In-house repeater?

Question

At one time I was active in the local SKYWARN program, but then we moved and I find myself 10 miles from the local repeater. Given the various obstructions between it and me, I can't really hit it unless I'm up in the attic or on the roof. To make matters more challenging, the repeater is northeast of me, and normally our weather comes from the southwest.

Of course, I can put up an antenna, run the necessary cabling and hit the repeater, but that leaves me stuck at the end of the cable, at times when mobility may be essential (I use a dual-band handheld).

The solution I have in mind is a repeater attached to the antenna which I can reach anywhere from inside the house. The house repeater (or reflector, or relay, or whatever the proper name would be) is attached to the external antenna where it won't have any problem hitting the SKYWARN repeater.

Will this work, and what equipment do I need?

Mike Waters · Answer 1 · 2019-03-14T22:13:24.240

9

The simplest way of accomplishing your goal doesn't require a conventional and expensive repeater system. It's completely passive (no electronics needed).

Put a Yagi on your roof pointed at the repeater. Put an upside-down ground plane in your living area. Connect the two antennas with coax. You now have a passive repeater!

Signals picked up on the Yagi will be radiated by the ground plane, and signals from your HT will be picked up by the ground plane and be radiated by the Yagi.

It goes without saying that:

The coax should be low loss and as short as possible
The antennas should be tuned for a good match.

edited Mar 14 '19 at 22:13

answered Mar 14 '19 at 22:03

Mike Waters

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"doesn't even need a repeater" — Arguably, this is a passive repeater. – Kevin Reid AG6YO Mar 14 '19 at 22:09
@KevinReidAG6YO Thank you for that, post edited to clarify. – Mike Waters Mar 14 '19 at 22:14
Passive repeaters don't really work. If it's marginal when on the roof, it will be 40 dB below marginal when passively repeated, maybe 30 dB below with the yagi. – tomnexus Mar 19 '19 at 14:34
@tomnexus Don't you think it's at least worth trying, since this is at higher power levels and with less loss than wi-fi? Another wifi example – Mike Waters Mar 19 '19 at 16:10
Related QRZ thread with several success stories. – Mike Waters Mar 19 '19 at 16:13
@tomnexus Your Friis citation seems to indicate it shouldn't be a big challenge to exceed repeater receiver's MDS given OP's distance from a (assumed) 2m repeater. – Brian K1LI Mar 19 '19 at 18:26

Traveler_3994 · Answer 2 · 2019-03-19T19:06:30.243

My solution to your problem (that I also have) was to buy a mobile radio that will do cross band repeat mode, such as the Icom IC-2730A. It runs (at this time) about $280. It sounds expensive, but.... when you are not at home, you have a really nice dual band mobile radio for your car/truck that puts out 50W. It is a great mobile radio that is easy to install in any car.

When I have it hooked up in my home QTH and I am sitting in my basement shack, I can listen to the local SKYWARN repeaters, flip over to listen to NOAA weather radio stations or the local police and fire services. When I want to move around the house or back yard, I put it into cross band repeat mode with my HT and it works fantastic. (Make sure you only enable cross band repeat with ham frequencies!)

You can make it do VHF -> UHF or UHF -> VHF. I put a nice dual band antenna (I used the Diamond X50A) up at the peak of the roof and it is very low profile that the HOA has not complained about. Plus it just looks cool!

Another use is to cross band repeat from your car to the HT like the Highway Patrol cars do. A lot of them run VHF low-band to the car and UHF to their HT's. I always thought that was a really cool setup. When they transmit on their in-car radio, it goes out on VHF low band and does not repeat to the HT, so no feedback! When out of the car, the HT goes into the UHF side and out the VHF 110W low band side.

This is also a great setup if you are camping or hiking or running a public service event where you cannot quit reach the main repeater.

Hope that gives up some ideas! 73

PS - The Kenwood TM-V71A is a little bit more, but a lot easier to setup cross-band repeat. See this link for the Icom setup: https://www.eham.net/ehamforum/smf/index.php?topic=115770.0

score 0 · Answer 3 · answered Mar 19 '19 at 13:39

For what it's worth, I have essentially the same situation. I can hear the repeater with my handheld, but access is spotty. My solution was to use my IC-706 as a receiver tuned to a non-repeater frequency (because audio and squelch lines are easily accessible) and utilized a relay board (https://www.amazon.com/SainSmart-101-70-101-4-Channel-Relay-Module/dp/B0057OC5O8) to use the squelch line to key my UV-3 tuned to the repeater's input frequency. I just have to program my handheld to a split frequency with an odd offset. It's not pretty, and I wouldn't recommend it for regular use, but it works.

Also for what it's worth, my first stab was to use the Ham Shield and an Arduino. It worked, but the shield can't handle strong signals, so the audio was unintelligible.

Hey thanks for the guys. I'm liking the Icom solution, nothing against Kenwood, but I've had Icom stuff all my ham life (+20 years). — J_C_R, Mar 22 '19 at 21:16

In-house repeater?

3 Answers3