primarily) as well as 40m and 10m... I've got a lunch meeting with the team on another item today... I'll reconfirm the numbers and take a minute to walk off the distance to calibrate myself a bit more clearly.

Thanks for the link... and for the feedback..

ETA: 136 may be wire length before install...

[RoyGBiv]

Our available mounting points for the temporary wire are 3 masts on top of a building, where an inverted V between them is only about 60 feet if we want the endpoints to stay above the metal-clad roof line. Current thinking is to pick one mast as the balun end and see how far 132' reaches across the lot. Have to stay above 20 feet or so to avoid delivery trucks.... If that doesn't work out, we'll need to get clever about using some other anchor locations on the roof...

Looking at the notes for the temp wire... I'm seeing 136-feet, for 80 (primarily) as well as 40m and 10m... I've got a lunch meeting with the team on another item today... I'll reconfirm the numbers and take a minute to walk off the distance to calibrate myself a bit more clearly. .

Paced off 200+ feet from the mast on the building to the light pole on the far side of the lot.... With a second pole at about 80 feet and slightly off of a straight line. Current plan is to run from the mast to the far pole, using paracord to make up the distance (and insulation from the pole), and another length of paracord from the mid pole to help take out any sag...

I'll let the pros worry about wire length and tuning..

[mtnbkr]

I'm sneaking out of work at 10am this morning (started at 5:30, so it's not as lame as it sounds) since it's "read-only" Friday and virtually all of my cow-orkers will be offline by Noon (perk of working mostly with UK and EU folks). Besides, I was online at 7pm last night working with my Aus direct report, so I can justify sneaking out (my manager would agree except he's on leave this week and I'm in charge ).

Anyway, going to do a SOTA activation. RF weapon of choice is my KX2, my 10m EFHW (with the tuner, it also works as a quarter-wave 20m and 1/8th wave 40m antenna...not very efficient, but it does work), and my 57' "random long wire" antenna as backup. I'll start on 10m and work down into the lower bands if necessary.

This one involves a 6 mile RT hike in the Shenandoah National Park, so about 3hrs of hiking and 30-60 minutes on the summit. There is a non-zero chance of seeing bears or coyotes, so the ballistic weapon of choice is the Glock 48 (gotta keep it discrete as this is a national park and there can be hikers about).

Chris

[RoyGBiv]

I'm sneaking out of work at 10am this morning (started at 5:30, so it's not as lame as it sounds) since it's "read-only" Friday and virtually all of my cow-orkers will be offline by Noon (perk of working mostly with UK and EU folks). Besides, I was online at 7pm last night working with my Aus direct report, so I can justify sneaking out (my manager would agree except he's on leave this week and I'm in charge ).

Anyway, going to do a SOTA activation. RF weapon of choice is my KX2, my 10m EFHW (with the tuner, it also works as a quarter-wave 20m and 1/8th wave 40m antenna...not very efficient, but it does work), and my 57' "random long wire" antenna as backup. I'll start on 10m and work down into the lower bands if necessary.

This one involves a 6 mile RT hike in the Shenandoah National Park, so about 3hrs of hiking and 30-60 minutes on the summit. There is a non-zero chance of seeing bears or coyotes, so the ballistic weapon of choice is the Glock 48 (gotta keep it discrete as this is a national park and there can be hikers about).

Chris

Sounds fun!

Be sure to check in when you get back, or, at least tell us you have someone there to call SAR if you're not back by nightfall.