Dowkey replacement reccomendations

[k7iou]

I was wondering if there is a modern replacement or homebrew for
a RX TX relay with contacts for break-in and audio mute?
thanks

[Pete, WA2CWA]

I don't know of any coaxial relays on the market today that come with additional switch contacts.
http://www.rfparts.com/old_site/coaxial.html
You can homebrew the function by using a relay with "x" number of contacts to do whatever functions you want, keeping one set of contacts dedicated to controlling the coaxial relay.

[KA0HCP]

http://www.dowkey.com/_pseries_attach/_plk13_1_60a.pdf

Dow-Key Microwave is still in business and still makes the classic 60 Series switch.

They list themselves as 'distributors', and I can't find anyone else.  Didn't find anything at the Tessco website.   Contact numbers on the slick sheet, and area reps on the website.
http://www.dowkey.com/sales_rep_search.php

[WQ9E]

I make my own from "cube" style relays.  At a minimum you will need a 2PDT relay configuration, one to switch the antenna and another for receiver muting but I use 4PDT relays.  Besides the 2 aforementioned poles I wire one to short the receiver antenna input during transmit and the remaining is useful for other tasks, for example I don't use full break-in CW with most rigs and with my Viking 1 and Viking 2 the 4th set of contacts is used to keep the VFO "keyed" during transmit to avoid chirp.

You can either mount the appropriate connectors on a small box or use cables with connectors on one end that wire directly to the relay (or preferably to the relay via terminal strips to avoid stress on the relay connections).  Small relays with 10 amp contacts will handle about anything you are likely to run.  For high power AM rigs (500 watts input and up) I use a vacuum relay for the antenna switching with a regular relay to handle the other functions and I use a slow release circuit on the vacuum relay to avoid hot switching on break.

These relay boxes are inexpensive to build and far more reliable than old hamfest dowkey relays.

[k7iou]

http://www.ad5x.com/images/Articles/QSKBArevA.pdf
http://www.ad5x.com/images/Articles/AntennaRelay.pdf
Either looks like it will do the job.
What say you?

[WQ9E]

The second will be fine unless you run full break-in CW and generally for serious full break-in the receiver is going to require some additional attention so unless this is your forte I would skip the first design.

I still prefer using a 4 pole relay for the added receiver input protection/isolation and the versatility to control another piece of gear (VFO, external amp, etc.)  A 4 pole relay is available for about the same cost as a 2 pole.

[Todd, KA1KAQ]

http://www.dowkey.com/_pseries_attach/_plk13_1_60a.pdf

Dow-Key Microwave is still in business and still makes the classic 60 Series switch.

And IIRC, they now cost several hundred dollars. Adjusted for inflation, it's probably similar to the original cost. It's cool that they're still available, though. Like a trip to the past.

There are numerous other routes to go as Rodger points out. One thing to keep in mind is the power level you want to use. Dowkeys are okay for low power stuff. There was a good article in ER a few years back about failure modes, maybe done by Mike/W8BAC. I know we discussed alternatives for use with converted broadcast transmitters and the Dowkey wasn't one of them.

[k7iou]

Landed this on EBay today! 
$73 plus shipping

[Opcom]

The AD5X articles are great. Is there any real reason a properly bypassed, enclosed, filtered relay or contactor is electrically wrong?
I'd guess no, they are inside too many full size amplifiers.
Here, the RX port is always grounded by a set of contacts.

What are the thought on the kind of unit - relay vs contactor? (aside from contactors usually being single throw)

type of contacts? flat or convex? (Don't the convex ones force all the juice through the small area?)

self-wiping?

coating or plating on the contacts?

diameter of the contact faces? ( impotant for flat ones anyway)

Attached is a 2-contactor setup for using a transceiver with a TX that's an RF amp + modulator.
The advantage is that with no mains power, all things are disconnected from the antenna and when in RX, the TX output is grounded. This has reduced some occasional slight noise due to HV being on. (I Quit keying via the plate relays)
Disadvantage is when there is no mains power, RX is not accomplished.
There have been RF interference issues on TX with it to other stuff, that is, the coils etc. not bypassed as well as they should have been. The tags on the wire are just for labeling the signals.