• 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.

LMR400 to LDF4-50A for GMRS repeater..

Status
Not open for further replies.

ywhic

Member
Joined
Nov 30, 2012
Messages
24
So I got my GMRS test repeater setup almost.. (GM300 and SM50).. (yes I have my license)..

Got 1 foot sections of RG214/U with Silver Plated Amphenols with PL259 to N Male to go to the duplexer (flat pack 50w HK type)..

I have 25' of LMR400 going up to the chimney mounted antenna.. but on the RBuilder site it says to stick with Heliax.. so I found 45' of LDF4-50A for $51 shipped with factory N's on it..

I know the loss is like .661 db with the 45' Heliax where as I am at .681 with the 25' of LMR400 (both at 462mhz). which equates to 108w with the LMR400 and 116w with the Heliax with 5 dbd antenna gain..

If I cut the Heliax to 25' I would be at .368 db loss.. though I may leave that alone..

Does anyone think the LMR400 is that aweful for repeaters on here for the run from the duplexer to the antenna??? or do you think it will work fine??

I ask because weather in NJ is cold and I may not be able to do it for another month if snow gets here first..
 

WA0CBW

Member
Premium Subscriber
Joined
Dec 8, 2011
Messages
1,633
Location
Shawnee Kansas (Kansas City)
You would need some good test equipment to identify 1 db of difference let alone .3 db. You certainly won't be able to tell the difference by ear, even at 2db of difference. Either the hard line or the LMR would be just fine. It is probably more important that the connectors be weather proofed correctly.

BB
 

prcguy

Member
Joined
Jun 30, 2006
Messages
15,233
Location
So Cal - Richardson, TX - Tewksbury, MA
You should always strive for the least amount of loss in your repeater feed line, a few tenths of a dB here, a dB there adds up and suddenly you wonder why your repeater works like crap compared to someone else's on the same tower.

Another thing to consider is LMR400 has had complaints of Intemod type interference, probably from the dissimilar metals between the tinned braid and aluminum foil shield. You may not notice any problem with the system described but with a really sensitive receiver, a low loss, high isolation duplexer and maybe a preamp you might notice.

If you want a high performance repeater use the Heliax and the shortest run possible and the biggest antenna possible.
prcguy
 

kayn1n32008

ØÆSØ
Joined
Sep 20, 2008
Messages
6,601
Location
Sector 001
Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9780; en-US) AppleWebKit/534.8+ (KHTML, like Gecko) Version/6.0.0.600 Mobile Safari/534.8+)

Cut the Hardline to the length you need, the connector is not that hard to remove and re-install.

In reality the difference between 108w ERP and 116w ERP is zero.
 
Last edited:
Joined
Dec 26, 2004
Messages
1,217
Location
Tulsa
Re-using the connector on the LDF4-50 isn't a good idea, getting the center pin at the correct distance is critical, not worth the potential problems.
 

LtDoc

Member
Joined
Dec 4, 2006
Messages
2,145
Location
Oklahoma
For the length of run that you have and at the frequency you will use them on, there will be no practical or noticeable difference between the two cables. A fraction of a dB difference isn't worth worrying about, unless you've a huge number of them...
- 'Doc
 

VE6RHS

Member
Joined
Aug 11, 2005
Messages
39
Location
Chetwynd, BC Canada
LDF vs LMR

The primary reason for recommending LDF over LMR is noise.

In a duplex situation (a repeater), noise will be heard on weak rx signals if/when the LMR cable is moved/flexed. The two metals in the shield of the cabble rubbing together will cause rx noise.

So, if the LMR is tied down so it doesn't move, the LMR is just as good as LDF for your application. However, if the LMR is subject to any physical movement (wind?), you'll hear crackling "popcorn" noise on weak signals.
 

ywhic

Member
Joined
Nov 30, 2012
Messages
24
I ordered in a PL259 connector for the Heliax 1/2".. that way I can lose the N-PL259 adapter on the antenna end.. my duplexer has N so all is well on that end..

I may/may not cut the cable though.. I have to wait and get the PL259 in hand to see whats involved with cutting and putting it on..

I'd like to cut it to 25' just to not have the excess 20' laying in a coil inside the room.. which may be bad for it as well.. << any thoughts on that<<
 
Status
Not open for further replies.
Top