Comments on: OFF-GRID HAM RADIO: Simple Emergency Communication When the Grid Goes Down

By: Grouchy McGrouch

Grouchy McGrouch — Tue, 13 Jul 2021 18:29:49 +0000

In reply to Lee.

That’s correct, a dipole’s impedance is around Ohms. If it’s resonating nicely you can find a 50 ohm point. I’d still prefer to transform the 75 Ohm coax to 50 even though the matching circuit will also soak up some power. That’s just me, I tend to lean on the side of protecting the radio.

I like your site and the article. It’s hard as hell to communicate these topics to a general audience.

I love QRP ops and I think it can be super useful especially using NVIS for emergency, unjammable via ground wave and untraceable comms.

By: Mike Murphy

Mike Murphy — Mon, 11 Jan 2021 23:44:53 +0000

In reply to Lee. So there’s no way to match impedance such that 75 ohm line can be used with 50 ohm components. Good to know, thanks.

By: KG5EEU

KG5EEU — Thu, 07 Nov 2019 22:18:14 +0000

In reply to C-rock. C-rock: And that's why a pool of trained, licensed, and experienced amateur radio operators is critical to have! KG5EEU

By: Daniel L Conklin

Daniel L Conklin — Fri, 11 Oct 2019 21:28:41 +0000

In reply to Lee.

Wow, that’s just wrong. I make regular solid QSOs with a 4 watt 2 transistor CW transmitter on 40 meters with no more skill than my high powered Brothers. I also make low powered FT8 digital contacts around the world with only the skills of point and click. RG-6 75ohm coax can be used quite effectively if you are careful about the length https://www.jpole-antenna.com/2015/01/28/using-rg-59-or-rg-6-catv-cable-with-an-amateur-radio-antenna/

By: WP4QIN

WP4QIN — Fri, 11 Oct 2019 03:15:09 +0000

In reply to Lee. RG6 TV cable can be tuned by the stub method , by impedance matching baluns by capacitive coupling matching , by reactive tuning & other methods

By: WP4QIN

WP4QIN — Fri, 11 Oct 2019 03:09:57 +0000

In reply to Lee.

WP4QIN
Hurricane maria in Puerto Rico Demonstrated Government was ineffective to maintain any communication at all , i doubt California can maintain effective coms, in a Worst case scenario they are just kill boxes in the making …

I tell that also as a communications engineer …

By: Lynn Magnuson

Lynn Magnuson — Thu, 21 Dec 2017 19:21:54 +0000

In reply to Mike Crounse.

The link is to Icom’s website where you can read about it and/or download the owner or service manual for this rig.

http://www.icomamerica.com/en/products/amateur/hf/703/options.aspx

By: james

james — Thu, 09 Mar 2017 19:05:08 +0000

In reply to Gene Rodgers. Ditto to Mr Rodgers. HAM radios even modern radios will work on 75Ohm feeds but it does depend on what you call works. If all your looking for is to listen to news events then the 75Ohm feeds will allow you to listen all day to any frequency that's the easy part however, the missmatch will cause you much loss, put lots of stress on the finals, and of course kill your range. This is especially crucial as we are approaching the bottom of the solar cycle. This is where a good antenna will make or break your contact.

By: Gene Rodgers

Gene Rodgers — Sun, 15 Jan 2017 20:16:36 +0000

Ok Guys let me throw in a few words as an antenna builder and Broadcast engineer who has been playing in this field for 60 years.
Many Mobil and Base Ham radios are designed to work on 75 ohms. And will work on Tv coax though the loses are high and you will have to solder a PL plug on it. All CB Radios are designed for 52 ohm and will work temporarily on 75ohms but this miss match will cause excessive heat in the finials of the radio which will lead to failure. Modern ICs are not designed to handle much heat as everyone knows. The same applies to Ham with a 52ohn cable. If you must use a miss matched system I suggest you keep your transmit as short as possible to make your radio last longer and use a antenna match box or antenna turner to bring the deadly SWRs down, but hay when you think about it if you are going to buy a Ham or CB Radio why not spend a few extra dollars at the same store and buy the correct cable and antenna. MAKES SENSE TO ME… Note. A poor antenna system means poor range.

By: Wayne Burdick

Wayne Burdick — Fri, 03 Jun 2016 17:46:40 +0000

A quick-deployment alternative to coax is to simply attach a wire directly to the radio and toss it into a tree. Lay another wire on the ground as a counterpoise.

I’ve been using this method for years with the 10-watt-class HF radios my company designs (Elecraft KX3, and more recently the KX2, which is about half the size/weight). Both rigs have an internal, wide-range antenna tuner (ATU) option. At this power level, you can get away without any coax at all; just use a BNC-to-binding post adapter to get from the antenna jack to the wires.

73,
Wayne
N6KR