• To anyone looking to acquire commercial radio programming software:

    Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.

    If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.

    To obtain Motorola software see the Sticky in the Motorola forum.

    The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.

    For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).

    This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.

Anyone make a VHF/VHF duplexer?

Status
Not open for further replies.

N7SAC

Member
Joined
Mar 22, 2008
Messages
25
I would like to run two VHF radios into a single antenna in my vehicle. Is there anyone out there that makes a VHF/VHF combiner or duplexer? If not I guess I'll just have to drill another hole :)


--Scott
 

N8IAA

Member
Joined
Dec 19, 2002
Messages
7,240
Location
Fortunately, GA
I would like to run two VHF radios into a single antenna in my vehicle. Is there anyone out there that makes a VHF/VHF combiner or duplexer? If not I guess I'll just have to drill another hole :)


--Scott

Looks like you'll have to get the drill out. I checked Diamond and Comet websites. No VHF/VHF duplexers or triplexers. Unless someone out there knows of another company that makes them up.
Larry
 

AK9R

Lead Wiki Manager and almost an Awesome Moderator
Super Moderator
Joined
Jul 18, 2004
Messages
9,348
Location
Central Indiana
I would like to run two VHF radios into a single antenna in my vehicle.
Are you wanting to have two VHF radios that transmit from the same antenna? If so, then there's no easy answer. You'll need an antenna relay that cuts out the feed to one radio when the other is transmitting. Otherwise the transmitting radio will seriously overload the receiver of the other radio. If the frequencies are far enough apart, you could use pass-reject style of cavity duplexer like is used on repeaters, but they typically have very sharp tuning, so you'd lose the frequency agility of your radios. Oh, cavity duplexers for VHF are pretty big. A single cavity is typically about 4 inches in diameter and about 24 inches long. Also, again if your frequencies are far enough apart, there's a company in Canada called DCI (http://www.dci.ca/) that makes some nice RFI filters that might be sharp enough to block one radio from getting into the other.

If both radios are receive-only, a multicoupler would work. Some of the scanner dealers sell the Stridesberg (sp?) multicoupler. You could also do it on the cheap with a cable TV splitter.
 
Last edited:

N7SAC

Member
Joined
Mar 22, 2008
Messages
25
I would not be transmitting at the same time however I would like to be able to monitor with one while using the other. Otherwise I would just use a switch.
 

zz0468

QRT
Banned
Joined
Feb 6, 2007
Messages
6,034
If you're going to try the relay, you'd also want to add a sequencer to the PTT circuits of the radios to delay keying them until the relay switches. It wouldn't be expensive to come up with a scheme to allow two radios to share a single antenna, so long as you're content that one radio is deaf while the other is transmitting. A couple of antenna transfer relays and some semi-complex switching circuits would make it transparent to the user.

dbSPectra sells a control station combiner that will do exactly what you want, but it's going to be in the multi-thousand dollar class.

You're really just better drilling another hole.
 

N7SAC

Member
Joined
Mar 22, 2008
Messages
25
Thanks for all the info!

I think I'll probably just drill that other hole. I have 1 at the front of my Suburban and 1 at the back. The one up front is for VHF and the back one is UHF. I'll probably drill one in the middle and move the UHF antenna there. That way I have some decent space between the two VHF antennas.

--Scott
 

AK9R

Lead Wiki Manager and almost an Awesome Moderator
Super Moderator
Joined
Jul 18, 2004
Messages
9,348
Location
Central Indiana
Three antenna mounts on a 'Burb? That's almost nothin'. You have plenty of roof space. I have ten NMO mounts in the roof of my Expedition. Once I drilled the first hole, I figured I better plan for expansion. Only using six right now.
 

prcguy

Member
Joined
Jun 30, 2006
Messages
15,339
Location
So Cal - Richardson, TX - Tewksbury, MA
Shakespeare makes an RF sensed latching antenna relay that connects two VHF radios to one antenna and whichever on you transmit on gets the antenna connected. These show up on Ebay all the time for about $30.
prcguy
If you're going to try the relay, you'd also want to add a sequencer to the PTT circuits of the radios to delay keying them until the relay switches. It wouldn't be expensive to come up with a scheme to allow two radios to share a single antenna, so long as you're content that one radio is deaf while the other is transmitting. A couple of antenna transfer relays and some semi-complex switching circuits would make it transparent to the user.

dbSPectra sells a control station combiner that will do exactly what you want, but it's going to be in the multi-thousand dollar class.

You're really just better drilling another hole.
 

n8emr

Member
Joined
Oct 20, 2005
Messages
498
You can find in marine (boat) catalogs RF sensing devices but when you switched to radio 1, radio 2 has no antenna attached so you cant transmit or receive, When you key radio 2 radio 1 is now dead. It works geat if you have radio's in two location such as an up or lower helm on a boat or driver position and rear of RV but doest work well if you want both radio's active. 2 antennas is the best solution .
 
Status
Not open for further replies.
Top