Wire Antenna for SWL Only

[W5RGP]

I want to replace a wire antenna about 75 foot that currently goes up from 9:1 unum mounted near ground up a 30 foot mast
then across my roof which has a metal roof?

im thinking of coming up to eave of roof then around the house instaed of over house

this will be about a 250 foot wire antenna no

will i benefit from not taking it over roof or lose out on signals due to an added 2 turns around house instead of straight over roof

Thanks

 

[merlin]

I don't think you will gain much going around the house, especially in the weak signal arena.
Some food for thought though is getting your mast up to 45 to 50 foot.
Wire up a T2FD suspended as a slopper. The low end 5+ feet above ground. The center feed perpendicular with ladder line to the shack, or
19:1 balun and 50 ohm coax to the shack.
The antenna cut for the lowest frequency of interest. (120 foot goes 440 meters)
These are quite broadband, good to about 55 Mhz and nearly omnidirectional.
If not for the metal roof, a good antenna is the broad band terminated butterfly antenna. I don't know how well that will work with metal roof, but friends get great performance with these. Also HOA friendly.
Only two antennas I know to out perform these are the T3FD at 60 foot or more, OR a full wave rhombic.
A full featured preselector and ready for SWL championship given a good receiver.
Cheers

 

[W5RGP]

ok thanks ive got the new wire temporarily strung up just to check things and do some testing

I currently have balun at base of push up pole connected directly to ground rod then wire runs up to the top of the 30 foot pole
then about 250 feet into back yard

only have about 10 foot of coax ran to radio from balun

would balun be better off at top of mast so i dont have the 30 foot up then 250 back? if i did that id have about a 40 foot run of coax into shack from balun

 

[merlin]

Sound like you have an end fed Hertz and a balun should be at the closest end to your shack/radio.
You could top mast the balun leaving the down wire as a counterpoise. just a dog bone at the end.

 

[devicelab]

Bob, if you live in a rural area and have a low noise floor, then pick up this: Medium Aperture Loop Antenna ALA100LN N. Am.

Simply add your own 14ga wire -- I use 14ga clear jacket flexweave -- anything from 10m to 100m in length. (Mine is approximately 80m.)

You can thank me later.

PS. Keep the wire away from the metal roof. I have one too and it will just de-tune the antenna.

 

[ILSAPP]

Bob, if you live in a rural area and have a low noise floor, then pick up this: Medium Aperture Loop Antenna ALA100LN N. Am.

Simply add your own 14ga wire -- I use 14ga clear jacket flexweave -- anything from 10m to 100m in length. (Mine is approximately 80m.)

You can thank me later.

PS. Keep the wire away from the metal roof. I have one too and it will just de-tune the antenna.

Thanks for the information!
Have you tried to compare SWL with the ALA100LN with different lengths of wire?

 

[devicelab]

Have you tried to compare SWL with the ALA100LN with different lengths of wire?

Yes. At 10m it was the same as my 1m loop antennas. I tried it at around 30m and saw a drastic improvement but the location wasn't ideal for me. The key is getting it away from metal objects and any noise sources.

I have the loop amp at 2m from the ground on a tree and have tried to form an [ugly] triangle shape with the peak of the wire loop at around 15m. I use a fiberglass mast on my deck to get the wire up high. It's around 10m from the house so it helps with the noise.

Here's kind of the general idea. I was going for Option C here:

Sadly, my suburb is flooded with digital hash/noise and HF is not as much fun any more. One of these days I'd love to bring my wire loop out to the country and give it a go. It would probably be amazing.

Back in the '90s I used a Palomar Engineer 9:1 balun with 60ft of copper wire from R/S. It was only about 4m off the ground. That thing worked great with the Drake R-8. Of course, there was very little noise back then!

PS. FWIW, the 1m is probably best for VLF/LF/MW if that's your thing (and can rotate for directivity) The directivity stops <5 megs.

 

[ILSAPP]

Thanks for the detailed reply. Looks like I really need to consider the ALA100LN. I'm not interested in LF/MF, only HF.
Indeed I guess I have to look for the configs C, D or E for long distant weak signals HF reception.
Regarding wire length... wellbrook product information says the following:
" The ALA100LN is high gain balanced broadband amplifier using 8 low noise, high gain RF JFET transistors and is designed to be used with a customer provided 8-10m circumference wire Loop. "
Weird why they do not say to use more wire as it really improves the reception...

 

[jwt873]

Making the loop larger will help with the lower frequencies. Here's an article where a person built a 10 x 20 (200 foot) loop for his ALA100LN mostly for receiving MF/LF. My 10’ x 20’ Active Loop • AmateurRadio.com

I'm just running the recommended 10 meter circumference. It's a square at 8.5ft per side = 34 feet. It's kind of a sad looking thing.. Here's a picture: Wellbrook Receiving Loop

I got mine for DXing the Broadcast Band and NDB beacons. But.. It works really well.on HF frequencies. It does a good job of picking up the pirate stations on weekends in and around 6800 - 6900 kHz.

I also use it with my ham radio station. I chat on 80 meters with friends pretty well every morning. My IC-7600 has a jack for a receiving only antenna. I have the radio connected to a full size inverted vee for transmitting on 80 meters, and to the loop for receiving. The radio takes care of the switching. Key the mic and the RF goes out to the inverted vee.. Let go and it automatically switches back to the loop for receiving.

The signals aren't as loud on the receiving loop as they are when I receive them with the inverted vee. But there is much less noise. I might lose 3dB on the station I'm receiving but at the same time I lose about 6dB of noise. Using the loop makes weak signals even weaker, but surprisingly they're much more readable because of the reduced noise.

 

[ILSAPP]

Thanks for your feedback, really appreciated!
So probably not worth for me getting such a long delta loop wire as I'm not interested in LF/MF.
With such a high gain (26dB) of the ALA100LN seems that a 10m circumference loop wire may be a good candidate for HF.

 

[devicelab]

So probably not worth for me getting such a long delta loop wire as I'm not interested in LF/MF. With such a high gain (26dB) of the ALA100LN seems that a 10m circumference loop wire may be a good candidate for HF.

Well I wouldn't make any assumptions. I'd run both a 10m and 100m loop and see what you get. Your location, noise, receiver and atmospheric conditions will all play a part in your reception.

Also, I should point out that I use a HF-specific SDR on the loop antenna. I can tell you now that if you're using a desktop receiver it's much more of a challenge to determine SNR. It's super easy with a SDR. So just plan to run any antenna for several days before 'deciding' on one or the other.

 

[ILSAPP]

Well I wouldn't make any assumptions. I'd run both a 10m and 100m loop and see what you get. Your location, noise, receiver and atmospheric conditions will all play a part in your reception.

Also, I should point out that I use a HF-specific SDR on the loop antenna. I can tell you now that if you're using a desktop receiver it's much more of a challenge to determine SNR. It's super easy with a SDR. So just plan to run any antenna for several days before 'deciding' on one or the other.

Yes that will be my approach... I just antecipate that 10m loop will probably give me the best S/N judging by the high amplifier gain and the trend to overload the receiver. I'm using the Airspy HF+ as well as a KiwiSDR receivers for SWL.

 

[krokus]

Have you considered the loop on ground idea? Many people like them for receive.

The Loop on Ground Antenna - the "LoG"

A prototype receiving antenna for HF

kk5jy.net

 

[ILSAPP]

That's an interesting antenna to try... I just have to get the binocular core and the enclosure.
Thanks for the suggestion!

 

[krokus]

That's an interesting antenna to try... I just have to get the binocular core and the enclosure.
Thanks for the suggestion!

Another option:

https://www.amazon.com/Balun-One-Nine-v2-Barebones/dp/B07XJRTF94/ref=mp_s_a_1_17?crid=138FVI9U5E09D&keywords=9+1+balun+for+end+fed+antenna&qid=1667848467&sprefix=9%3A1+%2Caps%2C169&sr=8-17