Vic,
I built an antenna switch box using DPDT 10 amp contacts. The coils were
115 volt. I paralleled the contacts for 20 amps each. The SWR did increase
slightly but hardly noticeable. These relays came out of several
Henry 2000 D RF gens I parted out and are not RF relays. It's been working
fine for 4 years now. I've put as much a 2500 watts RF though the switch
box for short
periods of time ( 20 or 30 seconds ) on 20, 40 and 75 meters. It's only seen
about
1000 watts on 15 and 10 meters but should work find at 1500 for ssb use.
I don't remember the part number for these relays but I'll take the switch
box's cover
off and send the info to you if needed. Most likely, these same relays are
not being
build anymore. Oh, be sure to ground the common closed contacts.
73,
Larry, N5BIP
----- Original Message -----
From: "VE6JY Don Moman" <ve6jy@freenet.edmonton.ab.ca>
To: "Amps reflector" <amps@contesting.com>
Cc: "Vic Rosenthal" <vic@rakefet.com>
Sent: Friday, April 16, 2004 7:23 PM
Subject: Re: [Amps] Relays for RF switching
> I would suggest using the encapsulated sealed relays such as the Potter
and
> Brumfield RKS-5DW-12 (about 8$ in Canada) or the lighter rated - and
cheaper
> ($C2.50) Aromat JS1E-12v. I think both are in the DigiKey catalogue.
Both
> have given excellent service at legal limit at HF, indoors and out for up
to
> 10 years (so far) with no failures. The P&B ones are used in the DX
> Engineering remote relay box I have which is rated to 5 KW. I have used
> other misc relays in the junk box that have worked fine, the exception was
> another one of the lower voltage high current power relays you mentioned.
> As I recall (it was several years ago) it had poor SWR or isolation when
> tested so didn't use it. There must be significantly poorer dielectric
> and/or insulating properties in these relays when used at RF.
>
> 73 Don
> VE6JY
>
>
> ----- Original Message -----
> From: "Vic Rosenthal" <vic@rakefet.com>
> To: "Amps reflector" <amps@contesting.com>
> Sent: Thursday, April 15, 2004 05:11
> Subject: [Amps] Relays for RF switching
>
>
> > I needed a remote (indoor) antenna switching unit, and since I had
> > everything I needed in my junkbox, I decided to build it instead of
> > paying $140+ to Ameritron. I used some relays that I had purchased from
> > All Electronics for $1.50 each; they are "power relays" with contacts
> > rated 15a at 120 VAC. After all, 1500 watts into a 50 ohm line is only
> > about 280 volts and 5.3 amps.
> >
> > Hey, if it worked I'd be in the miser's hall of fame. However, what
> > happened is that the relays got quite hot after about 15 seconds at the
> > 1500 watt level. They are enclosed in little plastic boxes, but it's
> > possible to touch the bottom of the armature and it is hot enough that I
> > am afraid of what would happen in a contest or long rag chew.
> >
> > I'm wondering if anyone has ever done anything like this, and if so,
> > what kind of relays they used. Or, if someone has an Ameritron unit
> > handy, if you would be so kind as to look inside and see what kind of
> > relay they use.
> >
> > I'm also curious as to why the relays heat up.
> >
> > --
> > 73,
> > Vic, K2VCO
> > Fresno CA
> > http://www.qsl.net/k2vco
> >
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
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