Search found 140 matches

by Andrew (grayhat)
Fri May 17, 2024 12:29 pm
Forum: General Discussion
Topic: Squeezing 9dB from a dipole
Replies: 0
Views: 10

Squeezing 9dB from a dipole

I've always loved simple antennas and the dipole is one of the most common and simple ones; for such a reason time ago I started investigating about ways to maximize the performances of the dipole and, time ago, found a paper from Jari Perkiömäki (OH6BG) which explains how, using some optimal (yet m...
by Andrew (grayhat)
Fri May 17, 2024 10:49 am
Forum: Field Kits and Reports
Topic: My new all-purpose antenna system
Replies: 3
Views: 5751

Re: My new all-purpose antenna system

A nice "antenna combo kit" indeed :D !!

And here's an idea for you, if you add a third wire you may configure the antenna as a "T" and feed it between the vertical wire and a ground stake :)
by Andrew (grayhat)
Fri May 10, 2024 11:22 am
Forum: General Discussion
Topic: Strong geomagnetic storm approaching
Replies: 0
Views: 65

Strong geomagnetic storm approaching

The NOAA raised an alert for a strong (Class4) geomagnetic storm which will hit Earth between this evening and tomorrow, the storm is currently classified as G4 but given that the multiple flares may sum up, it may reach the G5 level https://spaceweather.com/archive.php?view=1&day=10&month=0...
by Andrew (grayhat)
Mon Apr 29, 2024 2:11 pm
Forum: Questions & Advice
Topic: EFHW/RW - Attaching wire to balun
Replies: 17
Views: 14428

Re: EFHW/RW - Attaching wire to balun

I'm going to try a 29/17 EFRW. My home antenna is a 35.5/17, and works well enough for me. For the choke, I'm using N6ARA's choke design - 12 bifiliar turns on a T50-43. I've got it all built, and I hope to get some time to try it out today. it all depends from the bands you're interested to cover ...
by Andrew (grayhat)
Sun Apr 28, 2024 8:00 am
Forum: Questions & Advice
Topic: RG-174 or RG-316
Replies: 7
Views: 9125

Re: RG-174 or RG-316

I was asking the OP... anyhow, 20ft of RG174 at 10MHz will have a loss of 0.6dB where the same lenght of the "humble" RG-58 will show a loss of 0.2dB not significative, sure, but when it comes to QRP/QRPp it's always a good idea reducing losses as much as possible, and then we don't know w...
by Andrew (grayhat)
Sat Apr 27, 2024 7:27 pm
Forum: Questions & Advice
Topic: RG-174 or RG-316
Replies: 7
Views: 9125

Re: RG-174 or RG-316

N8TGQ wrote: Sat Apr 27, 2024 6:54 pm I don't think you will see much difference when using short runs (around 25' or so). I have heard 316 is tougher, but it's also more expensive. I have a 20' length of 174 that's going on 5 years and about 100 outings. Never had any issues with it.

Good luck!

so... what's your pick, and why ?
by Andrew (grayhat)
Sat Apr 27, 2024 1:12 pm
Forum: Questions & Advice
Topic: EFHW/RW - Attaching wire to balun
Replies: 17
Views: 14428

Re: EFHW/RW - Attaching wire to balun

An example, using a radiator (wire) of 84ft and a counterpoise of 17ft a 9:1 and a wideband choke (Guanella) both wound on FTxxx-43, we'll have a random covering all bands (including WARC) from 80 to 6 meters with the help of an antenna matching unit by the way
by Andrew (grayhat)
Sat Apr 27, 2024 11:43 am
Forum: Questions & Advice
Topic: EFHW/RW - Attaching wire to balun
Replies: 17
Views: 14428

Re: EFHW/RW - Attaching wire to balun

as for the radiator length, see here https://k7mem.com/Ant_End_Fed.html#Not_Random_Multi ensure to add a good guanella choke after the 9:1 and use at least one counterpoise wire with a lenght around 1/16 Lambda at the lower frequency (e.g about 5m if the lowest frequency is 3.5MHz, eventually add a ...
by Andrew (grayhat)
Sat Apr 27, 2024 11:23 am
Forum: Questions & Advice
Topic: RG-174 or RG-316
Replies: 7
Views: 9125

Re: RG-174 or RG-316

https://www.alphaantenna.com/wp-content/uploads/2022/09/What-Coax-Should-I-use.jpg https://www.alphaantenna.com/wp-content/uploads/2022/09/What-Coax-Should-I-use.jpg consider that every 3dB of gain or loss the power doubles or halves, so a 3dB cable loss means that the antenna will receive half of t...
by Andrew (grayhat)
Thu Apr 25, 2024 6:11 pm
Forum: Questions & Advice
Topic: EFHW/RW - Attaching wire to balun
Replies: 17
Views: 14428

Re: EFHW/RW - Attaching wire to balun

looks good !

the carabiner hole is useful both when the antenna is deployed and to hang it to a backpack wnen the antenna is wrapped, the velcro stripes will help keeping the wire/coax wrapped