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View Full Version : Heath HD-1234 Connected two radios to one antenna



KM4GZH
12-20-2016, 10:02 PM
I'm thinking YES on this but, I wanted to be sure. I have a Heath HD-1234 coax switch. I want to connect two radios to one antenna. Is this ok? I have the manual and, it shows using two switches to connect multiple radios to multiple antennas. It is rated for 1000 watts. See attached photo. I'll connect the antenna to "C".

NQ6U
12-20-2016, 10:59 PM
It's risky. Given the sensitivity of modern radios and the isolation on most of those switches, you could end up blowing out the front end on your receiver(s). Better to build a patch panel.

K4PIH
12-20-2016, 11:11 PM
Ditto on the patch panel. Not enought isolation to keep harmful levels of rf from one radio getting into another.

WZ7U
12-20-2016, 11:15 PM
Boy, I'm glad you asked first. Imagine how mad you would've been

kf0rt
12-27-2016, 04:39 PM
The HD-1234 grounds all unselected SO-239's. As long as the switch is grounded, shouldn't he be okay?

NQ6U
12-27-2016, 05:03 PM
The HD-1234 grounds all unselected SO-239's. As long as the switch is grounded, shouldn't he be okay?

Theoretically, yes, but it's a DC ground for lightning protection/static bleed-off and we all know that the behavior of AC at radio frequencies often does not conform to what one expects in a DC circuit. It might work just fine; on the other hand, it might not. IMHO, it's not worth risking the front end of a receiver.

kf0rt
12-27-2016, 05:19 PM
Good point, though I guess I've never seen a problem with it in practice. Best not to risk it.

And heya, Carlo!

N8YX
12-27-2016, 06:40 PM
The one way you might safely get away with this - assuming the antenna is a multibander - is to use bandpass filters at the antenna connector of each transceiver, with a band-stop filter at each port of the switch assembly. The stop filters are tuned to the "opposite" frequency range, much like a set of duplexers in a repeater system.

If you substitute a power combiner and pass/stop filters, you could eliminate the switch altogether and use both radios at the same time...assuming different operating ranges for each.

NQ6U
12-27-2016, 06:42 PM
I've heard of people doing it without any problems but I've also heard otherwise so I guess it's a roll of the dice. You pay your money and you take your chances, I just think that the cost of crapping out is too high.

And heya right back at you Rob. How's your own fine self?

WØTKX
12-27-2016, 07:57 PM
Good point, though I guess I've never seen a problem with it in practice. Best not to risk it.

And heya, Carlo!

Be seeing you,camera boyo! :mrgreen:

http://1.bp.blogspot.com/-qNdP7LnalD0/T98wqrCtKTI/AAAAAAAAF1E/puh5Qsdz4HA/s1600/prisonermanyhappy2.jpg

kf0rt
12-27-2016, 08:04 PM
I can buy that and will count myself lucky -- run a similar switch here and haven't had a problem, but it occurs to me that I don't run a lot of power and the fact that I rarely transmit, well... RatsNest of switches here swaps an AVQ HF vertical and a 6 meter beam between the IC-7000 and a TS-570 by turning knobs. Been lucky, probably.

Life's been pretty good here this year. I finally decided I'm "done" with real work after 38+ years and cashed my final paycheck in August. My BP is just now coming down to a level of thinking about hobbies and stuff. Some of the old radio gear is starting to appear back on the desk.

Hope everybody here is fine as frog's hair, too. And what are the bands like? :)

kf0rt
12-27-2016, 08:05 PM
Be seeing you,camera boyo! :mrgreen:

http://1.bp.blogspot.com/-qNdP7LnalD0/T98wqrCtKTI/AAAAAAAAF1E/puh5Qsdz4HA/s1600/prisonermanyhappy2.jpg

Howcomeifidoreplywithquote,myspacekeydoesn'twork?

WØTKX
12-27-2016, 08:24 PM
sHAkethEcRUmbsOuTfrOmFReQUenTsHaCkSnAckAGe

:stickpoke:

KG4NEL
12-30-2016, 04:37 PM
Alpha Delta, et al, make switches with 60+ dB of isolation, but they ain't cheep.